Taxonomy Term en 19316 Hurricane in a Bottle: Testing Building Assemblies for Moisture Resistance

State-of-the-art testing chambers show that liquid-applied barriers outperform more typical weather barriers comprised of flashing, tape, and membranes.

BEA's building assembly test chamber in Clackamas, Oregon.
Photo Credit: Alex Wilson

When I was in Portland, Oregon for the 2014 Living Future Conference I had an opportunity to visit a facility in nearby Clackamas where building assemblies and components can be tested for water intrusion and water vapor penetration.

Prosoco, a leading manufacturer of liquid-applied membranes developed the Clackamas test facility with partner company Building Envelope Innovations (BEI).

A Cat 5 hurricane in a closed chamber

At the Clackamas test facility Building Envelope Analysis (BEA)—a joint venture between Prosoco and BEI—has two specialized test chambers that can be used to simulate weather conditions as well as more insidious humidity conditions that can drive moisture into wall assemblies or damage building components like insulation and sheathing.

With the large chamber we watched as the submarine-like glass doors were closed and the fury of wind and driving rain were cranked up on the controls. We could see on manometers just how much pressure the wall assembly was having to endure, and we could watch high-pressure nozzles spraying high-velocity streams of water at the assembly.

Tom Schneider of Building Envelope Innovations explaining operation of the large test chamber.
Photo Credit: Alex Wilson

The operator can turn a few dials and simulate 150 mph wind and driving rain—wreaking havoc on the wall assembly constituents.

Prosoco company president David Boyer and BEI director of operations Tom Schneider explained how the test chamber can easily be configured to test everything from plywood sheathing and flashing systems, to windows and weather-barrier tapes.

When we visited, a high-tech, European window that had been submitted by a local Passive House builder for testing was blocked off, because it had failed so miserably that we would have had water all over the place if it hadn’t been sealed off.

Prosoco’s interest in all this testing

We didn’t get into too much detail about building the test chambers, but it appeared that hundreds of thousands of dollars had gone into designing and fabricating them. Why would Prosoco and BEI go to all this effort and expense?

BEI developed and Prosoco manufacturers liquid-applied membranes for building assemblies, and the companies want to show off how much better they perform than the far-more-common assemblage of weather-resistive barriers and specialized building tapes.

Manometers and other gauges on the test chamber.
Photo Credit: Alex Wilson

The bottom line is that the liquid-applied weather barriers, such as Prosoco's R-Guard Cat 5 Air and Water-Resistive Barrier, do a lot better than the more common taped membrane systems. While one can question how accurately the test chamber simulates real conditions, the demonstration was compelling.

In addition to the large test chamber for testing whole wall assemblies and components, there was also a smaller chamber used for testing the permeability (or vapor diffusion) of specific materials—like plywood and weather-resistive barriers.

With this discussion, I was fascinated to learn that the standard methods we use to measure the permeability of different materials to water vapor are grossly flawed. David explained that the permeability of a material that has a listed perm rating (based on standardized ASTM test methods) of 36 may drop to a perm rating of only 2 when that material gets damp from high humidity.

The smaller test chamber used for measuring moisture diffusion through different materials.
Photo Credit: Alex Wilson

Prosoco and BEI have even more sophisticated test chambers in Florida and Kansas. In addition to testing the effects of wind and wind-driven rain, the Florida facility, which I’m hoping to visit sometime, can test resistance to sudden flood or tidal surges of three to four feet.

With growing focus on resilience and adaptation to climate change, dealing with storm surges in low-lying coastal areas will become more and more important.

For related information, see BuildingGreen's course on high-performance building assemblies, as well as our EBN feature, Verifying Performance with Building Enclosure Commissioning.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-06-04 n/a 19062 Low-Tech Cooling with This High-Tech Fan

The sleek, energy-efficient Haiku fan from Big Ass Fans will help keep us comfortable in our new house this summer

The Haiku fan in our upstairs guest room.
Photo Credit: Alex Wilson

As summer heats up here, I’m looking forward to trying out the high-tech ceiling fans we installed in our two upstairs bedrooms. First, let me explain why I like ceiling fans so much.

By moving air, moisture is evaporated from our skin, cooling us through evaporative cooling. With modest air movement in a room, most people will be comfortable at an air temperature at least five or six degrees Fahrenheit warmer than would otherwise be the case.

To clear up a misconception: ceiling fans do not actually cool the air in a room—in fact, they slightly increase the air temperature, because of the waste heat from the fan motor—but they allow you to be comfortable at a warmer air temperature. In other words, they raise your threshold of comfort.

If you are normally comfortable in the summer with the air temperature around 75°F, for example, with a ceiling fan operating, you might be just as comfortable with an air temperature of 81 or 82°F.

Because ceiling fans don’t involve the energy-intensive vapor-compression cycle, as do standard air conditioners, they use far less electricity, so they can save you a lot of money. A typical ceiling fan uses 90-110 watts of electricity, with Energy Star models averaging 65 watts.

For decades, ceiling fans have changed little. Often called “paddle fans” or “Casablanca fans,” most ceiling fans use rotating fan blades operated by standard AC (alternating current) electric motor. The waste heat generated by these fan motors necessitates the large, ventilated metal shroud that you see on most ceiling fans. Many of these fans become noisy as they age, as heat results in delamination of steel in the motor core.

Detail photo showing the Haiku fan in natural bamboo.
Photo Credit: Big Ass Fans

Enter the Haiku fan

Several years ago, the uniquely named company Big Ass Fans, long a leading manufacturer of very large fans used for commercial buildings and warehouses, introduced their first residential ceiling fan, trademarked Haiku. In late 2012, BuildingGreen, impressed by Haiku’s energy performance and elegance, named this a Top-10 Green Building Product for 2013. I was anxious to try out these fans in our new house.

The Haiku fan features a sleek, attractive, aerodynamic design for the airfoils (blades) in either bamboo or a plastic composite. All Haiku fans are 60 inches in diameter. Our fans are made of the composite material, in white; they elicit great comments from most visitors to our house.

Haiku fans have brushless, DC (direct-current) motors with advanced electronic controls; these are known as electronically commutated motors, or ECMs. The Haiku has seven speeds, compared with just three for standard ceiling fans. These features contribute to the very low energy consumption of just 2 to 30 watts, depending on the speed.

Haiku fans are by far the most energy-efficient fans rated by Energy Star, exceeding the Energy Star requirements by 450% to 750%.

Quiet operation and multiple settings

One of the features I’m most excited about is the incredibly quiet operation. At lower speeds, you can’t even hear the fan. Noise had kept us (mostly my wife) away from ceiling fans in the past.

Along with the multiple speeds, the fan can be operated in reverse (pulling air up rather than pushing it down), a timer can automatically turn it off, and there’s a unique “whoosh” setting that varies the fan speed to mimic natural breezes.

All these features are controlled by a very compact remote that fits into a plastic pocket that can be mounted to a wall. There are blue LEDs on the fan showing the fan speed. These stay illuminated for a few minutes then turn off.

With the high ceiling in the center, we were able to order a fan with a longer stem.
Photo Credit: Alex Wilson

A premium price for a premium product

Be aware that Haiku fans are not cheap. The composite fans (in black or white) list for $895 from the Haiku website. The bamboo fans (in a natural bamboo or a darker cocoa color) are $100 more. This compares with just $100 to $200 for most ceiling fans on the market.

Haiku fans can be ordered with different stem lengths, depending on your ceiling height, and for flat or sloped ceilings. They are also available with integral LED lights, though I haven’t seen those and can’t comment on how they look.

All Haiku fans carry a lifetime warranty.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-05-14 n/a 18517 6 Ways Our Household is Saving Water—And Energy

Saving energy isn’t only about using less electricity and fuel; it’s about saving water.

Our 1.75 gpm Kohler Bancroft showerhead.
Photo Credit: Alex Wilson

In this weekly blog, I’ve focused a lot of attention on the energy-saving measures at our new home—from the innovative insulation materials we used to the air-source heat pump heating system and our top-efficiency heat-recovery ventilator. What I haven’t said much about are the measures we’ve taken to reduce water use and why these measures save energy as well.

The water-energy nexus

Before getting into specifics, it’s important to note that there is a close relationship between water and energy—even when we’re not talking about hot water. At the macro scale, it takes at lot of water to produce energy.

With electricity generation, each kilowatt-hour (kWh) of electricity generated (based on national averages) consumes 2.0 gallons of water, according to a 2003 paper by National Renewable Energy Laboratory researchers (PDF download). This is mostly from evaporation of water at thermoelectric power plants, but also includes evaporation of water at reservoirs used for hydropower generation. (See The Water-Energy Connection, and Energy Could Be Twice as Thirsty by 2035.)

Other energy sources consume a lot of water in production. We can refer to this as the “embodied water” of these energy sources. Simply pumping oil out of the ground isn’t all that water-intensive, but when we start getting into “enhanced recovery” technologies like hydraulic fracturing (fracking) the water intensity goes way up—and can be a limiting factor. It may increasingly lead to conflicts with farmers in arid regions that are rich in underground oil and natural gas.

Kohler Forté single-handle faucet, delivering the full 1.5 gpm.
Photo Credit: Alex Wilson

At the same time, treating and distributing water and treating wastewater use a lot of energy (see Waste Water, Want Water). This is especially the case with municipal water and sewer systems, but even in rural areas with their own water systems, water pumping can be one of the largest energy consumers—to operate deep-well, 220-volt, submersible pumps.

Water conservation

It is with this context that I consider water conservation to be an extremely important priority. We are fortunate in Vermont to have plenty of water, but I’m just back from California, which is dealing with one of the most severe droughts in decades. Flying over the Sierras on my way there I was shocked to see how little snow cover there was.

So what are the water conservation measures we implemented at our new house?

Low-flow showerheads

We installed EPA WaterSense-certified showerheads that deliver 1.75 gallons per minute (gpm), vs. the federal standard 2.5 gpm for showerheads. We are very pleased with these showerheads, though I’ve also used a showerhead using just 1.5 gpm and been very happy with that, and I recently used a showerhead rated at just 1.0 gpm and found that to work just fine (see GreenSpec for our green showerhead criteria and product listings).

When we save water with a showerhead or faucet we also typically save energy use directly, since we’re using less hot water. Indeed, in replacing older, high-flow showerheads with new low-flow models, the payback for that change is often measured in months or even weeks, instead of years.

Low-flow faucets

The faucets in our two bathrooms are WaterSense-certified at 1.5 gpm, vs. the maximum 2.2 gpm. Interestingly, almost the entire plumbing industry has shifted to 1.5 gpm flow rates—the level required for WaterSense certification. Because we rarely turn on the faucet full-force, our actual consumption is a lot lower. Screw-in faucet aerators are inexpensive and can quickly convert most standard faucets to water-saving versions. (Again, see our GreenSpec criteria for faucets, and recommended products.)

Kohler Highline 1.28 gpf toilet.
Photo Credit: Alex Wilson

Low-flush toilets

We have two bathrooms: upstairs and downstairs. Both have high-efficienct toilets (see Residential Toilets) that use just 1.28 gallons per flush (gpf). I admit to having been somewhat skeptical that 1.28 gpf would be enough for satisfactory performance, but in the three months we’ve been in the house we’ve had zero problems. The toilets are performing beautifully.

Water-efficient clothes washer

I remember when I bought my first new clothes washer 25 or 30 years ago, I had to work pretty hard to find a water-conserving horizontal-axis (front-loading) model. At the time there was only one U.S. manufacturer producing such a product for home use (White-Westinghouse).

Fortunately, it is a very different situation today, with nearly every manufacturer offering such products. We bought a Whirlpool Duet washer, which I think is the best of the U.S.-made models. We had one in our last home and were very pleased with it. The only difference with this purchase is that the washer (and matching dryer) are larger, since Whirlpool shifted manufacturing to the U.S. from Mexico, and the units grew in size. (See our tips on selecting washing machines.)

Because we typically wash clothes in cold water, our direct energy use for clothes washing is very low.

Water-efficient dishwasher

We bought a mid-range dishwasher and are very pleased with it so far. We operate it with the no-heat-dry feature selected on a normal or light cycle to further reduce water and energy use. Roughly 90% of the energy use by dishwashers is for heating the water, so a water-conserving dishwasher also saves a lot of energy. With the Normal cycle and assuming typical soiling of dishes, a load of dishes uses just 2.9 gallons—far less than was the case a decade ago.

It’s worth noting that using a modern, EnergyStar-rated dishwasher typically consumes a lot less water than washing dishes by hand.

TapMaster knee- and foot-activated faucet controller.
Photo Credit: Alex Wilson

Knee-control kitchen faucet

We brought down from the house we moved out of a great kitchen faucet control system made by TapMaster that lets you turn the faucet on an off by either pressing your knee into one of the under-sink cabinet doors or by pressing a toe plate with your foot. This way you can easily turn the water on and off while you’re washing a pot or rinsing dishes. There’s no reason to leave the water running, so moderate water savings can be achieved. It’s also a huge convenience!

Final thoughts

In the years and decades ahead, water may well be a bigger challenge than energy in many areas of the U.S. and world. We should all do our part by using this precious resource efficiently.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-04-08 n/a 18460 Urine Collection Beats Composting Toilets for Nutrient Recycling

Human urine collection and use provides a better way to recycle nutrients than use of composting toilets.

Abe Noe-Hays of the Rich Earth Institute standing in front of a urine storage tank. Click to enlarge.
Photo Credit: Alex Wilson

Just when you thought it was safe to enjoy this blog over a cup of coffee here’s an article on…urine?


Let me explain.

Urine is a largely sterile, nutrient-rich resource that can be used in fertilizing plants. In fact, according to the Rich Earth Institute, the urine from one adult in a year can provide the fertilizer for over 300 pounds of wheat—enough for nearly a loaf of bread per day.

The Rich Earth Institute is a Brattleboro, Vermont-based organization that’s at the leading edge of the little-known practice of urine collection and use—something that’s emerging in Sweden and a few other places. This past Friday night roughly 200 people gathered at the Strolling of the Heifers’ River Garden in downtown Brattleboro to hear Abe Noe-Hays and Kim Nace from the Rich Earth Institute, along with a New York City comedian/activist, Shawn Shafner, discuss the idea.

Mixing waste and potable water

With conventional practice, human waste (urine and fecal matter) is mixed with large quantities of potable water and flushed down toilets. From there, it typically flows to municipal wastewater treatment plants where energy- and chemical-intensive processes use bacteria to break down organic wastes, separate out biosolids, kill pathogens, and release that water into rivers or aquifers.

Nutrients in human waste. Note that the dry mass of urine is actually greater than that of feces and that nitrogen and phosphorous levels in urine significantly exceed those of feces. Click to enlarge.
Photo Credit: Swedish data from the Rich Earth Institute

For those living in rural areas not served by a municipal sewer system, that wastewater flows into septic tanks where solids settle out and the effluent then flows into the soil through leach fields—in most cases with most of the nutrients in that waste filtering down into the underground aquifers. I learned when researching onsite wastewater disposal years ago for Environmental Building News (see On-site Wastewater Treatment: Alternatives Offer Better Groundwater Protection, as well as the more recent Waste Water, Want Waterthat the aquifers under rural New England towns almost always have nitrate levels that significantly exceed federal drinking water standards.

At the same time, in the chemical industry, tremendous quantities of natural gas are used in the Haber-Bosch process (invented in 1915) to extract nitrogen from the atmosphere, which is made up of roughly 78% nitrogen gas (N2), to produce ammonia fertilizer, the mainstay of commercial agriculture.

A urine-separating composting toilet.
Photo Credit: Alex Wilson

Utilizing human urine

When most people think of creating fertilizer from animal waste, they think of manure. Composted cow manure, for example, is widely sold in garden centers. But there are actually far more nutrients in urine than in fecal matter.

In human waste, 88% of the nitrogen is contained in the urine, along with 66% of the phosphorous, according to Swedish research, while nearly all of the hazards—including bacterial pathogens—are contained in the fecal matter.

The idea that the Rich Earth Institute has been advancing for the past several years is to collect human urine, sanitize that urine to kill any bacteria that may be in it (from urinary tract infections, for example, or fecal contamination), and then apply it on fields as a fertilizer.

Abe Noe-Hays (who used to work for our company, BuildingGreen!), has been leading the charge with this idea in the U.S. The Rich Earth Institute secured funding from the U.S. Department of Agriculture, through the Sustainable Agriculture Research and Education (SARE) program to study urine collection and use as fertilizer, and the Institute is into its second year of this study.

Collecting urine

Specialized urine-separating flush toilets are available in Scandinavian countries with front chambers for capturing urine (GreenSpec lists two. Abe Noe-Hays manufacturers a urine-separating composting toilet (listed in GreenSpec), and the Institute provides toilet insets for urine collection. On a larger scale, collection of urine from men’s rooms that have waterless urinals is particularly easy.

With the help of Best Septic Service in Brattleboro, the Institute collected 3,000 gallons of urine from over 170 participants in 2013.


According to most experts, simply storing urine for a while in a sealed container is enough to kill bacteria, due to the high alkalinity and ammonia from the urine. But the Rich Earth Institute is experimenting with faster pasteurization systems that heat the urine (including with solar systems that circulate solar-heated fluid through heat exchangers in the urine tanks). They are also testing various strategies for controlling odor—likely the biggest hurdle we face with urine collection and use.

Jay Bailey spreading diluted urine on a hay field in Brattleboro.
Photo Credit: Abe Noe-Hays

Land application

In Sweden urine is being applied on food crops, but to date, with USDA support and permits from the State of Vermont, the Rich Earth Institute has stuck with less controversial applications on non-food crops—specifically hay fields.

Initial results last year with undiluted urine and dilution rates of 1:1 and 3:1, dramatic improvement in hay production was seen (see photo).

Because urine may contain pharmaceuticals being filtered from the body by our kidneys, there is an important question about whether that could pose a problem for use of urine as fertilizer. This year, the Institute will begin an EPA-funded study to test whether residual pharmaceuticals in urine are taken up by vegetables grown on experimental plots.

Better than composting toilets?

I have long been a fan of composting toilets. I like the idea of not mixing human waste with potable water, and I’ve always felt that flushing away the nutrients in human waste was a lost opportunity. But when I learned about urine separation and use (believe it or not in a luncheon presentation on the topic at a conference in Houston, Texas in 2009), I began to see the benefits of urine separation over standard composting toilets.

With standard composting toilets, most of the nitrogen in the waste ends up being volatized as either nitrogen gas or ammonia—and lost into the atmosphere. With urine collection and use, the nutrients aren’t lost; they are recycled in a sustainable nutrient cycle. That's part of why EBN has called urine separation "the next wave of ecological wastewater management."

Urine application test plots; the darker-green strips were fertilized with diluted urine.
Photo Credit: Abe Noe-Hays

This is something we’re considering for Leonard Farm, though we have not installed such a system yet. For more information or to participate in ongoing studies, contact the Rich Earth Institute.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-04-02 n/a 18417 Can This Man Reinvent Concrete?

A California company, Blue Planet, is reinventing concrete and envisions a world in which the 8 billion tons of concrete used each year sequester billions of tons of carbon dioxide.

Pouring the foundation for our Dummerston Home; someday soon, concrete may be able to sequester huge quantities of carbon.
Photo Credit: Alex Wilson

I’ve been in the San Francisco Bay Area for the past week speaking at various conferences. (When I travel I try to combine activities to assuage my guilt at burning all the fuel and emitting all that carbon dioxide to get there. Between conferences, I’m now spending time with my daughter in Petaluma and Napa.)

I spent three days last week at BuildWell, a small conference organized by my friend and colleague Bruce King, P.E. that is focused on “innovative materials for a greener planet.” The roster of presenters included such well-known thought leaders as Ed Mazria, FAIA of Architecture 2030, who is leading an effort to shift to zero-carbon buildings by 2030; John Warner, Ph.D., the father of Green Chemistry, which is transforming manufacturing by reducing toxicity; and Mathis Wackernagel, the founder of the Global Footprint Network.

A less-recognized presenter (and attendee throughout the three days) was Brent Constantz, Ph.D., the founder and CEO of Blue Planet and a professor at Stanford University. (Blue Planet has no website currently.) Little did I know how audacious Constantz’s plans are: to reinvent concrete, transforming it from one of the world’s largest emitters of carbon dioxide into one of the most important tools to sequester the carbon dioxide emitted from power plants.

Ordinary Portland cement

The Portland cement used today in concrete and a wide range of mortars, stuccos, and concrete masonry units (CMUs) consists largely of two forms of calcium silicate (calcium oxide plus silicon dioxide) with smaller concentrations of aluminum oxide, ferric oxide, and sulfate.

Portland cement derives its name from its similarity in appearance to Portland stone, found on the Isle of Portland in Dorset, England in the early 19th century.

The primary raw material going into Portland cement manufacture is calcium oxide (CaO), which is produced by “calcining” limestone (CaCO3), under very high temperature and the intermediate formation of “clinker.” This calcining process drives off carbon dioxide (CO2). Because such huge quantities of cement are used globally about 1.6 billion tons), Portland cement production is one of the largest sources of our carbon dioxide emissions.

Portland cement produces CO2 both from the calcining of limestone (a chemical process) and from the tremendous energy inputs used in that calcining process.

Note that Portland cement is only one constituent in concrete, accounting for about 12% of the mass of concrete—the rest is from sand, water, and aggregate. It is the binder that glues the sand and aggregate together into a solid stone-like material.

(Read more in our special report on What You Need to Know About Concrete and Green Building.)

Calcium carbonate cement

Constantz is focusing on a very different type of cement: a calcium carbonate cement. The calcium is derived either from seawater or—in more inland locations—from brine, and the carbonate comes from the carbon dioxide in power plant flue gases. He envisions a system in which the CO2 is extracted from flue gases to produce both a calcium carbonate cement and limestone aggregate.

Blue Planet, which has attracted some large investors, believes that concrete produced with its CarbonMix cement and limestone aggregate would be carbon-neutral or even carbon-negative, meaning that the more of it you use the more carbon is sequestered—or pulled out of the atmosphere and forever locked up.

Blue Planet is carrying out research at one of California’s largest power plants: a natural-gas-fired plant on the coast at Moss Landing (south of San Francisco). The Moss Landing power plant, now owned by Dynegy, power plant produces four million tons of CO2 per year—CO2 that is contributing to global warming.

In producing concrete from CarbonMix cement, carbon emission reductions would be achieved in multiple ways: the production of Portland cement would be reduced; CO2 would be chemically tied up in the calcium carbonate cement; and the aggregate (a far larger constituent of concrete) would be limestone.

Using limestone as aggregate could be done immediately, with no changes in highway standards and concrete engineering standards. And Constantz claims that even the non-Portland cement could be used with very few changes—though the lower alkalinity in cement binder may mean that different re-bar is needed. (With standard concrete, the high alkalinity protects the steel re-bar from corrosion.)

Ancillary benefits of carbon-negative concrete

In addition to the huge benefit of sequestering carbon dioxide emitted from power plants, CarbonMix cement and aggregate production could provide a way to demineralize water. Such a facility would provide a wonderful complement to a desalination plant, for example.

In desalination, fresh water is extracted from seawater or brine in a process that concentrates the calcium and other minerals. Desalination is becoming more and more common, and getting rid of the highly concentrated brine can be a challenge. Texas, for example, has almost 50 desalination plants, nearly all of them using brine rather than seawater.

Reducing the mineral content of brine is also a key priority in fracking. The oil and gas industry would love to find someone wanting to use that brine, helping to purify it in the process.

Final thoughts

It remains to be seen whether Brent Constantz can realize his vision of transforming cement and concrete—among the most common materials used in construction today. If he can, it will be a game changer—something that attendees of BuildWell were quick to grasp. If he succeeds, fortunes will be made in the process and the world will be far better for it. I look forward to watching the progress of Blue Planet over the coming months and years. BuildingGreen will be reporting on this technology as it evolves.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-03-26 n/a 18403 Our Green Home Cost a Lot, But Yours Doesn't Have To

Our house cost a lot more than I would have liked, but many of the ideas used in it could be implemented more affordably.

We picked up these two salvaged garage doors for $500 total—while new they would have cost $3,500 apiece. Using salvaged materials can save a lot of money.
Photo Credit: Alex Wilson

My wife and I tried out a lot of innovative systems and materials in the renovation/rebuild of our Dummerston, Vermont home—some of which added considerably to the project cost. Alas!

The induction cooktop that I wrote about last week is just one such example.

For me, the house has been a one-time opportunity to gain experience with state-of-the-art products and technologies, some of which are very new to the building industry (like cork insulation, which was expensive both to buy and to install). We spent a lot experimenting with new materials, construction details, and building systems. While we haven’t tallied up all the costs, we think that the house came in at about $250 per square foot.

All this has raised the very reasonable question about whether all this green-building stuff is only feasible for high-budget projects.

So I’ve been thinking about what lessons from our project would be applicable to more budget-conscious retrofits. Here are some thoughts. (Also see our recent EBN feature article, How to Build Green At No Added Cost.)

Keep it compact. In renovating the old farmhouse we shrank the footprint, eliminating a kitchen addition that had been added perhaps in the 1920s. Fitting the kitchen into the main house meant some tricky design work, but it helped us contain costs with the exterior envelope and finishes. This cost-saving strategy applies whether with new construction or renovating an existing house. The cost per square foot will likely go up with a smaller house, but the total cost should drop—and there will be less volume to heat and cool.

Deep-energy retrofit with mineral wool. The cork insulation we used as an insulation wrap on the walls was really amazing, and I’m glad we used it, but if we were doing the project over with a more constrained budget, I think I would have gone with rigid mineral wool. Carrying out a deep-energy retrofit by wrapping a house in rigid insulation is never inexpensive and it depends on having deep enough roof overhangs, but with rigid mineral wool (such as Roxul ComfortBoard or the highest-density Thermafiber product) it can be a much more reasonable retrofit. (For more details on how to do a retrofit with mineral wool, see our insulation report.)

High-performance storm windows. While our low-emissivity (low-e) storm windows on the south and east facades aren’t installed yet, they can provide a reasonably priced alternative to window replacement with top-performing, triple-glazed windows. The idea is to keep the existing (prime) windows when installing exterior rigid insulation on a house and add window surrounds to extend the window openings to the new outer face of the walls—and then install the storm windows near the outer face of the window surrounds. (See GreenSpec for guidance on finding good exterior storms.)

Air-source heat pump. The heating system we went with on our house is a great option today for compact, very-well-insulated homes, while larger, ducted versions of these systems will increasingly make sense for replacing conventional gas or oil heating systems. On a cost per million BTUs of delivered heat basis, air-source heat pumps are significantly less expensive than propane and heating oil, and they can be pretty competitive with natural gas—especially if natural gas prices keep climbing. An air-source heat pump means electric heat, but that opens the door to generating the electricity you need—now or down-the-road—with solar. (To play around with heating cost comparisons, see our heating fuel cost calculator.)

Water-efficient products. We went with state-of-the-art water-conserving plumbing fixtures and appliances. The 1.75 gallon-per-minute Kohler WaterSense showerheads in our two bathrooms significantly reduce hot water use, compared with standard 2.5 gpm models, saving energy as well as water. And they don’t cost any more than standard models.

Rain-screen detail on exterior walls. We spent a little more installing strapping over the exterior sheathing so that the siding will have an air space behind it, but the cost is low enough and the durability benefits great enough that this should be standard practice today. We will save thousands of dollars over the years by having to paint the siding only every 15-20 years (I predict), instead of as often as every five years, and a big part of the difference is the rainscreen detail.

Salvaged materials. We were able to save some money—and with more concerted effort  could have saved a lot more—by making use of salvaged materials. We bought a salvaged newel post and balustrades for the stairs, for example, picked up a discontinued floor-demo front door, purchased salvaged timbers for post replacements in the barn, and bought superb two garage doors from the now (sadly) closed ReNew Salvage in Brattleboro. Using salvaged materials not only saves money, but it can also help the environment by allowing us to save in raw materials extraction and by reducing pressure on landfills.

These are just a few examples of how a green, energy-efficiency agenda can be achieved with an eye towards economy. Building or renovating with a goal of energy savings and environmental stewardship does not have to have a huge cost impact.

Fundamentally, it’s all about savings—saving energy resources and saving the environment. If we were to put an economic value on protecting the environment, those environmental savings with our house might have compensated for the increased cost of building. But we’re not there yet.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-03-19 n/a 18382 Safe, All-Electric "Induction" Cooking: Try This At Home

Induction cooktops respond quickly, avoid gas combustion, are tops in energy efficiency, and limit risk of burns.

Our induction cooktop blends in well with our matt-black Richlite countertop. Click to enlarge.
Photo Credit: Alex Wilson

One of our early decisions in the planning for our farmhouse renovation/re-build was to avoid any fossil fuels. If the State of Vermont can have a goal to shift 90% of our energy consumption to renewable sources by 2050, we want be able to demonstrate 100% renewables for our house today.

That decision meant using electricity, rather than propane, for cooking. Electric cooking was actually a very easy decision for us. When our daughters were very young, roughly 25 years ago, my wife and I replaced our gas range with a smooth-top electric range. I had read too many articles about health risks of open combustion in houses; I didn’t want to expose our children to those combustion products.

And I knew that even the best outside-venting range hoods don’t remove all of the combustion products generated when cooking with gas.

Deciding on induction

We were surprised back in the late ’80s how quickly we adjusted to an electric cooktop. It’s not as controllable as gas, but we made due just fine for 25 years. Nonetheless, friends always complained about electric cooktops being too slow or not controllable enough, so we wanted to try out the electric option that top chefs are increasingly turning to: induction.

Controls are very easy, though all electronic. I'm hoping they'll hold up.
Photo Credit: Alex Wilson

For our new house we bought a KitchenAid induction cooktop for our kitchen island. I had wanted to go with the technology leader, Miele, but at about $2,500 for Miele’s 30-inch model, the cost was just too high for our budget. Even the less-expensive KitchenAid version stretched our budget considerably.

What is induction?

Electromagnetic induction, which was discovered in the early 1800s by Michael Faraday, is the process in which a circuit with alternating current (AC) flowing through it induces current in a material placed nearby. It is key to the functioning of induction (asynchronous) motors and most electric generators.

In the case of induction cooking, there’s an electric coil under the glass surface of the cooktop through which AC electricity flows. This current, in turn, generates current in a ferrous metal (iron or steel) pan that’s very close to it (separated by the glass cooktop). Electromagnetic current flows through the bottom of the pan, but because iron and steel aren’t very good electrical conductors, that electric current is converted into heat—more specifically, into electric resistance heat, since the material resists the flow of electric current.

Because the stovetop surface doesn't heat up, induction cooktops are much safer than any other type. This pan of water boiled with no impact to the newspaper.
Photo Credit: Alex Wilson

The result is that the pan or skillet heats up and transfers that heat to whatever is being cooked. So, in effect, the pan becomes the heat source.

If you have a rice cooker, you’re probably already using induction cooking, since that’s how most rice cookers work.

This is different than conventional electric cooktops in which the cooktop itself is heated by electric resistance, and the heat is transferred to the cooking pot. Again, with induction heating, the cooktop only has electricity running through it as it induces heating in the pot.

Advantages of induction cooking

Speed and controllability. Because the pan generates the heat directly, induction cooking is very fast—heating up immediately when turned on and cooling down immediately when the current is reduced or turned off. Heat output can be adjusted even more quickly than with gas burners.

Energy efficiency. Induction cooktops are the most efficient of any option in transferring heat generated by the stove to a pot or pan. According to a study done by Lawrence Berkeley National Laboratory for the U.S. Department of Energy, gas cooktops are about 40% efficient, electric-coil and standard smooth-top electric cooktops are 74% efficient, and induction cooktops are 84% efficient (see Table 1.7, page 1–22). Before you get all excited, though, be aware that cooking accounts for less than 3% of average household energy consumption—so don’t expect an attractive payback for the extra cost of an induction cooktop!

Only ferrous metal pans work on induction cooktops—such as cast iron and stainless steel that a magnet sticks to the bottom of.
Photo Credit: Alex Wilson

Less waste heat. Another aspect of that energy efficiency is greater summertime comfort. We’ve only been in our house for a couple months so haven’t used it in hot weather (that’s for sure!), but a friend who has an induction cooktop raves about the summertime benefit of not heating up his kitchen as much as he used to with a gas cooktop.

Safety. Induction cooktops, like other electric cooking elements, avoid combustion and gas lines, so are inherently safer than gas burners. But induction cooktops go further, dropping a piece of paper on a cooktop that’s on can’t cause a fire. In fact, as shown in the photo, you can cook with a piece of paper between the cooktop and the pot (although doing so probably isn’t a good idea). The electromagnetic induction happens through the paper.

Drawbacks of induction cooktops

Ferrous metal cooking vessels required. Aluminum, copper, and some stainless steel cookware won’t work, so buyers of induction cooktops may have to invest in new pots and pans. Use a magnet; if it sticks to the bottom of the pot, it will work on an induction cooktop. Fortunately, there are lots of options, including plenty that are reasonably affordable.

High cost. While the cost of induction cooktops has dropped in the last few years, they are still pricey. We spent $1,400 on our 30-inch KitchenAid Architect Series II induction cooktop, and the list price of that model is $1,849. A comparable KitchenAid standard electric cooktop (non-induction) lists for $1,299. The high cost of induction today is partly because of the induction technology, and partly because induction is only available in the high-end product lines from appliance manufacturers. The cost should come down and induction gains popularity and spreads into lower-priced product lines.

Health concerns? There is some concern that the electromagnetic fields (EMFs) created by induction cooktops could be hazardous. I understand that the field drops off (attenuates) very quickly with distance from the cooktop, though I haven’t borrowed a gauss meter to actually measure EMFs from our cooktop. I haven’t read credible reports of health problems from induction cooking, but I couldn't rule it out.

Our cabinets were made by Greg Goodman of Brattleboro using native sugar maple along with Columbia Forest Products' formaldehyde-free PureBond hardwood plywood.
Photo Credit: Alex Wilson

Bottom line

I like our induction cooktop a lot. I’ve only had one frustrating experience: the time last month when I set out to make a big batch of chili for an office gathering and discovered that the largest of the skillets in our cookware set doesn’t work with induction elements, even though all the others do. I’m assuming that because the diameter of that pan is so large, the manufacturer used a disk of aluminum or copper, rather than steel, to conduct the heat to the edges more evenly.

Overall, my wife and I are very pleased with induction, though it does take some getting used to. We got a rimless model, and the black ceramic-glass surface blends in quite well with the black Richlite countertop material.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-03-12 n/a 18366 Heat Pump Water Heaters in Cold Climates: Pros and Cons

While a heat-pump water heater will save significant energy on a year-round basis, be aware that in a cold climate the net performance (water heating plus space heating) will drop in the winter.

Electricity consumption by our GeoSpring heat pump water heater in February. Note the spike mid-month when I switched the mode to "boost." Click to enlarge.
Photo Credit: here

We chose a heat pump water heater for our new house, and as I've recently discussed here, there are a lot of reasons why you might be doing the same.

Using an air-source heat pump, heat pump water heaters (HPWHs) extract heat out of the air where they are located to heat the water.

That means that a HPWH cools the space where it is located. That’s a good thing in the summer—it doubles as air conditioning—but in the winter it’s not so helpful. That’s especially the case in a cold climate in a house without a standard heating system.

Cooling the space where they are located

In a typical New England house that has a furnace or boiler in the basement producing a lot of waste heat, a heat pump water heater can use some of that waste heat and it’s not really very noticeable—the less efficient the heating system the less noticeable is the effect of the HPWH.

But we don’t have a heating system in our basement. As a result, our HPWH cools the space. With the cold weather we’ve had (as I write this it’s about –2°F) and our basement has stayed pretty cool: typically 50°F–54°F, though with the exceptionally cold weather we had a few weeks ago during a time of heavier hot water usage, the temperature dropped as low as 47°F. Our basement temperature would probably be considerably lower if my wife and I used a lot of hot water, but we're pretty frugal.

Minute-by-minute electricity consumption by the water heater over a two-day period. The line in green shows consumption through mid-morning on March 5th; consumption on March 4th is shown by the gray line..
Photo Credit: here

Robbing from Peter to pay Paul

In cooling the space where it is located, a HPWH makes the heating system work harder. In our house the heating system is a single mini-split air-source heat pump wall-mounted unit on a first-floor wall. That system delivers heat to the basement through the uninsulated floor and through the basement door, which we usually leave closed.

We also have a fan and ductwork at the top of our stairs so that, if we need to, we can pull warm air from the heated space in the house and dump that into the mechanical room in our basement. This is a back-up in case the basement gets too cold, but we haven’t used that fan because of its noise.

So our 18,000 Btu/hour Mitsubishi air-source heat pump has to work harder (and use more electricity) because it’s also indirectly heating our water. With the really cold weather we’ve had since moving into the house in early January, our air-source heat pump has been working pretty hard to keep up. And I think the HPWH has contributed to our first floor being a little cool—especially near the floor.

My friend Lester Humphreys in Brattleboro, who also has a HPWH in his basement but has an oil-fired boiler there as well, has done some back-of-the-envelope calculations to estimate how much oil he’s using for his water heating and asked me to look over his numbers:

“I calculated the loss from our living space through the floor to the basement using the formula Area x 1/R x delta T.  I figure our heat pump heater lowers the temperature in the basement by about 3 degrees, our wood floor has an R value of 2.75 and the basement ceiling is 1217 square feet.  This gives me heat loss of 1314 BTUs per hour.  Running 6 hours a day (probably a little high), a delivered heat efficiency of 70% for our oil system, this equals 2.4 gallons a month (about $9), which is not bad.”

With our hot water usage, the electricity consumption directly by the HPWH isn’t that great: 56 kilowatt-hours (kWh) in February—or about $8 worth at 15¢ per kWh, which is Green Mountain Power’s current residential electric rate. Consumption averaged a little less than 2 kWh per day in February, jumping to over 8 kWh one day when both of our daughters were visiting from out-of-town and we had to switch the water heater to the “Boost” mode (in which an electric resistance heating element supplements the heat-pump mechanism).

Along with that 56 kWh used by the HPWH, though, some of the 814 kWh used in February by our mini-split air-source heat pump heating system (about $125 worth), was for water heating. I haven’t calculated what our total water heating cost was for February, but that should be possible to do.

Slow recovery

Another thing to keep in mind is that HPWHs have a quite slow recovery rate—I think ours recovers at a rate of about eight gallons per hour. This is why larger water heaters often make sense with HPWHs, though I thought a 50-gallon model would be alright for our usage.

In mid-February, though, our younger daughter from New York City and our older daughter and financé from California were visiting, and we had a party. We still might have been all right with hot water, since we have WaterSense plumbing fixtures and a high-efficiency dishwasher, but our younger decided to take a bath after we had all done a lot of party prep. She ran out of hot water before the tub was all the way filled.

Fortunately, most HPWHs, including our GE GeoSpring model, allow you to change the mode. I normally operate the water heater on Heat Pump Only mode, but switched it to Boost mode for a few hours that Saturday.

The jump in power draw was dramatic (shown by my eMonitor). In Heat Pump Only mode, the power draw peaks at about 500 watts, but that jumped to 5,000 watts in Boost mode.


The other issue to consider with HPWHs is that they have fans and compressors that are noisy. I don’t think I would consider a HPWH if we didn’t have a basement and had to place the water heater on the first floor. We have fairly good acoustic isolation between our basement and first floor—and the water heater is in a mechanical room to which we can retrofit ceiling and wall insulation if the noise proves annoying.

So far, the noise isn’t very noticeable, but in the summer (when the air-source heat pump is unlikely to be running) we may find that we can hear the water heater—in which case I’ll probably insulate the mechanical room. Noise did play into our product selection; when I was researching options, the GE GeoSpring was the quietest HPWH I found.

Bottom line

In summary, we’re happy with our heat-pump water heater, despite the cold climate and the fact that we don’t have a waste heat source in our basement. I’m guessing that, for half the year, we’ll save at least 60%, compared with a standard electric water heater, while only 10%–20% in the cold months. Homeowners with a waste heat source in their basements will do better.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-03-05 n/a 18301 Picking a Water Heater: Solar vs. Electric or Gas Is Just the Beginning

Why we opted for electric water heating over a solar water heater

Our GeoSpring heat-pump water heater. Click to enlarge.
Photo Credit: Alex Wilson

As we build more energy-efficient houses, particularly when we go to extremes with insulation and air tightness, as with Passive House projects, water heating becomes a larger and larger share of overall energy consumption (see Solar Thermal Hot Water, Heating, and Cooling). In fact, with some of these ultra-efficient homes, annual energy use for water heating now exceeds that for space heating—even in cold climates.

So, it makes increasing sense to focus a lot of attention on water heating. What are the options, and what makes the most sense when we’re trying to create a highly energy-efficient house?

Solar-electric vs. solar-thermal water heating

If we had built our new house three or four years ago, I suspect that solar water heating would have been included—or at least very seriously considered. But as costs of solar-electric (photovoltaic or PV) systems have dropped in recent years, more and more energy experts are recommending electric water heating, rather than solar thermal, and using PV modules to generate the electricity—so it’s still solar water heating, but not as direct.

Late-afternoon photo of the PV system on our barn--which is about 100 feet from the house.
Photo Credit: Alex Wilson

That’s what we have done at our new place. We realized in our planning that we had a great location for PV modules on our barn roof, but we didn’t have a good rooftop location for solar panels on the house. PV panels can be located farther away from where the energy is being used than can solar-thermal panels, because electrons can be easily moved fairly long distances through electrical cables, while piping runs for solar-thermal systems have to be much shorter.

Also, PV systems also don’t have any moving parts to wear out or that require maintenance; freeze protection isn’t a concern; and pressure build-up from stagnation in full sun (if a pump fails or during a power outage) can’t occur. So PV systems are very attractive from a long-term durability standpoint.

And if we’re generating our electricity from the sun why not use some of that electricity for water heating? That’s what we decided to do: install a PV system and heat our water with electricity

The GeoSpring offers several different control options: heat pump only, hybrid (both heat pump and electric resistance — less savings than heat pump only), boost (faster water heating and less savings than hybrid), standard (electric-resistance only — no energy savings), and vacation (maximum savings when homeowners are away). Click to enlarge.
Photo Credit: Alex Wilson

Electric water heating

So if one goes with electric water heating, what are the options? There are three primary choices:

  1. Conventional storage-type electric water heater. This is an insulated tank that holds 30 to 80 gallons, typically, and includes either one or two electric-resistance heating elements. Better storage water heaters have more insulation, so less stand-by heat loss occurs.
  2. Tankless water heater. A tankless, sometimes called on-demand or instantaneous, water heater heats the water as it is used. This offers the advantage of eliminating the stand-by loss that occurs with storage water heaters. Whole-house tankless water heaters are most commonly gas-fired, but electric models are also available.

    The problem with the latter is that they require a huge amounts of electricity. An electric tankless water heater large enough to supply a shower and another use at the same time will require a 60-amp or larger circuit at 220 volts. If a lot of homeowners were to switch to whole-house electric tankless water heaters, it would put a huge burden on the utility companies that have to meet peak demand—particularly in the morning when a lot of people are showering.

    There are other issues with tankless water heaters, including that they don't necessarily save energy.
  3. Heat-pump water heater. A heat pump water heater extracts heat out of the air where the water heater is located (typically a basement) to heat the water. Because the electricity is used to move heat from one place to another instead of converting that electricity directly into heat (as with electric-resistance water heating), the energy yield per unit of electricity input is much greater.

    We measure that efficiency as the “coefficient of performance” or COP—a COP of 1.0 is, in essence, 100% efficient at converting electricity at your site into heat. Most heat-pump water heaters have COPs of 2 to 3, meaning that for every unit of energy consumed (as electricity), at least two units of energy (as heat) are generated.

    (Note that if we consider “primary” or “source” energy instead of site energy, energy losses during power generation reduce that effective COP considerably.)
It's a little hard to read in this photo, but I love having the user instructions right on the water heater. Click to enlarge.
Photo Credit: Alex Wilson

Choosing a heat pump water heater

A heat-pump water heater is what we decided on for our house. We installed a 50-gallon GE GeoSpring model and, so far, we’re very happy with it. The GeoSpring is currently available only in a 50-gallon size, though rumors suggest that a larger, 80-gallon, model could be introduced. Because water heaters operating in heat pump mode take a long time to heat water, larger tanks typically make sense. If our two daughters were still in the house, a larger heat-pump water heater would have been more important.

One of the factors that attracted us to the GeoSpring is that it’s now being made in the U.S. GE had made its first-generation GeoSpring in Mexico, but moved that production to the U.S. two years ago.

The GeoSpring doesn’t have the highest performance of any heat pump water heater on the market, but the GeoSpring costs a third as much as the most efficient model. It’s also quieter. (See our GreenSpec section on heat pump water heaters for detail on all the most efficient models available.)

Next week, I’ll say a little more about heat-pump water heaters, including some issues with placement and implications of the fact that heat pump water heaters cool off the space where they are located—depending on the season, that can be an advantage or disadvantage.

Understanding heat-pump water heaters is important, as they will soon become the standard at least for larger electric water heaters—based on efficiency standards that take effect in mid-April 2015.

*                        *                        *

By the way, Eli Gould (the designer-builder of our home) and I will be leading a half-day workshop at the NESEA Building Energy Conference in Boston on Tuesday, March 4, 2014. In this workshop, “What Would the Founder of Environmental Building News Do? Adventures on the Cutting Edge of Green Building,” we’ll be reviewing product and technology choices, describing lessons learned, presenting data on performance, and discussing, in a highly interactive format, some outcomes from this project that can be applied much more affordably in deep-energy retrofits. This should be informative and a lot of fun. I’ll also be presenting in the main conference, March 5-6, on “Metrics of Resilience.”  Registration information can be found here.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-02-26 n/a 18257 Insulated Vinyl Siding: Worth the Extra Cost?

Two studies indicate some benefits to using insulated vinyl siding, but more data is needed to win over this skeptic.

Setting aside the overall environmental profile of the oft-demonized PVC (check our coverage in this month’s EBN feature “The PVC Debate: A Fresh Look”), I’ve been getting a lot of questions about insulated vinyl siding—the vinyl siding with form-fitted expanded polystyrene (EPS) insulation permanently built into the back side of the double-four courses of vinyl siding.

Thanks to claims being made by the Vinyl Siding Institute and specific manufacturers, I’ve been hearing questions like these:

  • Does the EPS act as a significant thermal break, since it is continuous on the exterior of the building’s frame and sheathing?
  • Does insulated vinyl siding make a building more airtight?
  • What impact does the EPS have on the moisture performance of conventional, wood-framed exterior walls?

Intuition vs. numbers

It’s pretty easy as a building-science wonk to dismiss this product: the added R-value of EPS is R-2 to R-2.7.

Also,the long strips of EPS are only step-jointed, and therefore not airtight. And eliminating or significantly reducing the free-draining and ventilating space—which are touted as so important to the moisture performance of conventional vinyl siding—is certainly a significant moisture-management change.

Fortunately, we don’t need to rely entirely on speculation. Two recent field studies include evaluation of the hygrothermal performance of insulated vinyl siding:

Increased R-value

The industry study focused on thermal performance: increased exterior wall R-value, decreased thermal bridging, and increased airtightness. The study evaluated five different products from a range of manufacturers installed on five single-family detached homes, in five cities spanning three climate zones.

Standardized testing showed a range of increased R-value from 2.0 to 2.7; modest reductions in thermal bridging (as qualitatively assessed from thermal imaging); average increase in building airtightness of 11%; and utility bill savings ranging from 1% in Indiana to 11% in Colorado.

Conclusion? Insulated vinyl siding provided measurable but quite modest improvements in the thermal performance of these retrofitted existing homes.

Next time around, I’d like the Vinyl Siding Institute to measure airtightness under both pressurization and depressurization. (I checked with Newport Ventures, and airtightness testing was only under depressurization.) It would be interesting to see if pushing the insulated vinyl siding out and off the wall assembly (during pressurization) would generate different airtightness results than pulling it in (during depressurization). Both pressurization and depressurization are relevant to air leakage in real-world buildings.

Improved drying capacity

The NAHB Research Center study was a 22-month field investigation in Maryland (mixed-humid climate) comparing structural sheathing moisture content of multiple conventional wall assemblies that had wall claddings ranging from brick to stucco to conventional and insulated vinyl siding. The study included water injection testing (in August) at or near the structural sheathing layer. The water injection was designed to simulate leaking that might accompany a multi-day storm.

Both the insulated and conventional vinyl siding showed among the best drying capacities. The insulated vinyl siding performed the best (lowest structural sheathing moisture content) when there was no wetting event, and the conventional vinyl siding performed the best after the water injection testing. The slightly better drying capacity of the insulated vinyl siding was attributed to the warming of the insulated wall cavity by the siding insulation.

Conclusion? The introduction of the form-fitting insulation to the vinyl siding did not significantly reduce the drying potential of the vinyl siding in this field study.

Reasons are elusive

I have to admit to being quite surprised at the superior drying ability of the insulated vinyl siding; I would think that filling most of the free-draining space of conventional vinyl siding with form-fitted EPS insulation would significantly reduce both free drainage and convective drying between the vinyl siding and the rest of the wall.

It’s quite possible that the specific conditions of this field test—including the mild climate—explain some portion of the results; it would be great to test this supposition with field-testing in harsher climates and different wall configurations, varying more than just the exterior claddings.

What do customers think?

Enough building science; what is the demand for this unique product in the marketplace?

I asked Brian Knowles, project consultant with a Vermont company that installs quite a bit of vinyl siding, Jancewicz & Son, what he thought of the insulated vinyl siding products.

“The studies confirmed what my general sense of the insulated vinyl siding was,” says Brian. “The modest improvement in thermal performance is less of a selling point than the improved stiffness and sense of robustness that the insulated vinyl siding provides.”

Based on Brian’s estimates, the cost premium is significant: the insulated version of a colonial white siding, compared with the conventional product from the same manufacturer “carries a 50% cost increase” just for siding materials, he said. “The trim and finishing components for insulated siding are also at a premium and should be considered as well,” Brian adds. “However, the increases are much smaller,” up to 20%.


Editor’s Note

While the issues Pete has focused on here are about the hygrothermal performance of insulated vinyl siding, he and the rest of our GreenSpec editorial team took a more holistic view when deciding whether to list insulated vinyl siding.

We don’t list vinyl siding due to life-cycle concerns, so if we add the performance benefits of the EPS, are those issues overcome?

We’ll look for more data on an ongoing basis, but we are not currently listing this type of cladding. Our team is simply too concerned about the many health and environmental problems associated with PVC.

EPS also has its own problems—such as its use of flame retardants—and we’re not seeing enough evidence that insulated vinyl siding provides benefits that clearly overcome these problems. And speaking of performance benefits, if people are replacing a home’s cladding and choosing an insulated product, we think it makes more sense to consider a deep energy retrofit that would provide much greater R-value and airtightness than this product can offer.


2014-02-20 n/a 18253 Commissioning Our Home's Heat-Recovery Ventilator

To function properly, any ducted HRV has to be balanced after installation

Barry Stephens measuring the airflow through a ceiling register of our HRV.
Photo Credit: Alex Wilson

After choosing and installing our state-of-the-art heat-recovery ventilator (HRV), we completed a critical step in the installation of any HRV: commissioning, including the critical step of balancing the air flow.

This is absolutely necessary to ensure proper operation and full satisfaction.

Why commissioning is so important

The ducting runs in a ducted HRV system vary in their air-flow resistance. The two fans in an HRV should maintain neutral pressure—as much outgoing air force as incoming. Otherwise, with negative pressure in the house, radon and other soil gases could be drawn in, or with positive pressure, indoor air could be forced through the building envelope where it could cause moisture problems.

But beyond the two primary fans and pressure-balancing the entire house, the individual registers need to be balanced to ensure that you’re getting proper air flow through each of the supply and return registers. If this balancing step isn’t followed, the HRV might pull a lot more air out of a downstairs bathroom (which is closer to the HRV), for example, than a more distant upstairs bathroom.

The hand-held anemometer in a hood used to measure airflow.
Photo Credit: Alex Wilson

Balancing our Zehnder system

Barry Stephens, the business development and technology director at Zehnder America, came up to Vermont to commission and balance our Zehnder HRV. I didn’t watch the entire process, but was very impressed at the level of care that he gave to this task.

Barry used a hand-held device to measure airflow through the supply and return registers. This is a small hood that fits tightly over the register with an anemometer (wind gauge) allowing the airflow through the register to be measured in cubic feet per minute (cfm).

The flow through the registers (diffusers) can be adjusted in different ways depending on the type of register. Ceiling-mounted supply registers are adjusted simply by rotating the round, screw-mounted cover plate on the unit, which increases or reduces the gap and the airflow.

Measuring airflow through a wall register.
Photo Credit: Alex Wilson

Wall-mounted supply registers are adjusted by removing the cover plate and installing an insert that restricts airflow. Different-size disks can be added as needed to further restrict flow.

Exhaust ports are adjusted by moving the center component in or out.

After a round of adjusting, the airflow tests have to be repeated. Every time the flow through one register is changed it affects the airflow through the others. My sense is that there’s a lot of art involved in these adjustments; after balancing hundreds of systems, Barry and others at Zehnder America have a very good feel of how adjusting some diffusers will affect others.

I think for our system all this took several hours, though I’m sure I slowed Barry down with all my questions.

Condensate drain and controls

We realized before Barry arrived to commission our system that the condensate drain had never been hooked up during the installation. Zehnder HRVs have a sophisticated condensate drain with a specialized trap. Barry was able to carry out this installation quickly, though the fact that the trap hadn’t been installed over the previous several weeks meant that moisture got into the heat exchanger core, and this may have caused the frost protection system to work harder that it normally does, increasing electricity consumption.

While the user controls of the Zehnder ComfoAir 350 Luxe are elegantly simple, the behind-the-scenes controls are much more sophisticated—confirmed by paging through the 40-page installation manual (in English)—and I was very glad to be leaving the programming to Barry, though I’ll need to dig into those instructions when I want to change something.

We have two of these wireless controllers—one in each of our bathrooms.
Photo Credit: Alex Wilson

Experience to date

We commissioned the HRV the same day we set up an eMonitor energy monitoring system that allows us to track the electrical consumption of key loads in the house, including the HRV. While in normal operation the HRV uses very little energy, the intermittent frost-protection cycle does use a lot of energy—about 800 watts. During the last ten days of January (a very cold spell ), the unit used 65 kilowatt-hours (kWh), while this month (through February 16th) the unit has used 53 kWh.

I'm surprised at how high this consumption is and hope that some of it has to do with moisture having gotten into the heat exchanger core before the condensate drain was properly installed. I'll be very interested to see the annual consumption.

I love the simplicity of operating the HRV. From either bathroom I can either manually change the speed, or click on a clock icon to boost the unit up to the highest setting for either ten minutes (by tapping the button quickly) or 30 minutes by holding it down for three seconds. (Those times can be adjusted by going into the programming.)

As I noted last week, this isn’t the most affordable HRV you can get, but I feel very good about having what I believe to be the best and most energy-efficient model on the market.

*                        *                        *

By the way, Eli Gould (the designer-builder of our home) and I will be leading a half-day workshop at the NESEA Building Energy Conference in Boston on Tuesday, March 4, 2014. In this workshop, “What Would the Founder of Environmental Building News Do? Adventures on the Cutting Edge of Green Building,” we’ll be reviewing product and technology choices, describing lessons learned, presenting data on performance, and discussing, in a highly interactive format, some outcomes from this project that can be applied much more affordably in deep-energy retrofits. This should be informative and a lot of fun. I’ll also be presenting in the main conference, March 5-6, on “Metrics of Resilience.”  Registration information can be found here.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-02-18 n/a 18252 4 Resources Help Draw the Shades on Poor Window Performance

Predicting performance and rationally selecting window coverings—from awnings to films to cellular shades—is incredibly challenging, but real help is on the way.

Photo: Paul Sable. License: CC BY 2.0.There is a lot of interest in just how much (and at how low a price point) window coverings can improve building thermal performance.

Both the U.S. Department of Energy (DOE) and the U.S. Environmental Protection Agency (EPA) have been working on this issue; electric utilities would like to know how window coverings can fit into their efficiency programs; and both building professionals and consumers need objective guidance on how to compare window coverings—to each other and to window replacement.

Where does our industry stand on assessing thermal performance of window attachments, or coverings? There are four new or emerging resources that paint a more complete picture.

For the last several years, BuildingGreen has been working with Lawrence Berkeley National Laboratory (LBNL) on evaluating window coverings and their role in energy savings (as documented in our EBN feature article “Making Windows Work Better”). This effort was financially supported by DOE and was driven in no small part by a dedicated group of about 15 industry professionals in a project Advisory Committee.

Similar to the Efficient Windows Collaborative website, the centerpiece of the Efficient Window Coverings website is a selection tool. The main difference between the two selection tools is complexity.

Selecting windows is far from simple, but the number of attributes evaluated is relatively small and is exactly the same from window to window. Evaluating and selecting window coverings is complicated by the wide range of coverings—interior/exterior, adjustable/fixed, fabric/plastic/wood/metal—and the numerous functions the window coverings can serve or feature, as well as the choice of window over which coverings are installed.

The Efficient Window Coverings website selection tool currently covers 19 types of coverings and includes 18 distinct attributes.

Some of the attributes are assessed qualitatively (such as view, privacy, ease of egress), but others—like thermal performance, including insulation, airtightness, and solar heat control—will move from qualitative to quantitative assessment.

For some classes of products (such as venetian blinds, vertical louvered blinds, roller shades, solar screens, cellular shades, window films, interior and “storm windows,” and awnings), modeling programs like EnergyPlus and WINDOW have the capability of accurately predicting solar-optical, thermal and energy performance. However, for several other classes of products (such as pleated shades, drapes, Roman shades, roller shutters, louvered shutters, etc.), this capability is still under development. That leads us to the next new resource on evaluating window coverings.

Energy Savings from Window Attachments

LBNL recently completed a major modeling study: “Energy Savings from Window Attachments.” The study evaluated the thermal and optical performance of eleven window attachments for twelve cities, four residential building types, two HVAC systems, and three baseline window types.

Simulations began with the use of WINDOW and THERM for calculating thermal and optical performance of baseline windows with coverings, and then these results were pulled into EnergyPlus for modeling at the whole-building level. All of this required years of development work to bring the often thermally and optically complex window coverings into modeling capability.

Given all of the variables in this modeling study, it is not surprising that the results are quite varied and complicated. Here are some generalizations:

  • In northern and central climates (where heating energy is greater than cooling energy), interior window panels, exterior storms, and cellular shades save the most energy.
  • Combined critical design parameters of window attachments (designated “A” through “D” in this modeling study) were developed because of variability of design parameters between window attachment types and even within any one attachment type. These parameters were emissivity, reflectance, transmittance, and deployment (position for adjustable or operable attachments).
  • In southern climates, not surprisingly, the combined design parameter “A” (low emissivity, high reflectance, low transmittance) provided the greatest energy savings.
  • What is a bit surprising is that interior window panels and exterior storms maintained good energy savings in southern climates, with all exterior shading devices (solar screens, awnings) also doing well.
  • Deployment had a huge impact on results for operable/adjustable attachments.

This last generalization is completely expected, but how did the LBNL modeling study address the sticky issue of just how occupants use adjustable window attachments? That leads to the next new resource on efficient window coverings.

Residential Windows and Window Coverings: A Detailed View of the Installed Base and User Behavior

The LBNL modeling study of window attachment energy performance used the results of this DOE-sponsored window attachment market and user behavior study conducted by D&R International. Two very compelling results of this study are:

  • Inexpensive horizontal blinds are by far the most common window attachment (62% of installations).
  • While dependent on time of year and day, adjustable window attachments simply don’t get adjusted very much; they tend to stay up if they are up and stay down if they are down. 75%–84% of window coverings remain in the same position during the day, and 56%–71% of households don’t adjust coverings on a daily basis.

This study has big implications for energy savings:

  • Poorly performing, inexpensive horizontal blinds can be replaced for significant energy savings.
  • Assumptions made about user behavior of adjustable window attachments, or opportunities to improve energy savings by users more optimally adjusting their window attachments, can significantly affect the energy savings window coverings represent.

And while automation of window coverings was not a part of either study, it is easy to see that automation will have a big impact on energy savings of adjustable window coverings (and price, of course).

Has all this work on assessing window attachment performance really helped folks select the right window covering? Not yet, but that leads us to the latest development regarding efficient window coverings.

Certification and Rating of Attachments for Fenestration Technologies (CRAFT)

DOE has released a Funding Opportunity Announcement (FOA) for the development of CRAFT. From the FOA:

“The awardee will develop performance verification, and labeling standards for residential and commercial fenestration attachments. The successful applicant will also develop a Program to rate fenestration attachment energy performance and provide accurate and useful product comparison criteria, allowing end users in residential and commercial markets to assess the relative energy cost/benefits of fenestration attachments.”

As a part of this process, LBNL will continue its extensive modeling of window coverings to support CRAFT.

And at some point, we hope that just as the Efficient Windows website has become the main tool that the building community uses to select NFRC-rated windows, the Efficient Window Coverings website and selection tool will become the main way that building professionals select CRAFT-rated window coverings.

2014-02-15 n/a 18251 How We Chose Our Heat-Recovery Ventilator

Zehnder’s state-of-the-art HRV will provide years of service in providing fresh air with very low energy consumption.

Barry Stephens installing the condensate drain on our Zehnder ComfoAir 350 Luxe HRV. Click to enlarge.
Photo Credit: Alex Wilson

Balanced ventilation requires two fans: one bringing fresh air into the house and one exhausting indoor air (see 6 Ways to Ventilate Your Home). By balancing these two fans and the airflow through their respective ducts, the house is maintained at a neutral pressure—which is important for avoiding moisture problems or pulling in radon and other soil gases.

In a heat recovery ventilator (HRV) the two fans are in the same box, and they force air through a heat-exchanger core made of a corrugated plastic or aluminum. There are several types of heat exchanger cores in HRVs, and these effect efficiency and cost.

HRVs can have cross-flow heat exchangers or counter-flow heat exchangers. With cross-flow, the incoming and outgoing air streams are typically at 90° angles to each other. The heat transfer efficiency is good but not great: typically 50% to 70%.

With a counter-flow heat-exchange core, there is a longer pathway across which heat exchange occurs, so the efficiency is typically higher.

Zehnder's HRVs are larger than most, but that helps them achieve very low sound ratings and very high efficiency.
Photo Credit: Alex Wilson

Our Zehnder HRV

The HRV we installed in our new house is a Zehnder ComfoAir 350 Luxe. This is a Swiss-made, highly efficient HRV utilizing a counter-flow heat exchanger. In fact, testing by the Home Ventilating Institute (HVI) shows it to be the most energy-efficient HRV available. The American division, Zehnder America, is off to a rapid start, with about 800 installations in North America since its launch several years ago, according to Business Development and Technology Director Barry Stephens.

There are various ways to measure efficiency of HRVs. Apparent sensible effectiveness (ASEF) is the most commonly reported number for heat transfer efficiency. The HVI-listed ASEF of our Zehnder unit is 93%which is among the highest in the directory (though not quite the highest).

Another measure reported by HVI is the sensible recovery efficiency (SRE). This is a measure that corrects for waste heat from the fan motor that may be going into the incoming airstream, cross-flow leakage from the outgoing to the incoming airstream, and case leakage or heat transfer from the outside of the box to the airstream inside. These factors make it seem as if the heat transfer efficiency is higher than it really is; thus the SRE number is more accurate. With our Zehnder ComfoAir 350 the SRE is 88%—the highest that I found in the HVI Directory.

Zehnder's small-diameter ducting fits into 2x4 walls.
Photo Credit: Alex Wilson

In reviewing the HVI list of certified products, I found some other HRVs with higher ASEF values, such as a Broan-NuTone model with a listed ASEF of 95%, but that product had a SRE value of only 58%. With that product and most other HVI-listed models that have very high ASEF values, the SRE values are considerably lower, indicating that waste heat from high-wattage fan motors or other losses are boosting the ASEF values.

Another measure of efficiency is how much air is moved per unit of electricity consumed. Here we can look at the cubic feet per minute (cfm) of air flow per Watt of electricity consumption. With this metric, the Zehnder ComfoAir really shines, achieving a remarkable 2.58 to 3.25 cfm per Watt (depending on the fan speed). The Energy Star criteria for HRVs to be listed as EnergyStar is 1.0 cfm/W, and most good HRVs have air-delivery efficiencies only in the 1.0 to 1.5 cfm/W range. I was able to find only a few others with cfm/W values exceeding 2.0.

Zehnder ducting

Nearly as exciting as the superb energy performance of Zehnder HRVs is the ducting that is provided with them. The company produces ComfoTube ducting with a 3-inch outside diameter and 2.5” inside diameter. The outer surface is ribbed for strength and the inside smooth, for optimal airflow and quiet operation. The material is 100% high-density polyethylene, which is the most environmentally friendly plastic, in my opinion.

Ceiling-mounted exhaust port.
Photo Credit: Alex Wilson

The ducting diameter is small enough to fit in two-by-four interior walls. Because the airflow through the ducts is relatively low and sharp bends are eliminated, the airflow is very quiet. In fact, noise control is a key feature of all Zehnder products, and this is one reason the HRV itself is so quite large.

While some ducting systems for heating and ventilation are branched—with larger trunk ducts stepping down to smaller distribution ducts, Zehnder ComfoTube ducts are designed to be installed in a “home run” configuration—with a single, continuous duct extending from each supply and return diffuser all the way to the HRV. This feature also helps control noise, though it can make for a complicated spaghetti-like installation.

Three operation settings

Our HRV has three speeds, plus an extra-low “away” setting. Labeled 1, 2, and 3, the primary settings can be custom-set to deliver between 29 and 218 cubic feet per minute (cfm). As configured on our system, Setting 1 consumes 18-20 watts, Setting 2 consumes 30-35 watts, and Setting 3 consumes 80-85 watts. The Away setting uses just 7-10 watts.

Ceiling-mounted supply diffuser.
Photo Credit: Alex Wilson

There is a frost-protection cycle that goes on periodically in cold weather to prevent condensate from freezing in the heat exchanger core. This draws about 800 watts. The need for this can be greatly reduced by adding a ground-loop preheater. This circulates an antifreeze solution through a simple ground loop (tubing that can be buried along the house foundation during construction).


In my opinion, Zehnder makes the best HRVs and ERVs (energy-recovery ventilators) in the world. But you pay for that quality and performance. The system we have, a Zehnder ComfoAir 350 Luxe with ten supply ducts and ten return ducts, with their respective registers, and two remote controllers (for the upstairs and downstairs bathrooms) costs about $6,000. The geo-exchange loop, which we did not include, adds another $2,000.

While this is a lot to spend on ventilation, this integrated whole-house ventilation system obviates the need for separate bath fans, which can cost $300 to $600, installed, and some of that extra cost will be recovered over time through energy savings during operation, compared to standard HRVs.

Wall-mounted supply diffuser.
Photo Credit: Alex Wilson

The super-quiet, highly dependable operation is a nice bonus.

Next week I’ll talk about commissioning our HRV system.

*                        *                        *

By the way, Eli Gould (the designer-builder of our home) and I will be leading a half-day workshop at the NESEA Building Energy Conference in Boston on Tuesday, March 4, 2014. In this workshop, “What Would the Founder of Environmental Building News Do? Adventures on the Cutting Edge of Green Building,” we’ll be reviewing product and technology choices, describing lessons learned, presenting data on performance, and discussing, in a highly interactive format, some outcomes from this project that can be applied much more affordably in deep-energy retrofits. This should be informative and a lot of fun. Registration information can be found here.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-02-12 n/a 18231 6 Ways to Ventilate Your Home (and Which is Best)

How a green home really "breathes"

Should a green home require a piece of ventilation equipment like our Zehnder HRV?
Photo Credit: Alex Wilson

One of the features in our new house that I’m most excited about barely raises an eyebrow with some of our visitors: the ventilation system. I believe we have the highest-efficiency heat-recovery ventilator (HRV) on the market—or at least it’s right up there near the top.

But first, a lot of people may be wondering, should a "green" home require mechanical ventilation? A lot of people might think that this is just the kind of energy-consuming system that homes should be getting away from—while cracking windows for fresh air.

Why ventilate?

For centuries homes weren’t ventilated, and they did all right, didn’t they? Why do we need to go to all this effort (and often considerable expense) to ventilate houses today?

There are several reasons that ventilation is more important today than it was long ago. Most importantly, houses 100 years ago were really leaky. Usually they didn’t have insulation in the walls, so fresh air could pretty easily enter through all the gaps, cracks, and holes in the building envelope.

Also, the building materials used 100 years ago were mostly natural products that didn’t result in significant offgassing of volatile organic compounds (VOCs), formaldehyde, flame retardants, and other chemicals that are so prevalent in today’s building materials, furnishings, and other stuff.

Ventilation options

Ventilation can take many different forms. Very generally, systems can be categorized into about a half-dozen generic types:

  1. No ventilation. This is almost certainly the most common option in American homes. There is no mechanical system to remove stale indoor air (and moisture) or bring in fresh outside air. In the distant past, when buildings weren’t insulated, this strategy worked reasonably well—relying on the natural leakiness of the house. It’s worth noting, though, that even a leaky house doesn’t ensure good ventilation. For this strategy to work there has to be either a breeze outside or a significant difference in temperature between outdoor and indoors. Either of these conditions creates a pressure difference between indoors and out, driving that ventilation. On calm days in the spring and summer, there might be very little air exchange even in a really leaky house.
  2. Natural ventilation. In this uncommon strategy, specific design features are incorporated to bring in fresh air and get rid of stale air. One approach is to create a solar chimney in which air is heated by the sun, becomes more buoyant, and rises up and out through vents near the top of the building; this lowers the pressure in the house, which draws fresh air in through specially placed inlet ports. Many homeowners may think of opening windows as part of their ventilation strategy, but most people only open windows in the summer—if at all—and because of the pressure differential issue just mentioned, open windows don't guarantee good air exchange.
  3. Exhaust-only mechanical ventilation. This is a relatively common strategy in which small exhaust fans, usually in bathrooms, operate either continuously or intermittently to exhaust stale air and moisture generated in those rooms. This strategy creates a modest negative pressure in the house, and that pulls in fresh air either through cracks and other air-leakage sites or through strategically placed intentional make-up air inlets. An advantage of this strategy is simplicity and low cost. A disadvantage is that the negative pressure can pull in radon and other soil gases that we don’t want in houses.
  4. Supply-only mechanical ventilation. As the name implies, a fan brings in fresh air, and stale air escapes through cracks and air-leakage sites in the house. The air supply may be delivered to one location, dispersed through ducts, or supplied to the ducted distribution system of a forced-air heating system for dispersal. A supply-only ventilation system pressurizes a house, which can be a good thing in keeping radon and other contaminants from entering the house, but it risks forcing moisture-laden air into wall and ceiling cavities where condensation and moisture problems can occur.
  5. A ventilation system schematic from the Building Science Corporation fact sheet on balanced ventilation. Click to enlarge.
    Photo Credit: Building Science Corp.
    Balanced ventilation. Much better ventilation is provided through a balanced system in which separate fans drive both inlet and exhaust airflow. This allows us to control where the fresh air comes from, where that fresh air is delivered, and from where exhaust air is drawn. Balanced ventilation systems can be either point-source or ducted. With ducted systems, it makes sense to deliver fresh air to spaces that are most lived in (living room, bedrooms, etc.) and exhaust indoor air from places where moisture or pollutants are generated (bathrooms, kitchen, hobby room).
  6. Balanced ventilation with heat recovery. If there are separate fans to introduce fresh air and exhaust indoor air, it makes a lot of sense to locate these fans together and include an air-to-air heat exchanger so that the outgoing house air will precondition the incoming outdoor air. This air-to-air heat exchanger—more commonly referred to today as a heat-recovery ventilator or HRV—is the way to go in colder climates. A slightly different version, known as an energy-recovery ventilator (ERV), is similar but transfers moisture as well as heat from one airstream to the other, keeping more of the desirable humidity in the house in the winter and reducing the amount of humidity introduced from outdoors in the summer.

I’m a firm believer that all homes should have mechanical ventilation. With better-insulated, tighter homes that ventilation is all the more important. But even in a very leaky house, one can’t count on bringing in much fresh air or calm days in the spring and fall when there isn’t a pressure differential across the building envelope.

If budgets allow, going with balanced ventilation is strongly recommended, and if you’re doing that in a relatively cold climate, like ours, then providing heat recovery is a no-brainer. Mechanical ventilation always takes energy; with heat recovery the energy penalty of fresh air is minimized.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-02-05 n/a 18145 Cold Weather Tests the Limits of Our Mini-Split Heat Pump

Testing the limits of the air-source heat pump in our new house with this cold weather

The interior unit of our Mitubishi air-source heat pump. Click photos to enlarge.
Photo Credit: Alex Wilson

It’s been pretty chilly outside. A number of people have asked me how our air-source heat pump is making out in the cold weather. I wrote about ths system last fall, well before we had moved in to our new home. Is it keeping us warm?

First, if you want to get up to speed on the surprising and counterintuitive nature of how an air-source heat pump works, check out our primer on the topic—which includes a great diagram.

We’ve only been living in the house for a few weeks, but so far, so good. Our 18,000 Btu/hour Mitsubishi mini-split heat pump (MSZ FE18NA indoor unit and MUZ FE18 outdoor unit) is doing remarkably well in keeping us comfortable. We don’t have any oil or gas heating in the house, only the electric heat pump and a small wood stove that we’ve fired up twice so far.

The indoor heat pump unit is mounted on a wall next to our kitchen, and it’s been operating pretty steadily in this cold weather. (Even though we’ve heated with wood for decades and have all the wood we could ever use, I’ve been curious how the house will do just on electricity, so have refrained from using the wood stove.)

A thermometer in a bookcase on an outside wall diagonally across the kitchen-dining-living space from the heating unit is reading 66°F as I write this, with the outside temperature about 12°F. A thermometer in our upstairs bedroom read 70° when I got up this morning, and has typically been about 68°—and remarkably uniform.

Interior unit placement on a kitchen wall.
Photo Credit: Alex Wilson

When the mercury dropped to –6°F a few days ago, the house got colder. I saw one reading on the outside wall downstairs as low as 61°F and our bedroom got down to about 65°F. It was chilly enough that I fired up our small wood stove for the first time, and that fairly quickly raised the downstairs temperature to a comfortable 68°F. With our tight construction there are few drafts.

Monitoring our energy consumption

We have an eMonitor (made by PowerWise Systems of Blue Hill, Maine) installed to track the home’s overall electrical consumption as well as the consumption of a number of individual loads. The monitor has clips that clamp onto different circuits in the electrical panel as well as the electrical main coming into the panel, and it somehow measures electricity flow through those cables. We’re tracking consumption separately for our heat pump heating system, our heat-pump water heater, and our heat-recovery ventilator.

Most of the time the air-source heat pump has been drawing about 2,500 watts, with very brief spikes up to about 3,400 watts (I suppose those spikes occur when a pump or fan kicks on). To put this in perspective, the 2,500 watts in the standard heating mode is about twice what our KitchenAid toaster draws (1,200 watts), though of course the toaster operates for only short periods of time.

So far we haven't had to do any snow clearing from the outdoor unit, but in a heavy snow we likely will have to.
Photo Credit: Alex Wilson

Since we hooked up the eMonitor and started collecting data (five days ago), our Mitsubishi heat pump has used 221 kWh of electricity—during a fairly cold stretch. This is about what the entire solar-electric system on our barn cranked out during this period—and roughly three times the output of that portion of our PV system allocated to the house. (It’s a “group-net-metered” system, with two-thirds of the output going to neighboring homes.)

It will be interesting to look at this data over the course of months and years to see how the electricity consumption averages out over time and  how that compares to our solar production.

Heat distribution with point-source heating

Because our heat source is on a downstairs wall, I had been very curious how effectively heat would be distributed throughout our 1,600-square-foot house. The main kitchen-dining-living space keeps a fairly even temperature in the high-60s. A downstairs study or guest room at the far corner of the house and separated from the heat pump by a hallway and doors (with the door open) stays a little cooler, though watching a movie there last night was fine with a sweater.

Upstairs, the our bedroom on the north side of the house has maintained a remarkably constant 68-70°F on all but the coldest nights. When the outside temperature dipped to minus-6°F, our bedroom dropped to the mid-60s. Last night, with the outside temperature down to 7.5°F, we actually closed our door to keep the bedroom a bit cooler, and the temperature dropped from 70°F to 67.8 by morning.

The open stairwell does a great job at distributing heat upstairs. Our north bedroom stays 68-70°F.
Photo Credit: Alex Wilson

I don’t have a thermometer in the south bedroom, which is being used as a home office by my wife, but it feels about the same. There are two double-hung windows instead of a single casement window, so there is certainly more air leakage, but there is also solar gain through those windows.

Bottom line

All in all, we are very satisfied with the air-source heat pump. It works well, in large part, because our house is so energy efficient. This is a superb heating option (and cooling, by the way) for a house with a very well-insulated building envelope. Once we install the low-e storm windows on the double-hung windows on the south and east sides of the house, we should do somewhat better. (With our superinsulated house, the south and east windows are a weak point, both relative to air leakage and R-value.)

And on a cost per delivered Btu basis, with the air-source heat pump we’re spending just 58% of what we would spend on oil heat (assuming an Energy Star oil boiler operating at 83% efficiency with #2 heating oil at $3.91 per gallon vs. electric heat in an air-source heat pump with a coefficient of performance of 2.25 and electricity costing 15¢/kWh). (You can plug in your own assumptions and compare fuels on BuildingGreen’s online calculator.)

A summary of energy consumption in our house over the past week with this cold weather. The HRV had to work harder than it generally should due to moisture that got into it before we hooked up the condensate drain. Click to enlarge.
Photo Credit: eMonitor data from Alex Wilson

Plus, on an annual basis we should be producing as much electricity with solar as we consume—net-zero-energy. So we’re pretty happy. Warm and happy.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2014-01-29 n/a 18043 7 Green Building Wishes for 2014

Here are some green product developments I’d like to see in the New Year

A plug-in hybrid vehicle charged using a net-metered PV array at the Philadelphia Navy Yard. I want to see the market share of plug-in vehicles double next year. Click to enlarge.
Photo Credit: Alex Wilson

I spend a lot of time writing about innovations in the building industry—the cool stuff that’s coming out all the time. But I also like to think about what’s needed: stuff that’s not (yet) on the market or performance levels not yet available.

1) Rigid insulation with no flame retardants and insignificant global warming potential

We've been highly critical of the brominated and chlorinated flame retardant chemicals added to nearly all foam-plastic rigid insulation today as well as the high-global-warming-potential blowing agents used in extruded polystyrene (see Can We Replace Foam Insulation?). I would love to see affordable alternatives. They could be new formulations of polystyrene or polyisocyanurate that doesn’t require flame retardants or inorganic materials that are inherently noncombustible (see our review of cool new products from Greenbuild for some advances). I’m intrigued by advanced ceramics and could imagine a foamed ceramic insulation being developed that meets these criteria.

2) A really good exterior insulation system for existing houses

We need to dramatically improve the energy performance of existing houses (see The Challenge of Existing Homes: Retrofitting for Dramatic Energy Savings), and one important strategy for doing that is to carry out “deep energy retrofits” by adding a thick layer of rigid insulation on the exterior and installing window surrounds to extend the window openings out to the new outer plane. The easier and cheaper we can make this addition the better, as long as we adequately provide for air leakage control, drying potential, and other aspects of building science. This calls for a really good system—perhaps some or all of it prefabricated.

Window surround used with our deep-energy retrofit in which exterior insulation was added to the wall. We need to develop simpler, less expensive options.
Photo Credit: Alex Wilson

3) Even better air-source heat pumps for cold climates

I’ve written frequently about the tremendous innovation we’ve seen in the world of air-source heat pumps, particularly the minisplit systems from such companies as Mitsubishi, Daikin, and Fujitsu. The Mitsubishi unit we recently installed kept our new house toasty with the temperature dipping to –5°F last week, and it should be fine down to –13°F. But I’d like to see operability down to –20. I’d also like to see affordable air-to-water heat pumps that can deliver high enough temperatures to be effective for baseboard hot water (hydronic) heating.

4) Affordable, durable LED lighting at 100 lumens per watt and a CRI of 90

There have been dramatic improvements in LED (light-emitting diode) lighting in the past few years, but we need more improvement if the market share of LEDs is to surpass that of incandescent and compact fluorescent lighting. I’d like to see LED lights delivering 100 lumens of light per watt of electricity consumption while producing light quality comparable to that of incandescent light bulbs (color rendering index or CRI of 90 or higher), with heat management technology good enough that manufacturers can provide a five-year warranty—and all this at an unsubsidized retail price of $5 or less. I think all that will be doable soon.

5) Affordable options for delivering emergency power from solar-electric systems

2013 saw the introduction of the first inverter for grid-connected solar-electric (PV) systems that allows electricity to be delivered during the daytime when the grid is down (the vast majority of grid-connected PV systems can’t do this—see Islandable Solar—PV For Power Outages). We installed one of these at our new place. But when a battery system is added to a grid-connected PV system so that electricity can be delivered to critical-load circuits, the cost usually goes up by $10,000 or more. I’d like to see the brightest engineers put their efforts into bringing the cost of this down to what would be spent for a good-quality, whole-house generator (about $5,000). Today’s batteries are expensive, so this goal will be a challenge, but I think there would be strong demand for such a system.

The new Cree Bulb in high-color-rendering True White. While relatively affordable through Home Depot, costs need to drop further if LEDs are to capture significant market share.
Photo Credit: Cree

6) Technology to deter birds and bats from wind turbines

I’m a huge fan of wind power, but I remain troubled by news of bird and bat fatalities (see Utility Fined for Eagle Deaths Linked to Wind Turbines). It should be possible to develop systems that somehow warn off birds and bats. Perhaps high-frequency sound could be generated—too high-pitched for our ears—but noisy to birds and bats who get close. High-frequency noise tends to attenuate quickly, so perhaps such acoustic systems wouldn’t affect nearby residents.

7) 100% growth in plug-in electric vehicles

I believe that plug-in electric and hybrid gas-electric vehicles are among the most important innovations the automotive industry ever. They offer the potential not only for renewable energy sources to power our vehicles, but also the potential to dramatically change our power grid—with those battery systems stabilizing the grid and helping utility companies better manage supply and demand. Toward this end, I’m hoping to see 100% growth in plug-in hybrid and all-electric vehicle sales in 2014. That sounds like a lot, but doubling a small number is not unreasonable.

I won’t get all of these wishes in 2014, but perhaps we’ll make significant progress on some of them. We’ll all be the better for it.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-12-26 n/a 18001 Flywheels: A Cleaner Way of Stabilizing Our Electricity Grid

Beacon Power pushing the envelope and creating a more resilient utility grid with large-scale flywheel power storage

Schematic of Beacon Power's Energy Smart 25 flywheel.
Photo Credit: Beacon Power

After I wrote last week about a company developing power grid electrical storage systems using lithium-ion battery technology, a reader alerted me to another, very different approach for storing electricity to make the utility grid more stable and resilient: flywheels.

We've written before about flywheel electrical storage for use in data centers to provide instantaneous back-up power that can last for a few minutes until back-up generators can be started up. But I had not been aware of utility-scale projects that were in operation.

How flywheel electricity storage works

The idea with a flywheel for power storage is that a small amount of electricity is used to keep a heavy mass rotating at a very high speed—10,000 revolutions per minute (rpm) or faster. Then when power interruptions happen or some extra power is needed to stabilize the grid, that flywheel gradually slows down, generating power in the process. It essentially stores energy in a kinetic form until needed.

People like me who read Popular Science have been hearing about the potential of flywheel energy storage for decades; for me, it has been one of those technologies that has been perpetually “just a few years away" from commercialization.

Beacon Power leading the way with flywheel storage

Flywheels arriving by truck at the construction site.
Photo Credit: Beacon Power

The energy storage company Beacon Power, located in Tyngsboro, Massachusetts (north of Boston), has been a technology leader with utility-scale flywheel power storage since its founding in 1997. In September 2013 the company put online the first 4 megawatts (MW) of a planned 20 MW flywheel energy storage facility in Hazle Township, Pennsylvania. The full system should be completed in the second quarter of 2014.

Beacon Power almost became another Solyndra story. In 2010, Beacon Power received a $43 million loan from the government, and then filed for bankruptcy in October 2011.

Beacon Power’s bankruptcy was, in part, the result of a change in federal regulations that delayed the requirement for grid operators to pay more for electricity from sources that could feed additional power into the grid very quickly—this affected Beacon Power’s cash flow. Fortunately, the private equity firm Rockland Capital stepped in and acquired Beacon Power and has now paid back most of the Department of Energy loan.

The company is back on its feet and moving full steam ahead.

Stabilizing the utility grid with flywheel storage

Schematic showing the layout of a 20 MW Beacon Power flywheel system.
Photo Credit: Beacon Power

The Pennsylvania flywheel energy storage facility can almost instantly (in less than one second) begin injecting significant amounts of electricity into the grid. This will help to stabilize the utility grid—the operation of which is a constant balancing act between supply and demand. Adding this capability—whether with a flywheel or a more conventional chemical battery—makes the grid less prone to blackouts and, thus, more resilient.

The flywheel system is modular, comprised of many of Beacon Power’s Smart Energy 25 flywheels, each of which can deliver up to 25 kilowatt-hours (kWh) of electricity. When delivering power at a capacity of 100 kW, full discharge takes about 15 minutes. When providing 150 kW (heavier power draw), full discharge occurs in 5 minutes with only 12.5 kWh delivered.

The flywheel itself, according to the Beacon Power website, has a rotating carbon-fiber composite rim, levitated on magnetic bearings so that it operates in a near-frictionless, vacuum-sealed environment. It rotates at 16,000 rpm and is designed for a 20-year life with 100,000 full-discharge cycles.

The Hazle Township 20 MW installation under construction.
Photo Credit: Forbes Magazine

According to Beacon Power, the company’s flywheel power storage system “corrects imbalances more than twice as efficiently as traditional generators while consuming no new fuel, producing no emissions, and using no hazardous materials or water.”

The power grid of the future

Beacon Power’s flywheel system is one example of a variety of new energy storage technologies that promise to make tomorrow’s electric grid quite different from what we have today. As a higher percentage of renewable energy sources, such as wind and solar, feed power into the grid, it will become more and more important to have systems like this that can store power when there is excess available and deliver that power when needed.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-12-11 n/a 17919 Is There a Place for Vacuum Insulation in our Buildings?

For insulating our buildings, vacuum insulation panels may not be cost-effective, but they will become common in other applications

Microtherm's vacuum insulation panel, with a microporous substrate covered with an impermeable aluminum skin. Click to enlarge.
Photo Credit: Microtherm

I’ve recently worked on revising the BuildingGreen Guide to Insulation Products and Practices (available as part of a webcast), so I’ve been steeped in all sort of insulation materials, including some oddball products. One of those is vacuum insulation—operating on the same principle as a Thermos bottle.

Vacuum insulation is a great idea—in theory. To understand why, it helps to know a bit about heat flow.

How a vacuum slows down heat transfer

There are three modes of heat transfer: conduction, convection, and radiation, and if we remove most of the air molecules from a space—as occurs when we draw a vacuum—we largely eliminate the first two of those heat transfer mechanisms.

Conduction is the flow of heat from molecule to molecule. It’s the reason a cast iron skillet handle heats up, but thermal conduction also occurs across a layer of air, as kinetic is transferred from one air molecule to the one next to it. If we remove most of those air molecules by creating a vacuum, there will far less conductive heat flow.

Convection is the transfer of heat by moving molecules from one place to another. Warm air rises, and these convection currents carry heat—for example, this is the primary means that heat is delivered to a room from baseboard convectors (often called radiators). In a vacuum there are far fewer air molecules so convection of heat nearly stops.

A sampling of vacuum insulation panels from Nanopore.
Photo Credit: Nanopore

Only radiant heat flow occurs to a significant extent in a vacuum, because radiation is not dependent on air molecules. That’s why low-emissivity surfaces are so important in vacuum panels. The Stanley Thermos bottle has a very shiny, low-emissivity (low-e), inner surface that helps to reduce radiant heat transfer; the same sort of low-e surface is included in various vacuum insulation panels.

The net result is that an inch-thick vacuum insulation panel can provide a center-of-panel insulating value of R-25 or even more—compared with R-6 to R-7 for standard rigid foam insulation.

The “hardness” of a vacuum

The key property of a vacuum is it’s pressure or how “hard” it is. We often measure that with Torr units. One Torr is exactly 1/760th of a standard atmosphere (1.3 x 10-3 atm), or approximately 1 mm of mercury. With a very hard vacuum, more of the air molecules are sucked out, resulting a greater negative pressure. The walls of a typical Stanley Thermos bottle contain a relatively hard vacuum of 10-6 Torr. With such a hard vacuum, that Thermos bottle can keep coffee hot all day. By comparison, the vacuum in a flat vacuum insulation panel is typically no more than 1/1000th as strong (10-3 Torr).

The harder the vacuum, the more difficult it is to maintain it. Thermos bottles are made with a cylindrical design for optimal strength. With flat panels, it’s very hard to achieve comparable strength and maintain such a hard vacuum—particularly at the edges.

Using vacuums to insulate more than our coffee

If vacuums work so well to keep our coffee hot all day, why not use them to insulate our houses? Vacuum insulation panels have been used to insulate some high-tech demonstration homes, such as entrants in the Solar Decathlon student design competition in recent years, but high cost makes them impractical for real buildings.

There’s also the problem that puncturing that vacuum insulation panel will significantly reduce it’s insulating performance. (I can imagine how bummed one would be after spending thousands to insulate a home with vacuum insulation panels and then hearing a hiss while hanging a painting!)

However, these vacuum insulation panels (sometimes called VIPs) could make a great deal of sense in certain value-added products like refrigerators, freezers, water heaters, and entry doors. Whirlpool actually used a VIP that Owens Corning produced for a while (the Aura panel) in a high-efficiency refrigerator in the mid-1990s, but then dropped both the refrigerator and the use of VIPs.

But I believe the benefits of R-25 or more in a one-inch-thick panel are significant enough—especially as we try to get more usable volume in refrigerators without growing the exterior dimensions—to warrant the embrace of vacuum insulation. These could also be a great solution for exterior doors that are notoriously poorly insulated—as I’ve written about in this blog.

There are at least a half-dozen manufacturers of vacuum insulation panels today. Most, including Microtherm and Nanopore, produce panels that have a rigid, porous substrate surrounded by an impermeable metal skin.

Dow Corning's new vacuum insulation panel is encased in mineral wool to protect it. The company looks to incorporate this product into commercial building facades.
Photo Credit: Dow Corning

A new VIP on the market

The latest VIP  to come along is made by Dow Corning (no relation to Owens Corning). This panel, not yet widely available, is one inch thick and has a center-of-panel insulating value of R-39 and a “unit R-value” (accounting for the edges) of R-30, according to the company.

The Dow Corning product has a core made of fumed silica cake, a remarkable “microporous” material that provides R-8 per inch even without a vacuum. This material allows a very high insulating value even with a softer vacuum. The core is reinforced with silicon carbide and polyester fibers for structural support, and it is encased in an inner layer of polyethylene and an outer layer of polyethylene, polyester, and aluminum. The panels are vacuum-sealed, and the edges are heat-sealed.

According to an Environmental Building News article, these Dow Corning panels should cost $10-12 per square foot. At that cost, I believe VIPs can be very practical for those appliance and exterior door applications noted above.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-11-13 n/a 17895 Mineral Wool Insulation Entering the Mainstream

Owens Corning’s entry into the mineral wool insulation market with the purchase of Thermafiber, promises a higher profile for this insulation material

Thermafiber's new UltraBatt mineral wool insulation is distributed nationally through Menards. Click to enlarge.
Photo Credit: Thermafiber

I recently reported that a new mineral wool insulation product from Roxul can be readily used in place of foam-plastic insulation materials like polystyrene in certain applications. As part of our ongoing research into how builders and designers can make better insulation choices (see our full webcast and report on the topic), I have new mineral wool developments to report.

First, a little background: mineral wool, variously referred to as rockwool, slagwool, and stone wool, was one of the first insulation materials to be widely produced commercially—starting back in 1871 in Germany.

Rockwool International, the world’s largest producer of mineral wool and the parent company of Canadian manufacturer Roxul, began production of the material in 1937. The U.S. company Thermafiber, one of the largest U.S. producers of the material and a company poised for rapid growth today, was founded in 1934.

Mineral wool is made by melting the raw material, which can be stone (such as basalt) or iron ore slag, at very high temperature, spinning it like cotton candy to produce very thin fibers, coating those fibers with a binder to hold them together, and forming it into the insulation batt or boardstock material to meet specific product needs.

Mineral wool lost most of its market share when less-expensive fiberglass insulation came along, but unique properties of the material have been fueling a comeback in recent years—and this year the world’s largest fiberglass insulation company, Owens Corning, purchased Thermafiber. With this development, I’m expecting to see a lot of attention paid to mineral wool in the coming years—led by a new product introduction last week.

Mineral wool's pluses

Mineral wool is highly fire resistant, which has long made it an insulation material of choice in many commercial buildings. It achieves its fire resistance without the use of any flame retardant chemicals, which are widely used in most foam-plastic insulation materials—and which I believe to be a huge downside of those products.

Mineral wool is a heavier and more dense insulation material that fiberglass, giving it better sound-control properties and more effectively restricting air movement through it. When produced in boardstock form, mineral wool can be rigid enough to work as insulative sheathing, like extruded polystyrene and polyisocyanurate.

Mineral wool can also contain very high recycled content by using iron ore slag (a waste product from steel manufacturing). Some mineral wool products on the market have over 90% recycled content—higher even than cellulose insulation, though it is made from pre-consumer rather than post-consumer recycled material.

The downside to mineral wool

There are three major downsides to mineral wool. One is that mineral fibers can break off and become airborne; when we breathe those fibers in they can cause health problems. In the past there was some concern that mineral wool and fiberglass fibers might be carcinogenic, like asbestos. While those concerns have largely been dismissed, the fibers are still respiratory irritants. Installers of mineral wool should always wear quality dust masks, and the material should be adequately covered with drywall or coatings that prevent fibers from entering the indoor air in a building.

The second downside is the binder used to glue the fibers together. Manufacturers use a phenol formaldehyde or a urea-extended phenol formaldehyde binder. Formaldehyde is a known human carcinogen, and if a lot of it escapes into the indoor air, that would clearly be a health concern. Fortunately, the processing drives off nearly all of the free formaldehyde in the material, so formaldehyde emissions from mineral wool have extremely low formaldehyde levels—in some cases as low as background formaldehyde levels.

Nonetheless, there is a perception problem with formaldehyde binders—if not a real problem—and manufacturers are working on alternatives—as has occurred with fiberglass insulation. I fully expect that within a few years one of the mineral wool manufacturers will announce a biobased binder that works with mineral wool and the industry will fairly quickly convert to such a binder.

The third downside to mineral wool is that it can be hard to work with. Mineral wool boardstock is more compressible than rigid foam-plastic insulation, so installing strapping over it may take special care. In the batt form, the insulation doesn’t compress as easily as fiberglass to squeeze into odd corners and around wires. That can make mineral wool harder to work with—but it should also prevent some of the worst installation problems that occur with fiberglass. (The effectiveness of all types of batt insulation depends to a very significant extent on the care taken during installation.)

UltraBatt is an unfaced mineral wool insulation that offers very good fire resistance and sound control.
Photo Credit: Thermafiber

Thermafiber’s new mineral wool batt insulation

The latest news with mineral wool is the introduction by Thermafiber (now an Owens Corning company) of UltraBatt, a flexible batt insulation product for 2x4 or 2x6 walls. This follows Roxul’s introduction of a widely distributed mineral wool batt insulation product, ComfortBatt, several years ago.

UltraBatt is a fairly dense batt (not compressible like fiberglass batts) that offers very good sound control as well as relatively high insulating values. The 3-1/2” batts for 2x4 walls provide R-15, and the 5-1/2” batts for 2x6 walls provide R-23—though, as with all cavity-fill insulation, that actual “whole-wall” R-value will be lower, due to thermal bridging through the studs.

UltraBatt is comprised of 70% post-industrial recycled content. As for pricing, the national distributor Menards showed the online price to be about $31 per 40 square feet in the 3-1/2” batts, or about $0.77 per square foot. This compares with unfaced CertainTeed fiberglass batts at about $23 for 88 square feet, or $0.26 per square foot. The installed cost of dense-pack cellulose, meanwhile, is typically $1-2 per square foot for a 2x4 wall, though the pricing of any contractor-installed insulation is very dependent on the project.

I have not seen test data on formaldehyde (or other) emissions from UltraBatt, but I was told by Owens Corning that testing is underway and findings will be reported in 2014. I suspect that, like Roxul’s ComfortBatt, the formaldehyde emissions will be very low.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-11-06 n/a 17827 Insulation Quiz: The No-Foam Challenge

How well do you know your insulation? Photo: BuildingGreen, Inc.A lot of people are questioning the widespread use of foam insulation. Are you familiar with their concerns, and the upsides and downsides of alternatives?

What are all the environmental and health challenges presented by foam insulation products? What about the healthier substitutes? Are they ready for prime time?

These are some of the questions tackled by our new report, and accompanying webcast and course, Choosing and Detailing Insulation for High-Performance Assemblies. Even as more designers and builders are thinking twice about using rigid and spray-applied foam insulation, the alternatives to these products are sometimes misunderstood.

Our pop quiz tests your knowledge of the application-specific challenges and opportunities of these materials. Score yourself, and then read our answers and explanations below.

1) Toxic flame retardants, high global warming potential, and high embodied energy are all environmental reasons we are concerned about rigid foam insulation products. But it has a lot going for it in terms of performance: high R-value per inch, high compressive strength, and it’s easy to install. Which of the following is a performance-based reason you might think twice about using rigid foam?

A) It’s susceptible to ant and termite nesting and tunneling, even if completely dry
B) At best, it’s only semi-vapor permeable, and can trap moisture
C) Foam is relatively flammable, even with flame retardants added
D) All of the above

2) Rigid mineral wool has become a top pick for designers and builders looking to avoid foam insulation. They have had to make some changes, though, and overcome obstacles to do that. Which of the following is NOT a downside to using rigid mineral wool?

A) It’s not quite as “rigid” as rigid foam insulation.
B) Particularly in versions with higher compressive strength, its R-value is lower than foam insulation, and boards are heavier.
C) It’s not cost-competitive to purchase
D) It’s harder to cut than foam.

3) Which of the following insulation products are air barrier materials?

A) Extruded polystyrene insulation (XPS)
B) Polyisocyanurate
C) Closed-cell spray-polyurethane foam
D) Cellular glas, i.e. Foamglas
E) Cellulose
F) Cellular foam, i.e. Airkrete
G) Rigid mineral wool
H) Spray-applied fiberglass
I) Expanded polystyrene insulation (EPS)
J) Open-cell spray-polyurethane foam
K) Radiant barrier sheets

4) You want to avoid use of foam insulation in a wall assembly, but a tight air barrier is important to you. Which of the following are valid options?

A) you're stuck with foam—any high-performing building today uses some foam as an air barrier
B) use sheathing that acts as an air barrier and tape the seams
C) use concrete-masonry units (CMUs), or cast-in-place concrete
D) use high-performance caulks or gaskets at key junctions such as at floorplates and penetrations
E) B and/or D
F) B and/or C and/or D

5) Expanded cork insulation is _______, but is _______.

A) made of recycled wine corks; very low in R-value
B) 100% cork including the binder; labor-intensive to install
C) 100% cork except for the binder; high in VOC emissions
D) made in the U.S.; relatively expensive 

6) Cellular glass, i.e. Foamglas, is _______, but is _______.

A) made in the U.S.; relatively expensive
B) completely impervious to moisture and insects; not very high in compressive strength
C) completely inert when cut or scored; extremely heavy
D) usable at very high temperatures; very low in R-value per inch

7) Rigid mineral wool insulation is _______, but is _______.

A) made with recycled content; much more expensive than foam
B) higher in R-value than foam; not always stocked at regional lumber yards
C) low in embodied energy; new to many contracting crews
D) flame-resistant without flame retardants; not as rigid as rigid foam 

8) Spray-polyurethane foam is _______, but is _______.

A) sometimes made of high percentages of soy oil; still partly synthetic
B) an air barrier; laced with chlorinated flame retardants
C) one of the best available choices for insulating uneven surfaces; often applied with high global-warming-potential blowing agents
D) relatively inexpensive; reported to be linked with building fires and unusual odors in faulty installations

9) Avoiding toxic chemicals and allergens is particularly important to you in your choice of insulation. If you’re extremely thorough in avoiding toxic chemicals, which insulation is the best choice?

A) cellulose
B) cellular glass
C) cementitious foam
D) low-density wood-fiber insulation
E) wool
F) spray-in-place fiberglass

10) The ability of a building envelope to dry out in both directions if it gets wet is important to your project. Which insulation material might you take special interest in using?

A) foil-faced polyisocyanurate
B) rigid perlite board
C) low-density wood fiber insulation
D) extruded polystyrene (XPS)
E) high-density spray polyurethane foam

Our answers—and why

Question 1—D, all of the above. Extruded polystyrene in particular is known in the carpenter ant community as a favorable texture to nest in, even in the absence of moisture, and even though they don't technically consume it as food. Most foam insulation products are Class II vapor retarders. And even with the addition of toxic flame retardants, some foam insulation can ignite and contribute to a fire relatively quickly.

Question 2—C) It’s not cost-competitive to purchase. Mineral wool may require a special order through your supplier, but it is often less expensive than XPS— something we were surprised to learn in our research, and that may indicate a trend as mineral wool becomes more popular and domestic production increases.

Question 3—A through D are air barrier barrier materials, E through I are not, and with J and K, it depends. Air barrier performance, R-value, vapor permeability, and other key environmental performance data for these and other insulation materials is in our report. Why do we say "it depends" for open-cell spray foam and radiant barrier sheets? With the latter, the material itself is usually an air barrier, but it's not meant for that purpose. Fastening without penetrations and extensive taping or other seam-sealing would be required. With open-cell foam, it simply varies by the type of product.

Question 4—E) B and/or D. This is a bit of a trick question, because C would qualify on the merit of cast-in-place concrete, but CMUs are porous to air except when accompanied by mastic or sealant.

Question 5—B) 100% cork including the binder; labor-intensive to install. Expanded cork is processed under heat and pressure that activates a natural binder. It is relatively difficult to cut and install, as regular readers of our blogs may recall.

Question 6—A) made in the U.S.; relatively expensive. With some of the more exotic foam alternatives being imported from Europe, it may be surprising to learn that Foamglas has been made in the U.S. (at two different factories) for decades. For the record, its R-value per inch is respectable, it is completely impervious to moisture and insects, but it does emit a touch of hydrogen sulfide gas when scratched.

Question 7—D) flame-resistant without flame retardants; not as rigid as rigid foam. The answer to this question highlights a key benefit of mineral wool insulation, but also a downside, that it is not quite as rigid as foam, which some builders whine about when it comes to installing cladding over it. They should get over it, and just add plenty of continuous exterior insulation, which requires furring no matter whether it's foam or mineral wool.

Question 8—C) one of the best available choices for insulating uneven surfaces; often applied with high-global-warming-potential blowing agents. We have to admit that when it comes to insulating uneven surfaces, such as a retrofit of a masonry wall, spray-polyurethane foam (SPF) is hard to beat. But keep in mind the climate impact. And for the record, soy is typically only a token ingredient, and SPF has been linked—though some would say demonized—in fires and incidents of odors and chemical sensitivity.

Question 9—C) cementitious foam. Better known as Airkrete, the only product we're aware of that is sold under this description, cementitious foam is the most inert, nontoxic insulation product we are aware of. Each of the other products—even cellulose and its borates and wool with its allergenic properties—has a chemical ingredient or process, about which there is some concern.

Question 10—C) low-density wood fiber insulation. Best-known in the U.S. as the imported Agepan, low-density wood fiber insulation is becoming popular in advanced building systems, such as Passive House projects, in part because of its high vapor permeability, which enables good drying potential—especially important for airtight assemblies.

Your answers and comments

Our quiz was meant to be a little "tricky" and it is even rumored that the author had the BuildingGreen special report, Insulation Choices: What You Need to Know About Performance, Cost, Health and Environmental Considerations, in hand and referred to it frequently while writing the questions (he also says it's not only useful but very affordable, especially when coupled with the insulation details and video discussion included in the accompanying four-part course).
How did you do? Comments, questions, quibbles? Post them below.
2013-10-31 n/a 17823 Formaldehyde-Based Foam Insulation Back from the Dead

Urea formaldehyde foam insulation (UFFI) has been out of the spotlight, but going into a lot of buildings—often being referred to as Amino Foam.

Amino Foam is a highly flowable foam that can fill CMU cavities from below—rising as much as 18 vertical feet. Click to enlarge.
Photo Credit: cfiFOAM

In working on major updates and expansions to Insulation Choices: What You Need to Know About Performance, Cost, Health and Environmental Considerations, we’ve had an opportunity to dig into some of the insulation products out there that you don't hear so much about. Some of what we’re found has been surprising.

Anyone remember urea formaldehyde foam insulation (UFFI)? Back in the late 1970s and early 1980s it was the ultimate bad guy of the insulation world. Installed in hundreds of thousands of homes in the U.S. and Canada following the 1973 Energy Crisis, UFFI was found to emit high levels of formaldehyde in some circumstances and shrink considerably, resulting in performance problems.

The Canadian government spent millions of dollars insulating 80,000 to 100,000 homes with this insulation, then spent many more millions uninstalling it when reports of problems emerged. Canada banned the product, as did the Consumer Products Safety Commission in 1982 in the U.S.—though the latter later reversed the ban a year later.

The industry largely disappeared. While there had been 39 manufacturers of UFFI in 1977 and upwards of 1,500 installers, that dropped to just a handful by the early-eighties. Most of us pretty much forgot about the product.

UFFI is still around

The UFFI industry shrank to just seven manufacturers by 1981, then two large producers, Borden and Ciba-Geigy, ceased production. But the remaining five companies have continued to produce UFFI, though under different names. Most of those companies have gone to significant effort to avoid any association with UFFI.

Among the five manufacturers of UFFI today, you will variously see the material referred to as “injection foam,” “amino foam,” “aminoplast foam,” “tri-polymer foam,” “dry-resin foam,” and various combinations thereof. The only reference you’re unlikely to see is “urea-formaldehyde,” and if you ask manufacturers what the stuff is most will go to great lengths to obfuscate their response.

Used for insulating concrete-block construction

The primary application for UFFI today is to insulate hollow concrete masonry units (CMUs) or concrete blocks—and I think it is a fairly good solution for such buildings. It can be also used as a retrofit insulation for wood-frame cavity walls, but there are better products for wood-frame construction.

What is it?

To really understand what UFFI is, one may need a degree in polymer chemistry. cfiFOAM, which is the most forthcoming of the manufacturers in production today, describes the material as being “part of the family of amine/furan resins consisting of phenol, urea and melamine, coupled with an aldehyde.” The company explains in a fact sheet that “amino resins are thermosetting materials produced by reacting amine groups (NH3) with an aldehyde, such as formaldehyde.”

The reaction results in a blend of three different polymers, monomethylol, dimethylol, and trimethylol-substituted urea, which leads one manufacturer, C.P. Chemical, to refer to its insulation as TriPolymer Foam. This resin is further reacted with an acid catalyst in a condensation process, and the resultant resin is dried (sometimes in a kiln) to produce a powdered, dry resin that can be stored and easily shipped.

Insulation contractors use specialized equipment to mix the powdered resin with water, surfactant, and catalyst to create the injectable foam. By carefully controlling the mix of these different components, the release of free formaldehyde—one of the main problems in the past—is greatly reduced.

Phosphoric acid is often used in this process, and that chemical imparts some fairly good fire retardant properties. To the best of my knowledge, there are no halogenated flame retardants used in any of the amino foams—which is a significant benefit of the material.

Consistency of shaving cream

Amino foams are fully expanded at the time of installation—unlike polyurethane foams, which expand as they are sprayed into a cavity or onto a surface.

The foams are very flowable, and, according to Bob Sullivan of cfiFOAM, can fill vertically as much as 18 feet, though he cautions that rapid setting can be problematic with rises above 12 feet. The flowability allows the insulation to fill concrete cores very effectively, including around hardened mortar protruding into the cores.

Misleading information on performance

Along with confusing information about what the amino foams are—and their history as UFFI—some manufacturers have grossly misleading claims about performance. The material insulates to about R-4.6 per inch, which is quite good. You may see claims of performance as high as R-5.1 per inch, but if you read the fine print, you’ll find that the higher performance claim assumes measurement at 25°F instead of the more standard 75°F.

More significantly, you may see exaggerated claims about the resulting R-value of CMU walls insulated with amino foam. Tailored Chemical Products, the manufacturer of Core-Fill 500, continues to claim exaggerated R-values above R-14 for 8-inch CMU walls insulated with the company’s UFFI insulation.

In reality, the R-value of an 8-inch CMU wall insulated with amino foam is highly dependent of the density of the concrete. With very low-density blocks—85 pounds per cubic foot (pcf)—two-core, blocks insulated with this insulation provide a whole-wall R-value of 11.3. With heavier (more dense) concrete blocks the R-values drop. With medium-density blocks (105 pcf) the whole-wall insulating value drops to R-8.2, and with high-density block (125 pcf), the whole-wall R-value drops to R-6.0. The dramatic difference between the R-value of the foam insulation alone and insulated concrete blocks results from thermal bridging through the concrete webs in the blocks.

Formaldehyde offgassing

The major problem that led to the near destruction of the UFFI industry was the fact that the material can offgas formaldehyde. Back in 1982, when the Consumer Products Safety Commission temporarily banned the material, formaldehyde was considered a “probable human carcinogen,” but the hazard warning has been upgraded to “known carcinogen.”

Formaldehyde offgassing continues to be a concern with amino foams, but improvements in the chemistry by all of the manufacturers has significantly reduced offgassing. Amino foam insulation cannot be used in a buildings going through Living Building Challenge certification (because formaldehyde is a “red list” chemical that is banned in such buildings), but for a typical CMU building, the formaldehyde issue is not nearly as significant as it once was.

Shrinkage of foam

More significant than formaldehyde offgassing, I believe, is shrinkage that can occur with amino foams. Typical shrinkage after installation is 0.5%, but in some cases shrinkage can be as much as 2%, or even 4% according to some sources. According to cfiFOAM, the impact of shrinkage is accounted for in the reported whole-wall R-values by at least that company, but it’s still a big concern.

Bottom line

UFFI (a.k.a. injection-installed amino foam) has some quite attractive features, and I believe these to be a fairly good option for concrete masonry construction. Very significantly, it is the only foam-plastic insulation that does not contain halogenated flame retardants. Were it not for the shrinkage and the lack of clear information and transparency by most of the amino foam industry, I would feel even better about it.

To see our complete listing of UFFI manufacturers, along with similar evaluations of dozens of other insulation types, see Insulation Choices: What You Need to Know About Performance, Cost, Health and Environmental Considerations.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-10-30 n/a 17812 Electric Heat Comes of Age: Installing Our Mini-Split Heat Pump

Installing a Mitsubishi air-source heat pump in our new house

The indoor unit of our Mitsubishi minisplit heat pump. Click to enlarge.
Photo Credit: Alex Wilson

Thirty-five years ago, when I first got involved with energy efficiency and renewable energy, the mere suggestion that one might heat with electricity would be scoffed at by those of us seeking alternatives to fossil fuels.

Amory Lovins, founder of the Rocky Mountain Institute, likened using electricity for heating to “cutting butter with a chainsaw.” Electricity is a high-grade form of energy; it doesn’t make sense to use it for a low-grade need like heating, he argued. It made much more sense, we all agreed, to produce that 75-degree warmth with solar collectors or passive-solar design.

So, it represents a bit shift that I’m now arguing that electricity can be the smartest way to heat a house. And that’s what we’re doing in the farmhouse we’re rebuilding in southern Vermont. I should note, here, that all of our electricity is being supplied by a solar array on our barn.

Heat pumps

Technicians from ARC Mechanical installing the outdoor unit.
Photo Credit: Alex Wilson

Heating with electricity makes sense if instead of using that electricity directly to produce heat—through electric-resistance strip heaters—we use a device called a heat pump. For every one unit of energy consumed (as electricity), two to three units of energy (as heat) are delivered. This makes heat pumps significantly less expensive to operate than oil or propane heating systems in terms of dollars per delivered unit of heat.

Heat pumps use electricity in a seemingly magic way, to move heat from one place to another and upgrade the temperature of that heat in the process. Heat pumps seem like magic because they can extract heat from a place that’s cold—like Vermont’s outdoor air in January, or underground—and deliver it to a place that’s a lot warmer.

Very significantly, heat pumps can be switched from heating mode to cooling mode with a flip of a switch. In the cooling mode, they work just like standard air conditioners.

Ground-source heat pumps (often mistakenly referred to as geothermal heat pumps) rely on the ground (or groundwater) as the heat source in the heating mode (and heat sink for cooling), while air-source heat pumps use the outside air as the heat source and heat sink. Because temperatures underground are much warmer than the outside air in winter, the efficiency of ground-source heat pumps is typically higher than that of air-source heat pumps.

But the ground-source heat pumps are really expensive. Friends in southern Vermont have spent $35,000—or even more—to install residential-sized ground-source heat pumps. The cost is so high because of trenching or drilling wells.

The outdoor unit is secured to granite blocks.
Photo Credit: Alex Wilson

By contrast, air-source heat pumps are much simpler and far less expensive. The most common types today—and what we installed at Leonard Farm—are referred to as ductless minisplit heat pumps (see Ductless Mini-Splits and Their Kin: The Revolution in Variable-Refrigerant-Flow Air Conditioning). There is an outdoor compressor (a box about three feet on a side and a foot deep), an indoor unit (evaporator with blower) that mounts on an interior wall, and copper tubing that carries refrigerant between the two.

The typical installed cost of a ductless minisplit is $3,000 to $5,000, though many variables affect the cost.

These air-source heat pumps are viable today, even in cold climates, because of dramatic improvements in the past few decades. Much of this innovation has been driven by Japanese companies, including Mitsubishi, Daikin, Fujitsu, and Sanyo (now part of Panasonic). Several decades ago, air-source heat pumps only made sense in climates that rarely dropped below 30°F in the winter; today some of these systems, including ours, will function well at temperatures below zero degrees F.

Point-source heating and cooling

Ductless minisplit heat pumps are ideally suited for compact, highly energy efficient homes. Our house has R-values greater than R-40 in the walls and R-50 in the roof, plus very tight construction with a heat-recovery ventilator for fresh air. In tight, superinsulated homes, a single space heater (point-source heating system) can work very well, because with all the insulation fairly uniform temperatures are maintained throughout the house.

Completed installation.
Photo Credit: Alex Wilson

With our 1,700 square-foot house, the two upstairs bedrooms may stay a little cooler than the downstairs, but we like a cooler bedroom. In a larger house or one that isn’t as well insulated, several ductless minisplit heat pumps or a ducted heat pump option might be required.

Our Mitsubishi heat pump

We installed a state-of-the-art Mitsubishi M-Series FE18NA heat pump that is rated at 21,600 Btu/hour for heating and 18,000 Btu/hour (1-1/2 tons) for cooling. Marc Rosenbaum, P.E. ran heat load calculations showing peak heating demand (assuming –5°F outside temperature) about 23,000 Btu/hour, assuming the air leakage we measured several months ago, before the house envelope was completed. If the air leakage ends up being cut in half from that measured level, the design heat load would drop to a little over 19,000 Btu/hour.

We think the FE18NA model will work fine for nearly all conditions, but we are also installing a small wood stove—the smallest model made by Jotül—for use on exceptionally cold nights.

The indoor unit of our heat pump is about 43” long by 13” tall by 9-3/8” deep and installed high on a wall extending in from the west wall of the house—next to an open stairway to the second floor; it is controlled with a hand-held remote. The outdoor unit, installed just off a screen porch on the west side of the house is 35” tall by 33” wide by 13” deep. It is under an overhang and held off the ground by granite blocking.


Indoor unit installed.
Photo Credit: Alex Wilson

ARC Mechanical from Keene, New Hampshire did a great job with installation, and the system has now been turned on. We won’t move in until December, but it’s nice to know we have heat.

See also Putting the Duct Back in Ductless Mini-Splits, and 7 Tips to Get More from Mini-Split Heat Pumps in Colder Climates.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-10-22 n/a 17809 Can A Pending Standard for LEDs Prevent Another Lighting Debacle?

LED light quality is still not very good, but a new California standard could change that, and prevent another CFL-style consumer rejection.

Cree's TW Series LED Bulb provides impressive 93 CRI light quality yet costs less than $20.
Photo Credit: Cree

LEDs provide some of the most efficacious lighting available today, with some products offering over 100 lumens per watt, or lpw—an incandescent bulb is a paltry 15 lpw. Unfortunately, as consumers know from compact fluorescent lamps (CFLs), which have never been fully embraced, energy efficiency can come at the cost of light quality. Unless something changes, LEDs could become the next CFL, offering energy efficiency at relatively affordable prices, but with poor color and durability and limited dimming ability.

In this month’s Environmental Building News, we look at two products, Soraa’s MR16s and Cree’s TW Series LED Bulb, that offer innovative LEDs with demonstrably superior light quality to standard products (see Soraa: New LED Technology With Improved Color Quality). These lamps, however, are an anomaly in an LED industry where light quality plays second fiddle to efficacy.

Current standards

There are now thousands of LED products available, and the number is growing by the day, as computer chip makers and other manufacturers—many with no previous lighting background—enter the LED market. Most of these LEDs have a color rendering index (CRI) of about 80: the standard set by the U.S. Department of Energy (DOE) and Energy Star for CFLs, and also the standard used for rebate programs involving LEDs. (Color rending index uses a scale from 0–100, with 95–100 similar to natural light or incandescents.)

Why 80 CRI?

The origin of the 80 CRI standard traces back to when fluorescents were first adopted for office use, according to Michael Simnovitch, energy efficiency director at the California Lighting Technology Center.

 “80 CRI is just enough color to see white, and the minimum color that is acceptable in an office space,” he told me. Yet that same standard was then applied to CFLs used in people’s homes. Eventually, “Forces were set up to drive down the cost of fluorescent technologies,” claimed Simnovitch, “and at low price points, there is not much you can do to promote color quality and longevity.”

As a result, CFLs’ green glow, flicker, and other quality problems caused a backlash that the lighting industry is still trying to manage.

“Race to the bottom”

California has invested heavily in marketing these CFLs, but this effort has resulted in less than 20% adoption, according to Simnovitch, and light quality is largely to blame. To keep history from repeating itself, some industry experts are starting to demand higher-quality light from LEDs.

“Everyone is saying that 80 CRI is OK,” said Jim Benya of Benya Lighting Design. “It isn’t. It is a very distorted light source.” He stated, “We have to get away from this race to the bottom.”

In high-end retail spaces, where sales of consumer goods require quality lighting, retailers have already shifted over to 90–95 CRI LEDs, or are still using inefficient 95–100 CRI halogen lamps. Yet people question whether the difference between 80 and 90 CRI in LED is noticeable to the consumer in the home and is worth the added cost and energy penalty.

Simnovitch responds that the real issue is whether consumers notice the difference between the 100 CRI that they are used to in an incandescent lamp and an 80 CRI LED that doesn’t have a full color spectrum; people definitely notice that difference.

Soraa's Vivid MR16 LEDs provide a full light spectrum at 95 CRI. Note parts of the visible spectrum are missing from other light sources particularly CFLs.
Photo Credit: Soraa

The California Energy Commission’s new standard

Concerns over light quality have prompted action, and in late December 2012, the California Energy Commission (CEC) agreed on the Voluntary Quality Light Emitting Diode Specification for residential LED lamps. The CEC standard will be used to determine rebate eligibility for LEDs in California and includes tougher light quality standards of 90 CRI, a 4-step MacAdam ellipse for color consistency, noise- and flicker-free dimming from 10%–100%, and a minimum 5-year warranty.

The CEC is giving the LED industry through 2013 to catch up, but in 2014 the state’s rebate program will be tied to these tighter standards.


The CEC’s action is not taken lightly. There are reasons the DOE and Energy Star chose 80 CRI as a standard: it saves energy, and bumping the standard to 90 CRI will result in less efficacious lighting (LEDs lose 2 lpw for every 1-point increase in CRI above 80).

Benya argues that the tradeoff in efficacy is worth it. “We are simply going to have to give up some efficacy to gain light quality,” he said. “Until we start having this discussion, we are going to be making crappier and crappier LEDs.” And Simnovitch agrees, adding, “Our world is still at 15 lpw, so even if we move to 30 lpw [with wider adoption] it would be the largest energy saving leap in history.”  

Fortunately, the efficacy of high-CRI products is improving, and the cost is even coming down. Cree is now offering 93-CRI lamps that meet the new CEC standard, providing 13.5-watt (60-watt equivalent, 800 lumen, 59 lpw) and 8.5-watt (40-watt equivalent, 450 lumen, 53 lpw) light for less than $20, and less than $10 in some areas with rebates. These lamps are not as efficacious or inexpensive as the company’s 80 CRI versions, at 84 and 75 lpw for their $10, 9.5- and 6-watt products, respectively, but 59 lpw is still impressive.

This balance between cost, performance, and market conditions is not an easy one, however, and not all manufacturers are capable of engineering a high-performing bulb at a reasonable cost. Even Philips has succumbed to pricing pressures, quietly ceasing production of its L-prize winning, 92 CRI, 100 lpw LED lamp—the darling of the industry for a year or two and a BuildingGreen Top-10 award winner—replacing it with a less expensive 80 CRI version.

A bright but tenuous future

LEDs are at a crossroads. They are the future of lighting, consumers are starting to notice them on store shelves, and they are affordable to more than just early adopters, but are manufacturers going to continue to bet that 80 CRI is “good enough”? And will consumers care? California placed these same bets on CFLs years ago and lost. Will the new CEC standard change the odds for LEDs?


2013-10-16 n/a 17808 Our Deck Is Made from Pallets—But It's Not What You Think

Viridian tropical hardwood decking is reclaimed from shipping materials—and it should last decades

Installing Viridian decking on our front porch. Click to enlarge.
Photo Credit: Alex Wilson

We’re moving along with some of the wrap-up work on our house in Dummerston. One of those projects is installing the porch decking on both the front and rear porches and a handicapped ramp up from the garage to the back porch. (We plan to live there for a long time!)

For the decking, we used a product we recognized in our annual Top-10 Green Building Product selection last year.

The Viridian story

Viridian Wood Products produces tropical hardwood flooring, decking, paneling, and countertop material derived from salvaged wood sources, including tropical hardwoods. I have long been a firm believer that one should only use wood from tropical rainforests that comes from well-managed forests—and certified to Forest Stewardship Council (FSC) standards—or that is salvaged from other uses and diverted from the waste stream.

Back in 2004, Joe Mitchoff and Pierce Henley of Portland, Oregon, noticed that a lot of wood used for shipping manufactured goods—especially heavy iron and steel—was being landfilled at the Port of Portland. As many as thirty 30-yard roll-off dumpsters per ship of mostly four-by-fours were going to the landfill, and they recognized that this was amazingly beautiful tropical hardwood.

As many as thirty 30-yard dumpsters of wood waste are generated from each ship bringing iron and steel from the Far East.
Photo Credit: Viridian Wood Products

Mitchoff and Henley made arrangements with the Port to divert that waste—saving the Port disposal costs—and they figured out how to process the wood cost-effectively, milling it into a high-end flooring and countertop material, while recycling the comingled waste.

While I referred to this material earlier as "pallets," it's important to note that most or all of the material used by Viridian is blocking or "cribbing" used to stablize shipped goods. There is a lot of wood waste in pallets, more narrowly defined as the flat shipping structures often used by forklifts, but they are riddled with ring-shank nails and are far less cost-effective to reciaim. 

The wood waste is first heat-treated to kill any invasive insects that may be living in it (shipping materials have been one of the main routes of entry for invasive insects getting into the United States), then scanned for metal fasteners, kiln-dried, and milled into standard dimensions for the various markets they serve.

With the high volume of production and a 40,000 square-foot warehouse next to the Port, Viridian Wood Products has been able to achieve a dependable supply, which is critically important for nationwide marketing of salvaged wood products. The company has even expanded into other reclaimed wood sources—such as Douglas fir salvaged from high school bleachers, Douglas fir from structures in the Pacific Northwest, a rustic oak salvaged from truck decks, and old-growth redwood salvaged from wine casks.

Dumping tropical hardwood shipping material at the Viridian warehouse.
Photo Credit: Viridian Wood Products

Jakarta Market Blend

Because Viridian’s tropical woods are reclaimed rather than being cut from forests, the species vary widely and typically aren’t even known. We ordered a mix of wood known as Jakarta Market Blend – Dark Sort that is comprised of probably at least a dozen actual species. Some are very dark, almost black; others are a deep red; some have beautiful figured grain. The weight also varies greatly, with some having specific gravity that is significantly greater than that of water—in other words, this is wood that won't even float.

The great density of these tropical hardwoods also results in tremendous hardness and wear properties. With flooring, hardness is typically measured using the Janca Scale. The Jakarta Market Blend – Dark Sort flooring we got has a hardness ranging from 1100 to 3500, which makes it suitable for high-traffic commercial applications. By comparison, eastern white pine has a hardness of 380, hemlock 500, Douglas fir 660, cherry 995, teak 1155, red oak 1290, and sugar maple 1450.

As we were selecting from the batch of wood received from Viridian, I chose the heavier pieces for the porch flooring—so I suspect most pieces have a hardness well over 2000. The dimensions of the decking are 2-1/2” x 5/8” with random lengths up to 6-1/2’.

Installing decking on what will be our screen porch on the back of the house.
Photo Credit: Alex Wilson

FSC certification

All Viridian reclaimed wood is certified according to FSC standards. FSC has standards both for virgin wood (relating to forest management practices) and for salvaged wood. All Viridian product carries chain-of-custody certification according to FSC’s 100% Post Consumer Reclaimed standard. The chain-of-custody certification number for Viridian Reclaimed Wood is SW-COC-001962.


While the wood will gray over time, I wanted to treat it with an oil finish that would bring out and retain for at least a while the gorgeous colors in the wood, but I also wanted to use a natural finish that was environmentally responsible. I chose a product called Heritage Natural Finish. I found out about this oil finish at the Timber Framers Guild of North America Annual Meeting this summer, where I was giving a presentation on our house.

Heritage finish (which used to be called Land Ark Natural Wood Finish) is made from naturally processed linseed oil, tung oil, beeswax, pure citrus solvent, and pine rosin. Unlike some oil finishes, there are no heavy metal drying agents or petroleum products. We used Heritage’s Exterior Finish, which include a UV inhibitor and a mildewcide to inhibit mold staining. (The Original Finish does not include the mildewcide.)

Decking detail on our front porch.
Photo Credit: Alex Wilson


Don’t even think about installing Viridian Jakarta Market Blend flooring without pre-drilling. Eli Gould’s crew started out drilling as they might for standard decking—with slightly undersized holes, but they were breaking off the stainless steel decking screws right and left! This stuff is hard!

We installed ours on framing made of TimberSIL, a totally nontoxic pressure-treated lumber. With TimberSIL, sodium silicate is infused into the wood under pressure, and the wood his then heated in a kiln, which melts the sodium silicate into an amorphous glass. This glass surrounds the wood cells, protecting it from decay and insects and well as imparting fire-resistance.  


Viridian is a premium product that sells for a premium price. Pricing is somewhat higher than that of redwood decking and significantly more expensive than pressure-treated (PT) decking. But it should hold up as well as Ipé, which is typically more expensive. The price of the Jakarta Market Blend is $6.95 per square foot, though shipping will add to the price. According to Joe Mitchoff, one of the advantages of having a constant supply of salvaged wood is the ability to keep pricing fairly constant.

Pre-drilling with holes the full diameter of the screws is necessary for installing the densest of the Viridian Jakarta Market Blend decking.
Photo Credit: Alex Wilson

The TimberSIL framing we used is also more expensive than standard PT framing, but we think it will last a lot longer, helping us (and our children and grandchildren) achieve the long life that we are seeking with the house.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-10-15 n/a 17786 New Home Proves LEDs Are Ready to Supplant Older Lighting

LED lighting has come a long way in a very few years and can now fully supplant incandescent and fluorescent technology

Cree's new CR6 LED downlight for recessed cans.
Photo Credit: Cree

Our electrician was in last week installing lighting in our new home here in southern Vermont. Virtually all of our lighting will be LEDs—the state-of-the-art today in energy-efficient lighting.

LED stands for “light-emitting diode.” It’s a solid-state lighting technology that converts electric current directly into visible light. LED lighting has far higher efficacy (the number of lumens of light output per watt of electricity consumed) than incandescent lighting—which converts roughly 90% of the electric current into heat; only 10% into light.

Most LED lights also have modestly higher efficacy than compact fluorescent lamps (CFLs). The recessed LED lights we installed have an efficacy of 66 lumens per watt, which is not to different from that of CFLs, but LEDs are much more directional than CFLs, so they work better in recessed cans in delivering usable light to where you need it.

A CR6 installed in our access ceiling.
Photo Credit: Alex Wilson

Very significantly, LEDs are also better for the environment and human health than fluorescent lamps. With fluorescent lamps (both linear and compact), an arc of electricity passes through mercury vapor, which produces ultraviolet (UV) light; that UV is then turned into white light using a phosphor coating on the inside of the fluorescent tube.

Any time a fluorescent lamp breaks a small amount of elemental mercury escapes into the building; the mercury also gets into the waste stream when the lamps aren't properly recycled. While the elemental form of mercury is far less dangerous than compounds in which the mercury is bonded to carbon-based organic compounds, there is still risk.

Mercury is also needed in the metal halide and high-pressure sodium lamps that are common on highways and parking lots.

The other advantage of LED lights is the expected life—typically 25,000 to 50,000 hours, which is far longer than the 1,000 to 3,000-hour life of incandescent light bulbs and somewhat longer than most CFLs and linear fluorescents (10,000 hours for the former, 15,000 hours for the latter). I won’t quite believe the long-life claims for a few years, though; I’ve installed a number of early LED lights that failed prematurely after less than a year.

Recessed can in our access ceiling.
Photo Credit: Alex Wilson

Cree at the leading edge

There are lots of LED lights on the market—and more appearing all the time. The products we installed are made by an American company, Cree, which is based in North Carolina and continues to be one of the world’s top innovators with LED technology.

I first became familiar with Cree in 2007 when we recognized a breakthrough downlight product from LED Lighting Fixtures (LLF), as one of our Top-10 Green Building Products of the year. LLF incorporated LEDs made by Cree into their downlights, which set the bar for light quality from LEDs, and really established LED technology as a viable high-quality light source.

Shortly after that, Cree acquired LLF and entered the light fixture business—in addition to being a supplier of LEDs to fixture manufacturers.

Ongoing product innovation and a key company acquisition in 2011 of Rudd Lighting and their subsidiary company BetaLED, which has been the technology leader with outdoor LED lighting, has kept Cree at the front of the pack in the LED world.

The actual LEDs used in Cree lights are made in the U.S., though most if not all of the company’s fixtures are now produced elsewhere—no doubt to reduce costs and stay competitive.

Cree SL40 linear LED troffer in our basement.
Photo Credit: Alex Wilson

Downlights, surface lights, and light bulbs

We will have three types of Cree LED lights in our house: CR6 downlights installed in recessed cans in our ceilings; SL40 linear LED lighting fixtures for our garage and basement; and the new LED light bulbs that were introduced this year. The latter will be installed in light fixtures that can accept incandescent light bulbs, and those have not been installed yet.

But the downlights and surface-mount fixtures are in place and working beautifully.

The CR6 downlights are designed as retrofit lamps for six-inch recessed cans with Edison sockets that accept standard screw-base incandescent (including halogen) lamps. Cree also makes a version for the GU24 base, which is required for Title 24 compliance in California (because that type of lamp can’t be swapped for a less-efficient incandescent light bulb).

The CR6 lamps we installed use 9.5 watts to produce 625 lumens, which works out to just under 66 lumens per watt (lpw), though the Cree literature lists the efficacy as 61 lpw. This lamp is available in different color-temperatures (see Shedding Light on Light Quality). We opted for warm-white light with a color temperature of 2700K (lamps with cooler, whiter light, at 3000K, 3500K, and 4000K, are also available). In terms of light quality, the CR6 has an excellent color rending index (CEI) of 90. The light quality seems much like that of incandescent lighting that most people prefer in homes.

One of our SL40s with the light turned off.
Photo Credit: Alex Wilson

The Surface Linear, SL40, fixtures we installed function much like standard fluorescent fixtures that mount on a ceiling, but they’re more elegant and use LED technology. Ours are 40 inches long and consume 55 watts while producing 4,000 lumens (73 lpw). The light, with a color temperature of 3500K, is somewhat cooler than our CR6 recessed lights, but seems just fine for where we are using them. The light quality, with a CRI of 80, isn’t as high as that of the CR6, but it’s respectable—and comparable to most fluorescent lights.

This year, Cree has been making news with LED light bulbs designed to replace standard incandescent and screw-in CFLs. In March, 2013 the company introduced 60-watt and 40-watt equivalent bulbs (using 9.5 and 6.0 watts, respectively, for the warm-white version). Delivering 800 lumens using just 9.5 watts, this lamp has an amazing efficacy of 84 lpw. A cool-white version has an efficacy of 89 lpw.

While that lamp has a CRI of 80, just this month the company introduced a brand new TW (for True White) version with a remarkable CRI of 93. But in the soft-white (2700K) version, this lamp has an efficacy of only 59 lpw. To get the high light quality there is some sacrifice in efficacy.

Not only Cree

The most exciting thing about LED lighting today is that Cree isn’t the only innovator. There is intense competition by other companies, including Philips, who are driving the entire industry forward at a rapid pace. Light quality will keep improving while energy consumption will deep on dropping.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-10-02 n/a 17609 4 Insider Tips for Choosing Flashing Tapes, from a Real-Life Engineer

A research engineer at Pella Windows finally offers some adult supervision for our benchtop tape tests.

This post is part of a series on adhesives, sealants, tapes, and gaskets. Click here to view all the posts.

When the Wingnut Test Facility (WTF) took its tape testing protocols on the road, as I reported in my last post, a stranger stepped forward to politely offer some “adult supervision.”

It’s true that there aren’t any industry standards for testing tapes in dirty, wet, or cold conditions, says Jaron Vos, a research and field engineer for Pella Corp. That doesn’t mean manufacturers are ignoring the issue.

Welcome to the real world

According to Vos, in 2001 when Pella was developing its SmartFlash Tape, the company’s researchers focused on conditions they thought the tape would encounter during real use by real installers. They tried to replicate those conditions in the lab and got feedback from installers.

“It’s not that ASTM and similar test standards are not useful,” though, says Vos. “In fact, we used AAMA’s 711 extensively for measuring performance after trying to replicate jobsite or service life conditions.”

AAMA 711

AAMA 711, Voluntary Specification for Self-Adhering Flashing Used for Installation of Exterior Fenestration Products, is a pretty comprehensive set of minimum requirements for pressure-sensitive adhesive (PSA) tape performance.

Vos relates, “We tested a number of adhesives and backing options in an approach similar to AAMA 711 (although during initial Pella testing, AAMA 711 was not yet available). While it is difficult to say how many years of service life is simulated by any one of these tests, or how many other conditions we could try to simulate, we certainly spent some time and effort evaluating PSA tape materials.”

Below is a sampling of how Vos relates Pella testing to AAMA 711 (with Pella testing generally being more stringent than AAMA 711 conditions).

Pella’s four tips for flashing tapes

Vos shared several findings with us:

  • Kiss your asphalt goodbye. Vos: “We found that the asphalt tapes performed poorly in the extreme temperatures and reacted poorly with sealants.”
  • Acrylic can’t take the heat. “The acrylic tapes we tested were either too thin to self-heal or too thick and runny at high temperatures,” said Vos. NOTE: Vos did not test any of the high-end, solid acrylic tapes, such as Siga or Pro Clima tapes that we list in GreenSpec.
  • Watch your backing. “We also found that any tape with a mylar or polyethylene backing could not protect the adhesive from UV damage,” explains Vos. “Those materials also require a knife or scissors to cut and have varying amounts of ‘memory’ (they tend to pull the adhesive back from places you try to put it). Tapes that were too thick or have textured backing could create leak paths at their overlaps and unwanted material buildup. Tapes that were too thin couldn’t self-heal around fasteners.”
  • Rubber gets a bounce. This explains why the Pella SmartFlash tape ended up using a butyl rubber adhesive and aluminum foil backing: Pella asserts that its SmartFlash tape works well in both hot and cold, that its backing is UV resistant, and that the tape offers good sealing around tape penetrations. The tape is also designed to tear by hand, simplifying things on the jobsite and potentially reducing labor costs.

We still need better tests

It’s nice to have some additional perspective on this whole issue of PSA tape performance, but back at WTF’s underground laboratories, Dave and I have been cooking up two new tests: one that mimics the “bellowing” effect of wind pressure pushing in and out on the tapes and another that represents the shear that takes place across the tapes when they are stressed by movement of building components.

We’ll let you know as soon as we’ve made some progress on this more complex testing approach.

2013-09-11 n/a 17525 A Heat Pump Using Carbon Dioxide as the Refrigerant

A new generation of CO2-based heat pumps could avoid the high global warming potential of standard refrigerants and generate much higher temperatures

A Mayekawa Unimo air-to-water heat pump installation in Australia. Click to enlarge.
Photo Credit: Mayekawa

In researching and writing about building products for Environmental Building News over the past twenty-plus years I’ve had an opportunity to cover some fascinating breakthrough products and technologies. One such technology I was writing about a few weeks ago is the use of carbon dioxide as a working fluid for heat pumps

But let me back up with a little context about refrigerants. These are the fluids used in refrigerators, air conditioners, and heat pumps that transfer heat from one place to another in cooling or heating a space. This “vapor-compression-cycle” equipment takes advantage of the principle that compressing a gas absorbs heat and expanding it releases heat—so it’s a way to move heat from one place to another.

When this compression and expansion cycle results in a phase change (converting it from liquid to gas or vice-versa), significant heat can be absorbed and released.

Problems with refrigerants

Over the past 35 years, refrigerants have come under fire—both for their impact on the Earth’s protective ozone layer and for their global warming potential (GWP). HCFC-22 (R-22), a hydrochlorofluorocarbon, has long been the most common refrigerant. But it is being phased out according to the international treaty to protect the Earth’s protective ozone layer.

That’s a good thing, as R-22 is both a significant ozone depleter and a significant greenhouse gas. The HFC (hydrofluorocarbon) refrigerants that have replaced HCFC-22 are much better from an ozone-depletion standpoint (ozone depletion potential or ODP of 0), but they are still very significant greenhouse gases (high GWP).

An EcoCute water-to-water heat pump (next to the large tank) at the Somerston Winery in Napa Valley, California.
Photo Credit: Mayekawa

Using CO2 as a refrigerant

These concerns with HCFC and HFC refrigerants have led to interest in other chemicals that can be used as refrigerants, one of which is carbon dioxide (CO2). The Japanese have focused considerable attention on CO2-based heat pumps, and one Japanese company, Mayekawa, has been selling commercial-scale CO2-based heat pumps in North America for several years.

Mayekawa offers three different CO2 heat pumps, the EcoCute water-to-water heat pump, the Unimo air-to-water heat pump and the Sirocco water-to-air heat pump. (The product name, EcoCute, got a little bungled in translation from the Japanese. “Eco” is short for “ecological” in the U.S., while ”cute” is derived from a Japanese kyūtō, meaning “supply hot water.”) The term “EcoCute” is used generically by a number of Japanese manufacturers.  

All three of the Mayekawa heat pumps have 25 kilowatt (kW) motors, so they are considerably larger than the heat pumps used for homes.

High efficiency is an important benefit of such systems; they operate at a coefficient of performance (COP) of about 4.0. If they are configured to provide space cooling in addition to hot water (just the water-to-water and air-to-water models), the COP can be as high as 8.0.

Higher output temperatures

From a performance standpoint, the big difference with CO2-based heat pumps is that they can produce much higher-temperature output. Exactly why they can do this is complex and has to do with CO2 being a “transcritical” refrigerant and doesn’t fully change phase like other refrigerants—described in detail in the article on Mayekawa heat pumps that I wrote for the August issue of Environmental Building News.

Detail of the EcoCute heat pump at the Somerston Winery, showing a large buffer tank.
Photo Credit: Mayekawa

The EcoCute water-to-water heat pump and the Unimo air-to-water heat pump can produce water at up to 194°F—far hotter than that produced by standard heat pumps. This is significant, because it makes them viable for hydronic (baseboard hot-water) heating. As my friend and energy engineer Marc Rosenbaum, P.E. told me, if this can be done affordably, it will be a “game changer.”

One challenge with CO2-based heat pumps is that they need a fairly large lift temperature to operate. This is the difference in temperature in a heating loop between the supply and return temperature.

A standard gas- or oil-fired boiler may deliver 180°F water for hydronic heating, and return water in the heating loop at a temperature of 150°F after delivering it’s heat through baseboard radiators. So the boiler has to “lift” the water from 150°F to 180°F. That isn’t enough lift for a CO2-based heat pump. The EcoCute needs a minimum of about 45°F of lift to function effectively.

Higher pressure

The other challenge is that CO2 refrigerant cycles operate at far higher pressure than standard vapor-compression-cycle equipment. At the evaporator side the pressure can be about 600 pounds per square inch (psi), while in the gas cooler (which replaces the condenser in a standard compression-cycle device), the pressure can be 1,500 to 1,800 psi.

The higher pressure and the need for more robust (and more expensive) components to contain that pressure has slowed the development of CO2-based heat pumps.

An EcoCute installation in Quebec, Canada with multiple units.
Photo Credit: Mayekawa

The future of CO2-based heat pumps

I gather that several manufacturers of popular mini-split heat pumps are developing residential-scaled CO2-based heat pumps and that those heat pumps are currently undergoing testing.

It will be fascinating to see what emerges. What excites me is that such heat pumps increase the potential of providing more of our energy needs using electricity generated by sunlight as an alternative to burning fossil fuels. There are challenges, certainly, but such products could help us transition to a solar future.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-08-28 n/a 17501 What to Avoid in Interior Paints

Occupant health and performance are the key consideration when choosing an interior paint. Most people have heard of low-VOC paints, but there is a lot more to look for. And it’s easy to miss out on high-performing paints when low- or no-VOC is the main thing you’re looking for.

We have some editor's picks in this area, and we'll be offering more guidance like this in a members-only August 21st webcast.

First, check for emissions

First things first—paints that offgas a lot of VOCs are bad for installers and bad for occupants. Even after the air clears those compounds can adsorb onto fabrics and furniture in the interior and stick around.

There’s no perfect test right now for emissions from wet-applied products, so the best bet is to make sure it has both low VOC content (under 50 g/L), and has met California Section 01350 emissions requirements.

GreenSpec includes primarily paints that have both low VOC content (under 50 g/L or the lowest available in the category) and meet California Section 01350 or other more stringent emission protocols as verified through related certifications like MPI X-Green.

GreenSpec also lists products with a Pharos VOC score of 7 or above—demonstrating zero VOC content in the base paint, including “exempt” compounds. Exempt compounds are those that may be health hazards but aren’t typically counted in VOC content measures because they don’t contribute to smog. We consider it important to avoid these compounds.

Watch for added tints

Added tints, particularly darker colors, can be a major source of VOCs. A base paint that is marketed as low-VOC may not stay that way after being tinted. Keep your eye on this: even if the manufacturer has low-VOC tints in the product line, retailers may not be using them. GreenSpec typically only lists paints where the tints, as well as the base product, have low VOC content, or at the very least VOCs levels in tints are clearly disclosed so consumers can make informed choices.

Performance matters, too

If you have to turn around and redo that low-VOC paint after a couple years, it’s not very environmental, or low-VOC, is it? That’s why we pay a lot of attention to performance ratings. GreenSpec lists many MPI X-Green and Green Seal GS-11 certified paints—both certifications include performance requirements.

Editor's picks: Spec this, not that

So with all these things to look out for, what are our picks? Among some well-known brands, we recommend avoiding:

  • Sherwin-Williams Builders Solution: hasn’t been tested for performance
  • Dutch Boy Refresh: also hasn’t been tested for performance
  • Devoe Paint’s Regency paint and primer combo, which does not meet California Section 01350 criteria

These paints are among the favorite we list in GreenSpec, because they have low VOCs in both base and tints, offer excellent durability, and—in the case of Keim—are naturally resistant to fungi.

More guidance in our webcast

Looking for more of GreenSpec’s editors' picks? We’ll go into more detail with interior paints, as well as 10 other key product categories, in our August 21st webcast. Register now!

2013-08-12 n/a 17497 Beating the Achilles Heel of Grid-Tied Solar Electric Systems

A new inverter from SMA allows us to draw some daytime power from our PV system when the grid is down, even without batteries

The 18 kW PV array on our barn is a group-net-metered system with some of the output going to other houses. Click to enlarge.
Photo Credit: Alex Wilson

One of the biggest complaints I hear about most solar-electric (photovoltaic, PV) systems is that when the grid goes down you can’t use any of the power that’s produced. Consumers have spent thousands of dollars on a PV system, and during an extended power outage during a bright, sunny day when the PV modules are certainly generating electricity, they are disappointed that none of that electricity can be used.

This problem applies to net-metered PV systems that do not include battery back-up. Off-grid systems work just fine when the grid is down, but the vast majority of the roughly 300,000 PV systems in the U.S. are net-metered systems without batteries, and most of them lose all functionality when the grid is down.

Given my focus on resilient design (including my founding of the Resilient Design Institute last year), I wanted to install a solar-electric system at Leonard Farm that would have at least some functionality during power outages.

Full islanding capability

I wish we had full “islanding” capability with our PV system. Islanding refers to the ability for a PV system and the loads connected to it to be separated from the utility grid during outages so that no electricity could be fed into the grid and injure utility workers who are trying to repair down lines.

We have three inverters in our system that are housed in a downstairs room in the 1812 barn. The one with Secure Power Supply is the third from the right.
Photo Credit: Alex Wilson

Fully islandable PV systems require specialized inverters along with battery banks that allow them to function off-grid. The battery bank not only provides for functionality at night, but it also establishes the proper waveform during the daytime when the grid is down so that AC power can be delivered to the house.

Some islandable systems, such as the OutBack Radian and Schneider Electric’s Xantrex XW-series inverters, rely on a single inverter that can connect to the grid and a battery bank and switch back-and-forth automatically. Such inverters communicate with and draw electricity from the battery bank during a power outage and also send electricity into the grid during normal operation. These are sometimes referred to as bi-modal inverters.

There are other, battery inverters that can be added to a PV system that already has one or more PV inverters. Inverter manufacturer SMA offers such an option, the Sunny Island inverter that switches between the battery bank and SMA’s Sunny Boy grid-tie inverters with fully integrated controls. SMA’s approach is proprietary, in that the Sunny Island battery inverters only talk to Sunny Boy grid-tie inverters.

The MS-PAE inverters from Magnum Energy offer similar functionality, but can be integrated into systems with inverters from other manufacturers. There are various companies that package this type of inverter with a battery bank and the needed controls to provide islanding, or “AC-coupling” when the grid is down. MidNite Solar is one such packager of retrofit kits.

With any of these options for full islanding capability, there is a significant cost for this type of islanding capability. For a typical, residential-scale 6 kilowatt (kW) system, the cost ranges from about $8,000 to $16,000, according to Mark Cerasuolo of OutBack Power Technologies, who did an analysis of AC-coupling options. This cost includes the specialized inverter, battery bank, and necessary controls.

Detail of our Sunny Boy 5000TL-US inverter. The outlet beneath it provides emergency power during outages (when the sun is shining).
Photo Credit: Alex Wilson

A new, low-cost approach

As I said, we didn’t go with full islanding capability, even though I would have liked to do so—and may in the future. The cost of the battery system and other components was just too much for our budget that has been stretched pretty thin with our complex building project—which is finally nearing completion.

What we did do, however, was install a brand-new inverter from SMA that has an outlet that can continue delivering some electricity when the sun is shining during a power outage. SMA calls this feature “Secure Power Supply.” Mounted beneath our 5 kilowatt (kW) Sunny Boy 5000TL-US inverter is an outlet that can deliver 1,500 watts (12.5 amps at 120 volts) during the daytime the power grid is down. Unlike other islanding systems, there is no requirement for battery storage with this option.

This isn’t enough power to operate all the loads in our house that I’d like to power during a power outage, but it’s far better than nothing. The cost is essentially the same as a standard Sunny Boy inverter (though a separate outlet has to be installed). Ours was installed by Integrated Solar Applications in Brattleboro, which installed the  entire 18 kW net-metered system (with 6 kW being owned by a neighbor).

Like other models in the SMA TL line, our 5000TL-US is a transformerless inverter, which is smaller and lighter than standard inverters, and it offers even higher efficiency: roughly 97%.

Emergency power uses

While 1,500 watts is a significant amount of available power, this Secure Power Supply feature is not really intended for loads that have significant surges as they cycle on or that could be harmed by fluctuating current, such as refrigerators. It’s really designed for charging cell phones and laptop computers.

But I’ll be carefully examining power consumption and surge demand when we shop for a new chest freezer—it would be very nice to be able to power that freezer during the daytime during extended power outages.

Our PV array being installed on the structurally reinforced roof with standing-seam metal roofing.
Photo Credit: Alex Wilson

There may be a Sundanzer chest freezer, for example (a freezer made especially for solar systems that can work in DC or AC mode), that will work well with the limited output from our inverter. At the very least, we’ll be able to keep our cell phones and laptops charged and power our cable modem and router.

Still in limited supply

I had heard about the new 3000TL-US, 4000TL-US, and 5000TL-US inverters late last year, and heard that they would be shipping in the first half of 2013, but it turns out that we got one of the very first to be installed in the U.S.—or at least in the Northeast. Demand is very high for these systems.

I suspect that within a few years, most grid-tie inverters will include this emergency-power option. I haven’t had to test it out yet, but will be ready for that ice storm this coming winter!

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-08-07 n/a 17471 Smart Vapor Retarders: Not Just Your Grandmother’s Poly

New smart vapor retarders block most vapor diffusion when you want to eliminate risk of condensation, but allow vapor flow when you want drying potential

Our Pro Clima DB+ smart vapor retarder on the insulated roof. Click to enlarge.
Photo Credit: Alex Wilson

Nowhere in building design has there been more confusion or more dramatic change in recommended practice than with vapor retarders. Thirty years ago, we were told to always install a polyethylene (poly) vapor barrier on the warm side of the wall. Then we were told to forget the poly and go with an airtight layer of drywall (airtight drywall approach). Insulation contractors, meanwhile, often said to skip the vapor barrier; we need to let the wall or ceiling cavity dry out.

It made for a lot of confusion. And I’m not sure we’re totally out of the woods yet.

Some experts are now looking to vapor retarders whose vapor permeability changes based on the humidity conditions. We installed one of these new materials on our house.

Changing recommendations

Back when poly was the default choice as a vapor retarder (called vapor barriers back then), the recommended placement of that layer varied depending on where you lived. The rule was to install it on the “warm side.” In northern climates, that meant that the vapor retarder should be on the inside (installed on the inner face of wall studs and rafters) before installing drywall.

The idea was that we wanted to prevent water vapor from migrating from inside the house (where it was warmer) outward through the building envelope. As vapor-laden air cools off, it is able to hold less moisture, and if it gets cold enough the moisture in the air will condense (i.e., it reaches the dew point)—causing problems by wetting the insulation or rotting wood framing. By installing the vapor retarder on the inside of the wall, we would keep that water vapor out of the wall cavity where it might condense.

The DB+ was stapled to the rafters (really flanges of trusses) and the joints taped.
Photo Credit: Alex Wilson

In warmer climates, we were told to install the poly vapor retarder on the outside of the wall cavity, because the inside of the air-conditioned house was colder than the outside.  In this case the risk was that condensation could occur with moisture laden air moving inward through the building enclosure and cooling off.

But what about places where some of the time it’s warmer inside than outside and at other times it’s just the opposite: colder inside than outside. It turns out that this is the case in most of the U.S. Even in chilly Vermont, where I’m based, most new houses are now being built with air-conditioning—and after the heat wave this past July, I'm sure we'll only see more of it.

Confused? So is most of the building industry.

Smart vapor retarders

One solution to the changing conditions of a house during the annual cycle is to install a vapor retarder whose permeability (a measure of how readily water vapor can pass through) varies based on the humidity. These are often referred to as smart vapor retarders. The goal is low permeability in the winter when humidity is low but it’s critically important to block moisture flow and prevent condensation, and high permeability in the summer when humidity is higher and you want drying potential to both the interior and exterior

It turns out that the plain old kraft paper facing on fiberglass batts has this variable permeability property—as leading building science expert Terry Brennan explained to me. As humidity increases (in the summer), it becomes more permeable to moisture, while in winter, when the humidity drops, it becomes less permeable and a better vapor retarder. Terry describes it as “poor man’s vapor retarder.”

Strapping being installed for hanging drywall. Given the thickness of insulation, we opted to install strapping 12" on-center.
Photo Credit: Alex Wilson

About 15 years ago, researchers in Europe began working in a more focused way on variable-permeability vapor retarders. The first such product I heard about was MemBrain, made by CertainTeed’s parent company Saint-Gobain (headquartered in France) and available from CertainTeed in the U.S. MemBrain is a polyamide or nylon sheet with permeability that ranges from less than or equal to 1.0 perms in low humidity conditions to more than 10 perms under high-humidity conditions.

Two variable products are also made by Pro Clima in Germany and distributed by 475 High Performance Building Supply in Brooklyn, NY. Intello Plus is made from a polyethylene copolymer, and it varies in permeability from 0.17 in the winter to 13 in the summer. It comes in rolls 1.5 meters (59 – 1/16”) wide and 50 meters (164’) long.

DB+ is a less expensive, paper vapor retarder made by Pro Clima that varies in permeability from 0.8 perms with low humidity to 5.5 perms at high humidity. It is made mostly from recycled paper, and includes a fiberglass reinforcement grid. It comes in rolls 1.35 meters (53”) wide by 50 meters (164’) long. It is about 24% less expensive than Intello Plus.

Calculating moisture risk

There’s a software tool called WUFI that can be used to determine what the moisture dynamics are likely to be in a particular building assembly and climate. In our project, we were concerned about our roof assembly, because the sheathing was outside of the vented roof cavity. We worried that there might not be an adequate air barrier in the roof assembly.

Terry Brennan used WUFI to determine that as long as there is at least minimal roof ventilation we would be fine without a vapor retarder on the interior. But our roof dormers weren’t going to be vented and the main roof wouldn’t be vented above the roof valleys. So we decided to install a vapor retarder as an insurance policy.

To allow drying to either the interior or exterior, we decided to go with a variable-permeability product, and we opted for Pro Clima DB+. The performance isn’t quite as good as Pro Clima’s Intello Plus, but the cost was lower and DB+ had some environmental attributes—such as being made from 50% recycled paper and being recyclable.

This is one of the dormers, where we don't have roof ventilation.
Photo Credit: Alex Wilson


Installation of the DB+ was pretty straightforward. It went up after the Spider insulation had been installed. It was held taught over the rafters and stapled in place. Following installation for several days there was a reasonably strong ammonia smell. Ken Levenson of 475 looked into this and found out for me that it is from the ammonium phosphate that is added as a flame retardant. By the time strapping and drywall went up, the smell was gone.

We didn’t bother with the vapor retarder on the walls, because there we have a well-sealed air barrier in the middle of the wall—made from Zip sheathing with edges taped and extra air sealing using the EcoSeal product from Knauf.

We’re happy. The drywall is now mostly installed, and we look forward to never having to worry about moisture accumulating in our insulation. At least until the next theory of moisture control comes along….

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-07-31 n/a 17423 Getting to Know Spider Insulation

Spray-applied fiberglass insulation offers huge benefits over fiberglass batts and even has some advantages over cellulose

Spider insulation being sprayed into an open wall cavity. Click to enlarge.
Photo Credit: Alex Wilson

We’ve just completed the installation of a relatively new and (at least in New England) little-known insulation material called Spider. As a reminder, the house we are renovating (really re-building) in Dummerston, Vermont has provided an opportunity to try out dozens of innovative products and materials that I’ve long researched and written about in Environmental Building News.

Insulation has been a particular focus of the project, in part because some of the most common insulation materials on the market have environmental or health concerns, including halogenated flame retardants and blowing agents that contribute significantly to global warming.

In previous blogs I described Foamglas, a cellular-glass material, that we installed under the foundation slab and on the outside of the foundation walls, and expanded-cork boardstock insulation that we installed on the outside of above-grade walls spanning over the wood framing. Here I’m covering the third innovative insulation product we used on the project: a spray-applied fiberglass product made by the Johns Manville Company called Spider.

Spray-applied insulation that doesn’t require netting

Spider insulation is installed into open wall and ceiling cavities in much the same way that damp-spray (or wet-spray) cellulose is installed. Like cellulose, it fills very well around wires, penetrations, and any irregularities in the wall cavity—it performs far better than fiberglass batts, which I think should only be considered on very small jobs where bringing in an insulation contractor can’t be justified.

The spray nozzle coats the fibers with an acrylic binder as they exit the nozzle.
Photo Credit: Alex Wilson

The fiber insulation is sprayed from the truck and as it is blown into the wall or ceiling cavity the fibers are coated with a small amount of acrylic binder. That makes the fibers sticky (thus the name “Spider”) so they stay in the cavities. It even works in overhead cavities, where netting is required with cellulose.

As with damp-spray cellulose, the cavities are over-filled, then the excess is trimmed flush with the inner face of the studs or rafters. This is done with a special “scrubbing” or “screeding” tool, which has a wide, electric roller that spans two studs or rafters.

As Spider is installed, a second worker vacuums up the material that doesn’t stick to the cavity or is scrubbed off, and this goes back into a hopper in the truck. With the most advanced installation equipment, as was used on our project by Environmental Foam of Vermont, the recovered insulation is mixed with virgin material at a ratio that can be adjusted. For overhead blowing into cathedral ceilings, a higher proportion of virgin insulation is recommended for better adherence, while a higher proportion of the recovered insulation can be used in walls.

Because the fibers pack tightly and install at relatively low density, a lot of insulation can be loaded into a truck.
Photo Credit: Alex Wilson

Comparisons with cellulose

I have long been a fan of cellulose insulation, and I have actively promoted it over the years. But spray-applied fiberglass has some advantages that I came to appreciate while working with and chatting with the installers.

While cellulose has higher recycled content (about 80%—the rest being flame retardant, usually borates), Spider has reasonable recycled content: 20% post-consumer and 5% pre-consumer recycled glass.

Spider goes in at significantly lower density: typically 1.8 pounds per cubic foot (pcf), while cellulose is typically installed at 3.5 to 4.0 pcf. For our cathedral ceiling application, we were worried that the 15” insulation depth would be so heavy with cellulose that it would cause the drywall to bow inward between the strapping.

The insulating value is slightly higher with Spider: R-4.2 vs. 3.7 to 3.8 for dense-pack or damp-spray cellulose.

As fiberglass is sprayed into the wall or ceiling cavity through a 4" hose, excess is vacuumed up and returned to the truck through a 6" hose..
Photo Credit: Alex Wilson

Acoustic performance is similar; both work very well at blocking noise. According to Johns Manville, Spider installed in a 2x4 exterior wall, with 1/2” particleboard siding, 1/8” pressed-cardboard sheathing, and 1/2” drywall, provides an STC (sound transmission class) rating of 43, which is much higher than a comparable wall with fiberglass batt insulation and somewhat higher than a wall with cellulose.

Fiberglass is an inorganic fiber, so if it gets wet it may dry out better than cellulose—though you don’t want any fiber insulation material to get wet.

From a health standpoint, cellulose and Spider are both made without formaldehyde, but Spider doesn’t require a flame retardant, while cellulose does. While the borate flame retardants used in cellulose have always been considered safe for humans, the Europeans have recently challenged that contention, and those chemicals are being considered for addition to the European REACH program. There has in the past been concern about respirable glass fibers potentially being carcinogenic, but this concern has largely disappeared, and with Spider few fibers seem become airborne.

Spider installation is far less dusty than cellulose. I was working in the house during most of the two-day installation, and I was amazed how little insulation was in the air. I wore a dust mask, but was otherwise unprotected. My arms and eyes didn’t get at all itchy, as they do when I have installed fiberglass batts. The installers were wearing shorts and tell me that they experience no itchiness.

A special "scrubbing" tool trims the insulation even with the inner face of studs and rafters.
Photo Credit: Alex Wilson

For our installer, Kent Burgess of Burlington-based Environmental Foam of Vermont (an insulation contractor who installs a wide variety of insulation materials, despite the name), one of the biggest advantages over cellulose is that he can fit about two-and-a-half times as much of the bagged material into his truck than with cellulose. This is mostly  because it goes in at a lower density, but I think the packed bags are also more dense. For a large job this can mean avoiding the need to return to home base to fill up with bags of material.

Kent used to install a lot of cellulose, but he far prefers Spider now. He is fairly new to Spider—having purchased equipment only last fall—so he was able to convince his mentor, Kyle Novak, of Advanced Insulation Systems in Travers City, Michigan to make the 12-hour drive east to help out of our job. The deep, sloped-ceiling application was tricky, and Kyle’s experience would be invaluable, since he has been installing Spider since early 2006, not long after it was introduced to the market.

Cost and performance

Kent says that Spider averages about 10% more expensive than damp-spray cellulose, but costs have a lot to do with the size of the project and the distance traveled. For a project further from his home base, using Spider can avoid the need for a return trip to pick up more material. In that case, Spider will be significantly less expensive.

Kent says the price of installed Spider averages about $1.50 to $1.65 per square foot for a 2x6 wall, or roughly 28-30¢ per board-foot, vs. maybe 24¢ per board-foot for cellulose. A quality closed-cell spray polyurethane foam (SPF) job will cost 80¢ to $1.00 per board foot for a large job, and with SPF there is the issue of how much can be installed at a time (because the curing is an exothermic reaction, and the foam heats up). Plus, Spider is a lot safer; supplied-air respirators aren’t needed with Spider, while they are with SPF.

After trimming the insulation and cleaning up, the job looks great. A variable-permeability vapor retarder will be added on the insulated ceiling--thus the prep at the closet partition.
Photo Credit: Alex Wilson

The drawback is the cost of getting set up to install Spider. Kent has about $70,000 invested in the equipment.

In the seven years Kyle has been installing Spider he’s had no real problems. “I think it’s the greatest thing on the face of the Earth,” Kyle told me after spending a day-and-a-half spraying the material. “It doesn’t settle,” he said, and customers love the look of the finished job.

When Kyle has gone back into houses insulated with Spider to do repairs or additions and opened up walls, he has seen absolutely no problems.

For cavity-insulation applications, Spider is a great option. Cellulose is also a great product, but for deep installations and sloped ceilings, I don’t think anything beats Spider today. Fiberglass batts aren’t even in contention.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-07-22 n/a 17319 From Tyvek to Pro Clima: The Evolution of Weather-Resistive Barriers

We’ve come a long way from the early Tyvek housewrap; our experience with the German Pro Clima Solitex weather-resistive barrier

Pro Clima Solitex weather-resistive barrier installed on our home. Click to enlarge.
Photo Credit: Alex Wilson

I remember years ago—I hate to remember how many; it must have been around 1982 or 1983—writing for New England Builder (now the Journal of Light Construction) about Tyvek housewrap. It was then a fairly new product—and really a new idea: a material that would wrap over the outside of a house to provide an air barrier and improve energy performance.  

Tyvek wasn’t actually new in the early 1980s—it was invented by DuPont in 1955 and first commercialized in 1967—but it was new enough in the building industry that two technical experts from DuPont trekked up to Vermont to give me a dog-and-pony show about it. New England Builder was gaining a reputation as a leading purveyor of practical, on-the-ground information for builders, and DuPont wanted to get the message out.

I used Tyvek houswrap on our 1788 house, which I was then in the process of renovating. I had removed the old shingle siding, repaired some rotted sills, replaced some sections of board sheathing, insulated on the interior with fiberglass between the studs (plus an inch of extruded polystyrene on the interior of the studs), and I wanted to provide a reasonable air barrier on the exterior.

Tyvek after 30 years.
Photo Credit: Alex Wilson

Tyvek seemed like the way to go. It is a spun-bonded polyolefin (polyolefins are polymers, usually either polyethylene or polypropylene, made up of long chains of carbon and hydrogen) that comes in a roll wide enough to provide a continuous layer on the outside of the house. It seemed ideal.

Thirty years later, doing some repairs to drainage around the house I had opportunity to remove some of that Tyvek, and I was struck by how much it had deteriorated. It turns out that Tyvek—at least the formula that was being used thirty years ago—was significantly damaged by surfactants in wood siding. (I didn’t know enough then to provide a rainscreen detail using strapping, which would have separated the wood siding from the Tyvek and improved the housewrap’s durability.) The material almost disintegrated in our fingers as we examined it.

Evolution of weather-resistive barriers

We installed Solitex Mento 1000 over 6" of expanded-cork exterior insulation, taping it to the pre-wrapped window surrounds.
Photo Credit: Alex Wilson

A lot has happened with housewraps in the 30 years since DuPont paid me that visit. I was just on the DuPont website, and the first thing I noticed was that there are now nearly a dozen types of Tyvek: the standard HomeWrap, StuccoWrap, a roof product, a handful of commercial products, Tyvek tapes to seal one layer to another, plus all the non-building-related products for mailing envelopes, protective haz-mat suits, etc.

Following DuPont’s success in creating a new type of product, there were lots of entrants into the housewrap industry: Typar (cleverly named to confuse the user into thinking it was Tyvek?), various perforated polyethylene films, and some textured products that try to achieve a sort-of rainscreen (air space behind the siding).

In fact, in the building-science community the good-old housewrap has evolved into the weather-resistive barrier. It’s either an attempt to impress clients with a far-more-impressive-sounding product that justifies the cost, or perhaps an effort to mirror the dry terminology found in building codes. These barriers are supposed to keep out rain and wind (air flow), yet they need to be permeable enough that any moisture that finds its way into the building enclosure can evaporate and escape to the exterior.

For more on WRBs, see Choosing the Best Housewrap: A New Standard for Weather Barriers.

Enter the Europeans

So what did I use on our current house project? We ended up going with a German weather-resistive barrier (WRB) called Solitex Mento 1000, made by Pro Clima and distributed in the U.S. by 475 High Performance Building Supply in Brooklyn, New York. (475 is a specialized building material supplier serving low-energy and Passive House construction.)

Strapping installed over the WRB.
Photo Credit: Alex Wilson

Solitex is one of a number of European WRBs that go beyond typical American products in their performance. The other that I’m somewhat familiar with is SIGA Majvest Exterior Wall Membrane, a Swiss WRB distributed in the U.S. by Small Planet Workshop in Olympia, Washington.

Solitex Mento 1000 is a high-performance WRB that offers both very good water penetration resistance and very high water-vapor permeability. According to the company and 475, the product resists a 33-foot water column even as it provides 38 perms excellent numbers in both cases. 

Meanwhile, it goes a long way toward restricting air flow through the wall or roof assembly, with air permeance of 0.00004 cubic feet per minute (cfm) per square foot, according to standardized test methods (ASTM E2178).

Technically, Solitex Mento 1000 is a three-layer monolithic TEEE film (Thermoplastic Elastomer Ether Ester) with polypropylene protective layers. By being monolithic, it has no pores, so it is more weather-resistant than standard housewraps, while actively transporting vapor outward during the heating season. This means that the TEEE functions at lower pressure differential between inside and outside, than the more common microproous/woven products.

“With traditional housewraps,” explains Ken Levenson of 475, “the vapor permeance is from the microscopic tears in the woven membrane, which the vapor can push through,  while with the monolithic membrane with no tears or pores, it is the actual molecular structure that is transporting the vapor.” As such, because traditional wraps resist vapor diffusion at lower pressures, there is greater chance of moisture build-up filling the pores which can block vapor movement, while the molecular structure of the monolithic membrane moves the vapor at very low vapor pressure differentials, avoiding the danger of blockage.

Also, the membrane’s performance will not degrade from surfactants in cedar siding, according to Levenson.

Installing Pro Clima Solitex Plus WRB to form the vent space under the roof sheathing. The WRB is caulked and stapled to the top chords of the rafters.
Photo Credit: Alex Wilson

It is recommended for exterior walls and roofs. With roofs, it can even serve as a temporary roofing layer until roofing is installed. In our roof system, we used a slightly different version, Solitex Mento Plus (with a reinforcing grid), as a layer to achieve the air space under the roof sheathing. The WRB provides both a waterproof layer to shed any water that may get into the air space and an air barrier in the insulated roof system.

Cutting sections of Solitex Mento Plus for between the rafters in forming the air space above the insulation; the WRB will protect the insulaton from any moisture that gets in, while allowing the insulation to dry out if it does get wet.
Photo Credit: Alex Wilson

Pro Clima Solitex comes in 1.5-meter (59”) rolls that are 50 m (164’) long. Edges and overlaps are sealed with Pro Clima Tescon tapes.

Compared with the very lightweight, nine-foot-wide rolls of Tyvek, the installation may be more time-consuming, but I am confident that we have a weather barrier that will do a superb job of protecting our house, while helping achieve the airtight construction we are seeking and allowing any moisture in the wall cavities to escape.

I’m hoping this WRB will still be doing its job in 75 to 100 years, when it will be time to replace the siding on the home.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-06-25 n/a 17274 Installing A Group Net-Metered Solar Array

The 18-kW photovoltaic array on our barn roof is nearing completion

The first PV panels being installed on our barn roof. Click to enlarge.
Photo Credit: Alex Wilson

When we started planning the rebuild of our house and the rest of the farm in West Dummerston, Vermont my wife and I knew that we wanted to produce all of our energy onsite. That meant a solar photovoltaic (PV) system that would generate as much electricity as the house and barn are consuming—net-zero energy.

We also wanted to protect as much of the ten acres of agricultural land as possible. That meant we wanted to avoid a ground-mounted PV system. Wherever land can be used for farming—now or in the future—I prefer to install PV arrays on buildings, keeping the land open for agricultural uses.

Fortunately, the 1812 barn has a long roof facing almost due south. That would be the perfect location for the solar array. Our builder, Eli Gould, spent several months restoring the barn, which involved replacing damaged posts, adding sturdy granite supports under those posts, rebuilding several dry-stone walls to support the barn sills, lowering and leveling the floor, replacing some timber framing elements (including about a dozen round-log joists that we cut on the land), and reinforcing the roof to hold the solar modules.

After stripping the old roofing and repairing the original sheathing, a new layer of roof framing and roof sheathing was added.
Photo Credit: Alex Wilson

To maximize durability, we wanted the roof to be sturdy and not flex with wind or snow loads, so after stripping the layers of metal and asphalt roofing, we added a layer of 2x6 and 2x4 framing to the roof structure, flattening the roof plane at the same time. Zip sheathing went on over that, and then the roofing.

Standing-seam metal roofing

One of our goals for the whole project has been to maximize durability, so we spent quite a while debating different roofing materials. We wanted the solar panels to be able to attach to the roof without any penetrations, so that meant standing-seam metal roofing. S-5 brackets for the solar array tracks clamp on to the raised seams of the roofing with absolutely no penetrations of the roof. If panels have to be removed down-the-road for some reason, that’s relatively easy to do.

For the roofing itself, we chose 24-gauge Englert galvalume 1301 roofing with the company’s low-gloss Ultra Cool coating. According to James Hazen of the company, Englert’s paint line is one of the cleanest operations of its kind in the world, with 100% of solvent fumes from painting, drying and curing operations captured. The captured paint fumes are burned with all the recovered heat used in manufacturing. The company expects a 150-year life for the roofing. Roofing contractor Travis Slade, of River Valley Roofing in Putney, Vermont, has done an incredible job installing the standing seam roofing.

Standing-seam roofing nearly completed on the south roof.
Photo Credit: Alex Wilson

Group net-metered system

We have a great location that can hold an 18-kilowatt (kW) PV array, but we don’t need a system that large. So last fall we began investigating community solar options, and we found a neighbor who wanted to buy 6 kW out of the 18 kW system. In other words, this neighbor will actually own a third of the PV system that’s on our barn roof.

This option for someone else to own part of a PV system in a different place is referred to as group net metering, and Vermont is one of the few places where this can be done. Green Mountain Power bends over backwards to facilitate such systems, which is wonderful. Through this option, someone without a south-facing roof where PV modules can be installed can look elsewhere for a good south exposure.

Because the 12-kW system that we will own is still larger than we will need for our house and barn (at least until our farm needs expand), we will plan to sell our excess capacity to another Green Mountain Power customer.

S-5 clips clamp onto the standing seams of the roof to avoid penetrations.
Photo Credit: Alex Wilson

Selection of the PV modules

At the recommendation of our solar installer, Integrated Solar Applications, in Brattleboro, we are installing highly rated REC 250PE modules. The modules are rated at 250 watts, have 15.1% module efficiency, and come with a 10-year product warranty and 25-year “linear power output warranty” (guaranteeing that the degradation of power output will not exceed a 0.7% per year). REC is a Norwegian company with the silicon raw materials produced in the U.S. and silicon wafer, PV cell, and PV module manufacturing being done in Singapore.

Poor reliability and early failure of PV modules has been in the news lately, so I’m relieved that ours aren’t simply commodity Chinese-made modules (though some Chinese products are no-doubt fine).

Panels secured to the mounted tracks.
Photo Credit: Alex Wilson

In future columns I will address other features of our PV system, including “islanding” capability that will provide us with some electricity even when the electric grid is down.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-06-12 n/a 13956 Mineral Wool Boardstock Insulation Gaining Ground in the Homebuilding World

Roxul ComfortBoard IS has some important environmental and performance advantages over XPS and polyisocyanurate insulation

ComfortBoard IS, Roxul's exterior insulation board, is being distributed nationwide in the U.S. at thickensses up to 3".
Photo Credit: Roxul

Readers of this Energy Solutions blog may be aware that I’ve been critical of some of our foam-plastic insulation materials. I’ve come down hardest on extruded polystyrene (XPS), which is made both with a blowing agent that contributes significantly to global warming and with a brominated flame retardant, HBCD, that’s slated for international phaseout as a persistent organic pollutant.

So I’m always keeping an eye out for alternatives. I’ve written here about two of those alternatives that I’ve used in our own home: a cellular glass material called Foamglas with high compressive strength that works very well below-grade; and Thermacork, an all-natural rigid insulation material made from expanded cork.

I like both of those materials a lot, but they have two big problems: high cost and limited availability. They just won’t be able to enter the mainstream home building industry—not yet, anyway—since they cost more than twice as much as XPS and polyisocyanurate and are hard to get hold of.

Enter ComfortBoard mineral wool boardstock

With this context, I was thrilled to learn recently that Roxul, a Canadian manufacturer of mineral wool (or rock wool) insulation and part of the global, Denmark-based Rockwool International, has been gaining traction with its residential ComfortBoard IS in the U.S. Plus, the company has a new, even higher-density boardstock product coming out this month for commercial applications.

Rigid boardstock mineral wool has been available in the U.S. for decades from at least four manufacturers, and it is widely used in commercial construction. But it’s never been widely available for home building.

That is changing as Roxul ramps up national distribution of ComfortBoard IS, which was first introduced about a year ago. (A few years earlier the company began national distribution of its ComfortBatt product for cavity-fill applications.)

ComfortBoard IS from Roxul’s Milton, Ontario factory is third-party-certified to have a minimum recycled content of 75%, and product can be specified with recycled content up to 93%.

Residential installation of ComfortBoard IS.
Photo Credit: Mark Gorgolewski

ComfortBoard IS, the residential product, has a density of 8 pounds per cubic foot (pcf) and is available in four thicknesses: 1-1/4", 1-1/2", 2", and 3". The company has the capability to produce the product up to 6" thick—which could offer an attractive option for Passive House builders and those interested in deep-energy retrofits—but because thicker panels requires a special production run, those options are only available in truckload quantities.

The insulating value of ComfortBoard IS is a very respectable R-4.0 per inch. That’s lower than XPS (R-5 per inch) and polyiso (about R-6.0/inch), but there will be no “R-value drift” (reduction in R-value over time), which occurs with foam insulation materials that rely on lower-conductivity blowing agents that slowly leak out or allow air to leak in.


A very attractive property of ComfortBoard IS is the high vapor permeability. A two-inch layer of the insulation has is about 30 perms, which means it’s highly "breathable." If the ComfortBoard is installed on the outside of the wall the high permeability will allow excellent drying potential to the exterior. This approach, in which the sheathing layer provides the continuous air barrier, is gaining many fans in the building science community.

ComfortBoard IS has a textured outer surface (see photo), which may even aid moderately in that drying potential (acting like a rainscreen). When asked about this, Paraic Lally, the North American Manager for Specifications at Roxul, told me that the texturing is a function of the manufacturing process and not designed to provide a rainscreen; thus, the orientation of installation is not important..

Another feature of mineral wool that I hadn’t appreciated before is the very low coefficient of thermal expansion with temperature. According to Roxul, the coefficient of thermal expansion of ComfortBoard is just 5.5 (10–6 m/m°C), compared with 80 for XPS and 120 for polyiso. In applications where temperatures fluctuate significantly (like on the outside of a wall in a cold climate) this can be a real problem.

As Martin Holladay has reported on, shrinkage of XPS insulation used as an outer sheathing layer can be significant enough to totally separate the tongue from groove at XPS joints, thus eliminating that thermal break role of the exterior insulation.

Formaldehyde binder

All North American mineral wool today is produced with urea-extended phenol formaldehyde binder. This raises the prospect that the material could release formaldehyde, and it means that the insulation cannot be used in Living Building Challenge projects, because formaldehyde is a "red-list" chemical in that rating system.

From what I understand, however, the high-temperature processing of the mineral wool during manufacture drives off any free formaldehyde, and test data I've reviewed (for the ComfortBatt product, not ComfortBoard) showed formaldehyde levels to be at or below background levels. So, other than the concern that mineral wool can't be used in Living Building Challenge projects, I don't consider the formaldehyde binder a big deal. But I'd love to hear other thoughts about that.

Typically installed over sheathing, if structural bracing is provided, ComfortBoard can be installed without exterior sheathing.
Photo Credit: Roxul

Availability and price

I was pleasantly surprised recently when I asked Leader Home Center in Brattleboro, Vermont to price a number of insulation materials for an update to BuildingGreen's encyclopedic report on insulation. The contractor pricing for ComfortBoard IS came to $0.64 per board-foot, compared to $0.48/bd-ft for standard polyiso, $0.75 for fire-rated polyiso (Thermax), and $1.07 for XPS.

While pricing will doubtless differ in other regions and for different quantities, the fact that ComfortBoard is in the same ballpark as these other materials is great. Even after correcting for the lower insulating value (you need more thickness of ComfortBoard to achieve R-10 than with the foam plastics), Comfortboard IS locally was more affordable than XPS: roughly $1.59 per square foot at R-10 for ComfortBoard vs. $2.14/sf @ R-10 for XPS.

Dimensions and installation

Although Roxul literature shows ComfortBoard IS being available in three sizes—24" x 48", 36" x 48", and 48" x 96"—it is most commonly stocked in the smaller sizes. This may be because the larger panels will be fairly heavy. At 8 pcf, a three-inch-thick, 4' by 8' panel weighs 64 pounds—not an insignificant weight to wrestle into place.

To achieve a reasonably thick, four- to six-inch layer of exterior insulation for a deep-energy retrofit of Passive House wall system will require a double layer (unless you have the ability to order by the truckload). This can be an advantage because is allows overlapping the panel joints (only square-edge product is produced), but it will likely increase labor costs.

Rigid mineral wool may also take some getting used to from an installation standpoint. It can be cut with a hand saw, though I can’t (yet) report on cutting the product from personal experience. Minimum one-inch-diameter washers or nail/screw heads are recommended for attachment, and when strapping is installed on the outside to produce a rainscreen, that strapping has to be screwed into wood studs through the insulation. Because it is mineral-fiber product, a dust mask and gloves should be used when working with it.

Commercial ComfortBoard on the way

Just as exciting as the increased availability of ComfortBoard IS is a commercial version that’s about to be introduced: ComfortBoard CIS. It is similar to the residential product, but produced at a higher density of 11 pcf. Like Comfortboard IS, it can be ordered up to 6" thick, but standard thicknesses will be only up to three inches.

While I am pleased to have used Foamglas and cork insulation on my home, I suspect that Roxul’s ComfortBoard will find its way into my next project.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-05-15 n/a 13019 Why Can’t I Buy a Non-Toxic Sofa?

Photo – Greg Habermann (Remixed under CC BY 2.0)After years of living with a nice-looking but rather uncomfortable daybed in our living room, my family and I went shopping for a new sofa. We explored a range of styles and configurations, trying to find something that looked good, would be cozy, durable, and fit in our rather small space. Oh, and we also wanted to avoid bringing toxic and ineffective flame retardant chemicals into our home.

According to the Chicago Tribune, The New York Times, and Environmental Building News, the polyurethane foam that makes almost all cushions so comfortable is infused with several pounds of persistent and bioaccumulative toxins that are supposed to help suppress fire. Including those ingredients might be understandable if they actually worked, but there is little evidence that they do. The tests that supposedly show that they work were done on samples that contained huge amount of the chemicals—ten times more than anyone actually uses.

How did they hoodwink us into using these chemicals?

So why do all cushions contain this toxic, ineffective stuff? Because the chemical companies that make it have managed to convince California regulators that it’s needed to reduce death and injury in fires. The tricks that they used to hoodwink the regulators are truly outrageous—check out the Tribune exposé or this summary for details. These chemicals are only required in California, but very few manufacturers want to deal with stocking separate inventory just for California, so they use the treated foam in all their products.

As much as I’m looking forward to relaxing on a more comfortable sofa, I just can’t see exposing my family unnecessarily to these chemicals, which can cause cancer, developmental and neurological problems, and impaired fertility. One particularly noxious chemical, chlorinated tris, is being phased out of use, only to be replaced by others with similar chemistry that have not been adequately tested, according to the Green Science Policy Institute.

Companies unresponsive to pleas for a safer sofa

The Institute does offer a helpful list of manufacturers who either avoid them entirely (by not selling anything in California) or who offer to make an untreated version. But so far we haven’t found the style and configuration we’re looking for on that list.

It would seem that offering untreated foam as an option wouldn’t be so hard, given that manufacturers routinely offer a wide range of fabrics and other options on their products. But most companies whose products we liked (and could afford) were unable or unwilling to fulfill this request. These included big national chains that sell online (Pottery Barn, Restoration Hardware, West Elm) and companies that sell through local distributors. I was disappointed to discover that even active members of the Sustainable Furniture Council (Rowe Brands, Lee Industries, American Leather), which posted a warning about these chemicals, have not been responsive to my pleas for a safer sofa.

There may be hope coming from Califronia

There is hope. The California regulation governing this activity, Technical Bulletin 117, is in the process of being updated. The proposed TB 117-2013 can be met without the use of flame retardants.. As long as it doesn’t get torpedoed along the way, by the fall of 2013 the dependency on flame retardants should be gone. A year or two from now (depending on how long it takes the manufacturers to work through their existing inventory), I shouldn’t have to worry about the toxic load I’m inadvertently buying when I buy a new sofa.

In the meantime, I’ll keep looking asking those companies that make sofas I like if they can make me one without the toxins. I hope you’ll do the same, so they’ll get the message and make the switch sooner. And, whether or not you live in California, it’s easy to write a letter to help make sure that TB 117-2013 gets adopted on schedule—read about how to do that here.

2013-05-14 n/a 12716 Shocking Truth About Tapes Emerges from Wingnut Test Facility!

Think you understand pressure-sensitive adhesives? Think. Again. (EDITOR’S NOTE: Do not try this at home.)

WTF at BuildingEnergy 13! Children, do not try this at home.
Photo Credit: Courtesy Peter Yost

My last post in this series on adhesives, sealants, and tapes ended with this line:

“We hope to follow up this baseline ideal conditions testing with more field-like conditions.”

Introducing the WTF research troupe

Well, it took a while, but we finally got a venue for some more testing of pressure-sensitive adhesive (PSA) tapes: the Northeast Sustainable Energy Association annual conference, BuildingEnergy 13.

NESEA premiered its Trade Show Demo Stages this year, calling the stage demos “Recess for building and energy professionals—Let’s play!” Sure seemed like the appropriate forum for us to premiere the Wingnut Test Facility (WTF), a new round of “benchtop” tape testing with a focus on field conditions: wet, cold, dirty, and just about all of the above.

They actually invited us to come do our tape testing on stage!

Our crack slapstick lab staff

Fellow WTF founder, Dave Gauthier (President of Vantem Panels here in Brattleboro) and I set up the testing this way (download the spreadsheet for details):

  1. Cold, wet application (no primer)—We put on our jackets and adhered the various tapes to rough OSB outdoors when it was about 28°–36°F (temps rose as we worked; see comments in spreadsheet). “Wet” meant this: we sprayed water from a standard spritzer bottle, then wiped off the OSB with our bare hands—to mimic what might be considered “prepping” the surface on a typical jobsite….
  2. Cold, wet application (with primer)—We used two priming materials: Pro Clima’s acrylic primer and 3M’s Super 77. We chose the Pro Clima primer because it is appropriate for acrylic tapes, and we had prior experience with it and could easily get ahold of a relatively small quantity from the supplier. We chose the multipurpose 3M Super 77 spray adhesive for the modified bitumen membrane and the butyl rubber flexible flashing product (a specialized primer would have to be specially ordered in quantity).
    After all the test samples were set up, we stuck them in a freezer, keeping them below freezing until we transported them to the NESEA demo stage in a cooler.
  3. Dirty application—To reflect another common jobsite condition, we took the substrates outside, smeared mud on them, and then “prepped” the surface by wiping off the excess with the palms of our hands. We did this testing inside at room temperature.

The tapes

We selected five tapes for this round of testing based on the following criteria:

  • They were readily available to us.
  • They were all popular with our local building science builder group (
  • They provided a selection of different adhesives.

Dave and I and our respective companies—BuildingGreen and Vantem Panels—have absolutely no relationship with any of these companies and no bones to pick or gains to be made with any tape companies, including these.

The five tapes were WR Grace Vycor, Dupont FlexWrap, 3M 8067, Huber ZIPWall, and Pro Clima Tescon No 1.

The “method”

Rather than hauling Dave’s Constant Rate Extension (CRE) machine down to Boston. we improvised with a spring balance and a hook(see photo). We pulled the sample till it hit a peak or something failed: the adhesive, the backer material, or the substrate (the substrate never really failed, although occasionally chunks of OSB let go before the adhesive or backer did).

A couple surprising and telling results from WTF testing. First, Tyvek-FlexWrap: it stretched without letting go up to the 35-pound peak—but ONLY while dry; cold and wet, the tape let go at just 8 pounds. Second, ZIP sheathing tape: cold and wet with water-based Pro Clima primer, it peaked at a disappointing 15 pounds of tension; with the general-purpose 3M Super 77, it peaked at 32 pounds. This might explain why ZIPWall's recommended primer is solvent- rather than water-based.
Photo Credit: Peter Yost

The disclaimer

No standard test methods currently come close to mimicking the stresses that these tapes will experience in an exterior building assembly—changes in temperature, moisture content, and pressure.

We are using our crude WTF methods to get a preliminary idea of the impact that various field conditions have on the strength and quality of the bond between the tape and the substrate (For a summary of our test results, see Sheet 2 in the attached excel file).

We desperately need better tests that actually reflect field conditions (more on that below).

The results

Having said that, Dave and I think the WTF test results suggest the following:

  • The substrate makes a really big difference; rough OSB is the most challenging for all of the tapes.
  • None of the tapes adhered as well under cold, wet conditions as they did when it was warm and dry. Is this decrease critical in terms of ultimate barrier continuity? We just don’t know.
  • When it is wet and cold, using a primer seems to bring tape performance back up.
  • For most of the tapes, warm and dirty conditions had far less impact on the quality of the bond than cold and wet conditions did.

4 tips for PSA success

  • All PSA tapes and membranes adhere significantly better to plywood than they do to the rough side of OSB.
  • When field conditions are less than ideal, strongly consider using a primer, one that is compatible with the PSA.
  • Make sure that the primer you select is chemically matched to the tape you are using.
  • With all due respect to the WTF, we need serious scientific efforts to determine just how PSA tapes perform under real conditions in assemblies over the long term.

Breaking news!

As I was writing this blog post, three important news items popped up:

  1. Building Science Digest, “Stuck on You”—Joe Lstiburek has quite a bit to say about how different pressure-sensitive adhesive tapes work and his company’s long-term experience and knowledge of tape testing over the last several years.
  2. Fine Homebuilding, “Backyard Tape Testing”—Martin Holladay has an article on his backyard tape testing in the latest issue of Fine Homebuilding. Martin ends up in the same boat we are: his tests are far from scientific or standardized—and he is the first to admit this right in his article—and his recommendations are couched in the uncertainty of his backyard experiment.
  3. Pella Window’s internal tape testing—While presenting at a recent conference, a research engineer from Pella let me know that they have done extensive tape testing designed to mimic stresses the tapes see in the field. Pella has tested its own SmartFlash foil-backed butyl tape as well as some other common flashing tapes as part of their installation systems.
    The researcher sent me some really cool information on their “real-world” tape testing, but only if I kept it confidential, at least for the time being. Watch for more coverage soon!

Next up from WTF’s underground laboratories

We need better tests: one that mimics the “bellowing” effect of wind pressure pushing in and out on the tapes, and one that represents the shear that takes place across the tapes when they are stressed by movement of building components to which the tapes adhere.

WTF is on the job. In my next post, I’ll share some top-secret photos of new testing equipment we’re working on. In the meantime, let us know about any backyard or benchtop testing you’ve done—and what you found out.

2013-05-02 n/a 12639 EcoSeal: A New System for Air Sealing Homes

Knauf Insulation's EcoSeal can provide significant air-sealing prior to installing cavity-fill insulation

Installing Knauf EcoSeal at our farmhouse. Click to enlarge.
Photo Credit: Alex Wilson

Getting back to our Dummerston, Vermont farmhouse this week, I’m reporting on our use of a relatively new product for air-sealing homes: EcoSeal from Knauf Insulation.

First some context: In the building science world, there is growing interest in achieving a robust air barrier at the sheathing layer of a house, with layers inside of that able to dry toward the interior and layers on the outside able to dry to the exterior. To make that work, the sheathing layer has to be tightly air-sealed.

In our house, we used Zip sheathing from Huber Engineered Wood as the sheathing layer with the joints taped. This is an oriented strandboard (OSB) sheathing that has a coating to improve weather resistance and reduce permeability—so it makes a great air barrier. The version of Zip used for wall sheathing is green and the version used for roof sheathing is a reddish color. Huber also makes a high-performance tape that’s used for sealing joints and edges of the Zip sheathing.

In working with an older house, like ours, there are inevitably some irregularities that make air sealing with the sheathing more difficult. With our house (originally built in the early 1800s), for example, there are beams at the top of the eave walls that extend four inches out from the wall plane (oddly), and we had to box those in with the sheathing. There may also be some air leakage at the joints, despite the taping.

EcoSeal comes in a 5-gallon bucket, and the pump unit has a 200-foot hose.
Photo Credit: Alex Wilson

So to achieve an airtight sheathing layer, it helps to add some air sealing from the interior. Some builders use a “flash and batt” system for this: a thin layer of spray polyurethane foam (SPF) is applied against the sheathing from the interior (up to about an inch thick) and the cavity is then insulated with batt or other cavity-fill insulation. The SPF is great at air sealing but pretty expensive as an insulation material, so flash-and-batt is a reasonable solution.

Another solution is to use one of two new products for sealing just the joints and cracks at the sheathing layer. Owens Corning makes the EnergyComplete system, and Knauf makes EcoSeal (warning: this link opens with an installation video that has a somewhat jarring soundtrack).

An acrylic air-sealing system

EcoSeal is an acrylic product that is applied using high-pressure paint-spraying equipment. The installer arrived with two five gallons buckets of the bright-blue acrylic material that was the consistency of very thick paint. The system comes with a long, 200-foot hose, so the pump and bucket can stay in one place in the house while the work proceeds. The pump is very quiet.

The installer started on the first floor and worked methodically around the room sealing all the joints and cracks, them moved upstairs. We had arranged for someone from Efficiency Vermont to come down with a blower door (a device used for testing the air tightness of a house) and run the blower door during the EcoSeal installation.

Jennifer Severidt from Efficiency Vermont adjusting her blower door.
Photo Credit: Alex Wilson

Here’s how a blower door works: a fan in the blower door depressurizes the house enough to maintain a 50 pascal difference is air pressure between the inside and outside—as measured by an integral manometer (air pressure gauge). Instrumentation in the unit calculates the cubic feet per minute (cfm) of air flow going through the fan to maintain the 50 pascal pressure differential.

The blower door, as we used it, did two things: first, it exaggerated the air leakage so the installer could feel cracks that needed sealing; and second, it allowed us to measure the success of the air sealing.

EcoSeal doesn’t expand as it is installed (as do foam sealants), and it takes up to day to fully cure. The cure time depends significantly on the environmental conditions—temperature, humidity, etc. Our house was fairly cool during installation, so the cure time was significant. The material can span up to about a 3/8-inch gap, according to Knauf, and it remains flexible.

Jennifer's blower door showing 651 cfm at 49.3 pascals. The pressure changes with outdoor conditions.
Photo Credit: Alex Wilson

If EcoSeal gets on surfaces where it doesn’t belong (as occurred once during our installation when some got on one of our windows), it easily washes off with water. We were in the house throughout the installation and could barely smell it, so I’m confident that it has low VOC (volatile organic compound) emissions.

Significant measured improvement

When we started EcoSeal installation, the blower door was showing 950 cfm of air leakage at 50 pascals (cfm50). During the course of about four hours of work on the air sealing, that air leakage rate dropped to 640 cfm50. That’s an improvement of a third—not bad.

Given the volume of the house, 640 cfm50 is equivalent to 1.6 air changes per hour at 50 pascals (ACH50), which is very respectable for a new house, let alone a renovation.

Sealing on the second-floor gable wall.
Photo Credit: Alex Wilson

More about EcoSeal

Knauf Insulation introduced EcoSeal in January 2011. It’s still a very new product, with only 100 installers nationwide, according to Brett Welch of the company. He estimates that about 2,500 homes have so far been sealed with the system.

In houses where there hasn’t been as much attention paid to air tightening (no taped sheathing), a more typical tightness achieved is 2.5 – 3.0 ACH50. Welch said EcoSeal has also been used in a few Passive House projects, where air tightness of 0.6 ACH50 must be achieved.

EcoSeal costs $200 - $250 per five-gallon bucket, according to Welch, with 2-3 buckets typically required for a house. He estimates 6-10 hours of labor for an installation, bringing the total installed cost into the $1,000 to $1,500 range. It can be installed at temperatures ranging from 20°F to 115°F, though at the low temperature range, the material in the bucket must be fluid and the cure time is longer. It can be stored at 35°F to 120°F.

A Palo Alto Passive House under construction that used Owens Corning's Energy Complete system.
Photo Credit: Alex Wilson

Similar system from Owens Corning

While Knauf’s EcoSeal is a one-part system, Owens Corning’s EnergyComplete is a two-part system that is foamed in place. It expands slightly as it is installed and sets up very quickly—in less that a half-hour. I don’t have personal experience with EnergyComplete, but visited a Passive House under construction in Palo Alto in late-2010 that had just been sealed with the system, and was impressed with it.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-04-16 n/a 12572 Installing Cork Insulation

Climbing the learning curve in working with a new insulation material

Sliding a slab of precisely cut cork insulation against a door jamb. Click to enlarge.
Photo Credit: Alex Wilson

What do you do if you’re a builder and your client (that would be me) hands you a material that no one’s ever heard of, let alone installed in this country, and asks you to insulate his house with it? A lot of smart builders would run the other way. Eli Gould, our partner in the Dummeston, Vermont farmhouse we’re renovating (really re-building), took it on as a challenge.

Last week I wrote about the cork insulation that we’ve installed—the last of it went up at the end of last week. Here I’ll review some of the installation details that Eli and his crew figured out—including such seemingly minor issues as how to cut the stuff.

Planning for the cork months ago

When we first started talking about expanded-cork insulation last summer, we requested some samples to work with. Along with being a designer-builder, Eli has an R&D company, PreCraft, Inc., through which he works on figuring out better building systems and how advanced building components can work together. This involves a lot of prototyping, and Eli jumped at the opportunity to get his hands on some cork.

Eli's crew used various saws to cut the cork, including this specialized tool for timber framing.
Photo Credit: Alex Wilson

Amorim Isolamentos, which manufacturers the cork insulation in Portugal, sent over several bundles of the boardstock insulation so that we—mostly Eli—could figure out how we would use it and exactly what we wanted to order. The material is available in thicknesses from a half-inch to about 12 inches and with square or shiplap edges. The exposed face of the cork we used is about 18" x 36".

From an energy performance standpoint we wanted to achieve at least R-40 in the house walls and achieve that with a combination of cavity-fill insulation in the walls and rigid insulation on the exterior. We planned to use Zip sheathing from Huber Engineered Woods as the air barrier (with all edges and joints taped), allowing the interior insulation system to dry to the interior and a moderately permeable exterior insulation to dry to the exterior.

Had this been new construction, we would probably have picked a very different insulation system that relied just on (less expensive) cavity-fill insulation, but we were dealing with an existing 200-year-old frame as out starting point, so we decided early on that exterior rigid insulation would be part of the system, and to meet our R-value goals we opted for six inches of cork.

Because we had installed six inches of another innovative insulation material (Foamglas) on the outside of the new foundation walls, continuing the six-inch, non-structural layer upward on the wall made a lot of sense. The six inches of cork would add about R-21 to the wall system.

An old two-person cross-cut saw removed a much smaller kerf and the large teeth did a good job at removing sawdust.
Photo Credit: Alex Wilson

Shiplap edges

In experimenting with the cork samples we recognized that tight joints—as you can achieve with rigid foam insulation—would be hard to achieve with the product, so we wanted to avoid joints extending through the material. Installing two layers of 3" cork was an option, overlapping the joints, but we opted to order 6" material with shiplap on all edges so that through-gaps would be avoided.

Working up from the foundation, the bottom edge of the first course of cork was beveled to match the drainage bevel that we created with the Foamglas foundation insulation. That first course was installed on top of a metal termite-flashing layer that our roofer, Travis Slade, made up.

The shiplap was configured so that any moisture running down the outside of the cork would remain on the outside and not extend through it. At the corners of the building, the overlaps were tricky—but needed to ensure that no gaps extended through. Frankly, I’m not sure how Eli’s crew figured that out—but they did a great job.

The sloped sills in the window surrounds made for some tricky cuts.
Photo Credit: Alex Wilson

Cutting cork insulation

Just about every conceivable option was tried for cutting the cork: from tools our great-grandfathers would have used to high-tech timber-frame tools. The large teeth on a two-person crosscut saw proved very effective at minimizing the kerf thickness and keeping the kerf cleaned out as they cut, but a chainsaw-like timber-framing saw proved best for bevel cuts, though it created at fairly thick kerf.

One of the nice things about working with cork is that all the sawdust on the ground from the cutting is fully biodegradable. In fact, it may make a nice mulch!

Complicated angle cuts

There was really tricky detailing at the window surrounds. The bottom and top edges of the surrounds (see my earlier blog on window surrounds) are pitched, so the cork insulation had to be cut with a matching bevel and slid in. We wanted a fairly tight fit for energy-performance reasons, but they had to be able to slide the cork in. And in doing so, they had to make sure that the pre-applied Pro Clima Solitex weather resistive barrier (housewrap) on the window surrounds would remain exposed so that it could be properly overlapped and taped to the housewrap being installed on the whole house. Tricky detailing indeed.

Similarly challenging details had to be dealt with at the roof edge—both at the eaves and gable end, but the completed job looked great! Sadly, the cork is now hidden by the housewrap, but I loved admiring it before it was covered.

To hold the cork in place we used angled screws through the thinner top of the panel. Strapping will be screwed into the framing to hold the cork tightly.
Photo Credit: Alex Wilson

Securing the cork

As the sheets of cork were attached to the wall, the upper shiplap edge was screwed into the framing with angled screws. Once the housewrap layer is entirely installed, full-dimension, 1" x 3" strapping will be installed vertically and screwed into the framing with 8” Simpson Strong Tie screws. The screws will be countersunk into the strapping, providing a little over an inch of purchase into the Zip sheathing and framing. Horizontal clapboard siding will then be nailed onto the strapping.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-03-27 n/a 12564 Cork Insulation on Our Farmhouse

Why we chose cork exterior insulation for our net-zero-energy house

Installing cork insulation on our farmhouse. Click to enlarge.
Photo Credit: Alex Wilson

Among the innovative—some might say weird—products we’re trying out at our Dummerston, Vermont farmhouse, none is more unusual than the expanded cork insulation we’re currently installing as a layer of exterior rigid insulation. As I mentioned in a blog last summer, cork insulation has a great story behind it.

Cork? You’ve got to be kidding!

I first learned about expanded cork insulation years ago when exploring the attic of a 1920s-era home in Brattleboro. I found a rigid boardstock insulation comprised of cork with plaster on one side. It was made by Armstrong, which was then a company making cork products but is today one of the world’s leading manufacturers of flooring and ceiling products.

It turns out that the product was invented by accident in 1893 in New York City by a boat builder, John T. Smith. The cork granules he used to fill life preservers became clogged in a large tin funnel, and that slipped into the coals of a fire used to steam oak staves. When the owner of the shop discovered the tin funnel the next morning he expected the cork to be burned up, but instead it had expanded to fill the form and solidified into a solid block.

Smith experimented with the process and patented it as Smith’s Consolidated Cork, which he licensed to Armstrong. It was used for several decades for insulating buildings—especially cold-storage buildings. The apple storage building at historic Scott Farm in Dummerston, built in the 1920s or ’30s, is insulated with this product.

Detail of the cork insulation. Click to enlarge.
Photo Credit: Alex Wilson

Why I like cork

Cork is a remarkable material. It is the outer bark of a species of oak tree (Quercus suber) native to the Western Mediterranean region. This thick, spongy bark protects the trees from fire. It can be peeled off every nine or ten years, and grows back. The bark is still harvested in Portugal, Spain, Algeria, Morocco, Tunisia, France, Italy, and a few other countries much as it was 2,000 years ago.

The primary use for cork is for wine bottles. The “corks” we all know are punched out of the bark in a really simple process. The residual cork (about 65-70% of the material) is processed into granules that are processed into a wide variety of uses.

To make cork flooring, floor underlayment, and gaskets, the granules are glued together and sliced into thin layers. Cork makes a great flooring material, because it is soft underfoot (resilient) and it absorbs sound. You will often find it in libraries, for example, due to those acoustic properties. My aunt and uncle installed cork floors in their Connecticut house in 1951, and that flooring is holding up very well more than 60 years later.

Cork is produced from ecologically rich forests that support significant biodiversity, including the endangered European lynx.

The cork arrived three-to-a-pack, and we've been storing it in our barn all winter. Click to enlarge.
Photo Credit: Alex Wilson

Avoiding foam insulation

The primary reason I’m excited about using cork insulation on our house is that I don’t like some of the chemicals used in conventional foam insulation. Extruded polystyrene is made with a blowing agent, HFC-134a, which is a very potent greenhouse gas that is contributing to climate change, and nearly all foam insulation materials contain hazardous brominated or chlorinated flame retardants. I’ve most recently written about these concerns here.

Cork, by contrast, contains nothing but cork—nothing! As it is produced today by Amorim Isolamentos, S.A., the granules are poured into large vats and heated with steam in an autoclave at about 650°F for 20 minutes. The heat expands the granules by about 30% and releases a natural binder, suberin, that exists in the cork. There are no added ingredients.

Isn’t cork a limited resource, or isn’t there a cork blight?

I get these questions whenever I mention cork. As far as I can tell, these were rumors that were started by companies making synthetic bottle stoppers for the wine industry that were trying to take away market share from natural cork. No, to the best of my knowledge there isn’t a blight.

Bundles of cork awaiting installation.Click to enlarge.
Photo Credit: Alex Wilson

Cork is a somewhat limited resource, so cork insulation will never come to dominate the rigid insulation market. But the resource is not disappearing and clearly it is a renewable resource.

The sad part of the story is that as synthetic corks and screw-lid wine bottles have replaced traditional natural-cork bottle-stoppers, the demand for cork has dropped. I’m told that in some parts of the western Mediterranean region, cork oak forests are being cut down and the land converted to other uses.

Shipping cork to Vermont from Portugal

I’ll admit that shipping cork across the ocean is a significant downside. While ocean shipping is very energy-efficient (far more efficient than shipping over land), the fuel used—a low grade of diesel—is very dirty. I struggled with that as I thought about the use of this material for our house. I’ve reviewed an analysis Amorim Isolamentos has done on the carbon footprint of their material, and it’s not too bad.

Detail of the cork.Click to enlarge.
Photo Credit: Alex Wilson

Ultimately, I decided that by publicizing our use of this material I would help generate demand that might help preserve the cork forests. I don’t expect that the U.S. will ever become a huge market, but for people wanting natural and rapidly renewable building materials or who have chemical sensitivities, cork is an option that can be considered. (Relative to chemical sensitivities, care should be taken to make sure that there isn’t sensitivity to the odor of expanded cork, which has a somewhat smoky smell—no doubt due to the heating.)

Our use of cork insulation

We are installing cork as a layer exterior insulation on our farmhouse. The air barrier for the significantly rebuilt early-1800s house is a fully taped and airtight Zip sheathing layer. On the interior of that will be 7-1/2” of cavity-fill insulation. On the outside of the sheathing is the 6” layer of cork.

The building enclosure is designed so that the cavity-fill insulation layer can dry to the interior (if it ever gets wet), while the cork can dry to the exterior. On the outside of the cork will be a layer of housewrap (a high-performance German product, Pro Clima Solitex, distributed by 475 High Performance Building Supply), vertical strapping to create a rainscreen, and wood clapboard siding.

Installation proceeding. Click to enlarge.
Photo Credit: Alex Wilson

We ordered the cork with shiplap edges so that joints would not extend all the way through the material. We had debated ordering 3" thick cork and overlapping the joints—and that strategy would have worked fine—but we decided that we could save on labor with the thicker panels.

Next week I’ll provide some specifics on how the cork insulation is being installed. Eli Gould and his crew have done a wonderful job at figuring out how to work with the stuff—some of the details are quite tricky.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-03-19 n/a 12556 Transparency in Building Products, and HPD, Gain Momentum

With the HPD now available as a recognized format, design professionals have started to request its use by manufacturers.

[Editor's Note: This guest post comes to us courtesy of Russell Perry, FAIA, managing director of SmithGroupJJR's Washington, D.C., office.]

The global movement towards transparency gains steady momentum. In the design and construction world, the 2012 Greenbuild conference saw the launch of the Health Product Declaration (HPD) format, the launch of the eagerly awaited Declare format, and USGBC CEO Rick Fedrizzi’s spirited defense of practitioners’ need to know what chemical exposure comes with material choices.

The HPD format dates from a meeting called by the Healthy Building Network and BuildingGreen in July 2011. This ad hoc group, representing all aspects of the building industry, sought a means for members of the design and construction industry to make more informed choices about materials. It conceived of a standard format for reporting product content and associated health information of building products.  A working group was formed that issued a draft and ran a year-long pilot program with thirty manufacturers, leading to a launch of the HPD late last year.

Use at design firms

With the HPD now available as a recognized format, design professionals have started to request its use by the manufacturers who wish to have their products considered for specification and use.  In the past few months, HKS, SmithGroupJJR and Cannon have all issued letters to the manufacturers in their databases with versions of this same request.  Other firms are on the verge of making their own requests. Some of them are like to follow Cannon’s lead with a provision that, over time, only materials that are fully disclosed will be welcome at “lunch-and-learn” educational sessions and allowed in the office library.

Here at SmithGroupJJR, the request for disclosure and transparency has led to a series of contacts from manufacturers who are seeking more information about this position and are looking for guidance in how to comply.  Without question, we are very happy to see this reaction to our firm’s position.

Leadership search

As with any standard or format, the initial usage is exposing opportunities for greater clarity and ease of use.  These improvements can only help accelerate adoption.  To facilitate the speedy development of the program and to expand its use, the HPD Collaborative, the group administering the format, is now seeking its first permanent Executive Director. The job description as posted at, calls for an exemplary green building professional with working knowledge of building materials and the associated health concerns, deep knowledge of green building rating systems, practical experience in the industry and a record of working with various constituents to achieve goals.  The position can be filled anywhere in the country and can be part-time or full-time.  Interested applicants should submit resume or CV, and letter of interest to by Wednesday, March 20.

The HPD Collaborative imagines that by this summer, within two short years, it will have travelled the full path from an idea to a robust standard format backed by a functioning organization and led by respected practitioners from the industry.

Russell Perry, FAIA, is the managing director of SmithGroupJJR's Washington, D.C., office and its Corporate Sustainability Initiative. He is a board member for the HPD Collaborative and a member of the EBN Advisory Board.

2013-03-14 n/a 12551 Windows 2.0 – Report from Leonard Farm

Building complex window surrounds for a deep-energy retrofit

Insulated, splayed window surrounds that will frame the exterior wall insulation. The Pro Clima housewrap on the window surrounds will be taped to the wall housewrap after insulating. Click to enlarge.
Photo Credit: Alex Wilson

A few weeks ago I reported on the amazing, high-tech Alpen, R-12 (center-of-glass) windows that we installed on the north and west facades of our farmhouse in Dummerston, Vermont. At that time I promised to report on the other windows we were installing on the south and east facades (windows 2.0 if you will).

First some context:

With our new home, we are creating a demonstration with dozens of cutting-edge energy-saving and green building features and products that one can include in a new or existing home. As someone who has written about such products for several decades now, this is a lot of fun—though the decision-making often remains a challenge, since there are so many great products and materials to select from.

With our house—the rebuild of a 200-year-old Vermont Cape—we wanted to demonstrate what one might do to dramatically improve the energy performance of existing windows if those windows are in good enough shape that one can’t justify replacement. So that’s what we set out to do on the south and east facades—only we installed new windows, because what had been there (installed in the 1970s I suspect) were small and didn’t serve our needs.

In our product research, we were looking for was a solidly built wood window that would look great in an historic home, not cost too much, and offer reasonable performance.

Two members of Eli's crew pre-fabricating a window surround. Click to enlarge.
Photo Credit: Alex Wilson

Good quality, honest wood windows

The new windows we installed on the south and east walls are wood, double-hung Norwood windows with a high-solar-gain low-e coating. They are made in New Brunswick, Canada, reasonably affordable, and—by most standards—energy efficient. But the center-of-glass R-value is only about a third of what we achieved with our high-tech, quad-glazed, triple-low-e coated, Alpen windows.

We decided to install these windows in the plane with the wall sheathing (Zip sheathing from Huber Engineered Woods serves as the wall system’s air barrier) and then build window surrounds to frame the six inches of exterior insulation to be installed on the walls. This will be a fairly common need with existing houses if we are to carry out “deep-energy retrofits” that rely on exterior insulation.

Roofer Travis Slade and some of his handiwork. Click to enlarge.
Photo Credit: Alex Wilson

Our Norwood windows use a specialized low-e coating from Guardian Glass Industries. It is a sputtered coating (like most low-e coatings being used today), but it has very high transmissivity. In other words, it is highly transparent, both to visible light and solar heat gain.

Both of those glazing properties were important to us: the visible light because we want our house to have as much daylighting as possible with unimpeded views of the gorgeous surroundings; and the high solar heat gain because, on the south, we want to benefit from passive solar heating.

The windows use Guardian’s ClimaGuard 75/68 glass (PDF file), and in our double-glazed configuration with a half-inch gap filled with argon, the windows provide 75% visible light transmittance, a solar heat gain coefficient (SHGC) of 0.684, and a U-factor of 0.275 (R-3.64).

Ready for storm windows

We were willing to accept the relatively low R-value (3.6 is a far cry from 12.2 that we achieve with the Alpen Windows), because we’re planning to add high-performance storm windows toward the outside of the window surrounds. We haven’t figure out exactly what type of storm window we will add, but our designer-builder, Eli Gould, designed the window system with an added storm in mind.

Eli refers to our window surround system, which can accept storm windows, as the WindowPLUS™ system. Functions include extending the wall out to the plane of the exterior insulation, providing a framework for the sophisticated system of air-sealing and weather-protection components, providing a thermal break at the window edge, housing the high-performance storm windows, and potentially providing a space to house a hidden, roll-down screens or shades.

Specialized peel-and-stick tapes from 475 are being used to produce weather-protected and airtight window installations.
Photo Credit: Alex Wilson

Our hope with the storm window is to work with some leading manufacturers to envision and build the ideal storm window for deep-energy retrofits. It will be highly durable with a frame made of either aluminum or fiberglass, and it will include low-e glass. We’re trying to figure out whether it will include an integral screen with an operable glass panel, or whether—like old-fashioned storm windows—require seasonal removal. The more durable storm window will also offer protection of the wood-framed prime windows..

With our application we are trying to determine whether having two low-e coatings—one on the prime window and one on the storm—will cause the temperature between the two windows to get too high. This may inform the type of low-e coating we use or other material decisions. With older prime windows that don’t include low-e glass, this wouldn’t be a problem. In fact, we would like to see a storm window developed that could be configured with insulated, low-e glass for an even higher level of performance.

Splayed window openings

Another great feature of Eli’s WindowPLUS system—one that took some real figuring—was to splay the openings so that more light will enter and the view out will be less restricted. Our total wall thickness will be about 15 inches, and without the splayed openings it might seem that one is looking out through tunnels.

Norwood window installed prior to adding the window surround.
Photo Credit: Alex Wilson

Eli developed a system that allowed these splayed window frames to be pre-fabricated and installed with lapped weather barriers (high-tech German products that we got from 475 High Performance Building Products, a specialized product distributor targeting the Passive House movement) and a pre-formed metal sill cladding.

Next-up: the tricky installation our exterior cork insulation.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-03-13 n/a 12463 FTC Cracking Down on False R-Value Claims

Large fines levied on companies making deceptive claims about R-values

Exaggerated claims, like this one for SUPER THERM, claiming R-19 for a coating of paint, are getting the attention of the Federal Trade Commission. Click to enlarge.
Photo Credit: Superior Products International.

Most of us want to do the right thing in improving the energy performance of our homes. We research energy-saving products like appliances and insulation. We search the internet or clip ads from the paper looking for products that will save us the most energy (and money). We look for the most R-value for the money. Well-meaning homeowners do this all the time.

But it turns out that in a troubling number of situations there’s a significant discrepancy between claimed and actual performance. With insulation materials, for example, exaggerated R-value claims became so rampant in the 1970s—when adding insulation to homes came into vogue following the 1973 oil embargo—that the government stepped in to regulate energy performance claims.

The threat of fines hasn’t been as successful as we might have hoped, as exaggerated claims have long continued. Some long-overdue legal actions against insulation companies in January 2013, however, may finally begin to rein in these scams.

The Federal Trade Commission Finally Doing Its Job

When R-value scams became common in the 1970s, the U.S. Congress passed legislation assigning the Federal Trade Commission (FTC) to the task of policing R-value claims. The so-called “R-Value Rule” was adopted in 1979. That rule helped to some extent, but grossly exaggerated R-value claims have continued.

A $350,000 fine leveled against Edward Sumpolec, doing business as Thermalkool, Thermalcool, and Energy Conservation Specialists, on January 9, 2013 may cause insulation producers and installers to be a little more careful with their claims. These companies were selling both liquid-applied coatings and radiant-foil insulation materials.

According to a January 31, 2013 FTC press release, “Sumpolec’s advertising included false claims such as ‘R-100 paint,’ ‘This . . . reflective coating will reduce wall and roof temperatures by 50-95 degrees . . .’ and ‘Saves 40 to 60% on your energy bills.’” The U.S. Department of Justice, working on behalf of FTC, won the order on the merits of the case, without requiring a trial. This was the largest fine ever levied on an insulation company based on a violation of the FTC R-Value Rule.

Avoiding scams

Inflated R-value claims like Sumpolec’s are so blatantly obvious that most consumers won’t be duped by them. But there are many, many cases where the claims aren’t quite as over-the-top, and it’s very easy for reasonably smart consumers to be duped.

I don’t know how many calls I received over the years from friends and family members who are thinking of contracting to have their attics insulated with radiant-barrier insulation or radiant paint or extraordinarily high-R-value rigid insulation.

If it sounds too good to be true, it probably is.

It’s not just insulation

Exaggerated energy performance claims aren’t limited to insulation. I have often seen ads in our local newspaper’s weekend magazine for seemingly magic electric quartz space heaters, and one can find outrageous savings claims for fairly ordinary windows, exaggerated claims for the benefits of weatherizing services, and highly misleading claims about home-scale wind turbines.

There was even a class-action lawsuit against Honda Motors for unrealistic mileage claims with its Civic Hybrid (we’ve had ours since 2003 and just turned over 170,00 miles).

Share your examples of outrageous claims

Consumers deserve to have access to clear, accurate information on the energy performance of products they buy. And manufacturers who violate that trust deserve to be called out for their deceptive claims. I’d like to compile examples of these outrageous claims and then publicize them—somehow.

(I may have to let my lawyer weigh in on how aggressive I can afford to be in this campaign for truth in advertising.)

Send links to unrealistic energy claims by manufacturers or service providers to me directly, or post comments below.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-02-20 n/a 12422 Wind Power: Why it Doesn’t Make Sense Everywhere

I'm a huge fan of wind power, but we should recognize that some applications of wind don't make sense

Aerovironment wind turbines on the Boston Museum of Science. Performance has been poor and Aerovironment has discontinued the product. Click to enlarge. 
Photo Credit: David Rabkin, Boston Museum of Science

At least in our neck of the woods, wind power is very much in the news these days. The Vermont legislature is debating whether to institute a three-year moratorium on what detractors refer to as “industrial wind power,” and debate is raging in the nearby towns of Windham and Grafton, Vermont about a potential wind farm. I figured I should weigh in.

As readers of this blog know, I am a strong proponent of renewable energy, including wind power. But I’m also not shy about pointing out situations in which wind power doesn’t make sense. This week I’m going to focus on those misguided or less attractive wind power applications. Next week I’ll cover where we should be heading with wind power and discuss projects like the one proposed for Windham and Grafton.

Don’t put wind turbines on buildings

Wind turbines almost never make sense on buildings—even tall buildings. When I started researching “building-integrated wind” a few years ago for my newsletter, Environmental Building News (EBN), I thought I was going to write an article that painted a positive picture of putting wind turbines on top of buildings. After all, tall buildings can get the turbines up high where it’s windier, and like rooftop photovoltaic (PV) systems, the power is generated right where it will be used.

But the more I dug into it, the more clear it became to me that building-integrated simply does not make sense.

First, wind turbines installed on buildings have to be small so that they won’t affect the building’s structure, so the power-generation potential is limited.

Second, wind turbines generate significant noise and vibration. That can be okay when the turbines are a quarter-mile away, but on a building it can be a real problem—particularly with a steel-framed commercial building that transmits noise and vibration throughout the structure.

Third, dealing with turbine installations on buildings increases costs significantly. Special attachments are required, and loads may have to be distributed downward through the building.

Fourth, even if the economics work out it’s hard to believe that insurance companies would embrace the installation of wind turbines on buildings. I suspect that insurers would raise insurance rates significantly, due to the increased liability—or perceived liability—of blades flying off wind turbines or rooftop towers collapsing and damaging roofs. Insurance rates wouldn’t have to rise very far for those costs to exceed the value of the generated electricity.

Finally, it turns out that all that wind swirling by tall buildings is highly turbulent. Wind turbines don’t like turbulence; they do much better with like laminar wind flow. Some types of wind turbines apparently do better with turbulence than others, but most don’t perform well in such conditions.

An installation of the Swift Wind Turbine at the Boston Museum of Science. Swift turbines were developed by Renewable Devices in Scotland and are manufactured in Michigan. Click to enlarge. 
Photo Credit: David Rabkin, Boston Museum of Science

The lack of performance data

When I was researching my EBN article, I spent weeks trying to track down performance data on building-integrated wind turbines, but could find almost none. I knew that that data was being collected by manufacturers (up to a dozen manufacturers were producing wind turbines specifically designed for installations on buildings), and the fact that they didn’t want to share it made me suspicious that it was far worse than those manufacturers were claiming.

With a lot of anecdotal evidence of extremely bad performance of building-integrated wind turbines, I got more and more discouraged about the practicality of putting turbines on buildings, and I ended up titling my May, 2009 EBN article “The Folly of Building-Integrated Wind.” Wind turbines don’t belong on buildings.

After my article came out, I finally tracked down some performance data from the Boston Museum of Science, which installed building-integrated wind turbines from five different manufacturers. As I suspected, the performance was terrible—far lower than manufacturer claims. You can learn more about the Museum of Science wind power experiments here.

With ground-mounted wind turbines, smaller is not better

Even when we stick with ground-mounted wind turbines, the performance and economics of small machines (a few tens of kilowatts (kW) of rated output and less) is usually very poor. With wind turbines there is a huge economy of scale. Home-scale wind power rarely makes good economic sense—except in locations where there is strong, steady wind.

I’m disappointed by this. I would really like to think that I could install a cost-effective wind turbine at my home, but I can’t. A good site for wind power—where there a strong 15 mph wind much of the time—wouldn’t be a place you’d want to live. And with small wind turbines you can’t put them too far from the place where the power will be used or fed into the utility grid. So even if your property rises up to a ridge, putting a small wind turbine there may not be feasible in terms of getting the power down to your house or feeding it into the power grid.

Studies I’ve examined where actual performance of small, ground-mounted wind turbines has been collected, the measured output has been significantly below the predicted output. Plus, the maintenance requirements are significant. Compared with the alternative—arrays of PV modules that just sit there with no moving parts—it’s just a whole lot more difficult to justify small wind. The economics usually don’t work.

Next week, we’ll look at where wind power can make sense: much larger wind turbines that can be aggregated into wind farms.

BTW, I’ll be presenting an all-day, pre-conference workshop, Skills for Building Resilient Communities, with three colleagues, Don Watson, FAIA, Joel Gordes, and Maureen Hart, at the Northeast Sustainable Energy Association’s annual Building Energy Conference on Tuesday, March 5th. Details can be found here.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-02-06 n/a 12399 State-of-the-Art Windows Installed in Our New Home

Top-performing quad-glazed windows from Alpen installed with three low-e coatings and krypton gas fill

R-12 windows from Alpen with three low-e coatings and krypton gas-fill. Click to enlarge.
Photo Credit: Alex Wilson

Having written about windows and emerging window technologies for longer than I care to admit (since before low-e coatings even existed), I must say that it’s incredibly fun to be building a house and having an opportunity to try out some of the leading-edge stuff I’ve been writing about.

In my effort to create a “demonstration home,” we are actually installing two very different types of windows in the 1812 farmhouse rebuild that’s underway. On the north and west facades we’re installing state-of-the-art, fiberglass-framed casement and awning windows from Alpen High Performance Products. These windows, which we ordered from Pinnacle Window Solutions in Maine, are the subject of this blog.

On the south and east facades (which you see from the road) we’re doing something very different that I’ll describe in a future blog.

Fiberglass frames

Traditionally, residential windows have been wood-framed. I love the look of wood, and if properly maintained, wood windows can last a long time: the twelve-over-twelve windows in the late-1700s house we currently live in are still hanging on after more than 200 years. But there are drawbacks to wood, including decay and the need for regular maintenance.

Besides wood, the primary materials used for window frames today are vinyl (a misleading abbreviation for polyvinyl chloride or PVC), aluminum, steel, and fiberglass. Due to the very high conductivity, aluminum and steel are less common today in residential windows. Due to its low cost, vinyl has increased dramatically in popularity, finally surpassing wood as the leading window frame material a few years ago.

This quad-pane awning window has two suspended Heat Mirror films. Click to enlarge.
Photo Credit: Alex Wilson

A lot of wood windows try to achieve the best of both worlds with vinyl or aluminum cladding on the exterior (for durability) and exposed wood on the interior. I think this is a nice compromise between appearance and durability and I recommend cladding for most wood windows.

The Alpen windows we installed are fiberglass-framed. Fiberglass is much stronger than vinyl, it has a much lower coefficient of thermal expansion (i.e., it doesn’t expand and contract as much when warmed by the sun and cooled at night), and it has hollow cavities that can be insulated with polyurethane insulation.

Our window glazings are 1-3/8" thick—much thicker than standard insulated glass (typically 7/8” or 1”). With the polyurethane insulation, these frames provide an insulating value of about R-4.3 (U=0.23), as calculated using industry-standard methods. Being fiberglass, they are highly durable and should not require maintenance—though fiberglass does take a coat of paint much better than vinyl, should we ever choose to paint them.

Outrageously high-performance glazing

While standard windows today are double-glazed (two layers of glass separated by an air space), our Alpen windows are quad-glazed—meaning there are four layers of glazing. The inner and outer glazings are 1/8" glass, while the two inner glazings are suspended polyester films.

On three of these layers of glazing there are low-emissivity (low-e) coatings. The outer pane of glass is made by Cardinal Glass Industries and includes a high-solar LoE-180 coating on the inner surface of that pane (the #2 surface in window-industry parlance). This low-e coating is appropriate in northern climates because it lets a lot of solar gain through and it’s clearer to look through.

The suspended polyester films both have Heat Mirror 88 coatings (on the #4 and #6 surfaces). Heat Mirror, made by Southwall Technologies, was actually the first type of low-e coating to be commercialized back in 1981. Heat Mirror coatings are available in various forms (HM88, HM77, SC75, HM66), with the number indicating the transmittance through the glazing; HM88 allows the most solar gain.

This bladder contains krypton and is connected to the inter-glazing space in the window. It allows for pressure equalization during shipping; the connecting tube will be crimped and cut. Click to enlarge.
Photo Credit: Alex Wilson

Another important strategy for reducing heat loss through windows is to substitute a low-conductivity gas for air in the air space. Argon is commonly used as a gas-fill, and for windows the size of ours replacing air with argon would boost the insulating performance by about 28%. For our windows, though, Alpen used a mix of 90% krypton and 10% air. This results in a 40% improvement over argon and a 79% improvement over air!

Energy performance

So what do all these bells and whistles provide in terms of energy performance? I was astounded when my friend at Alpen, Robert Clarke, sent me the following performance numbers:

  • Performance for the glazing only (calculated using Window 6.0):
  • Center-of-glass R-value: 12.2 (U=0.082)
  • Solar heat gain coefficient: 0.44
  • Visible transmittance, Tvis: 62%
  • Light-to-solar gain ratio (Tvis/SHGC): 1.4
  • Passive performance coefficient (SHGC/U-factor): 5.3
  • Winter interior glass surface temp. (assuming 0°F outdoor, 70°F indoor, 12 mph wind): 65°F
  • Acoustic control (STC): 34
  • UV blockage (380 nm): 100.0%

The National Fenestration Rating Council (NFRC) has developed methodologies for testing and reporting unit or full-frame window performance. Our window configuration has not gone through that NFRC testing, but estimated full-frame values are as follows:

  • R-value: 8.3 (U=0.12)
  • Solar heat gain coefficient: 0.39
  • Visible transmittance: 51%

An R-12 window (R-8 unit value) is hard to believe. This insulates as well as a 2x4 wall insulated with fiberglass, yet also brings in significant solar gain and daylight, while providing clear views to the outdoors. I look forward to reporting on the performance and durability of these windows over time.

Alpen HPP a leader in window technology

We have installed these exceptional windows partly as a research experiment. Since our house will not be up to Passive House standards (a rating system that originated in Germany for super-low-energy homes), I’m not sure we would have been able to justify such high-performance windows if Alpen’s Robert Clarke hadn’t wanted me to have them and provided them at a great price.

I’ve known Robert and his company Alpen, for many years. He and Alpen have been the leaders with high-performance windows in the U.S. since way back in the mid-1970s, consistently way ahead of the curve in introducing new technologies.

Several years ago Clarke sold Alpen Windows to Serious Materials, a venture-capital-funded company that sought to change the world with innovative products and materials. But Serious Materials may have spread itself too thin, and there were some quality-control problems with their windows.

Last year, Robert and a partner were successful in buying back Alpen from Serious Materials. I’m hopeful that the company can regain its stature at the top of the window-performance pack—and give the European Passive House windows a run for their money.

It is thrilling to have installed in our home in Dummerston what may be among the highest-performance windows in the country.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-01-30 n/a 12336 Making Healthier, Greener Foam Insulation

A proposed change to the residential building code (International Residential Code) would eliminate the need for halogenated flame retardants in many applications

For this Passive House in New York's Hudson River Valley, 12 inches of XPS were installed beneath the concrete slab. With proposed changes to the IRC, subslab insulation wouldn't need to be treated with flame retardants. Click to enlarge.
Photo Credit: Jordan Dentz

As readers of this blog know, I’ve come down fairly hard on certain types of foam insulation over the years. The downsides include the blowing agents used in extruded polystyrene (XPS) and most closed-cell spray polyurethane foam and the flame retardants that are added to all foam-plastic insulation to impart some level of fire resistance.

Now there’s an effort afoot to change building codes in a way that would allow manufacturers to remove the hazardous flame retardants. This is the subject of a just-published feature article in Environmental Building News (log-in required).

This is a significant energy issue, because layers of foam insulation provide the easiest way to achieve the level of energy performance needed to approach net-zero-energy performance. If we’re going to add a lot of foam insulation to our homes, we want that to be safe for the occupants and the environment.

Flame retardants used in foam insulation

We don’t want insulation materials to catch fire, so it is logical to add flame retardant (FR) chemicals to these materials if it will prevent them from catching fire. That’s the reason HBCD (hexabromocyclododecane) is added by all polystyrene insulation and TCPP (Tris (1-chloro-2-propyl) phosphate) is added to most polyisocyanurate and spray polyurethane foam  insulation. These are both halogenated flame retardants—the first using bromine, the second chlorine.

The problem with these halogenated FRs is that they have significant health and environmental risks. The HBCD that is used in all polystyrene (both extruded and expanded) is being targeted for international phase-out by the Stockholm Convention on Persistent Organic Pollutants. It is highly persistent in the environment and bioaccumulative in the food chain; it is believed to cause reproductive, developmental, and neurological impacts. Less is known about the TCPP used in spray polyurethane foam and polyisocyanurate, but there is significant concern in the health and environmental community.

Building codes require that foam-plastic insulation meet a very specific flammability standard. But building codes also require—for most applications—that foam insulation has to be separated from living space by thermal barriers, such as gypsum drywall.

The efficacy of flame retardants compared with thermal barriers

Combustion studies that were done in the 1970s showed that if the insulation is not protected with a thermal barrier, there is no correlation between the presence of FR and the extent of the resultant fire. Thus, the inclusion of a FR does not seem to appreciably increase the fire resistance of foam insulation, according to a peer-reviewed technical paper recently published in the journal Building Research and Information.

However, thermal barriers like half-inch drywall work extremely well at containing fires. The 15-minute protection provided by half-inch drywall gives occupants time to escape a fire. In other words, of the two measures used to impart fire safety to a building assembly (FRs in foam insulation and thermal barriers) almost all of the fire safety benefit is provided by the thermal barrier.

A house under construction in Naperville, IL wrapped in XPS that will be thermally separated from the living area. Click to enlarge.
Photo Credit: Alex Wilson

Changing building codes to allow elimination of flame retardants

Because the vast majority of the fire safety in a building enclosure is provided by the thermal barrier, a group of environmentally aware architects, chemists, and code experts is seeking to change building codes to allow non-FR foam to be used in applications where adequate protection is provided by a thermal barrier. (Disclosure, I have been involved in this initiative.) The code change would allow the FR-free foam to be used below-grade, where the insulation is sandwiched between concrete and earth (hardly a fire risk), and where the foam is separated from the living space by a 15-minute thermal barrier, such as half-inch drywall.

For the former application (below-grade insulation), I believe it’s a no-brainer. Over half of XPS is installed below-grade, so I think there could be a very viable product free of FRs for this application. The change to building codes wouldn’t mandate the elimination of FRs, but it would give manufacturers the option to do so if they chose to. Eliminating the FR for above-grade applications where there is a 15-minute thermal barrier isn’t a slam-dunk, but I believe the case being made is strong.

Changing building codes, however, is a long, challenging process; I don’t know what chances the initiative has. In my article research, manufacturers expressed reservations that they don’t want to have to produce, distribute, and market two different lines of material, and they point out that they also have to be concerned with fire safety of material being stored and during construction (before drywall is installed).

On the other hand, though, foam insulation manufacturers spend a lot to incorporate FRs into their products. The insulation contains a not-insignificant amount of these chemicals: 12.5% TCPP in open-cell spray polyurethane, 4% TCPP is closed-cell spray polyurethane, and 2.5% HBCD in extruded polystyrene. A lot of the strategies for “greening” building products increase the manufacturing costs, while removing expensive FRs should reduce costs. So there is some interest by the industry in this change.

As described in our Environmental Building News article this month, “Getting Flame Retardants Out of Foam Insulation,” the code-change initiative is being targeted, initially, at the International Residential Code. If successful, an effort to change the International Building Code (for commercial buildings) will follow.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2013-01-08 n/a 12274 Open-web rafters for superinsulated roofs

Open-web, parallel-chord joists with solid-wood diagonal struts for use as superinsulated roof rafters.

Open Joist Triforce rafters being installed on our house. Click to enlarge.
Photo Credit: Alex Wilson

Last week I wrote about an innovative foundation insulation material, Foamglas, that we used in our new house in Dummerston. This week I’ll talk about the open-web rafters we’re using to achieve a superinsulated roof.

First, a little background. To create highly insulated roofs there are several approaches:

When the insulation is installed in the attic floor (creating an unheated attic), it’s easy to obtain very high R-values inexpensively—it’s cheap, that is, as long as you don’t count the cost of the lost living space by creating an unheated attic. Basically, you just dump in a lot of loose-fill cellulose or fiberglass on the attic floor, filling the joist cavity and more.

I’ve heard of as much as two feet of cellulose insulation being installed in this manner, achieving about R-80. To make room for a lot of insulation at the roof eaves, it’s usually necessary to install “raised-heel” trusses for the roof framing (so that the insulation thickness at the edges is not significantly compromised.

The Triforce joists are made with solid-wood diagonal struts and glued, finger-jointed connections. Click to enlarge.
Photo Credit: Alex Wilson

If you want to insulate the sloped roof, creating living space—as we are doing—you can either install very thick rafters (14 inches or more) that can be filled with cavity-fill insulation, or you can provide more modest roof trusses or rafters and then add a layer of rigid insulation on top of the roof sheathing. An advantage of the latter approach is that the layer of rigid insulation controls the “thermal bridging” through the rafters or top chords of the roof trusses.

To keep the insulation costs down and minimize our use of foam-plastic insulation, we opted for the former option—putting all our insulation in the rafter cavities rather than installing a second layer of outboard insulation.

Finding deep-enough rafters

To achieve the 16-inch depth we wanted for insulation and an air space under the sheathing, we used open-web, parallel-chord trusses as the rafters. These trusses, typically used as joists, have diagonal bracing or “struts” and are made by in Quebec by Open Joist Triforce.

Unlike most parallel-chord trusses, Tri-Force uses solid wood, rather than OSB, and finger-jointed glue joints rather than metal truss plates for attaching chords and webs. Some experts are concerned about the long-term durability of OSB webs in more common I-joists and the metal fasteners in standard roof trusses.

The chords on Triforce joists are either 2x3s or 2x4s, and the diagonal struts are solid-wood 2x2s. Connections between the struts and chords are achieved with precision-machined grooves and polyurethane adhesive. The wood is all northern, slow-grown spruce, rather than plantation-grown southern yellow pine or poplar.

Detail showing finger-jointed glue joint. Click to enlarge.
Photo Credit: Alex Wilson

Triforce joists include a section of OSB at the ends so that the length can be adjusted. This permits manufacturing in standard lengths and keeps the costs down.

Providing a stem wall and roof overhang

In our case, to expand the living area in the upstairs of our compact house, Eli Gould added “raised heels” to the roof trusses. The OSB tails on the Triforce rafters made this fairly straight-forward, though it certainly involved some additional labor. The design at the roof eaves also provides for nearly two feet of roof overhang—a high priority in keeping moisture off the wall and away from windows and foundation.

Despite the extra work with the raised-heel and overhang, the rafters went up quickly. Eli’s crew worked all-day on the Saturday before Superstorm Sandy came through to get the roof up and sheathed with Huber’s Zip sheathing (with joints taped). They were able to keep everything remarkably dry.

Insulation options

We have not made a final decision about the type of insulation we will use for the roof. We are deciding between dense-pack cellulose and acrylic-stabilized, blown-in fiberglass (probably Johns Manville Spider). With 14 inches of insulation, the difference in weight between cellulose (at about three pounds per cubic foot) and Spider (1.8 pounds per cubic foot) is significant.

With either material, we believe that by stapling up mesh-fabric baffle on each rafter we will be able to fill each rafter cavity completely—including all the corners where the diagonal struts intersect the chords. The small amount of acrylic adhesive in the JM Spider product may prove to be a significant benefit to us in fully sealing the cavities—so we’re leaning in that direction.

We think the fabric will help us achieve complete filling of the rafter cavity with fiber insulation. Click to enlarge.
Photo Credit: Alex Wilson

The two materials provide similar insulation values: about R-4.1 to 4.2 per inch for the JM Spider fiberglass and about R-3.7 per inch for dense-pack cellulose. With 14 inches of insulation, that would come to about R-58 with JM Spider, vs. R-52 with dense-pack cellulose.

From an environmental standpoint, cellulose has higher recycled content (about 80% recycled newspaper), though fiberglass insulation is now made using a significant amount of recycled glass (mostly from beverage containers). Johns Manville fiberglass is certified to have minimum 25% recycled glass content (with 80% of that recycled content being post-consumer).

Flame retardants are not required in the fiberglass, while borate and ammonium sulfate flame retardants are used in cellulose.

Here's the product listing in our GreenSpec database.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.



2012-12-04 n/a 12260 5 Cool New Products from the Greenbuild 2012 Expo Floor

From high-tech BIPV to smarter plugs for the home, we found lots of great new products at Greenbuild this year.

Lutron's Serena remote-controlled shades install easily and are inexpensive compared to most automated shades.
Photo Credit: Lutron

Greenbuild is always a great time to find new products and reconnect with friends and colleagues. It’s a busy, rewarding, and exhausting few days—especially this year, since the trade show was spread across three buildings and a couple of city blocks.

I did a lot of walking, but it was worth the effort. Here are a few of the products I spotted on the expo floor.

Health Product Declaration

One of the most exciting developments rolled out at this year’s Greenbuild is not really a product: the introduction of the Health Product Declaration, an open standard used to promote the transparent disclosure of product ingredients and their health impacts.

Many companies have already signed on to supporting this important initiative, and many had booths at Greenbuild, including ASSA ABLOY, Interface, Prososco, Crossville, InPro, Stego, and Teknion.

BIPV windows from Tropiglas

Tropiglas was displaying its building-integrated photovoltaic (BIPV) window technology, which uses a polymer layer sandwiched between two panes of glass. When sunlight passes through the first pane, it is captured by the inner layer and directed to the edge of the glass (similar to how optical fibers work), where standard monocrystalline PV cells convert the light to electricity.

The glass is free of visible cells, unlike most current BIPV glazing options, whose cells block part of the view. But the efficiency is only around 4% (35 watts/m2, 80% transparency, 90% IR blocking, SHGC< 0.41). The company claims the manufacturing process is similar to that of low-e coatings, so it shouldn’t cost much more to manufacture, but of course, you still have to contend with the other PV components and wiring.

Tropiglas is still looking for glazing partners but expects to have product on the market in 2013.

Energy enhancements for SafePlug products

SafePlug products protect occupants (particularly children) against electrocution and monitor plugs against overloads or discrepancies in the electrical flow that could lead to fires or damage electrical equipment.

The company’s products can now also increase energy efficiency: they control plug loads so that phantom loads are eliminated and occupants can monitor and turn off appliances. The SafePlug Energy Manager (find it in GreenSpec here) installs over standard outlets and comes with an “Energy Server” and “Energy Manager Outlets.” The outlet and server do not require an Internet connection for communication, but the server can be connected to Ethernet or Wi-Fi for remote monitoring.

Aquatec water submetering

The Aquatec submeter from the German company Sika (GreenSpec listed here) can be attached directly to a shower, urinal, or other fixtures to track and display water usage data. That information can then be downloaded via optical sensor or sent wirelessly and accessed remotely via any Internet-connected device.

Aquatex is available in white or clear, so you can see the inner machinations, and in a “split” version, where the mechanism and display are separate for easier installation and viewing.

Climate Wizard evaporative air conditioner

Climate Wizard (see it in GreenSpec here), from the Australian company Seeley International and distributed in the U.S. by L&H Airco, is a refrigerant-free indirect evaporative air conditioner similar to the Coolerado we list in GreenSpec and reviewed for EBN back in 2008.

The Climate Wizard uses fans with energy-efficient electronically commutated motors (ECM) to move air through a heat exchanger that contains both wet and dry channels.

Climate Wizard is a refrigerant-free evaporative air conditioner that provides cool, dry, fresh air along with energy savings.
Photo Credit: Seeley International

Heat is transferred across the membrane from the dry to the moist channel, where it is vented into the atmosphere.

The cool, dry, fresh air then passes into the building to provide cooling. Climate Wizard uses 6.6 gallons of water an hour for the 10 kW model (about 2.8 tons cooling); a 15 kW (4.3 tons) version is also available.

Climate Wizard is used primarily in commercial applications, but a residential unit is undergoing testing.

Affordable remote-control shades from Lutron

Lutron rolled out a couple of new products at Greenbuild, including its Sensor Layout and Tuning Service for fine tuning the performance of occupancy and daylight sensors so they work as advertised; and a KOOLBLACK rollershade material that reduces solar heat gain to the level usually only attainable with light-colored fabrics.

But the product that caught my eye was the company’s battery-powered, motorized Serena Remote Controlled Shades. Though not new (they were introduced at the end of 2011), these residential cellular shades are easy to install by a homeowner and can be operated via either infrared (IR) or radiofrequency (RF) controls. They can even be integrated with other lighting controls.

A more sophisticated control system is available in the company’s Sivoia line. These shades are powered by four standard D batteries, which should last three years, according to the company, because of its unique power management technology. Several material and color options are available, including double-cell and room darkening versions that have R-values of 3.6 and 4.3, respectively.

Starting at less than $280, they seem like a bargain in the remote-controlled shade industry.

And more!

There were, of course, a lot more vendors and products at Greenbuild, such as organic, drought-resistant grass with deep roots that requires minimal mowing; onsite water treatment systems that process water for graywater reuse; continuous insulation rainscreen claddings with mineral wool insulation; and more.

Look for those in upcoming blog posts and product reviews.

2012-12-03 n/a 12224 Gaining Experience with a New Material

Using Foamglas instead of polystyrene to insulate beneath our basement slab and on the foundation walls.

Eli Gould cutting Foamglas for use under our basement slab. Click to enlarge.
Photo Credit: Alex Wilson

In my role with Environmental Building News and our GreenSpec Product Database, I get plenty of opportunity to research and write about innovative building products. That’s one of the really fun aspects of my job.

On occasion I also get an opportunity to try out new or little-known materials. In the construction of our new home in Dummerston, Vermont—actually the rebuilding of a 200-year Cape—I’ve had opportunity to get some real experience with lots of products. One of these is a cellular glass insulation material known as Foamglas (check out Foamglas in GreenSpec).

Why we need a product like Foamglas

I’ve written often about the problems with extruded polystyrene from an environmental and health perspective. Relative to performance, extruded polystyrene (XPS) is a great product. It is water-resistant so can be used below-grade; it has high compressive strength so can be used beneath a concrete slab floor; it insulates very well (R-5 per inch); and it’s inexpensive. These properties make XPS the nearly universal choice for sub-slab and exterior foundation insulation today.

We installed 4"-thick Foamglas as sub-slab insulation. Click to enlarge.
Photo Credit: Alex Wilson

But along with these benefits are some significant downsides. All XPS today (as well as expanded polystyrene, EPS) is made with the brominated flame retardant HBCD that has recently been added to the Stockholm list of Persistent Organic Pollutants (POPs) and is being banned in much of the world. HBCD provides some level of fire protection, though some studies suggest that its benefits are greatly exaggerated—and that that protection, if real, is irrelevant below grade.

In addition, XPS is currently made with the blowing agent HFC-134a, which is a potent greenhouse gas that contributes to global warming. And some of the petrochemical-derived raw materials, including benzene and styrene monomer, are carcinogenic—though once converted into polystyrene, that carcinogenicity is not present.

From a performance standpoint, XPS—like most other foam plastic insulation materials—is readily tunneled through by subterranean termites, carpenter ants, and other wood-boring insects.

In this photo you can sort-of see the cellular structure of the rigid material. Click to enlarge.
Photo Credit: Alex Wilson

Foamglas to the rescue

Foamglas is a cellular glass, rigid boardstock insulation material. It has high compressive strength, excellent moisture resistance, and tremendous fire resistance without the use of flame retardants. It is moderately well-insulating at R-3.4 per inch (32% lower than XPS), and it’s made without environmentally damaging blowing agents. It is also about the only insulation material that is totally impervious to wood-boring insects—a useful property for below-grade applications—particularly in a warming planet with termites extending their ranges north.

Foamglas has actually been around a long time—since Pittsburgh Corning introduced it in the 1930s—but it is used primarily for high-temperature industrial applications, such as insulating steam pipes and furnaces. It’s use as an insulation material for buildings remains very uncommon, though this use is increasing in Europe.

Even though Foamglas is significantly more expensive than XPS and its per-inch insulating value is lower, the environmental and health benefits made me want to try it out on our own home.

We installed 6" Foamglas blocks on the exterior foundation walls using a polymer-cement adhesive. Click to enlarge.
Photo Credit: Alex Wilson

Our use of Foamglas

We installed four inches of Foamglas under the basement floor slab and six inches on the exterior of the foundation walls. Our designer/builder, Eli Gould, and his six-person crew not only did admirably with this little-known material, but he came up with what I believe is a great option for adhering Foamglas to a foundation wall.

We were debating whether to use Pittsburgh Corning’s recommended solvent-based adhesive (“tar”) or their acrylic formula (a greener, water-based tar), which apparently doesn’t have quite as good performance properties as the solvent-based option. But the recommended solvent-based formulation sounded quite hazardous (it’s a two-component adhesive with one component consisting of three different types of diisocyanate and the other component consisting of petroleum asphalt, coal bitumen, naphthenic distillate, and hydrocarbon solvents). We wanted a well-performing adhesive, but the solvent-based option didn’t sound like something we wanted to expose workers to during installation or surround our home with. 

Eli tested different engineered cement products, as modern polymers have dramatically changed the adhesive capabilities of cement in the last couple decades. They are also free of VOCs and sounded far safer from a health and environmental standpoint.

Mixing the Ardicoat waterproofing material—an acrylic gets mixed with a proprietary mix of Type I and Type II portland cement.
Photo Credit: Alex Wilson

We settled on a polymer cement product  made by Ardex used for adhering stone veneer onto masonry walls, and it worked beautifully. The two companies (Ardex and Pittsburgh Corning) were so intrigued by our field-testing that they have begun conversations about testing and developing this alternative adhesive system.

Ardex also supplies a waterproofing coating that we applied over the Foamglas on the foundation walls: Ardicoat Plus. We used this in place of conventional asphalt-based (tar) coating, and I feel really good about not having hydrocarbons from the coating seeping into the groundwater or being released as VOCs.

Innovation and performance

Our foundation ends up with a respectable R-12 under the basement slab and R-22 on the exterior of the foundation walls. That’s not up to Passive House standards, but it should be good enough to enable us to achieve net-zero-energy performance with a PV system supplying power for an air-source heat pump. And it should last literally hundreds of years—a lifespan that I believe we should be aiming for in home building today.

We spent more for the Foamglas foundation insulation than we would have with XPS, but it feels good to have put my money where my mouth is relative to spurring product innovation and demonstrating greener building material options.

Eli and I also hope that by leading this sort of collaboration we may be able to help drive down the costs while broadening the market for Foamglas and other innovative products. With Foamglas and other inorganic products like this that may come along, we hope to see more durable, insect-resistant foundation systems that can help reduce energy consumption while minimizing health and environmental impacts.  

A layer of polypropylene mesh gets embedded into the Ardicoat for strength and flexibility.
Photo Credit: Alex Wilson

Foundations are not the only part of the building in which Eli and I plan to help companies “connect the dots” in developing better buildings. We’re working on innovative window solutions for existing homes, superinsulated roof systems, and modular components to speed construction—but those are topics for future columns.

Who knows, maybe we can even convince some leading manufacturers to move to the Brattleboro area and help to spur economic development in the region.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-11-29 n/a 12213 A Few Product Highlights from Greenbuild

The Greenbuild conference, as usual, was the place to find out about innovations in green building products.

Agepan THD wood-fiber insulative sheathing is now being sold by the Small Planet Workshop. Click to enlarge.
Photo Credit: Small Planet Workshop

I attended the Greenbuild Conference and related meetings in San Francisco last week. This is the largest conference and trade show in the green building field, and it is increasingly becoming the national event where large manufacturers roll out new building products.

Described below are a few product highlights from the trade show that caught my eye as I wandered around. I only got through about a quarter of the trade show.

Wood-fiber insulation from Germany

In Europe it is becoming increasingly common to use high-permeability wood fiber sheathing as an exterior insulation material, and at least one such material was on display at the conference. The Small Planet Workshop in Olympia, Washington, is now distributing the German product Agepan THD. These 2"-thick panels insulate to R-5.7 (R-2.3 per inch) and have a high perm rating of 18—meaning that water vapor can pass through it fairly easily.

It’s hard to say whether wood-fiber insulative sheathing will gain followers here, but there is growing interest in wall assemblies that won’t trap moisture, so products like these are worth keeping an eye on. The Small Planet Workshop also distributes the expanded-cork boardstock insulation that I’ve written about previously and that I’m planning to use on my own house in Dummerston, Vermont.

Vacuum insulation moving into the main stream?

Vacuum insulation has been around for a while, but it has never made inroads into the market—despite a major effort for Owens Corning to do so with its Aura panel way back in 1992. Dow Corning is going to give it a shot. After premiering its Vacuum Insulation Panel (VIP) at the Living Future Conference in May of this year (see BuildingGreen article and GreenSpec product page), the company made a bigger splash at Greenbuild.

Dow Corning’s VIP is sold in 24" by 36" panels in thicknesses from a quarter-inch to an inch-and-a-half. The panels have a fumed silica core that is 95% pre-consumer recycled content, wrapped with an aluminum skin, and 1"-thick panels provide an insulating value of R-39 (center-of-panel).

Dow Corning’s vacuum panel is being specified in commercial-building facades to insulate spandrel glass (in all-glass curtainwall buildings, the opaque glass that spans between glazing), but I believe the primary application for VIPs will be in appliance manufacturing where high insulation performance in thin layers is desired (refrigerators, freezers, and water heaters). A press release on the product with a link to a downloadable information sheet is found at this link.

A high-R-value coating with silica aerogel

Silica aerogel is a bizarre material. Aerogel the lowest-density solid known. It transmits light and insulates extremely well, owing to its molecular structure. For the past decade, the Cabot Corporation has produced silica aerogel granules under the brand name Lumira (previously Nanogel) that are used in daylighting panels that provide diffused light even while offering remarkably high insulating value (about R-20 in a 2-1/2" panel), and the material is also incorporated into a felt-like mat that can be used in roofing fabrics. Find Lumira in GreenSpec here.

At Greenbuild the company introduced a new formulation of silica aerogel, Enova, that can be added to paint to provide a thin, insulating coating. A very effective demonstration in the booth used a piece of aluminum that was half painted with this 2 mm-thick coating and half uncoated with a refrigerated space behind. You could feel the dramatic difference in temperature, since the aerogel coating significantly reduced heat flow through the material. A key benefit will be preventing condensation.

Zehnder’s top-efficiency HRV now certified by the Home Ventilating Institute

Zehnder is Swiss manufacturer of high-efficiency heat-recovery ventilators (HRVs) for whole-house ventilation. Represented in the U.S. by Zehnder America since 2010, the company is defining the future of high-performance ventilation. All of the company’s HRVs carry Passivhaus certification, and the company’s Novus 300 HRV recently earned certification with the Home Ventilating Institute (HVI).

Based on the HVI test methods, the Novus 300 achieves “apparent sensible effectiveness” of 94% to 96% and “sensible recovery efficiency” of 90% to 91%, significantly exceeding the performance of any other HRVs in the HVI Certified Products Directory. One of the company’s ComfoAir models (see GreenSpec product page) also carries HVI certification, and others in the line will be certified.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-11-19 n/a 12206 Google Gives USGBC $3 Million for Healthy Building Materials Research
This indoor space at Google has sustainably forested wood floors, soy-based furniture, and ample daylighting.
Photo Credit: Christophe Wu / Google

In one of the biggest announcements to come out of Greenbuild 2012 in San Francisco thus far, the U.S. Green Building Council (USGBC) has announced a $3 million grant from Google to support work on healthier building materials. Google has already been a pioneer in keeping toxic chemicals out of building products used in its building projects (see A Peek Inside Google’s Healthy Materials Program), but this grant takes its public support for research and advocacy in this area to a new level.

The grant was announced by Scot Horst, senior vice president for LEED at USGBC, in an unscheduled insertion to the opening plenary at Greenbuild, with Horst noting that the donation had been finalized just the day before. Horst did not provide details on what the grant would support, but USGBC chairman Rick Fedrizzi's subsequent remarks during the plenary made it clear that USGBC as an organization was prepared to emphasize the following points:

USGBC hasn't yet announced details of the grant and what timeframe it will operate under, but we will update this blog as new information is available.

2012-11-14 n/a 12202 Top-10 Products for 2013 Take the Long View on Resilience and Durability

Resilience and building science are the focus for our eleventh annual BuildingGreen Top-10 product awards.

Last year's BuildingGreen Top-10 product awards were the first to emphasize resilient design. This year, in the wake of more droughts, wildfires, and the last straw—SuperStorm Sandy—our need to focus on resilience is ever more urgent. Hand in hand with resilience is durability: sound building science helps prevent moisture problems that can compromise our buildings during normal times as well as during and after extreme weather events.

Below you'll find the basics, but you can get a lot more details about each product on our press page—including relevant LEED credits and contact info for each company.

If you're at Greenbuild this year, please stop by the manufacturers' booths to congratulate them and learn more about these forward-looking products. You might also be able to squeeze into Alex Wilson's presentation about the products, bright and early Friday morning!

Amorim expanded-cork boardstock insulation

Photo Credit: Amorim Isolamentos, S.A.

Amorim expanded-cork boardstock insulation is a 100% natural, rigid-insulation material produced from natural cork. The material insulates to R-3.6 per inch, offers excellent acoustic control, is highly durable, has high vapor permeability, and meets fire-safety requirements (Euro Class E, based on EN 13501) without flame retardants.

Atlas CMU block with CarbonCure

Photo Credit: Atlas Block

Atlas CMU block with CarbonCure significantly improves the carbon sequestration process of concrete curing by taking CO2 supplied from local industrial sources and injecting it directly into concrete masonry units (CMUs) during production using a specially designed mold. Injecting CO2 into CMUs during manufacture also improves their strength, reduces the amount of portland cement required, and speeds curing.

Cyber Rain irrigation controllers

Photo Credit: Cyber Rain

Cyber Rain irrigation controllers were the first product to be certified to U.S. Environmental Protection Agency WaterSense standards for weather-based irrigation controllers. The systems use local weather data along with plant, sprinkler, soil, slope, and sun exposure data to calculate evapotranspiration and provide just the right amount of water to maintain the health of different plant species and avoid overwatering.

GeoSpring hybrid electric water heater from GE

Photo Credit: GE Appliances

GeoSpring has an energy factor of 2.35 in hybrid mode and has a first-hour rating of 63 gallons. It offers four operating modes, ranging from all electric-resistance (using two 4,500-watt elements) to all-heat-pump operation. Among stand-alone heat-pump water heaters, the GE GeoSpring is also the quietest.

Haiku ceiling fans by Big Ass Fans

Photo Credit: Big Ass Fans

Haiku ceiling fans have brushless, electronically commutated DC motors for increased energy efficiency. Designed for both residential and commercial applications, Haiku ceiling fans use 2–30 watts, significantly exceeding Energy Star requirements. The fans come with an LED display and remote control, and can spin in reverse.

LoE-i89 glazing from Cardinal Glass Industries

LoE-i89 glazing is a sputtered indium tin oxide hard-coat that can be installed on an exposed surface of an IGU. This option allows two low-e coatings to be used on a double-glazed IGU, and it enables a double-glazed window to achieve a level of performance that was previously achievable only with triple-glazing.

Proglaze ETA Engineered Transition Assemblies from Tremco Commercial Sealants & Waterproofing

Photo Credit: Tremco, Inc.

Proglaze ETA is a complete assembly system comprised of sealants, membranes, primers, and flashings (all its own products) and insulation and sheathings (from other manufacturers) designed to integrate well together. Tremco offers an industry-first warranty on the performance of the air and water barriers.

Viridian Reclaimed Wood

Photo Credit: Viridian Reclaimed Wood

Viridian Reclaimed Wood processes wooden pallets, crates, and packing materials in its Oregon facility and then creates flooring, tabletops, paneling, veneers, and other products for use in commercial and residential buildings. This FSC-certified reclaimed wood includes European beech, oak, spruce and pine from Russia, and “Jakarta market blend,” a mix of Asian hardwoods.

XS-P Series streetlight from Cree Lighting

Photo Credit: Cree Lighting

The XS-P Series incorporates Cree LED light engines and BetaLED’s NanoOptic Precision Delivery Grid optics to deliver 100 lumens per watt of either 4000K or 5700K light precisely onto the ground where needed. The XSP is designed to be affordable, with a payback of as little as three years, yet it is compatible with dimming drivers and is available with optional occupancy sensors, remote monitoring, and other lighting controls.

WUFI software from Fraunhofer IBP and Oak Ridge National Laboratory

WUFI software is a family of PC-based modeling tools that calculate heat and moisture transfer in multi-layer building components over time. The tools help predict and manage long-term moisture risk in a variety of building assemblies in any climate conditions.

2012-11-13 n/a 12179 Masonry Heaters

One of the cleanest and most efficient ways to burn wood is provided by high-mass masonry heaters.

A Tulikivi masonry heater made of soapstone with an integral bake oven and bench.
Photo Credit: Tulikivi

Over the past two weeks I’ve written about wood stoves and pellet heating. This week I’ll focus on another way to burn wood cleanly and efficiently: using a masonry heater.

A masonry heater, also called a masonry stove or Russian fireplace, is a wood-fired heating system that is fired intermittently at very high temperature to heat up the large quantity of thermal mass, which then radiates heat into the home. The heater has a circuitous path through which the flue gasses flow. Here, the heat is transferred to the stone, brick or other masonry elements of the heater.

Key benefits of masonry heaters

From an environmental standpoint, masonry heaters burn fuel very rapidly at a high temperature. This results in very complete combustion with little pollution generated. Except when first starting the fire, there should be no visible smoke.

From a performance and comfort standpoint, masonry heaters take a long time to heat up, but they then continue radiating heat for a very long period of time, typically 18 to 24 hours. The outer surface of a masonry stove never gets as hot as a cast-iron or steel wood stove, but it retains its heat much longer. The surface area provides a large radiant surface, contributing to comfort.

Operation of masonry heaters

Unlike a wood stove, where you typically start a fire and then keep it going for a long period of time by adding fuel, with a masonry heater you operate it in batches, and the fuel is typically entirely burned by the time the next fire is started. This means that you have to start a lot of fires—which some people will find less convenient.

Because the firebox may not be very large in a masonry heater and because a fast-burning, intense fire is desired, the firewood is cut and split differently. Often the length of acceptable firewood is less than with a wood stove (sometimes as short as 12 inches), and the optimal diameter of split wood is smaller—typically 3-5 inches.

A custom masonry heater built by William Davenport using granite and marble.
Photo Credit: Masonry Heater Association of North America

Because the heat from a masonry heater won’t warm up a space quickly (it may take several hours for the outer surface to reach peak temperature and peak heat delivery), it isn’t as effective as a wood stove at quickly taking the chill off. You need to plan ahead. And if it’s going to be a sunny autumn day and you have a lot of south-facing windows, starting the masonry heater in the morning may result in a period of overheating later in the day when the solar gain peaks.

Some masonry heaters include bake ovens or warming areas built into the modules, offering a nice feature for those interested in wood-fired baking. Others include integral benches for seating.

Product options

Masonry heaters are often custom-built, and such units can satisfy a wide range of design needs and special requirements. Because they are large and heavy, provision must be made for such units—such as a concrete slab or concrete bearing walls beneath the heater. The Masonry Heater Association of North America is an excellent resource on masonry heaters and includes a directory of masonry heater builders.

There are also some manufacturers of modular masonry heaters that can be assembled relatively easily. The best-known manufacturer is the Finnish company Tulikivi . Tulikivi heaters are made from soapstone or ceramic and are available in a wide variety of styles, both with and without bake ovens. Some include integral bench seats.

If a house has the space for it, a masonry heater is often the best way to heat with wood. In new construction, particularly in rural areas, it’s definitely worth looking into. Find the more efficient and less emitting masonry stoves in the masonry heater section in GreenSpec.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.


2012-11-01 n/a 12176 How to Prevent Your Worst Building Assembly Fears from Coming True

Expensive callbacks and lawsuits can result when you don’t attend to the assembly details.

Directional drying is designed into high-performance buildings, and all three control layers must continuously manage water, air, and heat. Note how the air barrier is primarily accomplished at the interior and how difficult it is to prevent thermal bridging at structural framing if exterior rigid insulation is not used.
Photo Credit: Steve Baczek Architect

We’ve all heard the nightmare scenarios: water leaks that mar the finest architectural features of a new building; air leaks that cause hidden mold or rot inside the walls; thermal bridges that compromise occupant comfort and energy performance.

Money on the line

These scenarios have two things in common: first, they could all land you in court. Second, they are all preventable if you’re giving each building assembly detail the time and attention it deserves.

During a recession, most firms are already working with knifeblade-thin margins, so it can be tempting to cut corners. While the “extra” work required to get the details right might seem expensive in the short term, it’s a good long-term investment.

In this month’s EBN feature article, Peter Yost and I take a look at how industry leaders are changing the way they practice architecture in response to the increasing complexity of—and increasing demands on—our buildings and building assemblies.

Energy demands put the pressure on

We all want energy-efficient buildings, but there are tradeoffs: when you decrease the energy flow through a building assembly, you have to be a lot more careful about every little air leak and thermal bridge; otherwise you risk moisture problems.

This challenge is even greater because more sophisticated, multilayered building systems may have properties we don’t know about or forget to check. For example, all building materials—not just the ones we call retarders or barriers—affect vapor movement to some degree; serious moisture problems can occur if the permeability of each assembly component is not accounted for in assembly design.

Tricks of the trade

In our article, we go through the four essential features needed to ensure good hygrothermal performance, and we’ve included lots of beautiful, detailed cross-sections from leading residential and commercial building science experts to give you ideas for solving common problems, such as:

Also Read

How "Smart" Vapor Retarders Work

Hidden Seam Failures? We Put Flashing Tapes to the Test

Sustainable Sealants: The Problem of Predicting Service Life

  • Continuing thermal, air, and bulk water barriers at the parapet of a low-slope commercial roof
  • Achieving thermal barrier continuity where a residential wall meets the slab
  • Allowing water drainage at a commercial foundation without compromising the thermal barrier
  • Continuing the air barrier at window heads and sills in a deep residential exterior wall
  • Creating a continuous air barrier at a residential eave
  • Minimizing thermal bridging through a commercial balcony assembly

Special building science issue

As a matter of fact, this whole issue of EBN is chock full of building science know-how and includes:

Upcoming report

I’ll just leave you with a little teaser: our whole editorial team is currently expanding on all this work in a new report on high-performance building assemblies. It’s due out just before the holidays—so put it on your wish list, and watch this space for more details soon!

2012-10-29 n/a 12146 NSF’s Fly Ash Ruling and Post-Consumer Alchemy

Since when are coal-burning power plants “consumers”? A look at NSF’s dubious recycling definitions.

BioCel carpet backing replaces petroleum-based polymers with those made from soybeans and contains Celceram fly ash as recycled content.
Photo Credit: United Textile

Fly ash, a by-product of coal combustion, is considered “post-industrial” or “pre-consumer” recycled content by just about everyone…with the notable exception of NSF, which recently, and inexplicably, decided to label fly ash “post-consumer” for its NSF-140 carpet standard.

NSF justifies this labeling change—explored here by the Healthy Building Network’s Tom Lent—as follows:

“It is our contention that coal is consumed by the utility (the end consumer of the coal) in the process of production of electricity and that Celceram [Boral’s branded fly ash] is a product that can no longer be used for its intended purpose (i.e., the generation of heat to create steam) and would otherwise be sent to the waste stream.”

Hmm, industrial waste is now post-consumer recycled content? It is a dubious argument at best.


GreenSpec’s fly ash policy

For now, GreenSpec supports the use of fly ash in building products such as concrete because it improves concrete’s performance and replaces a significant amount of portland cement, which is energy-intensive to produce and generates carbon dioxide and other hazardous emissions during calcination.

As before this “post-consumer” flap, GreenSpec does not support the use of fly ash as a filler in products such as carpet backing where its use does not significantly reduce greenhouse gas emissions.

Toxicity concerns

The main reason for this was brought up Tom Lent: fly ash contains trace amounts of mercury and a number of other toxicants. These can be released into the watershed when landfilled, but when fly ash is used in concrete, the minerals become part of the chemical reaction and the toxicants “bound,” minimizing the risk of exposure or leaching, but that’s not the case when it’s used in carpet backing.

Even the data about leaching from concrete are not conclusive, however, and we are keeping an eye on the research. Some people think fly ash should not be used in green buildings, but it is important to remember that portland cement also contains hexavalent chromium and trace amounts of hazardous compounds, so eliminating fly ash from concrete will not entirely eliminate toxicity or potential end-of-life disposal concerns.

NSF is tarnishing its certification

Fly ash is a complicated issue, and we don’t need to add to the confusion, but NSF might be doing just that by erroneously boosting the number of LEED credits available for recycled content and watering down the NSF-140 Platinum standard.

Carpets that now meet its “gold” standard could be transmuted into “platinum,” encouraging other carpet manufacturers to include fly ash in their products. And if you want to avoid fly ash in carpet, good luck finding that information among the NSF-140 documentation, as the credit information for individual products is not readily available to the public.

Moving forward

GreenSpec is going to stay consistent with its longstanding policy and will not follow NSF’s decision to label fly ash in carpet as “post-consumer” recycled content.

And we join HBN in calling for LEED to do the same. From now on, GreenSpec will scrutinize NSF-140 Platinum carpets and will continue to reject any that contain fly ash.



2012-10-25 n/a 12139 Heating With Wood Pellets

What to like and what not to like about pellet stoves and pellet boilers.

Our Quadrafire pellet stove, which we can operate even during a power outage. Click to enlarge.
Photo Credit: Alex Wilson

We have a sort-of love-hate relationship with our pellet stove. My wife leans more toward the latter, while I see the benefits outweighing the negatives. In this column I’ll outline the primary advantages and disadvantages of pellet heating.

Advantages of wood pellet heating

Regional fuel. The fuel is—or can be—local or regional in origin. At a minimum it’s not fuel that’s coming from places where they don’t like us—like the Middle East. When I’m buying pellets, the source is a significant consideration. I’m willing to pay slightly more to have my pellets come from nearby plants in Jaffrey, New Hampshire or Rutland, Vermont.

Carbon-neutral. The life-cycle of wood pellet production and use can—and should—be close to carbon-neutral. With natural gas, propane, or heating oil we’re taking carbon that was sequestered underground millions of years ago and releasing that as a greenhouse gas into the atmosphere (where it contributes to global warming). When we burn wood pellets we’re still releasing about the same amount of stored carbon into the atmosphere, but that carbon was sequestered in the wood fiber over just a few decades, and if we’re managing our woodlands properly (replacing harvested trees with new ones) the entire life cycle results in almost no net carbon emissions.

Relatively clean-burning. Wood pellets are a lot cleaner-burning than cordwood. This is because pellet combustion is aided by a fan that supplies a steady stream of air to the burn pot. When I first start up my pellet stove—as the electric heating element heats up the pellets to start the combustion—there’s some smoke produced, but once the pellet stove is operating there is no visible smoke being generated. (This is a reason to set the temperature differential on the control relatively high—so that it won’t cycle on and off too frequently.)

Infrequent stoking. Pellet stoves have integral bins that can be filled every few days in cold weather, and most pellet boilers have stand-alone bins that hold several months’ worth of pellets. Regular stoking isn’t required—unlike with a wood stove. If a pellet stove is your only heating system in a space (as is the case with our apartment) how long you can go away depends on the energy efficiency of the building, expected outdoor temperatures, the volume of pellets your stove or bin holds, and the thermostat settings. With our pellet stove, we can go away for about three days in the coldest Vermont weather as long as I leave the thermostat set fairly low.

Convenient. With a pellet stove you don’t have to handle firewood. I’m sure I’ve cut, split, stacked, and burned a couple hundred cords of wood over the decades, and I know that it’s a lot of work. With pellet stoves you’re still handling the fuel—usually 40-pound bags of the rabbit-food-size pellets—but it’s more convenient than dealing with firewood.

Economical. Pellets are less expensive than heating oil, propane, or electric-resistance heat, so you can save money if you would otherwise use those fuels. You may save more money with a pellet stove by heating only a few rooms instead of the whole house—though there are often ways to do that with other heating system as well.

Disadvantages of wood pellet heating

Noisy. There’s no getting around the fact that pellet stoves are noisy. There are typically two fans: one to supply combustion air to the burn pot and another to circulate heated air into the room. I find the noise annoying; my wife hates it. It’s certainly a far cry from a silent wood stove in our living room. There’s a Wiseway Pellet Stove that supposedly operates passively, but haven’t seen one in operation yet. Pellet boilers are noisy too, but they’re typically in the basement or a separate building, so it’s not a problem.

Electricity dependent. When you lose power a pellet stove or pellet boiler can’t operate (unless you have one of those new Wiseway stoves). This is an important consideration not only in rural areas prone to power failures, but also more generally in an age of global climate change with more intense storms forecast. With our own Quadrafire Mt. Vernon AE pellet stove, I bought a kit that allow me to operate the DC fans using a 12-volt automotive-type battery during a power outage. It won’t auto-start using the DC power, so you have to start it by hand with kindling or starter paste, but at least it can be used to keep a space warm when the grid is down.

Comfort. Pellet stoves don’t deliver radiant heat. I love pulling up a chair in front of our wood stove on a cold winter night and sitting down with a good book. That radiant heat seems to warm you inside and out. Pellet stoves—at least the one we have—don’t heat up in the same way and radiate heat. Nearly all the heat is delivered by fan-forced convection. It’s just not as pleasant.

Plastic bags. Unless you get pellets delivered in bulk you produce a lot of polyethylene plastic waste from the bags. The first two years we had our pellet stove I was able to buy bulk pellets that were delivered in reusable thousand-pound totes that sat on pallets. I had to carry the pellets upstairs in five-gallon pails, but at least I didn’t generate all that waste. Unfortunately, the company that had delivered those totes disappeared, and I had to switch to the more typical 40-pound plastic bags (which we reuse as trash bags). I believe that as pellet heating becomes more common, bulk delivery of pellets will become more available.

Complex. Unlike wood stoves, pellet stoves have moving parts that can wear out and that require maintenance. There are blowers, temperature sensors, an auger to deliver pellets, and other components. Most retailers recommend annual servicing, which can add significantly to the total operating cost of a pellet stove or pellet boiler.

Less control over the fuel. If you have a woodlot you can cut and split your own firewood. That’s not the case with pellets. Pellet factories use massive presses to extrude wood fibers through dies to create the pellets. Do-it-yourself pellets aren’t an option.

Not always cheaper. While pellets are less expensive than most other fuels, they may not be cheaper that natural gas or air-source mini-split heat pumps. Use our Heating Fuel Cost Calculator to compare costs per unit of delivered heat. In the Northeast, pellets typically track with heating oil—going up when heating oil prices spike, though generally remaining significantly lower. If you can order pellets in bulk rather than buying them in 40-pound bags, there may be some savings—but not all that much. And there have occasionally been shortages of pellets, driving prices up substantially.

Bottom line

Pellets are a mixed-bag, but they offer enough advantages in many situations to warrant consideration. They provide a user-friendly option for relying on a relatively local, renewable fuel source. If Europe is any indication, the use of pellet heat in the U.S. is likely to increase significantly in the years and decades ahead.

Check out the high-performing, low-emitting pellet stoves that we've found in our GreenSpec section.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-10-24 n/a 12138 How Many Bikes Really Fit on that Rack?

Sometimes bikers have to improvise where to leave their bikes, but many common bike racks may be worse than nothing.

Bikers need wheel benders like a fish needs a bike lock.
Photo Credit: forkergirl, October 28, 2002 via Flickr, Creative Commons Attribution.

Biking cross-country from San Francisco to Boston with a friend in 2010, I saw few showers, and had even fewer shaves. As we paused for rest at various cities, towns, and trees across America, we attracted a lot of attention for looking like we lived out of the packs on our bikes (probably because we did).

But while we were seeing a lot of our bicycles, a lot of places we visited seem to have been designed as if bikes had never been seen there. Truth be told, where to lean our bikes while we stopped for a snack was low on our list of concerns (did you know that Cameron Pass over the Rocky Mountains peaks at 10,276 feet?), but as someone who often bikes around cities, finding a secure place to lock my bike while I go grocery shopping is sometimes a major problem. (For more on the importance of biking in green and resilient design, check out Alex’s article on Resilient Communities here.)

Maybe it wasn't the fully-loaded bike they were looking at.
Photo Credit: Martin Solomon


Bikers are commonly underserved

By choosing to bike instead of drive, bikers save energy, reduce greenhouse gas emissions, and get exercise. I would love to gripe about road rage directed at bikers or the lack of high-quality bike lanes in cities across the United States, but this post is about bike parking: bicycle racks.

Misleading product information

One of the most common bike racks in public places—informally called a “crowd control” bike rack (because it looks like it could also serve as a barricade) or a “wheel bender”—doesn’t provide adequate protection from theft or the elements. Further, many manufacturers of bike racks will claim that “crowd control” bike racks can accommodate many more bikes than they actually do.

Not all bike racks are used to their full potential. Choosing the right type of bike rack may help alleviate some problems.
Photo Credit: Editor B, June 29, 2011 via Flickr, Creative Commons Attribution.

As demonstrated by the picture to the right, many bike racks aren't used to their full potential. Only four of the 6 bikes in the picture above are using the rack as intended, and there doesn't appear to be any easy way to get more bikes in there. The bike rack was also installed near a tree that makes it tricky to use some of the spots. It’s not easy, convenient, or sometimes even possible to get the most out of them. It’s nearly impossible to safely lock your bike to the rack, as locking just your front wheel doesn’t actually protect your bike. Also, if someone slips and leans on your bike for support, well, you can imagine why they’re called wheel benders.

What to look for in a bike rack

It’s not difficult to find bike racks that fix most of the problems with “wheel benders”. Look for racks that support the frame of the bike, and make it easy to lock both the frame and a wheel to the rack. Be sure to install them in a way that maximizes their usability, and if possible, shelter them from the elements, either with a building or a dedicated structure. When fully used, bike racks should still provide easy access to the bikes by their users. Keep in mind that there are many innovative solutions out there, including bike lockers and racks that hang bikes on walls.

Is this really a priority?

Adequate bike racks may seem like a small problem compared to cyclist safety, but the lack of secure places to store bicycles is symptomatic of a larger problem: a serious lack of honest dialogue about what bikers and the greater community need.

When thinking about bike racks, it is important to understand how many bikers a bike rack will actually serve, as well as how secure they are (do they only protect your front wheel?) and what kind of protection they offer from the elements. For more guidance, check out our bike rack section here. Biking is a very sustainable and resilient form of transportation—it is time to have this conversation a little louder.

Bike racks: Not a joke

Are you surprised I haven’t mentioned LEED yet? As you may know, SSc4.2 in the LEED-NC rating system calls for a certain number of bike racks for buildings.

LEED critics are known to deride this credit for being given equal weight as other points that may appear more consequential.

I would challenge anyone who makes that argument to bike around any city or town for a day and report back here. Based on my experience, we need more, better-designed bike racks—not fewer. Choosing an appropriate bike rack is an opportunity to follow the spirit of LEED and bring more meaning to the credit.

2012-10-23 n/a 12102 Concrete and Green Building: Reducing Impacts, Avoiding Toxic Chemicals

Concrete and other cementitious materials have both environmental advantages and disadvantages. As builders and designers, should we be looking for alternatives or embracing concrete over competing materials?

A new report from BuildingGreen, What You Need to Know About Concrete and Green Building, takes a look at how these materials are made, presents the key environmental considerations relating to their production, use, and eventual disposal, and describes ways to reduce their environmental impacts.

The report is the first to address the proposed concrete product category rule (PCR) being developed by the Carbon Leadership Forum, and the reactions of stakeholders including the National Ready Mixed Concrete Association (NRMCA), builders, and architects. It describes how the new rule establishes a framework for evaluating concrete's environmental attributes, giving concrete an opportunity to compete against steel and wood in LEED v4 credits that it has lacked in prior versions of LEED.

The report includes the latest information for architects and builders on concrete constituents, applications and specialty products.

  • Overview: The green pluses—and minuses—of concrete.
  • Environmental Considerations: How to weigh concrete's ecological drawbacks and advantages.
  • Thermal Performance: Thermal mass... or thermal bridge?
  • Reducing Environmental Impacts: Ways to minimize concrete's environmental and toxicological footprint, enhancing its green attributes.
  • Using Fly Ash in Concrete: Are toxicity concerns a show-stopper?
  • Autoclaved Aerated Concrete: Widely-used in Europe, is it right for your project?
  • Polished Concrete Outshines Other Flooring Options: A functional, cost-effective, environmentally responsible innovation.

What You Need to Know About Concrete and Green Building, available for $49, is free to BuildingGreen members. Those who aren’t yet members can get the report for free when they sign up for a free 30-day trial of BuildingGreen Suite.

Earn continuing education credits

BuildingGreen members can receive continuing education credit for reading this report. The American Institute of Architects (AIA) has approved this course for 3 HSW/SD Learning Units. The Green Building Certification Institute (GBCI) has approved this course for 3 GBCI CE hours towards the LEED Credential Maintenance Program.

Upon completing this course, participants will be able to:

  • Recognize concrete's environmental footprint and how to reduce the quantity of concrete used in buildings.
  • List the advantages and disadvantages of at least three alternative types of concrete.
  • Explain the fly ash conundrum.
  • Summarize the benefits of polished concrete floors and multiple aspects of concrete structural components.


To earn continuing education credit, read this report and pass this quiz.

2012-10-18 n/a 12100 LED and Power: Quality Matters

LED replacement lamps look super-efficient on payback charts and utility bills, but they may be sucking more power than you realize.

LED replacement lamps like this one from Cree  have a high power factor; those intended for residential use often don't.
Photo Credit: Cree, Inc.

GreenSpec and EBN have reviewed a number of LED replacement lamps over the years and have reported on improvements in efficacy (light output in lumens per watt of electricity consumption), color, and light quality; lower costs; and its increasing acceptance.

In the EBN article LEDs: The Future is Here, we explored briefly how LEDs interact with the power supply, but we were surprised when an email from Stefan Bernath, Alberta infrastructure energy coordinator, came in describing how LEDs were affecting his building’s power supply.

His email got me wondering if power quality and LEDs are going to be a bigger problem in the future.

Efficacy and power quality

Some 60-watt equivalent LED replacement lamps now have efficacies of over 90 lumens per watt (lpw) compared with only about 14 lpw for a standard 60-watt incandescent. When an incandescent bulb uses power from the utility, it may not be very efficacious, but its power factor (PF)—basically the amount of power coming from the utility used by the lamp—is 100% (1.0 on a scale of 0.0 to 1.0).

LED luminaires with separate drivers have power factors greater than 0.9, which is excellent, but an LED replacement lamp only can have a PF as low as 0.5 (Energy Star requires a PF of 0.7; those lamps are listed in GreenSpec).

What is PF? Nancy Clanton, P.E., president of Clanton and Associates, used the following analogy: “If I pour beer into a glass and get some beer and a whole bunch of foam, the beer is the watts, which is usable power, but the foam is not usable.”

In other words, power factor represents the percentage of drinkable beer you have in your glass.

A customer using a 10-watt LED with a PF of 0.5 only pays for 10 watts, but the utility would have to generate twice that power in volt-amps to run that lamp; we end up thinking that we are saving more energy than we are—and the utility is paying for our foam.

Though the 20 volt-amps generated by the utility to run that LED is still much better than the 60 required to power the incandescent, as LED replacement lamps gain more market share, those 10 foam-like volt-amps are going to add up. If the true goal is to maximize the efficiency of utility power, use less fuel, and create fewer emissions, then the LED industry has some work to do.

Other LED inefficiencies

LEDs can have another effect on power in a building.  “LEDs are diodes and are trying to take a sine wave and turn it into a DC signal,” said Clanton, “and whenever you do that, you get garbage and junk on the line.”

This garbage is known as total harmonic distortion (THD). THD could potentially shorten equipment lifespan, increase power losses on the transmission line, heat up transformers, and affect the performance of the LEDs and other electronics. THD was a problem for early fluorescent fixtures and computer “cube farms,” and Clanton is worried we are repeating history.

According to Bernath, his team replaced about 500 40-watt and some 100-watt incandescent lamps with 8- and 12-watt LED replacements, respectively, at the Alberta Legislature Building (partially due to high replacement costs for incandescents in the high-ceilinged rooms). When electricians went back and measured power consumption, the team was surprised.

Though the energy savings were big (he predicts a payback of 0.64 years), they discovered that the THD of the LED replacement lamps was over 66% for the most efficient lamp on the market. “It [THD] was a big concern because it increased the current on the neutral wire,” he said.

Bernath is not too concerned because LEDs make up such a small percentage of the building’s overall load, and the gauge of the neutral wire can handle it, but wonders what the impact will be on the transformers and other equipment.

Residential/commercial split

The lamps used in the Alberta Legislature Building were A19-style LED replacement lamps, which are meant to replace standard screw-mount incandescent lamps, primarily in residential applications.

Gary Trott, vice president of product management at Cree said, “For our lamps, our spec is 20% THD with a power factor of 0.9.” This is a commercial standard, and makes Cree’s LED replacement lamps eligible for utility rebates. As usual, achieving this performance comes at a price.

“You can save a lot of money by having lower power quality,” said Trott. The drive to lower the price of LED replacement lamps and the lack of tough standards mean that fewer manufacturers are going to care about PF—and, especially, THD—which could have unforeseen consequences in terms of the nation’s power quality.

A standard on the horizon, finally

Trott is part of a group in California developing the California Quality Lamp Specification, which would improve on Energy Star standards by requiring a PF ≥ 0.9, along with a color rendering index (CRI) of 85. Though the standard does not address THD directly, Trott says that THD and PF are closely related, and as you improve the quality of the lamps to achieve a PF above 0.9, THD typically improves and becomes less of an issue.

When the California standard is developed and manufacturers can show that their lamps meet it, we’ll raise the bar for products listed in GreenSpec. In the meantime, I’m curious if any of you have had experience with LEDs and power quality. If so, we’d love to get your input.

2012-10-18 n/a 12075 Free Webcast on Toxic Chemicals in Buildings: Now Available Online

Did you miss the live webcast? Get it here for free—and take a quiz for continuing education credits too.

Guinea pigs everywhere want to know: do you know as much about toxic chemicals as a building professional should?

Nadav Malin and I had a great time presenting our webcast featuring BuildingGreen's new handbook, “Toxic Chemicals in Buildings: How to Find & Avoid the Worst Offenders,” to almost 500 participants in late September.

If you missed it—or if, like many audience members hoped, you wanted to see some of the slides again—now’s your chance. We've posted the video at the bottom of this page.

What it’s about

This webcast is designed to help you sort through the constant barrage of information about everything out there that “might be killing you” and help your clients build healthier buildings. Topics include:

  • Different approaches to information overload
  • What we know about toxic chemicals in our buildings
  • Coping with knowledge gaps
  • Tools for finding out more
  • Voices of experience

What they’re saying about the webcast

Participants in the live webcast gave us a lot of great feedback. Here are just a few of their comments:

  • Enjoyed the content and the enthusiasm of the presenters.
  • I found the presentation very thoughtful, well organized, and packed with lots of useful information.
  • It was an engaging webcast. I enjoyed it. Not as dry as I expected. :)
  • Great demystification of exempt VOCs and content vs. emissions.

Need continuing education credits?

OK, just in case that wasn’t convincing enough…you can also earn CEUs for this if you’re a BuildingGreen member.

Watch, listen, and then log in to your personal BuildingGreen account and take a short quiz to earn 1 AIA HSW-Sustainable Design learning unit and/or 1 LEED credential maintenance continuing education hour.

What are you waiting for? Click play, and we hope you enjoy!

2012-10-04 n/a 12071 A Growing Database of Healthier Building Products

The new Declare "nutrition label" and database will streamline the ardous task of finding Living Building Challenge-compliant products.

The Declare label lists ingredients with color coding, making it really easy to see which ingredients might be a concern. Click to enlarge.
Photo Credit: International Living Future Institute

After teasing the Living Building Challenge community for a couple of years with promises of an ingredient label for products, the International Living Future Institute has launched Declare.

The branding and basic premise of the program are as we described back in January, in the Environmental Building News feature article “The Product Transparency Movement: Peeking Behind the Corporate Veil.” While the original description focused on the idea of a product “label,” however, in practice most people will interact with Declare as an online list of red-list-ready products.

How manufacturers get listed

To be listed in the database and sport the label, manufacturers have to report details on what’s in the product and where the materials come from. They also have to pay a listing fee, currently set at $850 for the first year. Annual renewals are half that rate, and there are discounts for multiple listings.

There are only a handful of products on the Declare list at the moment, but the listing fee is a reasonable marketing cost for products that meet the Living Building Challenge criteria, so the list is likely to grow.

Also Read

Video: Why We Need Nutrition Labels for Building Products

UL and Perkins+Will Will Launch "Transparency Briefs"

LEED Pilot Credit to Promote Product Transparency—Not Performance

And ILFI makes it easy for teams to use Declare-listed products by simplifying the documentation requirements.

Products in Declare are deemed either “red-list free” or “LBC-compliant.” The latter means that they may contain red-listed ingredients but have been granted an exception allowing their use in LBC projects. Presumably teams using “LBC-compliant” products are still required to write letters to the manufacturers expressing their concern about the offending ingredients.

Synergies with other programs

For LBC projects, Declare serves a specific need and may eventually represent some competition to the much more sophisticated Pharos tool from the Healthy Building Network, which lists ingredients and their health hazards in conjunction with a comprehensive “Chemicals and Materials Library.” (Full disclosure: BuildingGreen markets and sells Pharos subscriptions.) Bill Walsh, executive director of the Healthy Building Network, views it more holistically, however, as “More positive momentum toward disclosure.”

Declare also duplicates some of the functions of the forthcoming Health Product Declaration open standard, and has stated its intention to endorse and support the proliferation of that standard once it is released this November.

Possible overlaps with LEED v4?

With its focus on the LBC red-list, Declare does not appear to be positioned to support compliance with the proposed LEED v4 credit “Building product disclosure and optimization - material ingredients.” In the fifth public comment draft of LEED v4 that credit cites the Green Screen List Translator’s Benchmark 1 hazards, which include many more substances than LBC’s red list.

But products that disclose all their ingredients through Declare can be used to earn partial credit, according to the latest LEED draft.

Declare is smartly positioned to do one thing well. As long as interest continues to grow in product ingredient transparency in general, and in the Living Building Challenge, Declare should grow well along with it.

2012-10-04 n/a 12041 Have Your Wood or Pellet Stove and Cleaner Air Too

Wood smoke is still a guilty pleasure in the northern U.S. and Canada. But newer wood stove technologies produce less smoke—and less guilt.

This gravity-fed pellet stove from Wiseway produces few emissions and uses no electricity.
Photo Credit: Wiseway Pellet Stoves

I love fall and the start of heating season here in Vermont: the leaves are changing colors, there’s frost on the grass, and the morning fog mingles with smoke from wood stoves, its scent triggering memories of home, family, warmth, and the pending winter.

There must be some primeval connection to smoke that I find comforting, yet I know that wood smoke is also a significant source of pollution in the form of fine particulates that are lung irritants and asthmagens; sulfur oxides and nitrogen oxides that cause acid rain; and polycyclic aromatic hydrocarbons (PAHs), benzene, formaldehyde, and dioxin that are carcinogenic. Fortunately, there are a number of newer wood stoves available that significantly reduce these emissions.

Wood can be sustainable—or not

For wood to be an environmentally viable fuel requires careful application—sizing stoves appropriately, using properly sized and dried wood, and operating stoves correctly—and you need an efficient wood-burning appliance.

Older wood stoves can have particulate emission rates of 30 or more grams per hour (g/hr), and many of these are still in use today.

Also Read

Resilient Design: Emergency Renewable Energy Systems

What's the Greenest Option for Home Heating?

A Heating Fuel Comparison App

For perspective, gas and oil furnaces have emission rates of about 0.001 and 0.02 g/hr, respectively.

In 1988, the EPA began limiting particulate emissions from wood stoves to 7.5 g/hr for non-catalytic and 4.1 g/hr for catalytic wood stoves, and the State of Washington tightened emission standards further, establishing 4.5 and 2.4 g/hr standards for these respective stoves. But wood stove technology has surpassed these regulations, and many stoves are now available with emission rates below 1.0 g/hr.

Just say no to smoldering

Gone are the days of placing logs in a chamber and dampening the fire to smolder for hours, releasing a little heat into the room and a big cloud of particulates into the atmosphere. Today’s stoves use either two combustion chambers that create intense heat and fully burn the wood; or they burn at a lower temperature and use catalytic converters to eliminate most particulates and transform combustion gases into water and CO2.

Both technologies have their pros and cons which have spurned years of “cat” versus “non-cat” debates: catalytic models create fewer emissions but require platinum or palladium converters that need to be replaced over time; and non-catalytic units are relatively simple to operate but are not quite as efficient.

Getting high-tech with pellet stoves

A third option, the pellet stove, burns compressed wood pellets and is known for low emissions (many release less than 1.0 g/hr). These typically require electricity to power controls and fans that improve combustion, turn augers to deliver pellets, and circulate the heat. The most efficient models, listed in GreenSpec, use electronically commutated motors and some come with battery backup options for use during power outages.

A pellet stove’s use of electricity and noise from the blower motor can be detractions, but there is now an alternative: one company listed in GreenSpec now offers a pellet stove that requires no electricity. The pellets are gravity fed and burn using two-stage combustion. The emissions from these power-free stoves are higher (1.9 g/hr) than those of the most efficient competitors, and they look a little funky, but they are quiet—and the company can even integrate a water-heating feature.

Getting cleaner burns from logs

There are a few wood stoves available that release less than 1.5 g/hr, including hybrid models as well as a few catalytic and non-catalytic stoves. The hybrid stoves combine catalytic and two-stage combustion, creating the lowest emissions of any wood stove and better than many pellet stoves.

 According to Rod Tinnemore, environmental specialist, who oversees Washington’s woodstove program, “Hybrid stoves work well at both low and high burn rates.” By combining technologies, some hybrid stoves now have emission rates below 0.5 g/hr. And though the EPA’s emissions ratings only account for particulates, “the catalytic converter will reduce carbon monoxide and PAHs as well,” said Tinnemore.

The performance of these wood stoves is impressive, yet the technology is still in its infancy, according to Tinnemore. Wood may never be as clean a fuel as natural gas, but using the new generation of wood and pellet stoves will help us reduce our dependence on fossil fuels and lower heating bills substantially, and maybe I can enjoy the smoke with a little less guilt.



2012-10-03 n/a 12000 Drainline Heat Exchangers

This simple system for recovering heat from wastewater makes a lot of sense—especially for families and commercial buildings that produce a lot of hot water.

Power-Pipe drainline heat exchanger. Heat from the hot water going down the drain pipe is transferred to water passing through the smaller-diameter pipes. Click to enlarge
Photo Credit: RenewABILITY Energy

Over the past few weeks I’ve written about various strategies to produce hot water efficiently. We’ve seen that tankless water heaters are more efficient than storage water heaters (though are not without their drawbacks), and we’ve learned that heat-pump water heaters produce two to three times as much heat per unit of electricity consumed as electric water heaters that rely on electric resistance heat.

But the unfortunate reality is that even with the most efficient methods of generating hot water, we still lose the vast majority of that heat down the drain. Domestic hot water is a once-through product. I’ve seen estimates that 90% of the heat in hot water is lost down the drain. Dan Cautley, an energy engineer with the Energy Center of Wisconsin, says that drain water “may be one of our largest untapped resources.”

It turns out that we can do something about that. Im the right application, drainline heat exchangers allow a significant portion of the heat from hot water going down the drain to be recovered.

How a drainline heat exchanger works

The process is pretty simple. A special section of copper drainpipe is installed beneath a shower (typically the largest hot water use in a home) or other hot wastewater source. This section of drainpipe has smaller-diameter copper piping wrapped tightly around it. The cold-water supply pipe leading into the water heater is diverted so that it flows through the small-diameter copper pipe.

When hot water is being pulled from the water heater to supply the shower, the water going into the water heater is preheated by the wastewater going down the shower drain. If it’s a tankless—rather than storage—water heater, the incoming water temperature will be higher, so less energy will be required to get it up to the needed delivery temperature—thus saving energy (though the tankless water heater has to be thermostatically controlled and, thus, able to deal with inlet water of varying temperature.

The man who invented the drainwater heater exchanger, Carmine Vasile, called the product a GFX, for “gravity-film exchange,” recognizing that water going down a vertical pipe forms a film that clings to the inner walls of the pipe where the heat can effectively be transferred through the copper to the supply water.

Several versions

There are four manufacturers of drainline heat exchangers that I’m aware of: Vasile’s original company, WaterFilm Energy of Medford, NY, and three Canadian companies: EcoInnovation Technologies of St-Louis-de-Gonzague, Quebec, which makes the ECO-GFX; ReTherm Energy Systems of Summerside, Prince Edward Island; and RenewABILITY Energy of Kitchener, Ontario, which makes the Power-Pipe.

Most of these have a single 1/2" copper pipe coiled around a length (typically three to five feet) of 2"- or 3"-diameter drain pipe.

The PowerPipe is a little different than the others. It has a header that splits the supply pipe into four smaller, square-cross-section pipes that provide more surface area for heat transfer.

Most of these manufacturers offer various lengths and diameters of drainline and can accommodate different supply pipe diameters.

No moving parts, nothing to wear out

The beauty of drainline heat exchangers is that there are no moving parts, nothing the wear out, and nothing to get clogged. Only fresh water goes through the small-diameter supply pipes; any hair or other materials pass through a standard, smooth drain pipe.

Maximizing recovery efficiency

According to an article in Environmental Building News, heat recovery efficiency can be as high as 60%—which can effectively double the water heating efficiency. Just how much benefit a drainline heat exchanger will provide will depend on usage patterns and how the plumbing in a house is configured.

Ideal for heat recovery is if all household members use the same shower (or have several showers drain through the same vertical length of drainline. It helps if the water heater is in a basement (or beneath the shower(s) and close-by, so that there is minimal length of supply piping from the heat exchanger to the water heater.

These systems are even more cost-effective in schools and commercial buildings that use a lot of hot water: school shower facilities, health clubs, laundromats, commercial kitchens, etc.


Installed in a new home, drainline heat exchangers typically cost $500 to $800 (including installation). Costs in multifamily buildings should be lower. In some states there are rebates available for such systems.

For more details on the individual products, check out our drainline heat exchangers in GreenSpec.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-09-26 n/a 11993 Dirty Tires Become Clean Floors in Pennsylvania’s Amish Country

Pastoral scenery provides a contrast to Ecore’s factory, where it produces unique recycled rubber flooring systems that could change the industry.

Lancaster County, Pennsylvania, home to one of the largest Amish communities in the United States, is also home to the headquarters of Ecore International, a company predominantly known for several rubber flooring offerings.

The Columbia–Wrightsville Bridge crosses the Susquehanna River, connecting York and Lancaster counties.
Photo Credit: pennstatelive, May 14, 2008 via Flickr, Creative Commons Attribution.

During a recent visit to Ecore’s manufacturing location in York, Pennsylvania (located in York County, adjacent to Lancaster County), I got an inside look at “itstru” (pronounced “it’s true”) technology, a process that Ecore has developed to bond a diverse variety of wear layers to a recycled rubber underlayment, resulting in interesting new possibilities for flooring options—flooring like vinyl or carpet, with the performance characteristics of rubber, and easy to install.

Removing impurities

Ecore processes 80 million pounds of rubber per year. 60 million of these pounds come from whole tires at the end of their useful lives, and 20 million pounds come from tire buffings, which are woodchip-size chunks generated during the retread process.

Used tires have chunks of glass, metal, stone, and other debris buried deep within them . Before Ecore can turn used tires into rubber flooring, all of these impurities have to be removed.

Ecore cuts up and runs rubber scraps through a series of cleaning and processing machines three times. To further protect the rubber from contamination, it is moved through the factory primarily by negative air pressure pipes in the ceiling of the factory. Avoiding transportation by forklift reduces factory errors and increases worker safety, says the company.

Rubber granules continue the cleaning and refining process on Ecore's food grade equipment.
Photo Credit: Martin Solomon

Keeping it clean

The air in the factory is clean enough that the small group of media representatives and Ecore executives that I was a part of could tour the floor safely and comfortably without masks (though we did wear goggles for eye protection). The air is being filtered constantly, and the whole factory floor is kept at a negative air pressure to draw in fresh air from outside.

In the process of making flooring products that have a high percentage of post-consumer recycled content, Ecore’s facility in York also produces very little waste. Steel scraps that are separated from the tires are collected and sold to recyclers and mills. Even the particulate that is captured from the air is collected and processed for use in the final product.

Ultimately, less than 1.4% of the material that passes through the facility is sent to the landfill.

A pile of steel shavings removed from tire scraps at Ecore's facility waits to be delivered to a steel recycler.
Photo Credit: Martin Solomon

Some doubts about the carpet

Eco98, a carpet manufactured by Ecore using itstru technology, contains up to 98% post-consumer recycled content. Plastic bottles are turned into the carpet fiber and laminated to recycled-rubber backing. However, Ecore has decided not to pursue certification to the NSF-140 standard—a key indicator of overall carpet sustainability—and as a result we at BuildingGreen are not listing it in GreenSpec (see the carpeting products that we do list here). Although Ecore indicated that they are waiting for the certification market to stabilize before they pursue more certifications, we at GreenSpec think that they may be avoiding certification to NSF-140 because the durability of the plastic fibers may hurt their score.

Will other wear layers adhered to a rubber underlayment meet GreenSpec’s tough criteria? We have an open mind about it, mainly because of rubber’s inherent advantages.

Why rubber?

Rubber flooring on its own provides a durable, resilient, slip-resistant, and anti-fatigue surface. For these attributes, it is frequently chosen in locations that experience high traffic and high levels of abuse, such as gyms and athletic centers.

Although Ecore offers several lines of stylized rubber flooring with colored flecks of EPDM, architects and specifiers often want a different design for spaces in which rubber flooring wouldn’t be visually appropriate. For a while, Ecore’s answer to this problem has been QT, a sound-insulating rubber underlayment with some of the benefits of rubber flooring.

Ecore’s itstru technology, which laminates a wear layer to a rubber backing layer, is aimed at broadening the market for rubber-flooring products. Ecore is in talks to partner with several flooring manufacturers who would be able to offer polyester, polypropylene, or resilient flooring wear layers.

Goliath backing David?

The new technology could have advantages for smaller players in the flooring industry as well. Companies that offer unique carpet fibers, for example, but aren’t big enough to develop their own backing technology, may find a valuable partner in Ecore.

Even big players may partner with Ecore with positive results: vinyl flooring companies that use itstru technology to integrate a rubber backing may reduce the overall PVC content in their products. As Ecore announces new partners in the coming months, itstru technology could potentially be the source for a lot of really interesting flooring options.

2012-09-20 n/a 11992 A Look at Heat Pump Water Heaters

New federal regulations beginning in mid-April 2015 will require that larger electric water heaters be heat-pump models. It’s time to pay attention to this option.

The GE GeoSpring heat-pump water heater is the quietest model I could find and the only one that's made in America.
Photo Credit: GE Appliances

Last week I wrote about “hybrid” water heaters, a relatively new type of water heater that includes features of both storage and tankless models. This week I’ll cover another type of water heater that is also (confusingly) referred to as “hybrid”: heat pump water heaters. These produce over twice as much hot water for each unit of electricity consumed as any other type of electric water heater (storage or tankless).

You’re going to be hearing a lot about heat-pump water heaters over the next few years, because new federal regulations that take effect in 2015 will require heat pump functionality for larger electric water heaters—more on that below.

Why it’s worth considering water heating carefully

Before diving into heat-pump water heaters and what makes them tick, it’s worth spending a minute to say why I’ve focused so much attention on water heating in this blog recently. As a fraction of residential energy consumption, water heating has become more and more significant over the past several decades.

In 1978, water heating accounted for approximately 14% of a home’s average energy consumption, according to the U.S. Department of Energy, compared to 66% for space heating. By 2005, those percentages had shifted to 20% and 41%, respectively. I assume that this isn’t because our water heaters are using a lot more energy, but rather that our houses are better insulated and our heating systems more efficient.

In an ultra-efficient Passive House (built to the German standard for low-energy homes that is gaining popularity in the U.S.), it’s not unusual for water heating to be the largest energy user in the house, and it can be as much as twice that of space heating.

Electric-resistance vs. heat-pump water heating

Up until recently, almost all electric water heaters relied on electric-resistance heat. Electric current flows through a special element with high electrical resistance, and the electricity is converted directly to heat. The conversion of electricity into heat is virtually 100% efficient—though heat loss from an electric storage-type water heater always results in an overall efficiency lower than 100%. (Note that if we’re looking at primary or source energy that the power plants use to produce the electricity, the efficiency is far lower.)

Heat pump water heaters are very different. Electricity isn’t converted directly into heat; rather it is used to move heat from one place to another. This is counter-intuitive because the heat is moved from a colder place (the room air where the water heater is located) to a warmer place (the water in the storage tank).

This seemingly magic process happens because a specialized refrigerant fluid is alternately condensed and evaporated in a closed loop. This process relies on phase changes of the refrigerant that capture and release significant amounts of heat.

A detailed explanation of the refrigerant cycle is beyond the scope of this blog. Trust me that it works. (It’s the same basic principle used in your refrigerator, which extracts heat from inside that insulated box and dumps it into your kitchen.)

The net result is that for every one kilowatt-hour (kWh) of electricity consumed, two or more kWh’s of hot water are produced. The energy factor, which is often thought of as a measure of efficiency, is 2.0 to 2.5 for most heat-pump water heaters on the market, while a 100% efficient electric-resistance water heater would have an energy factor of just 1.0.

Growing interest in these water heaters

There are a few heat-pump water heaters that have been on the market for decades, but these never really reached the mainstream. All that has changed in the past few years, however, as the largest water heater manufacturers, including A.O. Smith, Rheem, and GE have all introduced heat-pump water heaters.

While standard electric water heaters have no moving parts, heat-pump water heaters have compressors (to compress the refrigerant vapor causing it to condense into liquid) and fans (to circulate room air across the heat exchanger so that heat can be extracted from it).

Noisier than other water heaters

Be aware that these mechanical components produce noise—often significantly louder than a refrigerator. Heat-pump water heaters I’ve examined have noise ratings from 55 to 65 decibels (dB), which is a large range of variability (65 dB is ten times as loud as 55 dB). Most refrigerators are 40-50 dB.

If you are particularly sensitive to noise and don’t have an acoustically isolated place to install it, the energy savings from a heat-pump water heater might not be worth it.

New water heater regs to require heat-pump water heaters

New federal regulations that are due to kick in on April 16, 2015, will require that electric water heaters larger than 55 gallons have energy factors close to 2.0. The exact energy factor required is based on a formula that factors in the storage volume, but for all sizes in this category the required EF is close to 2—a performance level that can only be achieved with heat pump technology.

The energy factor requirements for smaller water heaters—up to 55 gallons in size—are also rising in April 2015, but will remain below 1.0 and will be achievable with a very-well-insulated electric-resistance water heater.

Heat pump water heaters rob heat from the house

Because heat pump water heaters extract heat from the air where they’re located, with most installations they increase heating loads somewhat. If you have an expensive fuel, such as baseboard-electric and are in a cold climate with a significant heating season, a heat pump water heater may not make sense.

These water heaters can make a lot of sense when there is a lot of waste heat, such as in a basement where an oil or gas furnace or boiler is located.

Size matters

Heat pump water heaters come in various sizes: from 40 to 80 gallons for products I know about. For most families, the larger sizes make sense, primarily because heat pump water heaters heat the water quite slowly—often just eight gallons per hour. Most heat-pump water heaters have different settings that regulate how readily the back-up electric-resistance elements will come on. With larger models, users can operate them on the heat-pump-only mode (the most economic) more of the time. The first-hour rating will give you a sense of recovery time, but which setting the water heater is on makes a big difference.

My next water heater will likely be a heat-pump model

I’m pretty sure we’ll install a heat-pump water heater in the house we’re currently renovating. Given what’s on the market today, I will probably select the GE GeoSpring water heater, a 50-gallon model that’s 10 dB quieter and half the cost of the German-made efficiency leader, Stiebel Eltron. I’ll also look at the Rheem Hybrid Electric and the A.O. Smith Voltex, which have the same energy factor (2.4) as the GeoSpring—though noise will be the biggest determinant. The GeoSpring is the only heat-pump water heater that’s made in America.

At an electricity cost of 15¢/kWh, a heat-pump water heater will be significantly cheaper to operate than the highest-efficiency, condensing propane water heater (we don’t have natural gas in southern Vermont)—even if propane were to drop to $2/gallon (far below it’s current price). Where natural gas is available—and assuming the price of natural gas remains so low—heat-pump water heaters will have trouble competing on economic grounds.

A big attraction to me of heat-pump water heaters is that they can be powered using a photovoltaic (solar electric) system. Our new place will be net-zero-energy and we hope to entirely avoid fossil fuels in the house.

Be aware that heat pump water heaters aren’t cheap. That GE GeoSpring I mentioned above lists for about $1,200, plus installation, and the Stiebel Eltron model costs about $2,500. Unlike electric-resistance water heaters, heat-pump models require condensate drains, which can add cost. By comparison, a standard electric or gas storage water heater can cost as little as a few hundred dollars.

Looking for a heat pump water heater of your own? Check out GreenSpec's guidance here.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.



2012-09-19 n/a 11404 Hybrid Water Heaters

A relatively new type of water heater combines features of both tankless and storage water heaters.

A.O. Smith's NEXT Hybrid water heater.Click to enlarge.
Photo Credit: A.O. Smith

In last week’s blog I compared tankless and storage water heaters and explained why tankless water heaters often don’t make that much sense.

This week I’ll describe a newer type of water heater that has some features of both storage and tankless designs and solves several problems that are common with tankless models. While these are referred to as hybrid water heaters, they are quite different from heat-pump water heaters, which are also often referred to as hybrid. I’ll cover heat-pump water heaters next week.

Some storage but also continuous hot water

As far as I can tell, the hybrid water heater was invented in 2006 by a relatively small company, Grand Hall USA of Garland, Texas, a company that also makes barbeque grills. Grand Hall’s Eternal Hybrid water heater defined this product type.

In 2010, the nation’s largest water heater manufacturer, A.O. Smith followed suit with their NEXT Hybrid, which the company has been promoting fairly actively.

Both are gas-fired tankless water heaters that have a small buffer tank, which is kept hot. The Eternal Hybrid has a two-gallon tank; the A.O. Smith NEXT Hybrid tank is probably about the same size, though the company doesn’t divulge the specifics.

There are two advantages of the buffer tank: first, it eliminates the so-called “cold water sandwich” problem in which someone taking a shower may suddenly get a shot of cold water from a standard tankless water heater; and second, it allows hot water to be delivered with even tiny loads, as might be delivered in a low-flow bathroom faucet. (With most tankless water heaters the burner isn’t activated unless the hot water flow exceeds 0.5 or 0.6 gallons per minute.) Like other tankless water heaters, its small size is another big benefit.

High efficiency, condensing technology

Both the A.O. Smith NEXT Hybrid and Eternal Hybrid use condensing combustion technology to exceed 90% efficiency. Grand Hall claims up to 98% efficiency with the Eternal Hybrid. The flue gases are cool enough that they are vented through a side wall using PVC or ABS plastic pipe. In fact, due to the acidic condensate, these water heaters should not be vented into a masonry chimney.

Like other advanced, state-of-the-art tankless water heaters, both products have electronic ignition rather than a standing pilot light.

Various sizes

The A.O. Smith NEXT Hybrid has a maximum gas input of 100,000 Btu/hour, which the company claims is enough to provide a “first-hour rating” of 189 gallons. (See last week’s blog for more on water heating ratings.)

A cut-away of Grand Hall's Eternal Hybrid water heater. Click to enlarge.
Photo Credit: Grand Hall

The Eternal Hybrid is available in three sizes with maximum gas inputs of 100,000, 145,000, or 195,000 Btu/hour. The minimum gas input is 16,000 Btu/hour for the smallest model and 26,000 Btu/hour for the other two. The largest of these models, the GU195, is available for modulating installations in which up to eight units are installed together for commercial applications.

The A.O. Smith NEXT Hybrid and the smallest Eternal Hybrid can be supplied with the 1/2-inch gas line; the larger Eternal Hybrid models require 3/4-inch gas lines.

Hot water output

The hot water delivery from these and all tankless water heaters depends on the temperature rise. The smaller, 100,000 Btu/hour models provide about 3.8 gpm at a 50°F temperature rise, but only 2.1 gpm at a 90°F rise. The largest Eternal Hybrid provides 7.6 gpm at a 50°F temperature rise and 4.2 gpm at a 90°F temperature rise—which should be plenty for two or three simultaneous showers.


As with most other tankless water heaters, cost is the Achilles heel. Prices of the A.O. Smith NEXT Hybrid are typically in the $1,800 to $2,000 range (not including installation), and I think the Eternal Hybrids are even more expensive. For the larger Eternal Hybrid models, there may also be the added cost of running 3/4” gas lines, instead of more typical 1/2”.

Yes, they appear to have some performance advantages over conventional tankless water heaters, but whether they will make economic sense over conventional gas storage water heaters will depend on the situation and usage habits.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-09-13 n/a 11403 Free Webcast: How to Find and Avoid Toxic Chemicals in Buildings

Phobia or fatigue? When it comes to toxic chemicals, we all have our own way of coping with information overload. A free webcast helps you sort it all out.

Do you know where the most toxic chemicals are in building products? Vinyl sheet flooring is a top hazard, but far from the only one.
Photo Credit:

Even if we try to ignore it, we are constantly barraged with information about dangerous chemicals in our food, our water, our dust, our air…even our grocery receipts.

The information is often sensationalized, always incomplete, and sometimes downright contradictory from one day to the next.

You can’t “go organic” at work

It’s hard enough to make choices about everyday things like organic food, antibacterial soap, or vinyl flooring in your own home.

As a building professional, your clients look to you to help them make solid, science-based decisions about even more complex products and materials. Decisions about a school, a multifamily building, or a commercial office space can affect a lot of people. Do you have enough information to answer the questions of concerned clients?

Other clients may be skeptical about the dangers of certain materials or worried that alternatives will cost too much, even if they’re interested in healthier materials. How do you cope with that?

Webcast cuts to the chase

There are no easy answers to any of these questions, but we do know how to identify and eliminate some of the worst hazards from our buildings. In a free webcast at 2:30 p.m. Thursday, Sept. 20, we’ll take a look at some successful strategies. “Toxic Chemicals in Buildings: How to Find & Avoid the Worst Offenders,” presented by BuildingGreen President Nadav Malin and myself, will include:

  • Different approaches to information overload
  • What we know about toxic chemicals in our buildings
  • Coping with knowledge gaps
  • Tools for finding out more
  • Voices of experience

VOCs, PBTs, and even more acronyms explained!

These strategies will include an in-depth look at a few issues, such as:

  • The highest-priority chemicals targeted for avoidance
  • Why VOCs are important but not the only thing you need to worry about
  • How to get better information about product ingredients
  • How key health hazards differ by product category
  • Great opportunities for healthier choices

The webcast is free, and participation makes you eligible for 1 AIA HSW-Sustainable Design learning unit and/or 1 LEED credential maintenance continuing education hour.

Register for the free webcast

2012-09-12 n/a 11363 Hidden Seam Failures? We Put Flashing Tapes to the Test

Flashing and air barrier seam tapes get buried deep in our walls where we rely on long-term performance without monitoring them. Are they doing their jobs?

Companies do their own more sophisticated testing, like this tensile test on ZIP Tape. The company has a whole video on its testing procedures, but it's more fun to try this at home!
Photo Credit: Screen shot from ZIP System video

NOTE: Read this whole series here.

Service life of tapes can determine the service life of an entire high-performance building assembly.

Performance testing of adhesives and sealants used in our weather barriers is improving due to new field-testing research, as we’ve written about before. However, the improvements in testing haven’t reached a critical product area: pressure-sensitive adhesive (PSA) tapes used for sealing seams in flashing, housewrap, and generally creating continuity in air and weather barriers. “I am unaware of any work being done on this issue, either laboratory or field tests,” says Christopher White, of the National Institute of Standards and Technology (NIST).

The most commonly cited adhesion tests for pressure-sensitive adhesive (PSA) tapes are as follows:

  • ASTM D3330 – Standard Test Method for Peel Adhesion of Pressure-Sensitive Tapes
  • ASTM D903-98-04 – Standard Test Method for Peel or Stripping Strength of Adhesive Bonds
  • ASTM D1876-01 – Standard Test Method for Peel Resistance of Adhesives
  • ASTM D3654 – Standard Test for Shear Adhesion of Pressure-Sensitive Tapes
  • ASTM D3330 – Standard Test Method for Peel Adhesion of Pressure-Sensitive Tapes

But none of these tests is ideally suited for lab-testing high-stretch construction flashing tapes, and none go anywhere near testing under field conditions. And since just about all tapes are used in concealed weather and air barrier systems, we really need a field-service-life prediction test.

 “Workbench tests” of flashing tapes

So we took matters into our own hands—or rather, our own workbench. Lately I have been just sticking a slew of tapes on different building materials and gauging how hard it is to pull them apart.

My efforts got a lift in technical rigor when I was discussing this with David Gauthier, president of Vantem Panels here in Brattleboro, Vermont, a local structural insulated panel (SIP) manufacturer. David is always looking for gaskets and tapes to recommend with his panels. He said, “Hey, I bet we could use our tensile tester on the tapes!” (Van Tem uses a tensile tester to assess the strength of the bond between their skins—mostly OSB—and their foam cores).

What were we thinking?

We have no illusions that the testing we performed is up to the rigor of ASTM D3330—the list of how our testing is different from the standard Test Method A is at the end of this article.

"Trying this at home" at first involved some pretty unscientific conditions; trying to rip strong tape off stuff is fun but doesn't tell you much!
Photo Credit: Peter Yost

There are a lot of key differences, so no conclusions should be drawn from this testing. In any case, not all manufacturers report D3330, so we needed to pick one set of conditions and run as many tapes as we had through that one. We hope this testing provides some suggestive information.

And here is a thought: maybe our “benchtop” testing will inspire (or anger?) some experts from PSA tape manufacturers or test programs to conduct some field or field-like service life performance testing. We’d love to see more manufacturers engage in testing along the lines of the Sustainable Building Solutions Test Facility Tremco has going, in partnership with the Department of Energy.

After all, if the sealant manufacturers have rallied behind the work of Dr. Christopher White at NIST on standardized testing for field service life prediction of liquid sealants, can’t the PSA tape manufacturers rally behind our humble work to develop some testing and data for the field service life of PSA tapes?

Some lessons learned from our testing

Here are some things we noticed based on our test results (click to download the spreadsheet).

  1. High-stretch tapes: All of our results are probably considerably lower than typical D3330 results. Consider this perspective offered by Forest Products Lab research chemist, Christopher Hunt:
    “Rate vs load. The faster you pull, the higher your load. Molecules relax over time, resulting in lower tensile load. If you pull slowly, the molecules have time to relax during the test. If you pull really fast, they don’t and so loads (as well as elongation before break) are less. How much difference is going 1" per minute instead of 12"?  Probably not big for this product, I’d guess that going at the specified speed may increase load by 10%–50%—but that’s only a guess. All the tapes will probably have similar effect, but not exactly the same.”
    And since MOST of the tapes we tested had very similar stretch outcomes (2:1; see column J – “Travel Ratio”), that helps our habit of comparing the test results of different tapes. The notable exception would be the DuPont FlexWrap; it yields considerably lower tensile results but its stretch ratio was 14 compared to 2!
  2. Difference between initial peak and (column G) and 2-inch peak (column F). Again, FPL research chemist Hunt:
    “The first versus second inch phenomenon is likely because of elastic vs plastic deformation. The first movement is like pulling on a spring – it wants to go back.  But you pull the spring too far and you’ve got a curly wire that never goes back. The difference is that you have exceeded the elastic limit of the material, and yes, the force required to keep stretching typically is less once you’ve passed this point. That’s why the standard is written that way—they want data on the stretched out material, not how hard it is to get started.”
  3. “Aging” of specimens – Ken Levenson of 475 High Performance Building Supply cautioned us that the solid acrylic adhesive used by Pro Clima tapes needs more time than other tapes to fully develop its adhesive bond—at least a couple of hours. Our results seem to support this; compare rows 17 and 31. The “aged” UNITAPE had significantly higher results. Compare Tescon VANA tape in rows 29 and 34; they “aged” results are much higher as well.
  4. Smooth vs. rough side OSB – PSA tapes just don’t stick to the rough side of OSB as well as the smooth side, period. Trouble is, some building inspectors mandate that the smooth side be to the interior (so that they can see the grade stamp—always on the smooth side—after the structural sheathing is covered with other materials, WRB and/or claddings). This puts the rough side to the exterior, right where you are likely to be taping seams for an OSB air barrier or window opening flashing if your windows are going in before your WRB.
  5. Performance comparison of different types of adhesives – we need more data on this one, but the results suggest that acrylics demonstrate stronger adhesion than modified bitumen. We can’t really say much about the only butyl rubber tape, since its far greater stretch ratio makes its peak so much lower than the other adhesive tapes.
    At the same time, the builder group that I worked with in the tensile testing, expressed interest in the combined performance/cost of the various tapes. The Huber ZipWall tape (solvent-based acrylic), at $20 per 75-foot roll, nearly half the cost of the Siga and Pro Clima tapes (solid acrylic) was a clear winner with the builders.
  6. This is just baseline data. The builder group was quick to point out how “unreal” this “benchtop” testing was: what about applying the tape at 5ºF, or when the substrate is damp, or after 10 years of extreme temperature cycling in the building assembly? Could be the solid acrylic tape manufacturer claims of superior performance be worth the higher cost?

    We hope to follow up this baseline ideal conditions testing with more field-like conditions.
Be careful with tape and OSB: no tape sticks well to the rough side, so smooth-side-out is best for taping seams.
Photo Credit: Peter Yost

Our testing vs. ASTM D3330

For more background into our test methods, here’s a list of how our benchtop testing is different than the ASTM D3330 Test Method A (tapes peeled at 180° angle to the substrate, as pictured, Section [1.1.1] in the standard).

  1. [1.4] High stretch at low forces – D3330 does not handle high stretch tapes particularly well; the high stretch can lead to high variability in the test results.
  2. [5.3] Comparing results of different tapes – the standard specifically states that the test should not be used to compare tapes; it’s mainly “for quality assurance use.”  (Say what? Why do manufacturers report D3330 test results or data available on their product performance?)
  3. [6.3] Panel (substrate): Method A uses a stainless steel panel as the substrate; we tested tapes on various common construction materials: A-C plywood (C side) and OSB (both rough and smooth side).
  4. [6.5] Adhesion tester – VanTem Panels’ tester is a constant rate extension (CRE) machine, but D3330 specifies the test rate at 12 inches per minute and the top speed of the Van Tem Com-Ten DFM5000 is just over 1 inch per minute, not a particularly good combination with our “high stretch” construction tapes. More on this above.
  5. [9.1] Width of specimens – Most construction tapes are 2 3/8-inches wide (60 mm); we decided to make ALL of our specimens this width.
  6. [11.3] “Aging” of specimen – The standard specifies that the test must occur within 1 minute of adhering the tape to the substrate. We had quite a bit of variability (up to one week…) in how “old” the adhesive bond was between the tape and substrate. More on this above.
  7. [19] Precision and bias – We did mostly single specimen testing, not even close to the number and tolerance for variation called for by the standard.

Clearly, our benchtop testing is VERY different than the standard and mainly about looking for some generalizations we might suggest from comparing tape test results. We don’t come anywhere near claiming ASTM D3330 results.

Your experiences

What have been your experiences—anecdotal or otherwise—in field service of flashing tapes? Please comment below.

2012-08-30 n/a 11362 Saving a Little More Energy With Exit Signs

Those ubiquitous exit signs use a huge amount of electricity; a little-known alternative to conventional LED products offers surprising savings.

An exit sign at Yale's LEED-Platinum Kroon Hall. Click to enlarge.
Photo Credit: Alex Wilson

In the years that I’ve been writing about energy and energy conservation (longer than I really want to admit), I’ve reported on several dramatic transitions in how we illuminate the exit signs in commercial buildings. For an energy geek, it’s been an exciting technology to watch.

Why care about exit signs?

Why do we even pay attention to exit signs—those ubiquitous red or green illuminated signs that direct our escape from a building should the need arise? They can’t use very much energy, can they?

Each one uses relatively little electricity, but they are on all the time. And we have a lot of them in our schools, factories, and office buildings. The U.S. Environmental Protection Agency estimates that there are more than 100 million exit signs in use today in the U.S., consuming 30–35 billion kilowatt-hours (kWh) of electricity annually.

That’s the output of five or six 1,000 MW power plants, and it costs us $2-3 billion per year. Individual buildings may have thousands of exit signs in operation.

From incandescent to fluorescent to LED

When I first wrote about exit signs, the vast majority of them were illuminated with two 15- or 20-watt incandescent lamps. These lamps often lasted less than a year, and an exit sign with two of these lamps used nearly as much electricity per year as an Energy Star refrigerator uses today. For businesses, the labor cost of replacing those incandescent bulbs could be nearly as expensive as the electricity they consumed.

Thus, there was a lot of excitement in the early 1980s when compact fluorescent lamps (CFLs) made their way into exit signs. One or two CFLs using a total of 10–15 watts replaced up to 40 watts of incandescent lighting, and they lasted several times as long. The low power factor of these CFLs actually reduced the energy benefit for utility companies (a complex issue that I won’t bore you with), but end-users saved a lot of money. The biggest downside was the small amount of mercury in each CFL.

CFL lighting for exit signs didn’t last long, however. By the early 1990s, LED technology emerged for exit signs. LEDs are solid-state lighting devices that use relatively little electricity, do not require mercury (as is required in fluorescent lamps), and last a very long time. Early LEDs were usually red or green (think of those indicator lights on your stereo equipment), which worked fine in exit signs. (White LED lighting for general illumination is a lot more challenging.)

The first LED exit signs dropped the electricity use down to 5–7 watts, and there are LED exit signs on the market today that use as little as 1.8 watts and still meet the emergency egress standards of building codes.

Energy efficiency regulations gave a huge boost to LED exit signs. A revision of the Energy Policy Act of 2005 set a maximum electricity consumption of exit signs at 5 watts (effective in January 2006), which effectively eliminated both incandescent and CFL exit signs.

With such low electricity consumption, LED exit signs can be coupled with relatively small battery back-up systems—a requirement (and significant environmental impact) for most exit signs.

Just as significant for bottom-line-conscious businesses is the very long life of LEDs. Most are rated at 50,000 hours—many times as long as incandescent lamps. The power factor is also better than that of CFL exit signs, which makes utility companies happy.

Enter electroluminescent exit signs

There isn’t a lot of additional gain to be squeezed out of a 2-watt LED exit sign, but there is some. A quite different technology allows fully compliant exit signs to be powered with less than a fifth of a watt—at least a ten-fold drop compared with most LED products.

Electroluminescent or light-emitting capacitor (LEC) technology produces a uniform layer of light rather than discrete point sources (as with LEDs). Limelite Technologies, the leading manufacturer of electroluminescent exit signs, describes how the technology works on its website.

Again, the savings from each one isn’t that great, but spread over tens of millions of products, the savings could be very significant.

Exit signs in our GreenSpec Directory

In our GreenSpec product database, we briefly listed CFL exit signs, then included dozens of manufacturers of LED exit signs. Today we list just two products: LimeLite of Maxwell, Texas (also at, which produces the Series 16 and Design Select exit signs, consuming just 0.18 watts each; and Greentorch (also at, which makes a wide range of LED exit signs including an LEC model using 0.25 watts and having an expected life of 30 years.

Our detailed criteria for exit signs are described here.

Exit signs to avoid

While there is a lot of good stuff in the exit sign world, there are some products to watch out for. One of them is “zero-energy” photoluminescent exit signs, which harvest ambient light from the space and will deliver needed emergency exit sign illumination for up to a couple hours during a power outage. These use glow-in-the-dark materials that are familiar in toys.

The problem is that code requires fluorescent lights to shine on these photoluminescent exit signs so that they will be fully charged and ready to provide that emergency illumination during a power outage. You will use more energy for the fluorescent light source to charge the exit sign than a standard LED exit sign will use to operate. Yes, the battery can be eliminated, but that still doesn’t justify the additional electricity use (in most cases).

The other product I like to stay away from is radioluminescent, or tritium-powered, exit signs. Tritium, a radioactive isotope of hydrogen, provides the illumination. While tritium emits fairly low-energy beta particles that aren’t strong enough to penetrate our skin, if we breathe in tritium gas or swallow tritiated water, the radiation can damage cells in our body. It’s a product I’d rather keep away from.

A detailed summary of exit sign technologies, including discussion of why photoluminescent products don’t make sense, is available in our EBN feature article on the evolution of exit signs.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.



2012-08-29 n/a 11315 Insulation to Keep Us Warm—Not Warm the Planet

An update on getting the global warming potential (GWP) out of insulation materials.

Today's closed-cell SPF has a global warming potential of 1,430, but if producers adopt new HFO blowing agents, it will drop to close to zero. Click to enlarge.
Photo Credit: John Straube

I’ve been pretty vocal about a big problem with some of our most common insulation materials: that they are made using blowing agents that are highly potent greenhouse gases.

All extruded polystyrene (XPS) and most closed-cell spray polyurethane foams (SPF) are made with HFC (hydrofluorocarbon) blowing agents that have global warming potentials (GWPs) many hundreds of times greater than that of carbon dioxide. (My apologies for contaminating this column with so many acronyms!)

Insulation: good news, bad news

Insulation materials help our homes save energy and, in so doing, they reduce the combustion of fossil fuels and the release of greenhouse gases.

But if the insulation material itself is made with a very-high-GWP blowing agent that may ultimately escape from the insulation, adding a lot of insulation may actually be a bad thing from the standpoint of mitigating climate change. All that was spelled out in my blog post two years ago, “Avoiding the Global Warming Impact of Insulation” and, in greater detail, in the EBN feature article on the same topic.

OK for ozone, bad for climate

With XPS, the blowing agent HFC-134a has a GWP of 1,430, meaning that it’s 1,430 times as potent as carbon dioxide (which is defined as having a GWP of 1). Nearly all closed-cell SPF is made with the blowing agent HFC-245fa, which has a GWP of 1,030.

Relative to global warming, these blowing agents aren’t as bad as the CFCs that were used originally, but they are as bad as the HCFCs (hydrochlorocfluorcarbons) that were adopted as second-generation blowing agents. (Both HFCs and HFOs are considered totally safe for the ozone, which is why CFCs and HCFCs have been phased out.)

Blowing agents: the next generation

Anyway, given all this, I’ve been closely following the developments by industry in coming up with alternatives that are neither ozone depleters nor significant greenhouse gases.

Two years ago, it appeared that the leading candidates were HFOs (hydrofluoroolefins), and Honeywell announced the development of such a product in 2011. And indeed, it was just announced last week that Whirlpool, the nation’s largest appliance manufacturer (with such brands as Maytag, Amana, Jenn-Air, and KitchenAid, along with Whirlpool), was switching to a new HFO blowing agent for the polyurethane insulation in all of it’s refrigerators.

Whirlpool will be using the new Solstice Liquid Blowing Agent made by Honeywell, one of the nation’s three producers of blowing agents (along with DuPont and Arkema). Solstice HFO has zero ozone depletion potential and a GWP of just 4.7 to 7.0—similar to that of the various hydrocarbon blowing agents used in expanded polystyrene and polyisocyanurate—and insignificant relative to global warming.

Efficiency boost an added bonus

Further, Solstice HFO will boost the R-value of the insulation material slightly. Compared with HFC-245fa, this HFO produces insulation with 2% higher R-value, and compared with hydrocarbon blowing agents it offers an 8%–10% improvement, according to Honeywell.

While the change is exciting, it is not immediate. The HFO has just received its approvals from the government, and it will take a while to ramp up production and convert refrigerator factories to the new foam. Whirlpool expects to begin incorporating the new blowing agents into its refrigerators in late 2013.

Spray-foam manufacturers slower to adopt HFOs

But what about the closed-cell SPF insulation that is commonly used to insulate buildings?

SPF manufacturers will probably be replacing the HFC-245fa with HFO…but it’s unclear exactly when that will happen. Rick Duncan, the technical director at the Spray Polyurethane Foam Alliance (SPFA), the trade association serving the SPF industry, told me that some SPF manufacturers (“system houses”) are conducting field trials with the new HFO blowing agents, but not all of them.

Unlike in 2003 when federal regulations mandated a switch from HCFC to HFC blowing agents due to ozone depletion concerns, there are no similar regulations requiring a switch from HFCs to HFOs.

It’s up to us

And the conversion takes time and is expensive—about one year and at least $100,000, says Duncan. With the building industry still in an economic slump, producers aren’t looking to spend a lot of additional money on product development.

Duncan believes, however, that when a new life-cycle assessment (LCA) report on SPF comes out that SPFA is now finalizing, customers will begin asking for lower-GWP foam and manufacturers will respond by producing it. From an environmental standpoint, open-cell SPF (which doesn’t include HFC blowing agents) has just 1/20th the global warming impact of closed-cell SPF.

12 inches of sub-slab XPS was used in this Passive House in New York State. It will take several hundred years of energy savings to pay back the global warming potential of that insulation. Click to enlarge.
Photo Credit: Jordan Dentz, The Levy Partnership, Inc.

Less action in the XPS camp

I was not able to get as much information from the extruded polystyrene industry about when the HFC-134a might be replaced with a lower-GWP blowing agent and whether there is a gaseous form of HFO that could work for that industry. (While a liquid blowing agent is used in producing SPF, a gaseous blowing agent is required for XPS.)

Jan McKinnon, the senior communications manager at Dow Building Solutions (manufacturer of Dow Styrofoam XPS), says that the company is looking for ways to reduce its greenhouse gas emissions. “Since the launch of our new formulation in 2010 [converting from HCFC-142b to HFC-134a], we continue to look at lowering our blowing agent global warming potential, and we have an active process in place to reduce it by 15%,” she told me. She said that they are actively evaluating alternative blowing agents for XPS, “but most of these technologies are still in their infancy.”

Not a great time to invest in products

Both the SPF and XPS industries have already gone through two major transitions: from CFC to HCFC blowing agents and then from HCFC to HFC blowing agents.

With a weak building economy and depressed sales of building materials, enthusiasm for a third major conversion has been limited. But I believe that there will be growing demand to produce products with as little impact on global climate change as possible—and if this year’s heat and drought continue, that demand may well grow.

Let’s hope so.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-08-22 n/a 11314 Adhesives and Sealants: Performance First, but Materials Matter

Exterior adhesives and sealants are formulated for performance, but some contain chemicals that pose risks to unprotected workers or the environment

The silicone found in many window caulks is not much of a health risk to onsite workers, but the chemicals used to produce silicon are coming under greater scrutiny.
Photo Credit: ArmaCo Construction

 NOTE: Read this whole series here.

As discussed throughout this series, adhesives and sealants used outside the building envelope have to adhere to the substrate and seal gaps, and they often need to be as durable as the building itself. Performance is the primary concern, and the chemical constituents often take a back seat. Unlike products used on the interior—where VOCs and other potentially hazardous chemicals can concentrate to create indoor air quality problems for occupants—for exterior products, exposure risk is mostly limited to workers who manufacture and apply the products.

Who’s guarding the chemical henhouse?

The majority of chemicals used in U.S. building products are not required by law to be tested for health or environmental safety, and companies do not have to list minute amounts of chemicals on material safety data sheets (MSDS), even if they bioaccumulate or are potent toxicants (see Chemistry for Designers: Understanding Hazards in Building Products).

Also Read

Are Chemicals Poisoning Your Perfect Designs?

New Concern About Pesticides in Exterior Paints

The New Anti-LEED

This lack of transparency makes it difficult to assess the full chemical profile of all the various sealants, adhesives, and gaskets on the market today.

The primary standard for emissions from wet-applied adhesives and sealants is South Coast Air Quality Management District Rule-1168, which is pending revision and does not cover tapes or gaskets. This standard establishes VOC limits and restricts the use of chloroform, ethylene dichloride, methylene chloride, perchloroethylene, and trichloroethylene in these products. Some sealants (and the primers required for some) may also fall under SCAQMD Rule-1113 for architectural coatings, if they are thinned enough.

GreenGuard certifies adhesives and sealants to its Children & Schools Standard based on emissions, but neither GreenGuard nor Rule-1168 addresses most chemical constituents found in the following adhesives, sealants and gaskets…but these chemicals can still affect the environment. Here’s a quick overview of the primary technologies used in these products.

Adhesives and sealants

Liquid, or wet-applied, adhesives are more likely to expose workers to hazardous emissions than are tapes or gaskets, with latex and solvent-free silicon products generally posing the least risk.

Though most are safe to the end user, many adhesives and sealants contain hazardous ingredients. Click to enlarge.
Photo Credit: BuildingGreen, Inc.

Polyurethanes, which contain isocyanates that may cause lung damage in workers, need to be properly mixed, applied, and cured, but proper ventilation and skin protection should also be used when applying certain acrylics, butyls, polyurethanes, and polysulfides.

Pressure-sensitive adhesives (PSA tapes)

PSA tapes are considered “articles” rather than sealants, so they do not require an MSDS and are not covered under SCAQMD Rule-1168 for wet-applied products. A tape’s built-in cover reduces emissions and worker exposure. Though products such as modified bitumen membranes or those that require volatile solvents can still be hazardous to workers, solid acrylic tapes have virtually no VOCs or other emissions and are considered a very low health risk.


Similar to PSA tapes, gaskets are not covered by emissions regulations, but since they contain no volatile solvents and are used in areas unlikely to expose occupants to emissions, these products are unlikely to be a health risk for workers or occupants. Manufacturing and life-cycle impacts are the main environmental concerns with gaskets. Polychloroprene, the primary ingredient in Neoprene, in particular, has been singled out because it is considered a persistent, bioaccumulative toxicant.

Keeping chemicals in perspective

The primary objective of exterior adhesives and sealants is keeping water, air, and heat in or out of buildings for the lifespan of the building. There are performance restrictions and limitations within each technology as well as overall cost considerations that inform what products to choose for a specific job.

When possible, select low-emitting tapes over solvent-based wet-applied products—such as solid acrylic tapes over butyl sealants—but there is a place for all these products, and by providing adequate worker training and protection as well as utilizing responsible manufacturing processes, the environmental and health impacts of these products can be minimized.


2012-08-22 n/a 11297 Sealing Without Stickum: Gaskets Make a Place for Themselves

Compressible gaskets keep air and water barriers continuous without liquid sealants or adhesive tapes. But they don’t all last equally well.

This Holst Architecture-designed Passive House project, Karuna House, includes gasketing on the sill plate—common in Northern Europe for decades but fairly new to the U.S.
Photo Credit: Hammer & Hand

NOTE: Read this whole series here.

In the U.S., we tend to put a lot of faith in caulks, tapes, and wet-applied sealants. But in Europe it’s a different story.

Some Gaskets can be used in place of tapes or liquid sealants, mainly as part of residential air barrier systems. According to Lee Jaslow of Conservation Technologies, a leading U.S. distributor of high-performance gaskets and one of the high-performance gasket listings in GreenSpec, the market for gaskets in residential construction is small but growing, with increased interest due to high-performance rating systems such as Passive House.

Memory is everything

Structurally, there are two types: air-filled bulb and cellular foam gaskets. The former are usually referred to as weatherstripping; despite the many different profiles, the fin and the air bulb distinguish these types of gaskets.

Cellular foam gaskets have tiny gas pockets throughout; these gaskets can be made from a variety of substances: PVC, Neoprene (polychloroprene), EPDM (ethylene propylene diene monomer), Santoprene (an Exxon Mobil proprietary cross between EPDM and polypropylene), and new-to-the-market silicone.

Also Read

Passive House Group Bans Certain Spray-Foam Insulation

Why's That on the Red List?

The key to all gaskets is compression and memory; gaskets must maintain their flexibility through different levels of compressive loading over time to keep water and air in or out. In general, there is a fairly strong relationship among these characteristics of gaskets: cost, durability, and load.

  • PVC gaskets are the least expensive and least durable and cannot be used with heavy loads, such as structural loading between floor and bottom plates.
  • Neoprene gaskets represent a mid-level cost/durability/load option.
  • EPDM and Santoprene are considered premium gaskets that are appropriate for structural loading, maintaining their memory over long periods of time.
  • Cellular foam extruded silicone gaskets are relatively new to the construction market and represent another premium gasket option.

Wet versus dry glazing

In commercial building, gaskets have a special application in one of two methods to set glazing.

“Wet glazing” is setting the exterior glazing using structural liquid sealants in a face-sealed system. The continuous beads of sealant are designed and installed to keep water out of the glazing set and system.

A conceptual "better glazing system" from the Whole Building Design Guide. Click the image to download as a PDF. 
Photo Credit: NIST

In a “dry glazing” set, gaskets accomplish the structural glazing set and are designed with drainage channels to move water off and out of the glazing installation.

Sneh Kumar is the Manager of Department of Energy Projects for Traco – Alcoa Building and Constructions Systems, working on high-performance curtainwall systems. “We use both dry and wet glazing systems, depending on the economics of the project and the manufacturer of the glazing,” says Kumar. “Same with the types of gaskets; the economics of the project and specific profiles of the glazing manufacturer drive this decision. I can tell you that both systems are very dependent on craftsmanship and quality control, one of the reasons we prefer systems for which the glazing set is a plant rather than a site operation.”

But what about service life?

It seems to boil down to experience.

When I asked both Jaslow and Kumar how they evaluate the service life of gaskets, they emphasized experience over specific studies or standardized tests, mainly because there simply aren’t any for how long various gaskets last in the field.

“We know that gaskets have been a key part of airtight homes in European countries such as Sweden for nearly 40 years,” says Jaslow.

Kumar says Traco uses a battery of ASTM tests and AAMA standards to gauge durability, but “it all comes down to experience at Traco; we know the products and systems that have performed for us over the last 20 or so years.”

So…sealants, tapes, or gaskets?

We know that each material can give initial continuity to our air and water barriers.

What we still don’t know is which systems and specific types of products sustain their performance over time. We are moving toward predictive, standardized tests of field service life for liquid sealants. And efforts such as the Tremco Sustainable Building Solutions Test Facility represent a huge step forward. And the gasket products we list in GreenSpec—silicone, EPDM, and other durable materials—are the best products out there right now.

But for the time being, keep your craftsmanship and quality control high, don’t skimp on spending for something just because it’s buried in the wall (skimp on the stuff that’s easier to replace, if you must!) and gather your own performance experience over time.

2012-08-15 n/a 11286 Sustainable Sealants: The Challenges of Predicting Service Life

Caulk joint sealants can be a major deciding factor in how long your building envelope lasts. Is there a better way to predict how long they last?

Mounted on the roof at NIST, this "weathering engine" tests sealant durability.
Photo Credit: National Institute of Standards and Technology

NOTE: Read this whole series here.

Durability, or service life, is critical to the overall performance of liquid caulk joint sealants in the water and air barriers in our buildings.

If we can figure out how long sealants actually last then we can come up with a prudent inspection schedule—and have a good idea of how they’ll fail and how to replace them. The good news about sealants is that they are generally exposed to view—unlike flashing tapes, which are generally buried and inaccessible. (More on tapes in a future post.)

Fairly assessing durability or service life

We are always hoping for that one magic test that fairly, accurately, and realistically portrays one or more performance attributes of our building materials.

The trouble is that, while field tests can be more realistic, they tend to introduce many uncontrolled or non-measurable conditions. And the trouble with laboratory tests is that they set, control, and measure many conditions, making them often far from what actually goes on in the field.

It turns out that we have plenty of useful standardized laboratory tests for both liquid sealants and tapes that we use in our weather and air barriers. That’s the good news. The bad news is that we haven’t had useful tests for the field service life prediction of those same sealants and tapes—until recently.

Field service life prediction of liquid sealants

For the last ten-plus years, I have been keeping loose track of the work of Christopher White at the National Institute of Standards and Technology (NIST). Back around 2000, he started an ambitious research effort to predict the field service life of liquid sealants. Each year or so, I would give Christopher a call inquiring about this work, and his perfectly amiable response was, “Still working on it, but nothing really to report yet.”

But last year in June, he surprised me. “Good news! I have published quite a bit now on the field service life prediction test research and am making good headway on related ASTM tests.”

The weathering engine

The centerpiece of White’s work on field service life prediction of liquid sealants is the test rig: a PVC weathering engine.

Also Read

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Designed to capture key aspects of sealant performance, its beauty is its relative simplicity (readily available components) and acceptability within the industry. The rig is made up of two basic parts—a fixed support frame (the doubled two-by hardwood supports) and a moving frame (the 4-inch diameter PVC pipes). These two frames are linked where the sealants are stressed between two plates, with the stress being monitored and measured by a load cell and linear variable differential transformers (LVDTs).

As temperature changes cause expansion and contraction of the PVC pipe and the sealant is exposed to other environmental factors (temperature, UV, relative humidity, precipitation) as recorded by the weather station, several key aspects of service life can be measured and then predicted as the result of the rig and test output.

White’s most important standardized testing effort to date is in revising ASTM C1589 (05), Standard Practice for Outdoor Weathering of Construction Seals and Sealants, to embrace the PVC weathering engine. This standard is currently being balloted within ASTM. With any luck, building professionals will soon be able to cite this standard as a leading performance criterion for liquid sealants— and manufacturers will cite this standard and results in their product information.



2012-08-08 n/a 11208 Expanded Cork - The Greenest Insulation Material?

Introducing all-natural expanded cork boardstock insulation to the North American market.

Expanded cork insulation is available up to 12 inches thick and can be used much like polyiso. Click to enlarge.
Photo Credit: Amorim Isolamentos

I’m always on the hunt for the latest, most interesting, and most environmentally friendly building materials, and I have particular interest in insulation products—partly because many conventional insulation products have significant environmental downsides. (See “Avoiding the Global Warming Impact of Insulation” and “Polystyrene: Does it Belong in a Green Building?”)

So I was thrilled to learn about expanded cork boardstock insulation made by the Portuguese company Amorim Isolamentos and just now being introduced into the North American market. Francisco Simoes, of Amorim, visited our office in Brattleboro in June and told us all about it.

Familiar to wine drinkers as the traditional bottle-stopper, cork is a natural product made from the outer bark of a species of oak tree that grows in the western Mediterranean region of Europe and North Africa. The bark is harvested after trees reach an age of 18–25 years and it regenerates, allowing harvesting every nine years over the tree’s 200-year life.

The outer bark of cork oak tree can be harvested every nine years. Click to enlarge.
Photo Credit: Amorim Isolamentos

In Portugal, the world’s leading producer of cork, these oak trees are federally protected, and many cork forests are certified to Forest Stewardship Council (FSC) standards. Harvesting is done by hand, much as it has for over 2,000 years. While cork oak forests in Portugal are expanding, cork’s market share for bottle stoppers is dropping as plastic stoppers and screw-off caps become more common—motivating the company to look for new markets.

Cork as a building material

I have long been a fan of cork flooring, floor underlayment, and acoustical wall coverings. These materials are made from residual cork that remains after punching cork bottle stoppers from the bark—which consumes only 25%–30% of the bark.

For cork flooring and these other products, the cork granules are glued together with a binder and then sliced into the finished products.

Expanded cork insulation is quite different. The same cork granules are used, but they are exposed to superheated steam in large metal forms. This heating expands the cork granules and activates a natural binder in the cork—suberin—that binds the particles together. In an in-depth product review about expanded cork insulation in the August issue of Environmental Building News I describe the fascinating history of this process (it was invented by accident in New York City in the late-1800s).

A billet of expanded cork coming out of an autoclave. Click to enlarge.
Photo Credit: Amorim Isolamentos

After producing these large billets of expanded cork, they are sliced into insulation boards in a wide range of thicknesses—in both metric and inch-pound (I-P) sizes. In I-P units, thicknesses from a half-inch to 12 inches are available—with dimensions of 1' x 3' or 2' x 3'.

The material is 100% natural, rapidly renewable as defined by the LEED Rating System, durable yet ultimately biodegradable, produced from sustainable forestry operations, and a by-product from the cork bottle-stopper industry. Though there is significant shipping energy required to bring it here, shipping by ocean-going vessel is relatively energy-efficient. It’s hard to imagine a greener building material.

Cork insulation performance

Expanded cork insulates to R-3.6 per inch. It has a density of 7.0–7.5 pounds per cubic foot and compressive strength of 15 psi (with 10% compression). It is intermediate in its permeability to moisture—with a 40 mm layer having a permeance of 2.2 perms. Although the expanded cork insulation gives off a smoky smell, a test report I examined showed the material to pass France’s stringent requirements for a dozen volatile organic compounds (VOCs) with flying colors. Cork also has superb sound-control properties.

A 40 mm layer of expanded cork insulation resists burn-through for over an hour. Click to enlarge.
Photo Credit: Amorim Isolamentos

From a fire-resistance standpoint, it meets the European Class E designation (the standard met by other rigid insulation materials) without the need for flame retardants that are used in the most common boardstock insulation products. A 40 mm-thick piece of the boardstock insulation held over a torch will resist burn-through for an 60–90 minutes, compared to less than 10 seconds for expanded or extruded polystyrene, which meets the same Class E designation. (The flawed manner in which we determine fire-resistance properties of materials is the topic for another article.)

Cork insulation has been used as a rigid insulation material for decades in Europe. It is not uncommon to install an 8- to 10-inch layer on exterior walls and a 10- to 12-inch layer on roofs. The first Passive House built in Austria (in 1995) used a 350 mm layer (nearly 14 inches) of the material. It is typically used as an exterior insulation layer, much like polyisocyanurate.

Cost and availability

North American distribution channels are just being set up, so pricing is far from certain. But Simoes told me the price to a distributor will be about $0.70 per board-foot, not including shipping, mark-ups, or the exchange rate. If those mark-ups come to 50%, the cost per board foot would be $1.05 and the cost to achieve R-19 would come to about $5.50 per square foot for cork, vs. $1.10 – $1.60 for polyisocyanurate insulation and $2.00 – $2.25 for extruded polystyrene.

That’s a significant upcharge for cork, but you end up with one of the greenest building materials anywhere. I’m so excited about expanded cork insulation, in fact, that I’m hoping to use it on an upcoming building project later this year.

You can read my full review of Amorim Isolamentos’ expanded cork insulation board at (membership required). You can also visit the company’s website or contact the company by e-mail:

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-07-31 n/a 11049 Saving Wood from the Landfill, Without the Supply Issues

Oregon-based Viridian upcycles shipping waste to make stylish flooring, tabletops, veneers, and other products

Once destined for the landfill, this wood was taken from shipping materials and upcycled into Viridian's Jakarta Market Blend flooring.
Photo Credit: Viridian Reclaimed Wood

Over the years, the GreenSpec team has looked at a lot of reclaimed lumber. It’s usually taken from barns and other aging structures, checked for lead paint and chemicals, and then turned into flooring and other products.

It’s rustic and attractive, but actually ordering it is fraught with supply challenges, so when Joe Mitchoff, co-founder of Viridian Wood Products, stopped by the office to show his company’s products to Alex Wilson and me, my expectations were not particularly high. I was, however, pleasantly surprised by the product and the story behind it.

The Process

Most of Viridian’s wood is not reclaimed from buildings. Instead, it comes from overseas shipping materials gathered from the Port of Portland, Oregon, and other area ports. Mitchoff and his business partner, Pierce Henley, discovered that the wooden pallets, crates, and other packing materials that came into the port everyday were sent to the landfill as a matter of course—up to thirty, 30-yard dumpsters per ship. “We found this tremendous waste at the Port of Portland,” Mitchoff said, and they began looking for ways to upcycle it.

At first, the recycling process was just a hobby, but it grew until the two had to set up a 40,000 square-foot warehouse next to the dock. They had to locate it there so the truckers would have easy access (otherwise, due to cost and time, they threatened to keep sending it to the landfill).

These shipping containers are filled with wood, steel cables, and strapping.
Photo Credit: Viridian Reclaimed Wood

The wood arrives at the facility commingled with steel cable, nylon strapping, and ship waste. “People have tried to mechanically sort it, but that doesn’t work,” said Mitchoff, so the sorting, grading, and de-nailing are done by hand. All that work pays off, though, as Mitchoff claims they recover, use, or recycle 99%+ of the material. For every thirty 30-yard dumpsters coming in, “we barely have one four-yard dumpster of waste going out.”

The wood reclaimed from this jumble is heat-treated to destroy insects, per international law, and further inspected by the Department of Homeland Security, which also sets traps for invasive species at Viridian’s warehouse (they haven’t caught any yet). The company does not use any chemically treated wood.

The Wood

Viridian’s wood usually arrives in 4" x 4" x 12' posts along with irregular pieces and includes European beech, oak (or “Fishtail oak” which has unique grain pattern), spruce and pine from Russia, and “Jakarta Market Blend,” which is a mix of Asian hardwoods sorted for consistent hardness. (Virdian also offers reclaimed Douglas fir from local warehouses and school bleachers.)

Also Read

The Many Faces of Reclaimed Wood

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All of this wood is kiln-dried and then either processed at a mill up the road from the warehouse or made into tabletops at a separate facility.


The Products

As mentioned, the main problem with most reclaimed wood is inconsistency. If a customer uses reclaimed wood on a project and decides at a later time to finish another room down the hall, that same wood may not be available, but Viridian gets a constant supply into the company’s warehouse. One of Viridian’s most popular woods is the Jakarta blend, a mix of woods that provides a “consistently inconsistent look,” according to Mitchoff. This combination should minimize any problems matching products in the future.

Viridian’s reclaimed wood is sold as flooring, paneling, and tabletops. “We do a lot of commercial work,” Mitchoff said, “with many of the tabletops going to restaurants.” The glues the company uses are radio-frequency-cured PVA glues, which are very safe. The finishes the company uses all meet California Air Resources Board (CARB) standards.

The wood, commingled with other shipping waste, is hand sorted and graded in Viridian's warehouse..
Photo Credit: Viridian Reclaimed Wood

Viridian is also making veneers from reclaimed wood. These can be adhered to any architect-specified core, though the company prefers PureBond substrates with no added urea-formaldehyde. Tabletop finishes are either UV-cured or zero-VOC, depending on the product, and have a “natural” look rather than a thick coat of polyurethane.

The Price and Availability

Viridian sells its products direct, primarily to architects and design firms instead of homeowners, with 50% of its customers in the Pacific Northwest and the remainder spread across the U.S. and Canada.

Jakarta blend currently sells for $6.95/ft2, Fishtail at $7.95/ft2, fir in the range of $5.50/ft2 to 7.50/ft2 (depending on face width and grain), and European beech at $5.95/ft2. Tabletops are “mid-30s to -40 per square foot” according to Mitchoff, depending on the wood and how difficult it is to mill.

Viridian also transforms bleacher seats, made from the highest grade of Douglas fir available, into tabletops, keeping the numbering and marks. The price of these bleacher products varies depending on availability, but is typically about $30/ft2. By comparison, table tops of Jakarta blend typically sell for $25-27/ft2.

Reclaiming perfectly good wood that would normally go to the landfill is a great use of resources, but according to Mitchoff, the company does not plan on branching out to other ports in the U.S. Viridian seems to have found a perfectly viable wood source that fills a unique niche in the reclaimed wood market.

2012-07-25 n/a 11103 The Results Are In: Green Builders and Designers Might Need Toxicology Summer School

We’ve run the numbers from our quiz on toxic chemicals in building products, and we all have some explaining to do. Put down your #2 pencils and listen up!

SPOILER ALERT: If you haven’t yet taken the GreenSpec toxic chemical quiz, head over and do it now—yes, before you read the answers.

Find out how you did

Find out below how well you did on the GreenSpec toxic chemical quiz. And feel free to brag, commiserate, add your expertise, or kvetch about “trick questions” in the comments.

Afterwards, if you want to learn more about toxic chemicals in building materials—or if you are looking for a simple, straightforward way to share your knowledge with colleagues, students, or clients—please check out the report we've just released, Avoiding Toxic Chemicals in Commercial Building Products: A Handbook of Common Hazards and How to Keep Them Out.

Which one applies to you?

20–25 points: Consider a career change: you should be teaching toxicology summer school!

13–19 points: You have a pretty good handle on how to design healthier buildings—but the unknowns could keep you up at night.

6–12 points: You know just enough about toxic chemicals to be dangerous!

0–5 points: What you don’t know can hurt you: consider brushing up.

1. Endocrine disruptors cause which one of the following?

Give yourself one point for metabolic irregularities, such as insulin resistance. You also get a point if you wished “all of the above” had been one of the answers. Give yourself a half point for choosing any other answer. Maximum of 2 points.

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We put this question first because we thought it was a dead giveaway. Silly us!

Endocrine disruption is probably the least understood area of toxicology. The effects of endocrine disruptors can be all over the map—and so the quiz answers were too. Just over 40% of respondents picked what we considered to be the best answer.

As one reader pointed out, certain endocrine disruptors are associated with all of these effects, so if you picked any of the other answers, you were not entirely wrong.

At the same time, insulin is a hormone, and an endocrine disruptor is, by definition, something that interferes with hormones. This is why scientists are starting to think that endocrine disruptors like bisphenol-A (BPA) might be contributing to increased obesity rates: they directly interfere with how we metabolize sugar.

Many people don’t realize that BPA isn’t just in our food; it’s in all epoxies and many other adhesives, coatings, etc.—and you’re likely to find it in lots of resins that might be part of your furniture too.

Even though endocrine disruptors might ultimately lead to any of the listed effects, each of the other options has another hazard type more closely associated with it: chemicals that primarily cause developmental delays are more likely to be classed as neurotoxicants; those that primarily cause genetic mutations are more likely to be classed as mutagens; and chemicals that primarily cause cancer are more likely to be classed as carcinogens.

2. Choose all answers that seem correct. Halogenated flame retardants in furniture foam and upholstery are problematic because...

Give yourself one point for each answer you chose, a maximum of 4.

  • …some are SVOCs?
    Yup. Under some conditions, these chemicals can volatize and affect indoor air quality.
  • …they might slough off the furniture into indoor dust?
    Absolutely. An even more concerning air quality problem.
  • …they might leach into groundwater and pollute ecosystems after disposal?
    Yes, and many of these chemicals are super nasty: persistent, bioaccumulative toxic chemicals (PBTs).
  • …they may not effectively prevent or slow the development of fires?
    Right again.

Just over half of the respondents knew that last one, which is unfortunate because it is probably the most important one of all: use of these chemicals is often justified for “safety” reasons, but they are highly toxic and don’t even do a good job of preventing fires. So what’s the point? (That’s not a quiz question, so here’s a hint: it has to do with keeping chemical companies in business.)

3. True or false?

Give yourself a point for each one you nailed, for a possible total of 6.

  • Building occupants can be exposed to mercury in fluorescent lamps only if a lamp breaks.
    True: that mercury stays sealed up during normal use. Read up on EPA’s guidelines for cleanup of broken bulbs if you don’t already know them. (25% got this wrong.)
  • Manufacturers must disclose all hazards in adhesives and sealants on the material safety data sheet.
    False: an MSDS is intended primarily to warn employers and workers of dangers that might come up when materials are being applied—not for those who are living or working in a space where materials have already been applied. not everything needs to be disclosed, and the most toxic stuff is often used in small amounts and won’t show up. (25% got this wrong.)
  • If you choose wood flooring, you don’t need to worry about VOCs.
    False: VOCs can be emitted from laminates, from engineered wood and bamboo flooring, and from flooring adhesives and finishes. (4% got this wrong.)
  • One of the biggest health concerns with carpet is exposure to mold and dust mites.
    True: Asthma is serious business, and exposure to some asthmagens can sensitize people who were not formerly allergic. Keeping carpet clean and dry is key to good indoor air quality. (40% got this wrong.)
  • Building wiring typically contains hazardous ingredients, including lead, which can enter occupied space via dust.
    True: the flame retardants and plasticizers, including lead, in that wiring can slough off in plenums and then into occupied space. (38% got this wrong.)
  • Boric acid, a flame retardant used in cellulose insulation, is just as dangerous as the halogenated flame retardants used in polystyrene.
    False: boric acid, although it can be toxic in large quantities, is nowhere near as nasty as halogenated flame retardants.  (28% got this wrong.)

4. Choose all answers that seem correct. Which of the following are ways that persistent, bioaccumulative toxic chemicals (PBTs) can move around in the environment?

Give yourself one point for each answer you chose, a maximum of 6.

How PBTs move up the food chain
Photo Credit: Peter Harris for BuildingGreen, Inc.

Blown by air currents
Yes, and this may be the main way that PBTs get to the most remote locations on the globe, but scientists still aren’t sure. (22% got this wrong.)

Carried through waterways
Yes, and this is a big problem when PBTs get into runoff—like from lead exterior paint or lead flashing. (9% got this wrong.)

Absorbed from soil by plants and microorganisms
Yup, and then many PBTs biomagnify up the food chain. (7% got this wrong.)

Absorbed through skin from water or silt by animals and humans
Yes, this is one of the reasons you’re not supposed to swim in contaminated water: you can absorb many toxic chemicals through your skin. (20% got this wrong.)

Transferred from mother to child
Absolutely; many PBTs show up in the eggs of exposed mothers and can cross the placenta in mammals. They may also be transferred in mothers’ milk. (15% got this wrong.)

Ingested when scavenging or hunting
Definitely—or, in the case of humans, when eating tuna from a can. (22% got this wrong.)

5. Which statement best sums up the “precautionary approach”?

Give yourself one point for correctly identifying the precautionary approach.

When possible, we should avoid materials that are suspected of being hazardous, even when there is not conclusive evidence.

Well done! Just 17% got this wrong.

6. A toxin is:

One point for this one, and hardly anyone gets to add it.

Any poison produced by a living thing, such as snake venom

In the toxicology world, a “toxin” is a poison produced by a living thing; other examples are botulinim toxin, aflatoxin in peanuts, and mold toxins. Chemicals in building products might be toxic substances or toxicants for short, or, if you must,  “toxics.”  

Just 6% chose the right answer! The majority thought it was “any substance that could poison people,” while a significant minority chose “any substance that bioaccumulates in organisms.”

7. “Exempt” VOCs are compounds that…

Give yourself one point for do not contribute to smog.

The word “exempt” here relates to the U.S. Environmental Protection Agency’s regulations about VOCs. EPA just regulates the ones that contribute to smog, which makes all other VOCs—including known health hazards—exempt. This becomes confusing on paint cans, for example (see question 8).

Just 33% of people got this right, with a plurality thinking that “exempt” meant “safe for indoor use.”

8. How much VOC content will you find in a zero-VOC paint?

Give yourself one point for It’s unclear because some VOCs don’t have to be counted for labeling purposes.

Just 66% of respondents knew this, and you can see why. “Zero” ought to mean what it says. Unfortunately, you can’t count on that, for two reasons:

  • Because the manufacturer only has to report the “non-exempt,” or smog-forming, VOCs (see question 7), you need to know not just reported VOC content but also how the product performs on indoor emission tests to get an accurate picture of potential health effects.
  • Even if we’re only looking at smog-forming VOCs, a paint, caulk, adhesive, etc. containing 5 grams per liter can still be legally labeled “zero-VOC.”

9. What is California Section 01350?

Give yourself one point for the CDPH Standard. And the two of you who picked “A spinoff from Beverly Hills 90210” get half a point, just for having a sense of humor.

The '90s called. They'd like to point out that back then there were also standards in California, even if they weren't very high.

OK, we have to admit this was a trick question. A steaming bowl of alphabet soup, and no Googling allowed?

Plus, as one reader complained (and we’re happy to hear more, so please use the comments section), Section 01350 covers not just VOC emissions, which is what the CDPH Standard Method tells you how to test for, but also a few other issues having to do with recyclability and resource efficiency.

But in most contexts, Section 01350 is referenced as a VOC emission testing protocol for building products—and the method of testing used is the California Department of Pubic Health (CDPH) Standard Method.

Since the 01350 specification also covers other things, we’ve seen a gradual transition, with references to “California Section 01350” being replaced by “CDPH Standard Method.” For all practical purposes, it means the exact same thing that people used to mean when they said “California 01350”—even though they’re not exactly the same thing.

A lot of certifications and other standards reference California 01350/CDPH emission testing methods—including the CHPS Guidelines for green schools in California, which was the most popular answer for this question, chosen by almost 50% of respondents. Although CHPS gives you credits for using products that meet the standard, it’s not synonymous with the standard, anymore than is LEED, Indoor Advantage, or any other system that references it. So CDPH Standard is still the best answer here.

10. Which of the following products would NOT be restricted by the Living Building Challenge Red List?

Give yourself TWO points for wood treated with copper azole.

Because if you know that much about the Living Building Challenge (LBC), we think that’s awesome! Just 20% of respondents got this one right.

As for the other answers:

  • OSB sheathing with phenol-formaldehyde binder is a no go. LEED gives credit for avoiding added urea-formaldehyde, but LBC nixes all added formaldehyde.
  • R-22 refrigerant may be non-ozone-depleting, but it contributes massively to global warming. LBC restricts all hydrochlorofluorocarbons (HCFCs), a class of chemicals that includes many refrigerants and blowing agents (including R-22).
  • Carpet tiles with 100% post-consumer recycled PVC backing might sound great to you, but all PVC is banned from LBC buildings.
2012-07-19 n/a 11100 The Ongoing Revolution in LED Lighting

LED lighting keeps on improving as yet another record efficacy is announced.

Cree's new XLamp XP-G2 LED chip delivers up to 165 lumens per watt. Click on image to enlarge.
Photo Credit: Cree

A few days ago I got yet another press release about a new efficiency record with LED lighting. These are almost commonplace as we ride the revolution that is redefining electric lighting.

To back up, let me provide a short synopsis of lighting technologies and history.

Incandescent lamps provided the first electric lighting, with Thomas Edison inventing the first commercially viable light bulb around 1880 (building on the inventions of many others), and the technology has changed relatively little since General Electric introduced tungsten-filament light bulbs in 1911. Electric current flows through a very thin, coiled filament made of tungsten wire and glows white-hot, producing light. With incandescent lighting, roughly 90% of the electricity is converted into heat, only 10% into light.

Lighting was revolutionized in the 1920s with development of fluorescent lights. With this technology, an electric arc is established in a glass tube filled with mercury vapor. The arc produces ultraviolet light and that light energizes a phosphor coating on the inner surface of the glass tube. That phosphor, in turn, fluoresces, emitting white light.

Various high-intensity discharge (HID) lighting technologies (mercury vapor, high-pressure and low-pressure sodium, and metal halide) also function by energizing mercury vapor, but with other gases that obviate the need for phosphors. Very concentrated light can be generated, which makes this lighting popular for street lights, stadium lighting, and such.

Enter LED Lighting

LED lighting is fundamentally different from incandescent, fluorescent, or HID lighting. LED stands for “light emitting diode.” It is a solid-state device made of a specialized semiconductor material that emits light when energized. The first LED lights were red or green (depending on the semiconductor material) and used primarily as indicator lights on electronic equipment. Blue and other colors came along later. The challenge has long been producing quality white light.

Over the past 10-15 years, developers have figured out ways to either combine different-color LEDs to produce—in aggregate—white light, or to use phosphor coatings to modify the emitted light color, so that we see white.

LED lighting avoids the mercury in fluorescent and HID lighting, and its efficacy (a measure of lighting efficiency in units of lumens of light produced per watt of electricity consumed) is now considerably higher than that of incandescent lighting, and the best LEDs now have higher efficacies than even the leading-edge T-5 fluorescent lamps.

When I first wrote about LED area lighting (as opposed to exit signs) in Environmental Building News back in 2002, I reported a breakthrough in LED performance. A new LED light source had just been introduced by Lumileds that provided a remarkable 24 lumens per watt. That was significantly higher efficacy than that of incandescent light bulbs, but still nowhere near that of fluorescent lamps. In the same article I quoted a researcher at Lumileds saying that he thought LED performance would eventually reach about 100 lumens/watt.

State-of-the-art LED lighting today

The press release I got a few days ago from Cree Lighting (one of the other major producers of LEDs and LED lighting products) reported that their newly introduced XLamp XP-G2 LED provides a remarkable 165 lumens/watt in a cool-white and 145 lumens/watt in warm white (assuming 25°C temperature). Measured at 85°F (accounting for worst-case conditions in a fixture), that XP-G2 efficacy drops about 8%--to 151 and 133 lumens/watt respectively.

Cree's CS18 eight-foot linear LED fixture. Click on image to enlarge.
Photo Credit: Cree.

Once those LEDs are incorporated into actual lighting products, the efficacy drops, but the best LED lamps and light fixtures today using earlier-generation LEDs can still provide well over 100 lumens per watt. Cree’s CS18 eight-foot linear light fixture for commercial buildings, for example, delivers up to 120 lumens/watt.

With smaller LED lamps that can replace incandescent light bulbs, performance isn’t quite up to 100 lumens/watt yet. Philips’ best EnduraLED bulb provides 900 lumens of light (more than a 60-watt incandescent bulb) using just 10 watts of electricity. That’s an efficacy of 90 lumens/watt.

The light quality from LEDs has also steadily improved. Both the Cree CS18 and Philips EnduraLED products mentioned above have a color rendering index (CRI) numbers of 90, which is better than almost any fluorescent lighting available. One of Cree’s LED lamps has a CRI of 93.

LED lights have a very long life. The Cree CS18 is guaranteed for five years and rated for 50,000 hours, while the Philips EnduraLED is rated for 30,000 hours—compared to about 20,000 hours for a typical linear fluorescent lamp (for commercial lighting), 10,000 hours for a compact fluorescent lamp (CFL) and 1,000 hours for an incandescent light bulb.

Most (but not all) LED lights are also dimmable. The Cree CS18 can dim to 5% and the Philips EnduraLED to 10%.

And I really like the fact that there’s no mercury involved.

Costs and durability

While the cost of most LED lamps and lighting fixtures is significantly higher than costs of incandescent and fluorescent products, costs are coming down as quickly as performance is going up. Lamps in the Philips EnduraLED family can be found for as little as $24 each, and I’m guessing that they will be less than $10 within a few years.

Be aware, though, that there are lots of low-quality LED lighting products on the market, often at significantly lower prices. The biggest problem with cheap LED products tends to be inadequate heat management, which shortens the life. I prefer to buy products from recognized manufacturers, but at a minimum, you should look for EnergyStar labels on LED lights that you are considering. The EnergyStar program for LED lights has a pretty good requirement for durability.

As LED lighting keeps improving, keep your eyes on our GreenSpec guide to help you find the best LED products.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

2012-07-19 n/a 11047 Stickiness Explained! Making Building Tapes and Membranes Stay Put

When you use tape to seal a seam or flash a sill, you need peel-and-stick performance—not “stick-and-peel.”

...or is it? Our confidence in tape might be a little misplaced.

NOTE: Read this whole series here.

While liquid sealants most often are used on the exposed surfaces of building enclosures, pressure-sensitive adhesive tapes (member link) and membranes are used one or even two layers deep in the building assembly to seal the margins of weather-resistive and air barriers and at penetrations such as window openings.

Their location means that they cannot be inspected, repaired, or replaced; we need to know that they will maintain their integrity and function for the full service life of the assembly.

What makes stuff “sticky?”

It’s pretty easy to take pressure-sensitive adhesion (PSA) for granted; from band-aids to masking tape to peel-and-stick membranes, we use them pretty much every day. But the science of PSA is complex and even a bit uncertain.

Also Read

Choosing the Right Sealant for the Job

Breaking the Bonds of Bad Sealant Jobs

Tape It? Seal It? Glue It? Sealing Weather Barrier Seams

We do know that certain large-chain polymers can “wet” (meaning that while they are solids, they can act like liquids when under mechanical pressure) to allow intermingling with the substrate at just about the molecular level, creating huge surface areas of contact between the PSA and the substrate. This intermingling allows small but cumulatively powerful electrostatic-like bonds to form.

These bonds are physical, not chemical (the two being distinguished by the former involving no permanent or irreversible changes to the two materials, and the latter involving both types of changes). In fact, you can stick certain PSA tapes to themselves, then go into a dark room, tear them apart, and see tiny blue sparks: these are the expression of the energy released as the physical bonds of adhesion are broken (check out this YouTube video for a cool way to have fun with duct tape).

The science of construction tapes and membranes

Sometimes we want PSA tapes to be modest and easily reversed—like a sticky note. But with PSA tapes and membranes in our building assemblies, we want that adhesion to be very strong and darn near irreversible.

We also want the tapes or membranes to be unaffected by temperature extremes, establish and maintain the adhesion in the presence of moisture, adhere to a wide variety of substrates, and tolerate the dust and dirt found on the surfaces of the building materials to which the PSA tapes and membranes will be applied.

The four basic types of PSA differ in how they meet all these properties and—not surprisingly—differ in cost as well.

Types of PSA

"Benchtop" testing of a Pro Clima PSA tape on a terra cotta drainage tile (using Pro Clima primer).
Photo Credit: Peter Yost

There are four primary types of PSA tapes and membranes: rubberized asphalt (modified bitumen), butyl rubber, acrylic, and silicone.

Rubberized asphalt and butyl rubber adhesives dominate in flexible membranes (generally thicker, more flexible and wider materials) and acrylic and silicone in tapes (generally less wide, somewhat less flexible and thinner materials), but this is not a hard-and-fast rule. Regardless of their properties and differences as described below, each becomes more effective and durable when properly weatherlapped and mechanically supported.

Rubberized asphalt

These PSA membranes are probably most familiar as the 3-foot wide ice-and-water shield details on roof eaves (WR Grace Vycor, for example). Rubberized asphalt (RA) membranes are among the least expensive membranes and also among the most temperature-sensitive, losing significant adhesion as the temperature drops below 40º–50ºF and becoming very soft, unstable, and likely to flow at high temperatures.

RA membranes bond reasonably well to some (but certainly not all) common building materials: wood, plywood, rigid vinyl (such as window flanges), and metal. They do not bond well to OSB, and some manufacturers recommend the use of a primer for many substrates, particularly OSB.

Chris Makepeace, a prominent building scientist from Edmonton, Canada (who popularized the PERSIST air- and water-barrier system), sums up modified bitumen membranes and the need for primers this way: “If you use a primer, it’s called peel-and-stick; if you don’t, it’s called stick-and-peel.”

Butyl rubber

Butyl rubber membranes were developed to augment RA membranes because they are less temperature-sensitive and maintain their tackiness at much lower temperatures than RA membranes.

They also stick well to more substrates. Butyl rubber membranes are more expensive than RA membranes. One of the most recognizable butyl rubber membranes is DuPont’s FlexWrap, which can be used on inside corners, like window sill corners.

Both rubberized asphalt and butyl rubber membranes are “self-healing;” they conform around penetrations, nearly sealing them.


Acrylic adhesives can be water-based, solvent-based, or “solid.” Water-based adhesives are the least expensive of the three and generally do not bond to as wide a variety of substrates as solvent-based ones.

Solid acrylic adhesives can form the strongest adhesive bonds at a wide range of temperatures and even achieve adhesion to damp or wet substrates. Solid acrylic adhesives are also VOC-free, and the absence of any solvents means little to no embrittlement of the tapes over time.

Both water- and solvent-based acrylics are cost-competitive with butyl rubber PSA tapes; the solid acrylic PSA tapes come with an additional premium.


Silicone adhesives are the only adhesives that will bond to silicone substrates, are quite expensive, and are not often found as PSA tapes or membranes in construction (with one outstanding exception being the silicone sheet used in the integrated Tremco ETA system [member link]).

Other considerations

Two other important aspects of PSA tape performance are the type of backing material and the amount of adhesive. The backing material can contribute to the overall durability of PSA tapes and determine the vapor permeability of the tape, (of particular importance in cold climates, where moisture accumulating under the PSA tape or membrane can freeze and degrade long-term adhesion).

The amount of adhesive per unit area of tape can also be a factor in the initial and long-term PSA tape performance; more adhesive can mean more robust performance, especially if a substrate is less than squeaky clean.

Installation & testing are key

Tensile testing of a SIGA PSA tape on the smooth side of OSB, using a Com-Ten DFM5000 tester.
Photo Credit: Peter Yost

Each of the above types of adhesives may need the addition of a primer to achieve a quality bond to certain substrates, such as concrete or OSB. And some tapes adhere much better to one side of the OSB over the other (most OSB has a “screened” side and a burnished side (the structural stamp is almost always on the slippery, burnished side).

The best way to select the type of PSA tape or membrane is to try it in the environment and on the substrate(s) in your assembly. Since I am right in the middle of some “benchtop” adhesion tests for a wide variety of common PSA construction tapes and membranes, I will come back soon with some of my own recommendations for PSA tapes and membranes. Until then, watch for another post on how to judge—and increase—the longevity of sealants and tapes.

2012-07-10 n/a 11031 Are Chemicals Poisoning Your Perfect Designs? Test Your Knowledge of Building Product Hazards

Take our quiz to find out how much you really know about VOCs, lead, toxic flame retardants, and other common hazards in building materials.

Sometimes you feel like you should wear a hazmat suit to the office—but it can be difficult to find a tie to match.
Photo Credit:

Food, toys, furniture, building products—just about everything around us—can contain chemicals that will make us very sick or even kill us if we are exposed at a certain level over a long period of time. Sometimes it seems like there’s some new killer substance in our homes, schools, and offices almost every day of the week.

Information overload

But news stories about these products usually provide little or no context to help people understand when they may truly be in danger.

A lot of people, overwhelmed by the constant scares and unclear on which products are actually hazardous, give up on keeping track of everything that might poison them.

Building industry professionals don’t have that luxury.

Also Read

Chemical Industry Attacks LEED; BuildingGreen Checks the Facts

Video: Why We Need “Nutrition Labels” for Building Products

New Concern about Pesticides in Exterior Paints

New Flame Retardant for Polystyrene—Too Much Like the Old?

Clients are paying attention, but they need your help

Knowing which building materials and products are likely to contain which toxic substances—and knowing when to minimize use of those materials or find less-toxic alternatives—comes with the territory. And the need for this knowledge is not just confined to the green building world anymore.

A recent Chicago Tribune exposé brought to light chemical industry deceptions that for decades have encouraged the pointless overuse of highly toxic flame retardants, raising awareness of this issue in the mainstream national press for the first time.

The Obama administration just made headlines for working to improve both indoor and outdoor air quality to reduce rampant asthma rates among low-income minority children.

And The U.S. Green Building Council’s LEED v4 rating system is moving toward a greater emphasis on chemicals of concern, creating a strong new incentive for chemical avoidance.

Will you be able to answer their questions?

As awareness of toxicity and the built environment becomes more mainstream, a thorough and up-to-date understanding will be in higher and higher demand. Are you keeping up? Do you know how to protect your clients—whether they ask for it explicitly or not?

Take our short quiz and find out. And no Googling, please!

We’ll publish the answers—and let you know how you did—in a blog post next week.

2012-07-07 n/a 10956 Specifications for LEED “Certifiable” Projects: 4 Approaches

Many owners and municipalities are requesting LEED “certifiable” buildings from their design teams. How is a specifier to respond?

The ZGF-designed "Living Learning Center" at the University of Oregon was designed to the LEED Silver standard but did not apply for certification. Colleges & universities frequently take this approach.
Photo Credit: University of Oregon

In our experience with over 200 (real) LEED projects, we have seen four approaches.

Approach 1: Declare an early victory

The team completes the LEED scorecard and declares victory. There is no mention of LEED in the project manual and the contractor is asked to “make the right green choices.” There is no review of the scorecard after construction. While this is clearly a useless LEED approach, there are many who accept this result. In fairness, some are municipalities that are not able to mandate certification, others are architects who believe their professional training and personal commitment is the correct measure of sustainability.

Specifier’s Response: As always, at least include low-VOC products, high-performance products, and construction waste management in your specs.

Approach 2: Sprinkle in some requirements

The team completes the LEED scorecard, makes a determination of which design credits could be easily achieved, and includes only a few requirements in the specifications. Perhaps construction waste management, FSC-certified wood, and Green Label Plus carpet are sufficient to demonstrate some interest in sustainable design. Data-intensive credits such as recycled content, regional materials, and low-emitting materials are typically avoided. Again, the scorecard is not evaluated after construction.

Specifier’s Response: Match the specs with the LEED credits selected. Include submittals at the level of detail that a LEED audit would require, such as chain-of-custody (CoC) documentation for FSC products and VOC levels for paints, coatings, sealants, and adhesives.

Also Read

Six Things LEED Consultants Do Wrong in Specs

Chemical Industry Attacks LEED: BuildingGreen Checks the Facts

Approach 3: Everything but submitting for LEED review

The team completes the LEED scorecard, includes it and all relevant requirements in the project manual, and collects all the data from the contractor, but does not submit to GBCI for certification. The team makes an internal evaluation of whether the goal has been obtained, and declares success. This approach is frequently taken at colleges, where those that manage the projects need to respond to various faculty and student initiatives. There is some certainty that LEED Certification would have been achieved, but typically there is no energy model, no commissioning—generally, little attempt at any credit which involves increased expense.

Specifier’s Response: Again, match the specs with the LEED credits selected. Note that the credit numbering and language for all the different LEED rating systems is slightly different—be sure which LEED program the team is following.

Approach 4: Go beyond LEED

The design team is actually committed to sustainability, and regrets the owner can’t or won’t fund LEED Certification. The energy model is developed early and really informs the design. Products that meet the VOC limits, regional goals, recycled content are specified into the project without reference to LEED. The contractor is asked to include sustainability in their product choices. The contingency fund for construction includes sustainability as a reason for a change order. After all, isn’t that what design is all about—understanding the owner’s requirements and delivering the best result for the funds available?


Specifier’s Response: Same as Approach 3 above, but now there’s the opportunity to go beyond LEED requirements. Make sure environmentally committed firms like Interface and Kingspan have an opportunity to bid. Ask the project owner what their standard products are, to help minimize waste in the future. Look downstream and make sure the NFPA fire door inspections are actually done and documented.

Also read Six Things LEED Consultants Do Wrong in Specs, by Mark Kalin—and join the discussion there.

Mark Kalin is President of Kalin Associates Specifications and currently Chair of CSI’s National Technical Committee. The firm has completed specs for over 200 LEED projects. Free spec downloads and position papers at

Check out GreenSpec for guidance on more sustainable building products to include in your project specifications.

2012-06-26 n/a 10918 Five Steps to Choosing Healthier, Greener Furniture

Furniture constantly touches our skin and can emit VOCs directly into our breathing zones. These five steps will help you make safer, greener choices.

Steelcase's lightweight Think chair is one of a handful of products that have achieved level 3 certification through BIFMA.
Photo Credit: Steelcase

We already have plenty to think about when it comes to the environmental and health profile of basic materials like wood and plastics. Complex assembled products like furniture multiply all those considerations.

What’s more, new products come out all the time, and their features can be radically different. And the nuanced interplay of function, aesthetics, ergonomics, and cost already choreographs a delicate dance for designers and specifiers. That's not even mentioning compliance with LEED IEQc4.5: Low-Emitting Materials: Furniture & Furnishings in LEED-CI or LEED for Schools. How do you stay on top of it—and still manage to pull green considerations into the mix?

One way is to step back a bit and think through what are the top green priorities for furniture.

1. Put health first

Desks, chairs, cafeteria tables: these interior products are in regular, close contact with building occupants, so human health has to be the top priority among many green considerations.

First, ensure the product isn’t emitting harmful VOCs. Look to Greenguard Children & Schools certification and to other certifications based on the California DHS standard (also known as California 01350).

Unfortunately, these standards don’t yet cover semi-volatile organic compounds (SVOCs), nor do they account for hazardous constituents like brominated flame retardants (BFRs) that don’t offgas into the air. Such ingredients can slough off the product over time and contaminate indoor dust, which ultimately makes it into our bodies as well.

(For example, due to California’s flame retardant requirements, Californians have the nation’s highest levels of BFRs—one reason Governor Jerry Brown just directed State agencies to revise these standards.)

Also Read

A Peek Inside Google's Healthy Materials Program

The End of Greenwashing? Five Myths About Product Transparency

Flame Retardant Rules Result of Deception, Says Investigation

Minimizing Exposure to Chemicals in Clear Wood Finishes

2. Discover each material’s story

Beyond protecting the health of occupants, the potential impacts to consider over the life cycle of the product multiply wildly depending on the complexity of the product and the materials used.

Every material has its own story, and that story—whether of FSC-certified wood or of the manufacture and composition of upholstery foam—tells a lot about the impacts of the product.

While keeping their limitations in mind, consider making environmental product declarations (EPDs) part of your spec process, and ask manufacturers when they will be releasing EPDs for your favorite products, or using other transparency tools.

3. Play favorites

You may be excited by the prospect of tracing the stories of different materials to their source—but time or budget constraints may require a higher-level view for many products.

Some furniture manufacturers consider sustainability a bottom-line issue: they go far beyond just recycled content, a tiny selection of niche “green” products, and pretty pictures on their websites. You may already know who these companies are. If they are consistently able to answer your questions about the environmental story of a product, they’re likely to be further down that path.

4. “Level” the playing field

Multi-attribute green product certifications like BIFMA’s “level” certification can also be a good indicator—a way to quickly pick out a set of greener products from what’s on the market.

Of course, there plenty of green products without level certification, and don’t forget that level certification has different levels; a company has to do a lot more to get level 3 certification (member link) on a product than level 1.

Also, it’s still worth digging a little: a company can get a lot of points toward level certification for management activities and other things aside from product characteristics.

5. Adjust your expectations

It’s just a fact of life: it’s easier to find greener options for some types of products than for others.

There are plenty of super-green office chairs, but for niche applications and for the low end of production costs, it can be a lot harder. Here’s a rundown of what to expect, category by category.

  • Office furnitureThe area with perhaps the most green activity and competition. There is an abundance of certified low-emitting products, as well as many products with BIFMA level 2 or 3 certification. There are also plenty of refurbished options if that meets the project’s needs.
  • Systems furniture—In this important subset of office furniture, there are also plenty of low-emitting products with BIFMA level 2 or 3. Modularity and ease of re-configuration are also key here. If simply rearranging parts can make the system work longer, that’s an easy win environmentally and financially.
  • School furnitureBecause of the focus on low-emitting materials in schools, there are now a lot of options here, so it’s worth looking for other environmental characteristics as well. Some companies, like Greenplay, go even further with extremely low-impact raw materials.
  • Residential furniture—In a residential setting, where there is likely to be lower air exchange and also children—a more vulnerable population—place increased emphasis on occupant health over other environmental concerns. The options vary by what you’re looking for, so be flexible and prepare to apply various lenses in making selections.
  • Medical furnitureThere’s still a limited set of low-emitting furniture. Make sure you’ve got that covered before looking for recycled content or other sustainable features.
  • Laboratory furnitureThere is a smattering of certified low-emitting products, from casework to countertops to chairs designed for easy cleaning. Some materials, such as metals designed to withstand chemicals, are also inherently low-emitting.
  • Upholstered furniture—Once you get into upholstery, there’s a lot more to be concerned with. Foams and fabrics include both a host of chemical hazards to watch out for in the products themselves and their own unique set of processing concerns. If upholstered furniture is optional, it may make sense to avoid it. If not, consider how much research and hassle you’re willing to undertake to find safer options. While the purest options may only be available from a few select, high-end manufacturers, you can get partway there be seeking out manufacturers with across-the-board health-based policies—like Ikea—that do a relatively decent job within practical market constraints and don’t make “green” a reason to charge a premium.
  • Custom furnitureIt’s increasingly possible to get both high-end individual pieces and large-volume custom furniture made to green specifications, as long as you work with someone already familiar with green materials. Don’t expect just any furniture craftsman to be willing to work with low-VOC adhesives and finishes.
  • CaseworkIf you go with metal, it’s low-emitting to start with, and emissions certifications like Greenguard Children & Schools don’t tell you much. If you’re looking at particleboard, on the other hand, the certification is critical. There are plenty of options for low-emitting casework, so you might want to look for more green features, but don’t count on an easy answer for medical casework or other specialty applications where there are few options.
  • Specialty applicationsThe rarer the application (multiple seating, detention furniture, etc.) the harder it’s likely to be to find greener materials—so if you have found some real

    gems, please let us know in comments! We’ll consider adding them to GreenSpec.
2012-06-20 n/a 10883 How to Choose a Sealant That Works

Any sealant can perform well in the right application, but knowing which to pick for your job is another thing. Our guide to sealants and how to use them.

NOTE: Read this whole series here.

Photo Credit: DAP

When selecting a sealant, these properties are typically the most important:

  • movement tolerance (rated by Class per ASTM C920, with 25 meaning joint movement of 25% of the linear width dimension of the sealant bead)
  • substrate compatibility
  • workability, particularly based on temperature
  • paintability and its converse—substrate staining
  • relative cost
  • service life
  • material constituency and hazardous content

There are seven basic types of liquid sealants, largely based on their chemistries and subsequent strengths and limitations. Each sealant’s suitability to an application is based primarily on its performance properties, the properties of the substrates, and cost.

Also Read

EPA Takes Action on Spray-Foam Health Risks
Spray-Applied Latex: A New Tool for Air Sealing
GreenSpec Products: Thermal and Moisture Protection
How Blower-Door Tests Measure Airtightness



Latex sealants are water-based, easy to tool, easy to clean up, paintable, and relatively less expensive than other types of sealants. Some premium latex sealants may be appropriate for exterior use (appropriate service life) and are rated for movement in classes 12½ and 25. Latex sealants may be best suited to interior finish applications.


Acrylic sealants are also paintable but are solvent-based and more difficult to tool. They are used more in commercial and exterior applications than latex and have very limited movement capacity (Class 7½). Acrylic sealants tend to be used in commercial construction in low-movement joints. Their cost tends to be in the low to moderate range.


Butyl sealants are solvent-based, synthetic rubber materials demonstrating strong adhesion to a wide variety of substrates. They have excellent weathering characteristics but tend to be stringy and difficult to apply. They generally have limited movement accommodation (Class 7½ ). Butyl sealants are sometimes used in curtainwall systems where adhesion to rubber materials is required. The cost of butyl sealants tends toward the moderate range.

The next group are sometimes called “high-performance” sealants and are most often used in commercial building assemblies.


Polysulfide sealants are particularly water- and chemical-resistant but do not tolerate much cyclic movement for a high-performance sealant (Class 12½ –25). Their use in buildings is most common in swimming pools and other locations where submersion must be tolerated. Polysulfide sealants often require a primer. They tend to be relatively expensive.


Silicone sealants are used in a wide variety of building applications because of strong performance characteristics: UV resistance, temperature resistance, highest movement capability (Class 50–100), generally longer service life, and continued flexibility over time. Silicone sealants can have a strong odor and take considerable time to fully cure. They can be used structurally in glass assemblies. Cost for silicone sealants is in the high range. Pure silicone sealants are not paintable.


Polyurethane sealants are tough—even abrasion-resistant. Unlike silicone sealants, they can be painted. They have excellent adhesion and good movement capability (Class 12½, 25, and 50). They can be stiff and more difficult to apply and tool than silicone and cannot be used in structural glass assemblies. As one of the “high-performance” sealants (including polysulfides and silicones), polyurethane caulks are relatively expensive.

“Hybrids” – MS Polymers

Hybrids are relative newcomers to the sealant world; they have chains (silyl) that modify both silicone and polyurethane sealants (MS stands for silyl-modified), combining some of the strengths of each. Their chemical profiles are better because they are solvent- and isocyanate-free (more on this topic in the last blog of the series).

So which one should I use?

As with most building materials, the answer is, “It depends.” The information above and in our GreenSpec guide should help a lot to match the best liquid sealant to the substrate, the application, and your budget.

But what about the other two properties: service life and material constituency? You will have to come back for more on these. The next post is about sealant service-life prediction, and the series will wrap up with material constituency considerations for both sealants and tapes.


2012-06-12 n/a 10841 Six Things LEED Consultants Do Wrong in Specs
Mark Kalin

LEED consultants are paid to lend their expertise to achieve a project’s LEED certification goals. Their decisions focus on achieving credits and their participation is absolutely vital to the project, but some can actually work against the project's sustainability goals. Here are the top six problems I see.

#1 Discouraging bidding by specifying unrealistic LEED requirements

When a specification requires a regional source, a recycled content percentage, and certain certifications for a product, the specifier has to be certain that conforming products exist. On a recent project, the only bidder for the doors couldn’t actually meet all the requirements and put in a premium price. Other bidders declined to bid citing the requirements of the specifications. The worst outcome was a project that decided to abandon certification because of unnecessary requirements in the specifications that pushed the project over budget.

Solution: Don’t use the specifications as a research tool. Either find out what’s available and specify what you want the contractor to purchase, or give the contractor options and flexibility to meet the LEED requirements, using a mix of products.

#2 Not recognizing that performance is a sustainable attribute

There is a roofing product that has 100 percent recycled content, is 100 percent recyclable, and is made from 100 percent regional materials. Unfortunately, it is only guaranteed until the first rain, since it’s made out of papier-mâché.

Solution: Performance is more important than recycled content for roofing. Always seek the highest-performing roofing material with a 20-year track record (which includes PVC). If you’re not going to keep PVC out of the inside of your building, why be concerned about PVC on the roof? Personally, I doubt that either PVC, TPO, EPDM, or modified bitumen are edible, and am more concerned about the damage that water intrusion can have on the inside of a building when the roofing fails.

#3: Adding ‘their’ language to the specifications.

Sorry, poetic language doesn’t buy products, nor does repeating all the VOC levels in every spec section make sense. The specifications are contract documents that contain the qualitative requirements for materials and assemblies. Subcontractors must put in bids with only a few hours to evaluate a project.

Solution: Specify products that comply with LEED requirements and require the submittals necessary to document the required credits.

#4: Believing manufacturer’s product literature

Not too long ago a flooring manufacturer overstated its sourcing and FSC claims. The product as promised was not the product as delivered—they never had a source for FSC wood. …And then there was that article in the magazine that claimed brick would earn 26 LEED points. …And then there was that insulation manufacturer that was fined $155,000. by the FTC for false R-value claims.

Solution: Ask the manufacturer to submit a sample of LEED documentation from a previous project as an example, instead of relying on marketing literature.

#5: Issuing a LEED Scorecard with “maybe” as an option

We all recognize that achieving some credits is uncertain until construction is well underway. However, “maybe” means “no” to a subcontractor if extra expense is involved.

Solution: At least one LEED consultant will not include a scorecard in the project manual. Others will reissue the scorecard monthly. The important thing is to hold the contractor accountable for making sure that the overall target is achieved, with a little cushion to allow for missing or faulty documentation.

#6: Calling LEED “good enough”

LEED is intended to point the project in the right direction and open up conversations about sustainability goals, but too often its goals are adopted without critical review.

Solution: The consultant should engage with the client about their intentions and priorities, and then revisit those throughout. That gives them the tools to answer questions like: Do you abandon the requirement for FSC wood once you achieve 50%? Is it the scorecard or sustainability that governs?

Mark Kalin is President of Kalin Associates Specifications and currently Chair of CSI’s National Technical Committee. The firm has completed specs for over 200 LEED projects. Free spec downloads and position papers at

2012-06-01 n/a 10791 New Concern About Pesticides in Exterior Paints

Although exterior paints have moved beyond lead and the most toxic solvents, new coatings contain biocides that may pose a different set of concerns.

Biocides play an important role in a paint's durability by protecting it from mildew, but biocides cannot make up for poor application practices.
Photo: Bob Cusumano, Coatings Consultants, Inc.

Most of us are familiar with the volatile solvents found in alkyd, or “oil-based” paints. These are typically hazardous airborne pollutants with large volumes of smog-causing VOCs. Coatings containing these solvents are regulated in many areas of the country, such as the South Coast Air Quality Management District (SCAQMD).

Biocides in coatings, however, have largely flown under the regulatory radar in the U.S. In the June issue of Environmental Building News, we take a look at the environmental tradeoffs of exterior coatings (member link).

Biocides: necessary or nefarious?

Biocides are used to protect latex paints from bacteria while in the can, acting as a preservative, and to protect a paint’s film from mildew and algae.

These biocides are necessary, but unfortunately paint breaks down, so over time they can wash off into the environment, where their impact is uncertain. There are many different types of biocides used in paint, including organic compounds such as IPBC (Iodopropynyl Butylcarbamate), OIT (octylisothiazolinone), terbutryn, diuron, isoproturon, and many others.

Some are persistent in the environment, are hazardous to organisms—particularly those at the base of the ecosystem—or may cause these organisms to develop biocide resistance.

Regulations ramping up

The U.S. Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires biocides be registered as pesticides with the Environmental Protection Agency (EPA), but the biocides in paint are exempt from FIFRA regulation unless the manufacturer makes claims that they improve human health.

Europe is taking a closer look at biocide safety as it relates to people and the environment, however. Its Biocidal Product Directive, which has a specific product group dedicated to biocides found in paint, has effectively banned once-common biocides such as carbendazim from the market.

The industry has responded with less-persistent products and delivery systems that minimize the amount required.

Reining in the chemical Wild West

There could be good reason to keep a closer eye on biocides in paint. Recent research from the École Polytechnique Fédérale de Lausanne in Switzerland estimates that coatings on façades in Lausanne release about 30% of their biocides into the environment annually (potentially hundreds of pounds of biocides), most within the first couple of years.

The corresponding author, Sylvain Coutu, pointed out in an email to me that the amounts are very site-specific, and “we estimate that only 0.035% of biocides that leach from façades actually reach surface waters (rivers, lakes), the rest being absorbed in soils and/or degraded during transport.”

Though the amount that reaches the watershed is small, it does not take much to affect the environment, especially considering that biocides can be found in nearly every exterior paint. (Don’t look for biocides on the material safety data sheet; manufacturers don’t have to list ingredients unless they make up 1% or more of the product, or 0.1% for carcinogens.)


The main job of exterior coatings is to protect the building, and the best way to do that is with a durable paint job.

Most paint ingredients today are a vast improvement over the lead stabilizers and volatile solvents of the past, but they may still contain some unsavory ingredients, so making them last—by using biocides, for example—may be the best way to minimize their overall environmental footprint.

This month’s feature explores some of the issues that affect paint durability and even provides a couple of environmentally responsible coating options that don’t need any VOCs or biocides. You can also find these high-performance coating options as well as stains in GreenSpec.

2012-05-30 n/a 10769 More Cool Products from the AIA Convention

Innovative energy-savings products from the AIA National Convention this month.

The energy-saving Haiku ceiling fan in bamboo. Click to enlarge.
Photo Credit: Big Ass Fans

Last week, I wrote about a number of innovative window and glazing products I came across at the AIA Convention in Washington, DC earlier this month. Here are a few other products I came across with energy-saving features.

Haiku fans from Big Ass Fans

Despite the over-the-top company name, Big Ass Fans has been at the forefront of ceiling fan development for some years now. The company is known for it’s large, well, big-ass fans that are used in improving comfort in large commercial spaces—overhead fans that may have diameters of up to 24 feet. Now the company has introduced a line of smaller, residential-scale fans that work in homes.

Before getting into the specifics of the Haiku fans, it needs to be pointed out that ceiling fans don’t actually cool a space (i.e., lower the temperature). What they do is make a space more comfortable by evaporating moisture from our skin. If you are normally comfortable in a space at 75°F, with a gentle breeze you can be comfortable at 80° or even 82°F. Not only do ceiling fans not lower the air temperature, they actually raise the temperature slightly—from the waste heat generated by the electric motor (so turn that fan off when you leave the room!).

The Haiku fans are exciting from an energy standpoint, because they are the first ceiling fans to use advanced, energy-efficient, electronically commutated, brushless, DC motors, and they have aerodynamically designed airfoil blades that move air more efficiently and more quietly than the blades in most ceiling fans. These features make Haiku fans up to 80% more efficient than standard ceiling fans. While a typical Energy Star ceiling fan uses about 65 watts of electricity (and generates substantial waste heat), the Haiku fans use just 2 to 30 watts, exceeding the Energy Star requirements for energy efficiency by 450 to 750%.

Haiku fans also offer highly sophisticated controls, with seven speeds, reverse mode, sleep mode, and timer controls, all handled through a slick remote control. The 60-inch-diameter blades are made from either an advanced composite material in black or white, or hand-finished, laminated bamboo in a caramel or cocoa finish. The shape is sleek and modern.

The downside? There’s a significant one: cost. A Haiku ceiling fan lists for $825 to $1,045, depending on the exact model. That cost would be hard to justify on energy savings alone, but combined with super-quiet operation and other features, this is a product well worth taking a serious look at.

EcoCore phase-change floor panel from Tate Access Floors

Phase change materials store a large amount of heat by melting (changing phase from solid to liquid). I wrote about the BioPCM material for walls and ceilings in Environmental Building News some months ago (requires log-in). At the AIA convention, Tate Access Floors introduced its EcoCore floor panel which has a micro-encapsulated paraffin phase change material in a concrete matrix. The phase-change material melts at about 75°F, absorbing a lot of heat in the process.

Access floors are popular in commercial building, because they provide a floor plenum that can be used to run wiring and cabling as well as to deliver heated or chilled air. Tate’s EcoCore floor panel looks just like it’s standard concrete access-floor panel—with a steel frame and waffle-like cross-section of concrete, averaging about an inch thick.

Tate Acess Floors' new EcoCore panel has microencapsulated phase-change material in the concrete. Click to enlarge.
Photo Credit: Tate Access Floors

The EcoCore floor panels are designed to be used in commercial buildings along perimeter walls, particularly west- and south-facing, where significant solar gain typically increases cooling requirements. The panels heat up when sunlight strikes them, melting the phase-change material and storing that solar heat rather warming the space. As the space cools below 75°F at night, the floor panels release that stored heat.

Savings are achieved both by reducing the peak cooling demand (enabling cooling systems to be downsized) and by shifting a portion of the cooling load to nighttime hours when cooler outside air can often be used for cooling and electricity prices are lower. Just introduced, the product has yet to be installed beyond prototype and demonstration projects, but the company is hearing a lot of interest in it.

The cost premium is about $1 per square foot for the EcoCore material.

Philips Ledalite’s unique light diffusers for LED lighting

In the lighting world today, it’s all about LED (light-emitting diode) lighting, which is going through technology advances by leaps and bounds. At the Philips Ledalite booth, the company’s MesoOptics technology for distributing light from LED light sources caught my eye.

LEDs offer various advantages, including higher efficacy (lumens of light output per watt of electricity consumption) than most fluorescent lighting. But light distribution can be a challenge, because LEDs produce highly concentrated point-source illumination. Philips Ledalite has tackled that problem using holographic technology in the diffusers of LED light fixtures to control the light distribution as required for the application.

Using this MesoOptics technology, Philips Ledalite can design some fixtures to deliver linear light, to illuminate a wall surface, for example, while others are designed to disperse that light more broadly for area lighting. It’s an example of the sort of innovation that is helping LEDs begin to capture market share from fluorescent and halogen (incandescent) lighting.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also coauthored BuildingGreen’s special report on windows that just came out. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.


2012-05-29 n/a 10748 Cool Window and Glazing Products from the AIA Convention

Glazing and window manufacturers showed off some highly innovative products at the 2012 AIA Convention in Washington, DC

Pythagoras Solar's new BIPV glass was one of two innovative glazing products on display at the Guardian booth at the AIA Convention. Click on image to enlarge.
Photo Credit: Alex Wilson

I just spent three days at the American Institute of Architects annual convention in Washington, DC, including a fair amount of time at the massive trade show there. I didn’t make it all the way through the acres of exhibits over the eight hours or so I walked the floor, but I saw some really interesting products. I’m highlighting here a few of the windows and glazing-related products I found.

SunGuard PVGU from Pythagoras Solar and Guardian Industries

Guardian Industries, one of the world’s largest glass manufacturers, showed off two new products at the show. One of these was a unique building-integrated photovoltaic (BIPV) glazing system developed by Pythagoras Solar and marketed by Guardian. Most BIPV Glazing systems have thin-film or crystalline PV cells integrated into the glass directly, so the visible transmittance and daylighting potential are significantly compromised. Pythagoras has developed a unique solution to this problem: an insulating glass unit (IGU) with integral bars of tiny PV cells  that intercept most of the solar energy striking the outside of the glass.

When you look out through Pythagoras glazing, the view is distorted, but some visibility is maintained and a remarkably high 49% visible transmittance is still achieved—so daylighting performance is still very good. When viewed from the exterior (see photo), you mostly see the PV cells due to the way light is refracted by the glazing.

The Pythagoras BIPV glazing produces up to 11.15 watts per square foot, which the company claims is up to three times the power density of most other BIPV glazings. The overall module efficiency is up to 12%, while the U-factor (assuming argon gas-fill) is a respectable 0.28 and the solar heat gain coefficient is 0.14—helping to control overheating. For more on this, visit Pythagoras Solar and Guardian’s SunGuard PVUG.

SunGuard EC dynamic glazing from Soladigm and Guardian Industries

Also on display in the Guardian Industries booth was a new dynamic glazing product: Soladigm glass. A few weeks ago I wrote about dynamic glazing, which can be tinted on demand to control glare and solar heat gain, and specifically SageGlass, the first company out of the gate with such a product that is commercially viable. Soladigm glazing, branded as SunGuard EC by Guardian, is made in Mississippi. Like SageGlass, it is an electrochromic glazing that uses electric current to tint the glass.

Soladigm’s coating is added to the #2 surface (the inner surface of the outer pane of glass in an IGU), and it can be used with clear glass or combined with a low-e coating on the #3 surface (the outer surface of the inner pane of glass). When used with clear glass, the tinting ranges from a visible transmittance of 62% and a solar heat gain coefficient (SHGC) of 0.47 in the untinted state to 2%/0.09 in the fully tinted state. When used with low-e glass, it provides 48% visible transmittance and 0.29 SHGC untinted and 2%/0.07 fully tinted. It is also available with four intermediate levels of tinting. The U-factor for these IGUs (assuming argon gas-fill) is 0.29 with clear glass and 0.24 for low-e glass and is the same whether tinted or not.

Like SageGlass, Soladigm’s coating consumes a small amount of electricity to achieve the tinting (0.1 watt per square foot) and about a third as much electricity (0.03 W/ft2) to maintain the tinted state. When the electric current is shut off, the glazing reverts to the clear state. For more information, visit Soladigm  or Guardian.

Graham Fiberglass Windows

I have just completed work on a new BuildingGreen report on windows, for which we did extensive research on the window industry, so I was surprised to come across a product (and frame material) that I had never heard of. Graham makes a high-performance window, primarily for commercial-building applications, that is available triple-glazed with U-factors as low as 0.15.

What is unique about Graham windows is the frame material: a fiberglass composite that is 80% glass fibers and 20% polyurethane resin. Fiberglass is a highly durable and strong window frame material that is much more thermally stable than vinyl (PVC), but all other fiberglass windows I am familiar with are made with a polyester, rather than polyurethane, resin. According to Graham, with polyurethane you can have a higher percentage of glass fiber, achieving better strength properties. (I learned later at the show that it is harder to bond coatings to polyurethane resins than to polyester resins, which may explain the predominance of polyester-based fiberglass composites.)

Graham windows, including the fiberglass frames, are manufactured in York, Pennsylvania. They are typically fitted with Cardinal glass, which is available with various types of low-e, including Cardinal’s new LoE-i89 coating for the #4 surface (facing the room) of an IGU. For more information, visit

Marvin Integrity Windows with triple glazing

For years I keep asking the largest window manufacturers when they will be introducing higher-performance products. Finally my wishes came true with Marvin’s fiberglass Integrity line. I learned at the Marvin booth that the company will be rolling out a triple-pane version of it’s popular Integrity line around the end of the second quarter of this year, though one of the Marvin reps in the booth allowed as to how that target date might slip.

There is nothing yet on the Marvin website about this window so I haven’t been able to examine performance specifications, but I think it will be a good choice for budget-conscious homebuilders and homeowners. It won’t match the high-end European Passive House windows in performance, but it will still be pretty good. Like most other fiberglass windows, the Integrity line is a fiberglass-polyester composite. A nice feature of the Integrity line is that only the exterior is fiberglass; the interior is wood, providing a nicer, warmer feel.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also coauthored BuildingGreen’s special report on windows that just came out. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.



2012-05-23 n/a 10717 UL and Perkins+Will Launch “Transparency Briefs”

New EPD summaries give a snapshot view of LCA data, but are limited by their document-centric paradigm.

This two-page summary of an EPD is a new format that seeks to make life-cycle assessment-based information easier to use.
Image Credit: UL Environment

Environmental product declarations (EPDs) are, in theory, the answer to our product information prayers. To the extent enabled by the appropriate Product Category Rule (PCR), a product’s EPD discloses environmental life-cycle assessment results including its ingredients and environmental impacts. If that information is validated and certified by a credible third party, so much the better. To better understand how all that works, check out BuildingGreen’s graphical EPD primer (PDF) and our feature article on product transparency (member link).

Current LCA methods are not very helpful for some key issues, such as human health, ecological toxicity, and habitat disruption, so most EPDs wisely omit those categories. Even the information that remains, however—a 20-30 page structured summary of an LCA study that might run 100 pages or more—can easily overwhelm designers and other potential users of all this information.

Brevity to the rescue

In an effort to make the key parts of this information more accessible, UL Environment (ULe) has now unveiled a new two-page “Transparency Brief” that summarizes the LCA results even further. ULe collaborated with Perkins+Will on this new format, building on that firm’s work in 2011 creating product transparency label for Construction Specialties, and with Interface, which had produced its own summary view of its EPDs when they first came out in 2011.

A single EPD often covers multiple configurations of a product, but to keep the Transparency Brief simple it is limited to just one configuration, so each EPD can spawn multiple briefs. You can see the new Tranparency Briefs, along with their associated EPDs, by searching UL’s so-called “Sustainable Products Database” for certification type: “Environmental Product Declarations.”

A good teaching tool

The Transparency Brief does a nice job highlighting the key EPD information, and serves as a useful teaching tool about LCA and EPDs, with explanations of the impact categories and tables listing ingredients, recycled content, and other data. This teaching function is enhanced by keeping placeholder cells even for non-existent information—though they could have gone even further to make it clear where current LCA’s don’t tell the entire story.

UL intends to make the format available to any EPD producer, according to Heather Gadonniex, Lead, Strategic Development and Innovation at ULe, and is differentiating its own EPDs with a new “badge” declaring that the Transparency Brief is based on a UL certified EPD.

Where's the app?

When it comes to the fundamental problem of making this information accessible and usable to designers and other decision makers, however, it’s not clear how much the Transparency Brief really helps. Its paper or PDF structure is stuck in the 20th-century document paradigm, which is not a great model for helping users sift through huge amounts of data and make comparative decisions. For reviewing data on individual products, a smartphone app model might be more helpful, with summary views of the data linking to additional details from the EPD and the underlying LCA as needed.

Why manage documents when we just need data?

Ultimately, however, users need access to this data in a way that they can easily compare and manipulate, ideally within the context of a data-rich design tool. I hope that the folks at ecoScorecard and Autodesk are burning the midnight oil (ok, so that’s a 19th-century metaphor) to bring us that functionality so we can stop managing documents to manage data.

More context always helps

New formats alone won’t solve this problem—we also need comparable data for many more products to put each product’s information in context. ULe hopes to be the provider—or at least the certifier—of most of those EPDs. It will be an interesting year or two as all this gets sorted out, along with the question of how the new Health Product Declarations (HPDs) factor into the mix. While it doesn’t solve many of the problems, the new Transparency Brief is a step in that direction.

2012-05-19 n/a 10706 Crucial State Incentives for Small Wind Turbines Still Need Work

As the small wind turbine market feels the pain of temporary holds on state incentive programs, turbine certification could bring the stability and improve the market’s reputation.

New Jersey placed a rebate incentive program on hold due to catastrophic mechanical failures of multiple small wind turbines.
Photo Credit: World Future Energy Summit

The reputation of the small wind turbine industry has tended to fluctuate as much as the output of some of its turbines. Consumers seeing the benefits of wind as a renewable alternative to fossil fuels have at times been burned by mechanical failures and less-than-expected power production.

And on their way to “saving the planet,” some turbine installations have been implicated in numerous bird and bat deaths. While there are numerous financial incentives to install wind, several state incentives have recently been put on temporary hold. These setbacks are potentially the most troubling, as incentives are generally regarded as key to increasing turbine installations.

Important federal incentives are struggling too, as the Obama administration requested only $4.6m for the Rural Energy for America Plan (REAP) in the proposed budget for fiscal year 2013. REAP had already suffered a 66% cut from 2011 to 2012, and the program awards totaled only 1 megawatt in 2011.

California’s “free turbine” problem

In California, the longest-running small wind incentive was put on temporary hold from March 4through November 9, 2011, because a sharp increase in the number of people requesting that the incentive cover most or all of the cost of an installed wind turbine worried the California Energy Commission (CEC). According to the CEC, the program wasn’t designed to completely cover the cost of wind turbines, as that would reduce the incentive to put the wind turbine in a location suited for harvesting wind power.

For consumers getting what amounts to a free wind turbine, the pressure to put the turbine in a windy area, maximizing effectiveness, is reduced. Further, the program becomes attractive to people for whom a wind turbine might not be the right choice. “About 85% of the requests totaling US$6.7m were for rebate amounts close or equal to the total installed cost of the systems,” says Larry Sherwood in a February 2012 article entitled “Can small wind certification buoy U.S. consumer confidence?” The CEC appropriately decided that it would rather not invest in underperforming wind turbines. 

New Jersey’s malfunction headaches

Manufacturing defects in Enertech wind turbines at two separate locations in New Jersey was cause for the state to put a hold on its rebate incentive for small wind turbines. The failure occurred in March of 2011, and the program is continuing the hold on new applications.

The program is exploring options to ensure the safety of the turbines as well as the financial security of the owner of a turbine that experiences a major failure not covered by the warranty.

Certification to the rescue?

The Small Wind Certification Council (SWCC) is certifying products to a standard designed to prevent turbine manufacturers from producing less durable products and claiming inflated production numbers. It is worth noting here that Enertech, though under contract to certify one small wind turbine model, has yet to begin testing the turbine for certification.

This certification process aims to bring stability and growth to a market plagued by inconsistencies. As the popularity of the certification grows, SWCC is also working with many states to integrate certification into their rebate programs. Hopefully, a more stable reputation will help the market grow and overcome other obstacles, such as permitting difficulties, that lie in the way of broader acceptance.

For more information, read Certification Gets Small Wind Turbine Market Turning in this month’s issue of EBN and find turbine selection guidance, including a list of recommended turbines, in GreenSpec.

2012-05-16 n/a 10675 Breaking the Bonds of Bad Sealant Jobs


Seals at window openings and other penetrations need to be done right the first time. Are your seals failing because of the most common application error—forgetting the bond break?

It's great they remembered the backer rod in this attempt to seal the joint, but with the depth of the sealant so skinny compared to the width, it's probably going to fail. Read on to learn why. 

NOTE: Read this whole series here.

Continuous air and water barriers are essential to healthy and high-performing buildings, but making these barriers truly continuous is more than just slapping on some building paper. It requires meticulous detail work. Sealants—properly applied—are a key part of that.

Sealants are liquid-applied substances tooled to a concave surface shape, with “edge bonding” to each substrate. In the case of air and water barriers, they connect one field of the wall to another or to the component in the penetration—the window, the pipe stack, the duct, etc.

Drawing a bead on proper joint sealing

Essential to any sealant application is a backer rod or bond breaker tape. These ensure that:

• adhesion is between the substrates only (no perpendicular stress from the back of the joint to weaken the focus on the connection between the substrates)

• the sealant is supported on the back side as tooling exerts pressure on the sealant

• the sealant bead is well-proportioned (ratio of width to depth of 2:1)

Backer rods come in various diameters so that they compress about 25% of their cross-section into the gap.

Open-cell backer rods have the advantage of “breathing,” allowing curing to the backside of the joint, and are not affected by any puncturing that might result during tooling. By contrast, closed-cell backer rods, if punctured during tooling, can offgas and create bubbling in the sealant. Closed-cell backer rods don’t absorb water, while open-cell ones do. A third type of backer rod is the “hybrid” bi-cellular backer rod; it does not outgas when punctured and only takes up moisture at cut ends.

Use the type of backer rod recommended or required by the sealant manufacturer.

Conventional moving weatherseal.
Photo Credit: Dow Corning Americas Technical Manual, page 56

Bond breaker tapes are particularly well suited to closed joints (no gap), where the two substrates are perpendicular to each other. Omitting bond breaker tape is incredibly common in this configuration—even though it is this perpendicular, or “fillet,” configuration that places the most stress on the sealant with any joint movement.

You can’t mechanically support a sealant joint the way you can a tape or membrane; the adhesion of the sealant to the substrates alone is what you are counting on.

The corner bond break relieves the stress on the non-compressible sealant bead.
Photo Credit: Dow Corning Americas Technical Manual

Performance testing

There are a slew of ASTM standards to consider for liquid sealant performance. The best guidance on this comes from the National Institute of Building Science (NIBS)
 Whole Building Design Guide (WBDG) Web Resource Page on Joint Sealants (pdf). This document also has useful sample specification information.

Just as important, though, is performance field-testing of sealants. Dow Corning’s 2011 Technical Manual (pdf, needs email address to proceed) includes a “Standard Field Adhesion Test.” Although clearly best suited for the commercial construction context, the concept and techniques can be applied to residential construction.

Field adhesion test.
Photo Credit: Dow Corning Americas Technical Manual, page 73

Seal the deal: Three tips for putting it all together

• Use liquid sealants as part of air and water barrier systems in exposed applications where they can be inspected, repaired, or replaced.

• Field-test sealants in addition to applying standardized tests in specifications.

• Use manufacturers that integrate their products into continuous barrier systems; one of note is the Tremco Engineered Transition Assembly. This approach fully specifies the air and water barrier system for commercial building assemblies, including: an ASTM test (E2357) for airtightness that includes a window in the assembly; project management and pre-construction meeting checklists; and a one-of-a-kind warranty against air and moisture infiltration.

NOTE: Establishing barriers at the cladding level of the building assembly is considered a “face-sealed” approach only appropriate for precipitation exposure of 20 inches annually, or less. And the appropriate approach for face-sealed, surface level barriers is the “weeped”, two-stage sealant system describe below.

Rainscreen Joint.
Photo Credit: United Professional Caulking and Restoration




2012-05-09 n/a 10621 Biobased PVC? Take Vinyl Industry Claims with a Grain of Salt

Making plastic from corn, soy, or sugarcane has some advantages--but fixing the petroleum problem barely touches what's wrong with PVC.

By the way, the "plant bottle" is not biodegradable, but it does recycle just like any other PET or HDPE bottle. After all, that's what it is. Just because a polymer's feedstocks come from a renewable source doesn't mean it is any more biodegradable, compostable, or even more environmentally friendly than any other plastic.

What if all of the common plastics in use today were made from renewable materials rather than from fossil fuels? Would they start looking better in the eyes of environmentalists?

This is no idle question. The plastics industry is exploring a wide range of approaches to sourcing today's typical plastics from biobased feedstocks, and their use in common products isn't too far off on the horizon. We're already seeing these entering the market. An early example is Coca Cola's "plant bottle," which uses PET or HDPE made from ethylene derived from renewable sources instead of fossil fuels.

Biobased PVC on its way

Some of these "drop-in" biobased options are already available, such as the HDPE produced by Braksem from Brazilian sugarcane. Others, like Solvay Indupa's plans to use sugarcane ethanol to manufacture PVC, are still in the planning stage--but more changes are on the way.

Are biopolymers green?

Finding alternatives to nonrenewable fossil fuels is certainly worth applauding; we can't get to a truly sustainable society without that. But that one accomplishment, if achieved, is still far from the whole story. In an earlier blog post and in this May's feature article, "Biobased Materials: Not Always Greener," (login required) EBN lays out an array of concerns.

Biobased materials, while sometimes better, have unique environmental and social impacts--some related directly to biobased sourcing and others related to impacts during manufacturing and use and after its useful life is over. Like any product, one using biobased materials would ideally have data to show that the overall impact is reduced relative to alternatives, and for some products the sourcing is the least of our concerns. Take biobased PVC, for example.

Petroleum is the least of our problems with PVC

Like most polymers today, PVC is derived largely from fossil fuels. PVC uses fossil-fuel-derived ethylene to produce naphtha, which is one component of PVC. PVC also uses industrial-grade salt to produce the vinyl chloride monomer that is the other main component. In addition to these basic building blocks, a variety of additives, including plasticizers, are added for specific performance properties.

But lets talk about the base polymer first. Solvay's use of sugarcane-derived ethylene in PVC would, according to Doug Smock at Plastics Today, "make PVC a 100% natural material from a polymer point of view." One could go so far as to argue that this "all natural" PVC is made of salt and sugar, which makes it sounds like something you'd find in your kitchen--rather than a substance of concern on a wide range of red lists. The vinyl industry has long used the words "table salt" to explain why no one should be concerned with PVC, so this is an easy next step in public relations.

The problem is that material sourcing isn't the issue with PVC--and the biggest concerns that have made PVC the subject of more debate than other polymers have come from problems on the "salt" side of the manufacturing process.

Dioxins--the most potent cancer-causing chemicals known to science--are produced in large quantity in the manufacture of the vinyl chloride monomer and then again when this chlorinated plastic is burned in incinerators and uncontrolled landfill fires. Getting the polymer from a biobased source merely sugarcoats PVC without addressing the fundamental problem.

Healthier Plasticizers?

Regarding the health of consumers and building occupants, the immediate indoor environmental concern with PVC is also not the base polymer. It's the additives, particularly phthalate plasticizers.

According to the Pharos Project listing for phthalates (login required), they have been identified as reproductive toxicants by the U.S. Environmental Protection Agency and are included in the Living Building Challenge Red List, LEED Pilot credits and the Perkins+Will Precautionary list.

Here again, there are an increasing range of biobased materials entering the plasticizer market, including Dow's Ecolibrium and a host of others. The jury is still out on these, but this is an encouraging trend. While being biobased doesn't necessarily guarantee that they're better, the new additives are a clear indication that polymer manufacturers and their supply chain are getting the message loud and clear: there is a market for safer and more environmentally friendly alternatives to phthalates and other additives.

Many of these biobased additives make claims about superior health and safety characteristics. If those claims pan out, it'll make a big difference for applications where phthalate-loaded PVC is currently the only option.

PVC needs to be cleaner--not just biobased

The move toward biobased polymers has a lot of potential--for both environmental improvement and for greenwash. But let's not forget in our necessary move away from fossil fuels that the polymers themselves are not the only problem. A truly revolutionary PVC alternative would contain no dioxin-producing compounds, and research on how to replace those is still in the early stages.

Editor's note: The research behind the EBN feature article is a joint effort by BuildingGreen and Healthy Building Network.

2012-05-02 n/a 10519 Rate Your Windows! (And Share Your Lessons Learned)

Windows are a big investment, and while they may look great on paper, how well do they hold up once installed? Do they meet your performance specifications? How responsive was the company to answering your questions and responding to complaints?

The GreenSpec team has already combed the world of windows available in the U.S. and Canada for manufacturers that can meet our tough performance specifications.

Now we need your help in providing ratings based on your actual experience as a customer--things like like whether the window failed the year after it was installed and the distributor won't return your phone call, or whether the manufacturer easily met your specs and installation was a dream. Please take five minutes and provide confidential 1–5 star ratings on windows you have experiences with.

Our team will compile your ratings and share them in aggregate with anyone who participates in this poll, as well as subscribers to GreenSpec and BuildingGreen's other publications.

Take the poll now and rate your windows!

2012-04-24 n/a 10657 Rate Your Windows! (And Share Your Lessons Learned)
Author name: 
Tristan Roberts
Blog Category: 
GreenSpec Insights

Windows are a big investment, and while they may look great on paper, how well do they hold up once installed? Do they meet your performance specifications? How responsive was the company to answering your questions and responding to complaints?

The GreenSpec team has already combed the world of windows available in the U.S. and Canada for manufacturers that can meet our tough performance specifications.

Now we need your help in providing ratings based on your actual experience as a customer--things like like whether the window failed the year after it was installed and the distributor won't return your phone call, or whether the manufacturer easily met your specs and installation was a dream. Please take five minutes and provide confidential 1–5 star ratings on windows you have experiences with.

Our team will compile your ratings and share them in aggregate with anyone who participates in this poll, as well as subscribers to GreenSpec and BuildingGreen's other publications.

Take the poll now and rate your windows!

read more

2012-04-24 n/a 10466 The Toxic Chemicals that Lurk in Unfinished Wood Floors

One might think that an unfinished wood floor is devoid of synthetic chemicals. It sure looks that way--but toxic preservatives may lie in plain sight.

Moist lumber is susceptible to fungal staining. This staining does not cause physical decay, but it looks bad. Commonly called "blue stain," the offending fungi may be yellow, orange, purple, gray, or red in addition to shades of blue. The stain penetrates into the sapwood and cannot be removed by resurfacing.

Lumber mills can prevent these blemishes without chemical treatment through standard air-drying practices or, especially in moist climates, kiln drying. 

However, a lot of lumber is treated with biocides called anti-sapstain treatments. While preventing visible blemishes, these can disfigure the toxicological profile of an otherwise benign product.

What is this stuff?

Anti-sapstain formulations have been used for millennia. Egyptians used powdered subcarbonate of soda to prevent the staining of papyrus, according to independent wood scientist Mike Freeman. During the Shang Dynasty in China, wood ash dissolved in water was used to prevent mildew growth on chopsticks.

These treatments grew more potent, and toxic, over the centuries. A couple hundred years ago, mercury was introduced. Then formulators found that blending compounds of mercury with chlorophenates (such as pentachlorophenol) was phenomenally effective.

Today's treatments aren't as bad as their predecessors


Fortunately, today's anti-sapstains used to treat lumber for wood flooring are not quite as poisonous as their mercury-based predecessors--but these biocides still introduce unnecessary, toxic chemicals into outdoor and indoor environments.

In my role as senior researcher for the Pharos Project, I stumbled upon these treatments while we prepared our opening set of wood flooring evaluations. I was looking for examples of unfinished solid wood flooring. We hoped that this would be a pretty straightforward category to evaluate: the main differences between products, we assumed, would be species and harvesting practices, such as whether or not the wood was sourced from an FSC-certified forest. But one company's website complicated matters.

Middle Tennessee Lumber sells unfinished hardwood flooring, and its website includes a helpful slideshow of its production process. The first slide shows the lumber in a chemical bath, with the caption: "We treat our green lumber with a special non-toxic solution that protects our boards from fungal infestation during the drying process."

Well, dang, I thought. There goes our hope for a clean review. I dug around for more information. I asked wood flooring companies for details on these chemical baths, how prevalent they are in the industry, and how "non-toxic" these solutions are. Believe me, there was no one-stop shop for this kind of information.

Some companies were more helpful than others. One wood flooring association executive told me by email, "I have talked to some unfinished hardwood flooring
manufacturers and they have no knowledge of this anti-sapstain treatment." Maybe he was telling the truth, maybe not--but one company was forthcoming, and even emailed labels of the typical products used in the industry. From there, I developed a profile of the ingredients of these treatments.   [see for the details]

Common active ingredients include 3-iodo-2-propynyl-butylcarbamate (IPBC), propiconazole, isothiazilines, and ammonium chlorides. These mixtures may also contain solvents and chlorothalonil. Many wood companies--particularly those in British Columbia--use borate mixtures such as borax and sodium carbonate.

How we can be exposed

These chemicals are biocides, which means they attack living organisms. It should not be surprising, then, that conventional anti-sapstain treatments are toxic to aquatic organisms and mammals, including humans.

The chemical application process introduces the first potential emission pathway for these toxicants. A German Federal Environment Agency study published just last month states that these surface treatments "may result in significant emissions. . . . Wood preservatives may be released to soil or water if the treated wood is dripping, either during or shortly after application."

An emissions scenario report from the Organization for Economic Co-operation and Development notes that emissions may also come from evaporations from the open baths, wind dispersal of dried salts, and discharges from the dipping tank.

Additional exposures may occur during the storage of treated lumber, where, the German agency states, "wood preservatives may be washed out of treated wood by precipitation, resulting in contamination of soil, groundwater and/or surface water."

The problems continue after installation

Potential exposures continue after treated flooring is installed indoors. Interior air is the "primary receiving environmental compartment" for treated floors, according to the German study. Biocidal treatments are long-lasting, and exposures may continue through the service life of treated floors.

There is currently very limited literature available on indoor exposures to the preservatives used on interior wood products. However, we can look at studies of historical treatments, especially pentachlorophenol (PCP), to inform our understanding of potential human health exposures. 

One study from a Polish environmental institute found that "PCP concentrations in indoor air can be expected to reach 30  µg/m3 during the first month after treatment. Considerably higher levels, up to 160  µg/m3, have been reported in houses with concomitant poor indoor ventilation. . . . (Residues in) uncovered floors may present a relatively important exposure route for infants and toddlers."

This indicates that modern wood preservatives can introduce reproductive toxicants (like sodium tetraborate pentahydrate), developmental toxicants (like propiconazole), and carcinogens (such as sodium o-phenylphenate) into the air in homes and workplaces.

Albino fungi to the rescue

But are these chemicals really necessary?  If kiln drying is not enough to prevent lumber from staining, then there may be a benign biological solution.  It may be possible to fight fungi with fungi.

Korean scientists are studying developed a strain of colorless fungal products--using natural mating techniques, not mutation or genetic engineering--that could supplant these chemical treatments.

The albino Ophiostoma piliferum fungus is a commercially available product, marketed under the trade name Cartapip. In 2003, scientists from the University of Minnesota and the University of Waikato (New Zealand) reported that by "applying a colorless strain of Ophiostoma to freshly cut logs, the fungus can preferentially colonize the sapwood, thereby capturing nutrient resources and inhibiting subsequent colonization by dark staining fungi."

The team noted that "sapstain has traditionally been controlled with anti-sapstain chemicals; however, toxicity concerns and the environmental effects of many chemicals used have prompted the search for alternative methods of control. Biological control using albino strains of sapstaining fungi is a new method that can be used."

Market pressure

Whether or not this all-natural method of preventing sapstain in freshly cut lumber takes off and replaces known hazardous chemicals depends largely on marketplace demand.

That's why we are raising this previously obscure issue, both in the Pharos Project, where we evaluate all new wood flooring in the system as containing these unhealthy chemicals barring any manufacturer evidence to the contrary, and in GreenSpec Insights.

I hope this information helps to kick-start a consumer/manufacturer dialogue resulting in a marketplace transformation that removes the toxics from unfinished wood flooring.

2012-04-18 n/a 10465 Minimizing Exposure to Chemicals in Clear Wood Finishes

High-VOC content is still the norm in clear wood finishes, but depending on the application you can minimize exposure and maximize durability.

Clear finishes help bring out the natural beauty of the wood, while protecting it from aging and the elements. Photo: Vermont Natural Coatings

Clear finishes can help protect woodwork against aging, scratches, moisture, and the chemicals found in common cleaners. There are natural, low-toxicity options for residential furniture, and factory-applied chemical finishes for commercial architectural woodwork, but there is no environmentally perfect finish.
Here at GreenSpec, when considering which coatings to list, we look for finishes that are low-VOC; contain no heavy metals, phthalates, or aromatic solvents; and/or are natural products with less environmental burden. Durability and ease of maintenance are important, too, so select the least toxic alternative with the greatest durability for the end use.

High VOCs are more the norm than exception

Clear finishes contain more solvent and fewer solids than paints, making high VOC content the norm. The current South Coast Air Quality Management District (SCAQMD) limit for VOC emissions from clear finishes is 275 grams per liter (g/l), 250 g/l for stains, and 730 g/l for shellac--all relatively high levels when you consider that zero-VOC paints are now common.
Not all VOCs are equal, however. Emissions from shellac, for instance, come from relatively benign ethanol (alcohol), whereas some lacquers emit toxic toluene and xylene. Waterborne polyurethanes use glycol ethers that are reproductive toxins. There are also exempt solvents--chemicals that scientifically are VOCs but are not regulated as much--such as acetone being used in place of more toxic alternatives.
Where a finish is applied is also relevant. Factory-applied finishes often have higher initial VOC levels but are allowed to fully cure before installation and so may pose less of an indoor air quality concern.

Natural oils sometimes aren't so natural

 Natural oils, such as linseed and tung, have been used as wood finishes for centuries. Sometimes called drying oils, they are applied as a liquid and penetrate wood pores. When exposed to air, they oxidize to form a protective finish. These oils bring out the wood grain, but because they scratch easily they are not ideal for heavy use areas.
Linseed oil, pressed from flax seed, is easy to apply. You simply rub it on and wipe it off after it soaks in--but it takes weeks to "cure," looks perpetually wet, and can support mildew growth, so it is impractical for most woodworking outside of some residential or specialty applications. Polymerized linseed oil is heated during production and dries faster, but this should not be confused with "boiled" linseed oil (BLO), which can contain heavy metal drying agents. Many companies have moved away from cadmium and lead agents and are using less-toxic cobalt, but that is still an aquatic toxin and not recommended.
Tung oil, from the seeds of the tung tree, forms a much harder (though still relatively soft) surface than linseed oil, resisting water and even some solvents. It also dries much faster and doesn't need drying agents, but it doesn't cure overnight, and you need to use many coats. It takes time, skill, and patience to apply a tung oil finish, making it impractical for large surface areas or most commercial applications. Tung oil also has an odor some people find unpleasant and can even trigger nut allergies in some people.
If you are looking to use natural oils, especially on a food-contact surface, check the ingredients on the label or MSDS;. Many products advertised as tung or linseed oil can contain petroleum-based, high-VOC thinners, oil substitutes, or heavy-metal drying agents, and they might not contain any tung or linseed oil at all.

Wood finishes from beetle secretions

Shellac also traces its roots back to antiquity. Made from resins secreted by the lac beetle of Thailand and India, shellac is sold in flake form and/or dissolved in alcohol.
Shellac finishes do not penetrate the wood and are easily scratched or damaged by water and alcohol, so they are not used in most commercial applications, but the damage is also relatively easy to repair, so it can be a good choice in lower-traffic areas. Shellac is used primarily as a wood sealant under more durable finishes, though the wax in shellac makes it incompatible with some polyurethane products.

Target Coatings' EM2000 is a commercial-grade waterborne alkyd clear finish with no HAPs and a VOC content of 23 g/l VOC.

"Varnishes" and other coatings

Once you move past these natural products, you trade in lower toxicity, gaining better durability and application speed.
"Varnish" is a catchall term for drying oils combined with acrylic and or polyurethane resins. The acrylics and polyurethanes are used for strength, and the oils aid in curing. These products form durable coatings but usually contain flammable, toxic solvents and are slowly being replaced by waterborne formulations.
Waterborne polyurethanes and acrylics can provide a similar durable, low-VOC finish. Not as safe as natural oils but far less toxic than those that contain aromatic solvents, waterborne acrylics and polyurethanes (they are often blended) contain glycol ethers as solvents, which are reproductive toxicants. If not properly applied, waterborne products can raise the wood grain and makes the wood look like it's coated in plastic. Repairing a damaged varnish finish (waterborne or solvent) is difficult.

Professional finishes

For commercial and residential architectural millwork, nitrocellulose lacquers that contain solvents are still common because they spray on and dry quickly so they can be sanded between coats. Less durable than varnish and waterborne polyurethanes/acrylics, these lacquers have very high VOC levels and use some of the most toxic solvents out there. Concerned about worker and occupant health, and motivated by customer requests, companies have now formulated waterborne "lacquers" that can be sprayed like lacquer but don't contain nitrocellulose.
All of these site-applied products have their positive performance attributes, but some pose significant health and environmental risks.

If possible, spray it at the factory

When possible, have woodwork sprayed at a factory and allow products to cure fully there. This also allows the emissions to be captured before entering the environment--or your building. There are quite a few Greenguard-certified products available that are factory-applied, but they are largely production-line products and require specific cure times (usually between 3 and 14 days) before the woodwork can be installed.
People with chemical sensitivities may find some wood finishes problematic, but allowing these finishes to fully cure should minimize indoor air quality concerns. GreenSpec lists a variety of wood finishes , and have added some new commercial finishes, so there are products to meet most any application.

2012-04-18 n/a 10430 Green Product Spotlight: Enhancing Resilience of Buildings

We need to create buildings and communities that are more resilient to natural disasters and other shocks. These building products can help.

Damaged by Hurricane Ike in 2008, this 19th-century house in Galveston, Texas, was moved, elevated, and renovated to LEED Platinum standards. In addition to insulation, solar panels, and rainwater cisterns, the house features natural ventilation via operable transom windows and a restored breezeway. Photos: Galveston Historical Foundation

As climate change becomes an ever greater reality, the need to create resilient buildings and communities becomes more important. Resilience is partly about adaptation to climate change and partly about common sense health and safety issues in an age of increasing resource constraints, growing economic swings, the greater vulnerability to uncertainties that lie ahead.

While much of resilience is about building design and community planning, as in the extensive checklist I included in the recent EBN feature article Resilient Design--Smarter Building for a Turbulent Future, there are aspects that relate to specific product selections. We recently screened the 2,300-plus green product listings in GreenSpec to identify products that specifically increase resilience.

Here are some of the products that are flagged in GreenSpec for contributing to resilient buildings and communities. In some cases this attribute is enough for us to consider a product green; in some cases not. (See What Makes a Product Green? for more on our process of product selection.)

Products that can provide heat or hot water during power outages

Examples of products that might get this attribute include clean-burning wood stoves, pellet stoves with DC power kits that allow use during blackouts, tankless water heaters that rely on battery-fired spark ignition or pilot lights rather than standard electronic ignition (models with pilot lights may not achieve high enough efficiency to be included in GreenSpec); pilot-operated, through-the-wall-vented, gas heaters that have piezo-electric-powered controls that achieve reasonable efficiency, and wood stove heat exchangers for water heating that function through passive thermosiphoning.

Renewable energy systems that function during power outages

Most inverters used for grid-connected photovoltaic energy systems do not work when the grid goes down, but some can; those inverters would earn this attribute. So would passive solar water heaters (thermosiphoning or integral-collector-storage) and active solar water heaters with integral PV modules to power the pump when the sun is shining.

Back-up power systems with environmental attributes

Standard fossil-fuel-fired generators would not achieve this attribute unless they had exceptional environmental performance (perhaps exceptionally clean-burning or with waste-heat capture), but PV-powered generators would earn this attribute. So could environmentally responsible battery and flywheel power storage systems.

Sun-blocking window attachments

The number of products that reduce cooling loads is enormous. To provide some focus, we specifically recognize here only those products that can be utilized quickly during a power outage and are highly effective, such as exterior roller blinds and sun screens.

Tubular skylights bring daylight in when electricity is off.

Tubular skylights and fiber-optic daylighting

Daylighting is a design feature that contributes to resilience in buildings, and as with energy-efficiency, there are numerous products that support this. To provide some focus, we designate tubular skylights and fiber-optic daylighting systems here, because these systems allow daylight to be delivered in places that are not reached by windows--spaces that would be unsafe in the daytime hours in the event of a power outage.

Onsite water storage and rainwater harvesting equipment

Cisterns, rainwater harvesting equipment, and related components that provide on-site water storage can provide critical water supply during extended power outages and during periods of extreme drought. Products that aid in the delivery of water during power outages, such as water-pumping windmills, hand-operated pumps, solar-powered water-purification systems, and gravity-feed spring components also enhance resilience.

Composting toilets and waterless urinals

Toilets and urinals that do not require water for waste conveyance are usable during water shortages or power outages when potable water is not available, thus boosting resilience.

Products offering storm or flood resilience

Hurricane tie-down straps and other structural components help buildings resist storm events, and flood dams and breakaway flood-release panels can protect buildings during flood events.

Moisture-tolerant construction and finish materials

After a flood, it's critical to the health of communities to restore habitability of buildings--if it was lost to begin with. GreenSpec lists as providing resilience interior finish materials that can survive wetting from floods without long-term damage, such as moisture-tolerant subflooring, non-paper-faced drywall, and polished concrete. Many other moisture-resistant building materials are in widespread use that we don't focus on here, such as tile flooring and cement board, even though these should be considered as part of resilient design.

Wildfire-resistant materials and components

In some parts of the country, resistance to wildfires is a top priority of resilience. GreenSpec considers resilience-enhancing products here such products as ember-excluding soffit vents, decking that meets stringent wildfire standards, fiber-cement siding, and noncombustible roofing.

Solar-powered electric vehicle charging stations and bicycle racks

Equipment and systems that reduce dependence on gasoline-powered vehicles can increase resilience, because of their benefits during potential gasoline shortages--and their ability to help us create communities less dependent on cars.

Urban gardening and farming components

Although this has not been a focus of GreenSpec before now, products and components that can help achieve higher levels of local food production could earn GreenSpec listing. Examples might include hydroponic components that are optimized for rooftop applications. What do you think? Would you like GreenSpec to recommend high-performing products in this category for your building projects?

We've started by adding this attribute to appropriate products already listed in GreenSpec for their other green features. Next, we'll specifically seek out products with this resilience characteristic--so keep your eyes out for new products in GreenSpec or others you think we should consider.

What other types of products do you think should be included here? We'd love to hear your thoughts. You can also read more blog posts on Resilient Design.

2012-04-11 n/a 10431 Scoring the Referees: How Pharos Judges Green Labels

[Editor's note: Today's guest post is authored by Bill Walsh, Executive Director of the Healthy Building Network.]

When building products carry different green certifications, how do you know which product is best? Maybe there is a way to compare apples and oranges.

As green certifications and labels have proliferated, so has greenwash. Even among legitimate certifications, conflicts and inconsistency have made them hard to understand.

How do you cut through the cacophony and get the information you want? The Pharos Project has independently organized information on about 48 major product certifications and products that carry those labels.

Start by finding products

If you want products certified to a specific standard, you can find the certification standard you are looking for on Pharos's certifications page or, alternatively, simply type the name of the standard into Pharos's search function. Once on the page for the standard you want, click on the tab labeled "Products with this certification in Pharos" and voila.

But getting a list of similar products with a similar certification sometimes doesn't translate to the real world. What do you do when you facing similar-looking products that carry different certifications?

Weighing products with different certifications

When searching within a product category, the Pharos Building Product Library helps you compare and evaluate products certified under different labels.  Each product record in Pharos documents and displays all of certifications that product has earned. Pharos generates scores for each impact category that account for these certifications. The more rigorous the certification, the higher the Pharos score.

For example, if two resilient flooring products boast two different certifications for indoor air quality, the product meeting the more rigorous standard will receive a higher score for that certification.

And if two products sport the same certification and score in one impact category, Pharos lets you easily take into account other impact categories to further differentiate. For example, it might be important to you to start your Pharos search to include only products that meet a certain VOC emissions standard, and then further refine the search to select for the highest renewable materials content from among those low VOC materials.

Compare certifications

Pharos helps you learn more about how the certifications compare in their rigor and what issues they cover, The certifications can be browsed as a complete list, browsed by category (Biobased, Recycled Content, etc.), or searched by name or certifying organization. Certifications can then be sorted by how they score in Pharos impact categories to give you an immediate comparison of which certifications are the most rigorous.

Each certification's detailed view includes a description, the Pharos score it earns, an explanation of how the certification impacts product scoring, direct links for more information, and a link to view a list of products in the Pharos Building Product Library claiming that certification. Pharos team tools allow subscribers to add personal or company tags to certifications to enable easy saving and sharing.

Behind the curtain: How our scoring works


Understanding how Pharos scores the certifications can help you understand how those certifications work. We start by looking at how the attributes that the certification is addressing and thresholds of performance it certifies compare against the Pharos ideal in a given category (the ideal of zero VOC emissions for the VOC score category, for example) and the benchmarks (in our 1–10 scoring framework) that we have established on the way to that ideal. Comparing different certification standards against a standard measure helps you better compare them.

We also examine the administration of the certification. An ideal certification is administered by an independent third party that manages the sample selection and chain of custody (getting the right sample quickly to the testing lab), and makes the determination of whether the product meets the standard.

Manufacturer claims can be considered rigorous if they are regularly audited by a governmental body (such as the California Air Resources Board, or CARB, in the case of formaldehyde regulations). Pharos drops certifications one point in score if they are administered by an interested or potentially biased party, the most common being a trade association (for example, the Carpet and Rug Institute's GreenLabel Plus) or if the claims are certified by an independent lab but the manufacturer does the sample selection.

No perfect 10 for VOCs--content or emissions

You many notice that no certification scores a perfect 10 in VOC emissions yet. The Pharos ideal in this category is an independent third-party certification with no detection of VOCs. You may be surprised to learn that no certifier yet offers this. They all certify to a variety of thresholds for acceptable VOC emissions.

Some products do indeed have zero VOC emissions and a manufacturer can document a claim of zero VOC emissions through a lab report but as described above, this report can only score a 9 because it is not certified by a third party.

You also might notice that no VOC content certifications get even close to a 10--why? Two reasons: First a number of known VOCs are exempted from most certification standards--why? Because most VOC certifications are based upon VOC regulations that reference the VOC's contribution to ozone smog. They were designed to combat outdoor air pollution, not to guarantee indoor air quality.  Thus, the common "definition" of a VOC is a political one, not a scientific one. This definition misses a number of important VOCs.

While the certifications have some catching up to do here, Pharos accounts for a greater number of actual VOCs and provides a higher score if full content disclosure from the manufacturer reveals no exempt VOCs.

The second reason is that some non VOC chemicals in wet applied products can actually create new VOCs in the curing process. So regardless of content, emissions testing is needed to insure that a product is not releasing VOCs.

As you can imagine there are even more surprises and conundrums that we encounter in all 48 certifications analyzed by Pharos. So head to the Pharos website, dive in, and be sure to share any ideas you have for refining or improving our analysis!

2012-04-11 n/a 10377 Beat the Bulb "Ban": LED Replacement Lamps in a New Light

The incandescent ban is here, but LEDs have improved rapidly in the last couple of years and there are now several bulbs that meet Energy Star criteria.

Toshiba's A19 450-lumen LED bulb is the equivalent of a 40-watt incandescent bulb yet only consumes 8.4 watts.
We've been hearing for years that "they're going to ban the incandescent bulb"--is that for real?
Starting on January 12, 2012, the Energy and Independence and Security Act of 2007 (EISA) began regulating energy-efficiency standards for 100-watt screw-in light bulbs (also known as Edison or A19 lamps). These bulbs are now required to use 27% less energy, or 72 watts or less, for the same lumen output.
Over the next couple of years, 75-, 60-, and 40-watt bulbs will have to have that same 27% reduction. And starting in 2020, EISA ups the ante and will require that most light bulbs be 60%–70% more efficient than today's incandescent bulbs.
The law does not mean incandescent bulbs will be illegal, but it will be a challenge for them to comply. Meanwhile, most LEDs already meet those standards.

Why move to LED replacement lamps?

You're probably going to to have to switch to LEDs eventually, but there are good reasons to do it now.
According to the U.S. Environmental Protection Agency (EPA), which runs the Energy Star program in a partnership with the Department of Energy, replacing one standard incandescent bulb in every home in the U.S. with an Energy Star-qualified bulb--CFL or LED--"would save enough energy to light 3 million homes" annually and prevent 9 billion pounds of greenhouse gases from entering the atmosphere.
Though more expensive, an LED has a few advantages over a CFL: LEDs are typically more efficacious, they don't contain mercury, they work well in cold temperatures, and they can be turned on and off repeatedly without affecting the lamp's lifespan.

Forget watts: Look for lumens

As we move away from incandescent bulbs, we have to stop thinking in terms of "XX-watt light bulbs." Watts simply tell us how much energy a bulb consumes and don't make sense as a metric for CFLs or LEDs.
Lumens, on the other hand, tell us the amount of light produced or how bright it is, and lumens per watt (lpw) gives us the amount of light produced per the amount of energy consumed. (See LEDs: The Future Is Here for more information on LED performance).Standard incandescent bulbs produce anywhere from 10 to 17 lpw, according to the DOE, so a 60-watt bulb is about 800 lumens; a new Philips EnduraLED produces 940 lumens while consuming only 10 watts, or 94 lpw.
New packaging for replacement lamps prominently displays lumen output, estimated annual energy costs, and lifespan. This should make it easier for consumers to find the amount of light they prefer and compare products, but it will take some getting used to (see table for lumen equivalents), and they might have to calculate lumens per watt on their own.
The Lighting Facts labels, such as this one for Toshiba's A19, now display lumens first and the watts toward the bottom.

Look for Energy Star-qualified LEDs

Energy Star lists LED A19 replacement lamps that are "omnidirectional" so they shine light down to illuminate the table or work surface, something many older LED replacement lamps (and some current models) could not do, and which limited their usefulness and appeal.
Energy Star-qualified lamps also have to undergo third-party LM-79-08 test methods for efficacy and color quality and must meet the following criteria:
  • A minimum of 50 lpw
  • A minimum rated life of 25,000 hours while still producing 70% of its original light (the light from LEDs typically fades away rather than the bulb failing catastrophically, so below 70% is considered the end of its service life)
  • Specific correlated color temperatures of 2700K, 3000K, 3500K, or 4000K (3000K is similar to the warm white color associated with incandescent bulbs--higher color temperature numbers mean "cooler" blue colors)
  • A power factor greater than 0.70
  • A color rendering index (CRI ) over 80 (Philip's L-Prize-winning EnduraLED 60-watt replacement has a CRI of 93)
  • A minimum three-year warranty.

Are we paying more and getting lower quality?

As with early CFLs, the two big complaints about LEDs have been high cost and questionable light quality.
Energy Star for LED replacement bulbs has helped lead to significant improvements in light quality, so it is less of a free-for-all in the marketplace (remember the cylinders with hundreds of individual LEDs masquerading as a lamp?). GreenSpec now lists Energy Star-qualified bulbs from Philips, GE, Toshiba, The Home Depot, and Technical Consumer Products.
Though some of these products are still quite expensive (Philips' 940 lumen EnduraLED is about $40), you can buy an Energy Star-qualified 40-watt replacement bulb from Home Depot made by Lighting Science Group for less than $10! And there are rebates available from local utilities and public service boards that can drop the price even further, making LEDs very cost-competitive, especially when you consider their long lifespans.

LEDs are not a panacea--at least not yet

Though LED replacement lamps are improving quickly, the technology still has some challenges to overcome.
They still don't look like an incandescent bulb, and the light from an LED is "different"--after all, there is no burning filament--so it may take time before consumers get used to them. And because LEDs are more like a computer chip than they are like an incandescent light bulb, they are affected by other electronics and wiring, so dimming may not be as smooth, they might flicker, or the color and light quality could change.
In most residential application, these problems will be minimal, but in commercial buildings with numerous LEDs and more electronics, the potential for problems increases. (Look for a follow-up blog on LED problems in commercial buildings)
Nevertheless, the lighting world has changed forever. So get used to thinking in lumens, and if you want to make the change to an LED replacement lamp you should try one in your home or business and run it through its paces so you know what you are getting. The energy savings will be worth the effort.

2012-04-03 n/a 10326 More Heat Than Light: Six Wrong Ways to Daylight a Building

Thanks to LEED and other standards, everyone's doing daylighting now--but not everyone is getting it right. Here's how it goes wrong--and how to do it right.

The Seattle Central Library has been lauded for its daylighting features, but many library patrons and staff have trouble with overheating and glare at workstations like these. Photo: Nadav Malin

You can't turn around these days without seeing a case study that mentions the use of natural daylight to help save energy and enhance the well-being and productivity of occupants--especially students and employees.

Unfortunately, almost as common are horror stories of fabulous green buildings that make their occupants miserable. Here at BuildingGreen, we've heard a tale or three about librarians wearing sun visors on the job, office workers using open umbrellas as parasols in their cubicles, and schoolteachers in award-winning buildings who keep the blinds closed constantly.

For our recent EBN feature article, "Doing Daylighting Right," we collected some of these stories, along with some really great tips from leading daylighting experts who have accomplished successful daylighting designs resulting in happy, productive building occupants and lower energy bills. But in case you're interested in how to get your daylighting design just wrong, we've put together six key tips for you below.

Overglaze it

If a little daylight is a good thing, then an all-glass building must be the ultimate, right?

Well, not so much. True design for daylighting involves intentional use of carefully chosen glazing. "There's been lots of work done by lots of people that shows that the more glass you have, the more energy you use," says Fiona Cousins, P.E., principal at Arup in New York. A 30%–40% window-to-wall ratio should provide plenty of daylight if the glass is located in the right place--high up to optimize penetration deeper into the space--Cousins adds. But if you want to forego the potential energy savings and make occupants as uncomfortable as possible, 100% curtainwall is definitely the way to go.

In seriousness, judicious use of high-performance curtainwall can be part of an energy-efficient building that still has the dazzle many designers and building owners prefer. Our research director Jennifer Atlee just put together some great guidance on standout curtainwall systems from GreenSpec and how to use curtainwalls with care.

Ignore orientation

Don't let little details like where the sun rises and sets get in the way! Looking for "connection with nature"? How about full-in-the-face glare that really gets our building occupants noticing the awesome power and life-giving force of the sun? Seeing their computer screens would only detract from this goal.

On the other hand, if you wanted to make it possible for people to work and study comfortably in their buildings, you'd end up with a lot of untidy asymmetry: shading systems that are different on the south than they are on the east or west; glazing that's "tuned" based on orientation; and clerestories or roof monitors that face north and south, never east and west.

Emphasize views and call it daylighting anyway

One of the most aesthetically pleasing ways to get daylighting wrong is to emphasize expansive views and then assume that any window area brings in useful daylight, even if the window extends all the way to the floor or is on the west orientation of the building.

A more thoughtful, occupant-focused daylighting design would separate the view windows from the daylighting windows and ensure that separate shading can be used for each. It would also provide solar shades for view windows to preserve the views while minimizing glare, relying on sophisticated modeling software to help determine the correct openness factor for such devices.

Skip the automated controls (or skimp on commissioning)

Studies have shown time and time again that you're more likely to realize energy savings from daylighting if an automatic daylight dimming system is installed in the building. One of the easiest ways to get daylighting wrong is to skip this system altogether in order to help your clients save money--or, failing that, to value-engineer commissioning of the daylight dimming system out of the budget.

If you would instead prefer to provide a workable daylighting system that will eventually pay for itself, experts agree that you'll fight tooth and nail to keep the automated controls in, and you'll work closely with the control system manufacturer, the commissioning agent, and the building owner to ensure that the system works exactly the way it should. This goes for automated shading as well.

Bump up the contrast

One of the lesser-known ways to spoil a well-designed daylighting system is through interior design. Because daylight modeling depends heavily on surface reflectance, a bold color palette can be a key part of darkening rooms, ensuring people turn on the lights more often and waste as much energy on electric lighting during daylight hours as possible. High contrast can also cause eyestrain--an emerging strategy for maximizing occupant discomfort, particularly in schools.

The lower panels in this office at the Yale Sculpture Building are filled with light-diffusing silica aerogel to provide insulation while bringing in daylight. Despite their translucence, the panels had to be covered with fiberboard in some rooms to control daylight entry. Photo: Alex Wilson

Keep occupants out of the loop

Unlike most other aspects of design, the success of daylighting depends heavily on occupant behavior, and occupant satisfaction is a key measure of success. There's nothing like a failure to communicate to really put the icing on the cake of poor daylighting performance. Occupants who don't know what interior lightshelves are for might stack books on them; occupants who don't understand how the lighting controls work might tape over the sensors; and occupants who aren't aware of the benefits of daylighting might just keep the blinds closed all the time.

In contrast, a project team trying to do good daylighting design will anticipate and design for occupant needs and habits--and will engage directly with building owners, managers, and occupants about how the lighting system works--in order to realize performance benefits from daylighting.

Doing daylighting right

If for some reason you're not satisfied with our six tips on how to do daylighting wrong and you're interested in more information on how to do it successfully, this month's EBN feature article takes a deeper look at the following issues and strategies:

  • The importance of integrated design
  • Preventing glare and excessive heat gain
  • Balancing electric lighting with daylight
  • Addressing cultural issues that make people turn on lights
  • Starting space planning earlier than you might be used to
  • Metrics and standards for daylighting
  • Exciting innovations in wireless lighting control systems
  • Guidance on daylighting products, such as lightshelves
  • Integrating daylight simulations with energy models
  • The importance of daylighting in everyday buildings
2012-04-02 n/a 10255 Toxicological Riddles: The Case of Boric Acid

Even water is toxic if you have too much. How do we keep a potentially harmful but necessary nutrient like boric acid at safe levels in our buildings and our bodies?

We've been using boric acid and borate compounds in products for generations, and then praised it's green virtues as in the blog post linked to above (click image). The full story is a bit more complex.

What do you do about a substance that is a biologically necessary trace nutrient, long considered nontoxic, and in a multitude of products--but that is also now listed on a major European Union chemical hazard list due to evidence that it is toxic for reproduction?

It's one of those riddles that I can imagine toxicologists love to play with but that drives everyone else crazy. Here's the story, and our approach to answering the riddle--for now.

REACH and the case of boric acid

In the summer of 2010, boric acid was added to the European Union's REACH SVHC Candidate list (to spell it out: REACH = Regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals and SVHC = Substances of Very High Concern). At BuildingGreen, we look to REACH as a bellwether for the direction U.S. toxic chemical regulation is eventually headed, so if something new is listed, we pay attention. Boric acid has been found to meet REACH criteria for classification as toxic for reproduction.

Huh? We've been using boric acid and borate compounds in products for a long time--in cosmetics, cleaning products (the laundry staple, Borax), as a 'non-toxic' pesticide and as an ingredient in building products. You find it in cellulose insulation, bamboo treatments, mattresses, termite protection systems, treated lumber, paints and coatings, and elsewhere. Furthermore, boric acid is a vital component to cellular structure in plants and a limiting micronutrient in agriculture. That means we spread it around on fields and elsewhere, We're eating it all the time and we have been for years.

But hazards aren't all-or-nothing

This issue illustrates why hazards aren't an all-or-nothing issue for toxicologists. Toxicology characterizes risk by evaluating:

  • the hazard--hazardous properties of the chemical or material by itself;
  • the likelihood of exposure--who might get exposed, and how--by what route and mechanism (inhalation of VOCs or dust, ingestion, or by absorbing it through the skin, for example); and
  • the dose response--what happens when the amount of exposure is small? Or large? Or at a particular stage of life?

How to evaluate these three things, independently and together, keeps toxicologists employed and makes the rest of us a little uneasy.

How about just keeping toxic stuff out?

Green chemistry--and Pharos--tend to take a different approach, noting astutely that the more we keep hazards out of products to begin with, the less the rest of it matters and the safer we are.

For some hazards, such as Persistent Bioaccumulative Toxic Chemicals (PBTs), we at GreenSpec think this is the only sensible approach. That's because these substances stick around for a long time and accumulate up the food chain, so exposure is basically inevitable and increases as long as the stuff is produced; you can't keep anything contained indefinitely. This is also a useful precautionary approach in general and a good philosophy for developing safer chemistries, safer products, and a healthier world--but it's not the only approach needed.

What do you do if a hazard is also a nutrient, depending on the dosage, and it's neither bioaccumulative nor persistent? This is where toxicology really shines, and this is the case with boric acid and borate compounds. It's said that any medicine can be a poison, depending on the dosage--which is a different way of saying the same thing. The trick is determining where it switches and making sure we're not getting too close to that threshold.

Putting borates in perspective

In the case of borates, here are some data points.

  • Boron is a critical micronutrients in plants.
  • Most common foods contain borates at concentrations of 1–20 ppm, so we ingest up to 1 mg/day in our normal diet.
  • The tolerable upper intake level for developmental toxicity associated with ingestion of borates, according to the European Food Safety Agency (EFSA) and others, is 10 mg boron per day for an adult and 3 mg boron per day for toddlers.
  • As I said earlier, borates are all over consumer, cosmetic, building, and agricultural products. (No, that in itself doesn't make them safe--lead used to be everywhere too.)

What we do with this information

Our resulting policy for GreenSpec is as follows:

  • Don't worry about low concentrations of borate compounds in products. It's simply not a problem.
  • Carefully scrutinize higher concentrations of borate compounds, particularly where they may show up in high enough quantities in dust to cause problematic levels of exposure to workers or building occupants (For example, borates can be up to around 20% of the weight of cellulose insulation).
  • Consider the alternatives and don't freak out. While recognizing the concern that exists, we'd be horrified to see a new consumer fear of borates lead to manufacturers substituting a poorly understood PBT in its place.

As we've typically done, GreenSpec will continue let you know when borates are a major known ingredient in products. We're not likely to exclude any products from GreenSpec based on this issue, but there may be some products for which we raise a warning flag.

Avoiding dust

Cellulose insulation, for instance, is one area where significant dust during installation and remodeling could be problematic--or it might not be. A NIOSH study from 2005 concluded that the amount of respirable dust from cellulose insulation installation is typically low (there may be a lot of dust but most of it isn't the right size to get into the lungs), and so they concluded additional studies on lab animals weren't needed. The gist was that installation dust can cause eye and nasal irritation, but isn't going to create lower respiratory conditions. However, most of that respirable fraction is flame retardants, and the eye and nose irritation may be from these additives. Additionally, the study made clear "the animal pulmonary toxicity studies and worker health surveys focused on acute [cellulose insulation] exposures and do not preclude the possibility of toxicity resulting from chronic exposure. The GreenSpec team hasn't uncovered any study that gives us confidence that chronic exposure truly is or isn't a concern, but we'll keep looking.

After a dusty remodeling project is cleaned up, though, it's hard to imagine how borate compounds in cellulose insulation could be a concern. According to the U.S. EPA Exposure Factors Handbook, adults ingest on average 0.56 mg/day of house dust, so it would be virtually impossible to ingest enough dust to get anywhere approaching the concern level for borates (note that we're worrying about ingestion not inhalation here because most of the particles are trapped in the "nasopharyngeal region" --that part of your throat behind the nose--and gets swallowed, so odd as it may seem it still counts as ingestion not inhalation).

Also keep in mind that any possible concerns are still nothing like the problems with brominated flame retardants (which are PBTs) that you find in some other insulation and that dust itself can be a workplace hazard. In short, it doesn't make sense to switch away from cellulose insulation to avoid borates when it's still one of the most benign flame retardants out there, but it does make sense to take precautions regarding dust creation and exposure and seek installation methods and contractors that minimize dust. That's good precaution all around.

Given the REACH listing, we're not going to be as wholly positive about borates being nontoxic as we used to be, since there are concerns. But borates aren't volatile, aren't easily absorbed through the skin, and don't bioaccumulate the way PBTs do. So if we don't see a way that enough of it's going to be inhaled and/or ingested, it's really not a huge concern.

How borates score in Pharos

In Pharos, borates are now flagged because they're on the REACH SVHC Candidate list. But like GreenSpec, Pharos makes a distinction between PBTs--for which there really is no reasonable "exposure" argument--and other hazards.

Presence of PBDE will automatically get spray-foam insulation a ToxCon score of 1 in Pharos--the worst possible score. In contrast, the presence of boric acid in cellulose insulation will give it a score of 3. This is a low score to represent the presence of the hazard but differentiates the level of concern relative to PBTs. You can also dig deeper with Pharos and see the percentage of borate compounds in the product. If it's a trace ingredient, it's probably not worth worrying about.

Between Pharos and GreenSpec, we'll do our best to ensure that you know how to evaluate the issues from all sides and get the data you need to make up your own minds.

2012-03-28 n/a 10204 10 Green Building Products They Still Make in the U.S.

It's not necessarily greener to source products made in the USA. But it sure does create jobs.

Let's get one thing clear: the issue of energy spent importing stuff from China is a red herring. The distance from ports in California to China is about twice the width of the continental U.S., but ocean freighters are about 7.5 times more energy-efficient than trucks, so the energy expenditure of any given product has a lot more to do with the transportation mode than with the distance it travels.

By sourcing just 5% of their products from U.S. manufacturers, builders could create hundreds of thousands of jobs. Below are a few products to start you off.

Nonetheless, reducing miles traveled by our products is probably good. Rail is about 9.5 times more efficient than trucking, so there are efficient ways to get goods across the continental U.S. Why not use them?

We also have strong environmental and workers' rights regulations in this country, and by keeping things local we are more likely to care about impacts.

It's the economy, not the environment

But these days, the biggest motivator is probably jobs.

According to ABC News, if every builder in the country sourced just 5% more American-made products, it would create 220,000 new American jobs. In a story about a Montana house being built entirely of U.S.-made materials, ABC's David Muir writes, "Even though certain goods are more expensive, in total, the cost of the house is nearly identical, given that other U.S.-made products are cheaper. The all-American home, which is not yet finished, is running only 1%–2% more than a foreign-sourced house."

The manufacturing of many building products has not been outsourced to China in the way consumer goods have, but there is a perception--and in some cases a reality--that many products are not produced domestically.

That's why we compiled this list of 10 green building products from regions across the U.S.: "Made in U.S.A." products that we list in GreenSpec.

Encore Particleboard by SierraPine: Oregon, California & Georgia

Encore industrial-grade particleboard, with 90% recycled content and FSC certification an option, is manufactured at three of SierraPine's five US locations--Springfield, OR; Martell, CA; and Adel, GA. Like many of SierraPine's medium density fiberboard products, Encore contains no added urea formaldehyde (NAUF). Instead of conventional urea-formaldehyde (UF) binders that can emit high levels of formaldehyde, Encore uses phenol-formaldehyde (PF), or phenolic, binder for emissions low enough to comply with strict CARB Phase II regulations (0.09 parts per million formaldehyde). Read more in GreenSpec.

SolarWorld: Hillsboro, OR

SolarWorld, one of the world's largest manufacturers of PV modules, operates factories in both the U.S. and Germany, producing modules and kits for residential and commercial installations. Solarworld was founded in southern California in 1975; today its sales and marketing offices remain there while production at its U.S. headquarters in Hillsboro, OR, supplies the company's customers in the U.S., Canada, and Latin America. Read more in GreenSpec.

Enercept Structural Insulated Panels: Watertown, SD

Enercept SIPs, made in South Dakota, consist of a core of expanded polystyrene--with up to 80% pre-consumer recycled content--laminated between two sheets of oriented strand board (OSB), which is available FSC-certified upon request. Read more in GreenSpec.

Hardcast Duct-Seal: Wylie, TX

Founded by rockabilly singer Boyd Bennett in 1965, Hardcast of Wylie, TX, manufactures a line of low-VOC, water-based duct sealants including Duct-Seal 321. Non-toxic and solvent-free, Duct-Seal is an industrial-grade sealant for metal or fabric duct, flex duct, and glass-fiber duct board. Read more in GreenSpec.

Nails are small, but their impact adds up. Just one house will require about 20 pounds of nails to build, and retrofit projects need them too. Choosing domestic and recycled makes a difference.

Maze Nails: Peru, IL

Maze is one of very few companies manufacturing nails in the U.S., and the only one advertising recycled content in its products. Made in Illinois from domestic recycled steel (65% post-consumer, 20% pre-consumer), Maze nails are available in all standard and most specialty styles and sizes. Highlighted in ABC's "Made in America" construction segment, Maze's pneumatic nails are mentioned as one of the complex reasons the "all-American home" project is barely over budget: while Chinese nails are a bit cheaper, says David Muir, "the American nails jam the nail gun far less often." Read more in GreenSpec.

Typar Housewrap: Old Hickory, TN

Typar offers several vapor-permeable polypropylene weather-resistive barriers for residential and commercial applications, with various ratings for permeability and UV resistance. As discussed in our article Choosing the Best Housewrap (link to "Choosing the Best Housewrap: A New Standard for Weather Barriers"), Typar meets the new ASTM standards for weather-resistive barriers. (Incidentally, Typar's main competitor Tyvek is manufactured both in Virginia and in Luxembourg.) Read more in GreenSpec.

Vocomp by W.R. Meadows: York, PA

Vocomp is a low-VOC, water-based acrylic curing and sealing compound for concrete finishing. Vocomp-20, with VOCs of only 4 g/l, has short application and drying times. Made in York, PA, Vocomp products were developed as water-based emulsions to eliminate the use of hydrocarbon solvents. Read more in GreenSpec.

SolarWall: Toronto, ON, and Buffalo, NY

SolarWall is an unglazed transpired solar collector that uses perforated sheet metal to preheat ventilation air. The manufacturing process begins in Toronto, ON, and is finished across Lake Ontario in Buffalo, NY. The metal cladding is attached several inches from the exterior of a (usually) south-facing wall, where it is heated by the sun. Fans draw air in through the perforations; as the air warms, it rises behind the cladding and is ducted into the building. Read more in GreenSpec.

Old-Fashioned Milk Paint: Groton, MA

Milk Paint is made from casein (milk protein) mixed with lime, clay, and earth pigments. Manufactured in Groton, MA, Milk Paint is sold in powder form, greatly reducing the energy used in shipping, with the customer adding water to make a pint, quart, or gallon size. Milk Paint is available in 20 historical colors, which can be blended or tinted. Read more in GreenSpec.

Vermont Natural Coatings PolyWhey: Hardwick, VT

Like Vermont Natural Coatings' other products, PolyWhey floor finish is manufactured in Hardwick, VT, using waste whey protein from the local cheese industry as a binder. This low-odor coating contains no toxic heavy metals and has VOC levels less than 180 g/L. Read more in GreenSpec.

Some of the highest-performing and most popular housewrap products are made in the USA. Photo: Fine Homebuilding

Green building can create green jobs

Some of these companies have been manufacturing in the U.S. for decades, while some were more recently founded with an explicit desire to create domestic jobs. And in a refreshing development, some companies are even bringing their operations back to the U.S. Neutex Lighting in Houston, TX, is moving its LED lighting plant from China to Houston; according to local TV station KTRK, manufacturing should begin by April.

Whatever your reasons for "buying American," finding products can be a challenge--searching store shelves for a U.S.-made needle in a haystack--and even manufacturer websites don't always mention their domestic production and may require a phone call to confirm.

We at GreenSpec want to know: What products do you try to source domestically? Which ones are particularly hard to find? Do they tend to be more expensive, and if so, is that offset by better performance?

2012-03-22 n/a 10191 Biobased Materials—Increasing Our Scrutiny

It's natural that we should gravitate toward biobased materials. But many of them are energy-intensive and toxic, so how do we judge what's best?

O Ecotextiles is an example of the kind of leadership company that has worked diligently to address environmental impacts at every step of their product's production--including careful attention to responsible sourcing of biobased materials. We discussed Ecotextiles in EBN and had them on our top-10 list of 2008.

It still seems like biobased materials should be better for the environment. Even after the LEED Wood Wars, even after all the stories of pollution and waste from industrial agriculture, it just seems logical that resources we grow as part of a natural cycle are greener than the ones we mine or extract.

This intuitive attraction may explain why various versions of "biobased" and "natural" claims, like the "rapidly renewable" credit in LEED 2009, have had so much staying power, why the building industry is just starting to take a much-needed closer look, and why it's still hard to figure out how to effectively evaluate the impact of these materials in our industry.

I applaud USGBC and its proposed LEED 2012 "sustainable sourcing" credit for trying to tackle this issue and appreciate the challenge USGBC faces in doing so. However, there's still some work to be done. There has been a great discussion on LEEDuser about this, particularly comments by Tom Lent of the Healthy Building Network and Mara Baum of HOK. Baum put it well when she said, "Wouldn't it be great if in 5 or 10 years we had an FSC equivalent for all major raw material industries? However, we still need a usable, justifiable version of LEED between now and then."

Here are some steps I propose for increasing our scrutiny.

First, Admit You Have a Problem

The environmental and health hazards associated with biobased products are myriad and complex, depending on the material. Below are some issues, but even this long list is not exhaustive.

  • Agriculture: intensive land use and deforestation, chemical use, fuel use, nutrient runoff and other pollution concerns, treatment of agricultural workers, etc.
  • Market realities & social justice: competition between food crops and crops used for fuel and products like building materials can disadvantage the already disadvantaged by raising the cost of food.
  • Processing: While 'biobased' materials can include materials like wood that are used almost as-is, many materials require extensive processing which can be quite energy-intensive, toxic, and polluting, and requiring fossil-fuel-based additives and processing aids.
  • Health: While many people assume that the VOCs from 'natural' materials don't present the same kind of health hazard as industrial VOCs, there's no definitive answer. Formaldehyde, which so much good and justifiable effort has been made to minimize, is common and naturally occurring. Also products made with biobased feedstocks are not necessarily any less hazardous than those made with fossil fuel feedstocks--it depends on what else is in them.
  • Percentages: Is 8% soy polyol worth getting excited about? At what percentage biobased content should we start paying attention?
  • Durability and end of life: In some cases biobased materials are compostable, but often not. Biobased plastics can complicate the recycling stream.
  • Emissions and more: There's a lively debate whether wool is good or bad for the environment. There's no doubt it's renewable, and can be produced in ways that appear low-impact, but whether methane emissions from sheep counteracts all the other good stuff is an open question.

Second, Set a Strong Goal, but Use the Stepping Stones We Have

Improving practices and figuring out how to assess and document more sustainable practices is going to take a while. There is no ready equivalent to FSC for most biobased materials aside from wood.

Certification to organic standards or other sustainable agriculture standards can provide guidance in some cases. There are any number of international certifications looking at different aspects of cotton production, including social concerns, and that's just scratching the surface. While not perfect, many of these ensure practices that are far preferable to standard agricultural practice and represent an existing raw material supply that can respond to a growing market generated by LEED. Leading manufacturers have already, appropriately, turned to these sources in seeking out responsible sourcing for biobased materials.

It seems only prudent to capitalize on the work that's been done while still providing direction for further improvement. This touches on the broader issue of the role of product (and manufacturing or harvest process) certifications in LEED around which there continues to be extensive debate. Biobased materials is yet another area where it behooves us to carefully assess the relevant concerns and possible mechanisms to address them, and then take great care in selecting approaches to fill in the gaps.

Deeper Research Is Coming

BuildingGreen and Healthy Building Network are collaborating on deeper research of these questions, so look for deeper treatment in an upcoming EBN feature article and in Pharos--digging into the issues for different materials and different product categories, what certifications and other measures exist now to help us evaluate 'sustainable sourcing' and other aspects of biomaterials, and what manufacturers are taking leaps beyond the norm in addressing these issues.

We welcome comments and insight on manufacturers you think are going above and beyond, issues you think are all too easily overlooked, or frameworks and certifications that address these issues.

2012-03-20 n/a 10164 Transparency in Action: Health Product Declaration Ramping Up

Life-cycle assessment, environmental product declarations, and corporate social responsibility reporting are a great start. But can we talk about health?

This sneak preview of the HPD for the imaginary "TuffStuff X42" should give you a sense of what the document will include. Click the image to enlarge this first page. For a PDF of the full HPD, click here.

Here at BuildingGreen, we're pretty excited about the rise of the product transparency movement (as you may have noticed from recent coverage in January's EBN and our related blog series) but also concerned about the limitations of the environmental product declaration (EPD) framework.

So we're even more excited about the emerging health product declaration (HPD) open standard--a voluntary format for reporting building product ingredients and related health hazards--and to announce the next step in the HPD's development.

The clock is about to start ticking on a 60-day Pilot Project in which the HPD will get tested and refined. With the support of the HPD Working Group--a volunteer organization of experts from the community of designers, specifiers, and building owner/operators--thirty leading building product manufacturers will complete the draft HPD for a selection of their products.

Assa Abloy opens the door

The pilot program was initiated at the recommendation of Assa Abloy, a global manufacturer of doors, locks, and security systems. The company volunteered to contribute to the HPD effort by using the draft format to report on some of its products as a means of troubleshooting and improving the first draft, and three more firms–Interfaceflor, Scranton Products and Yolo Colorhouse paints–quickly agreed to help.

The Healthy Building Network's newsletter gives details on the HPD pilot: the full list has now grown to 30 firms!

Why does BuildingGreen care?


Once the HPD is widely adopted, it will make one of our most challenging tasks--evaluating product composition as part of our GreenSpec screening process--much easier. More importantly, we expect that many companies will adopt cleaner formulations once product ingredients and their health hazards are widely known.

We're not just innocent bystanders here. The HPD Working Group was convened July 2011 by the Materials Research Collaborative, a joint initiative of Healthy Building Network and BuildingGreen--so we've been involved since the beginning. But we'd be excited even if we weren't involved. The HPD is designed to provide a vital missing piece in the tools available for product transparency, and we haven't seen anything else that does the trick.

This tremendous engagement and collaboration between the design and manufacturing communities show that the industry is ready. Click here (PDF) for a sneak preview of the HPD (for a completely made-up product, of course!).

2012-03-15 n/a 10152 Gypsum Board: Are Our Walls Leaching Toxins?

By any name--drywall, wallboard, or plasterboard--gypsum products may not be as innocent as we once thought.

Drywall, which makes up 15% of demolition and construction waste, leaches toxins and releases hydrogen sulfide gas in landfills.

Virtually ubiquitous in our buildings, gypsum board is widely seen as an innocuous building material. However, in the last decade, Chinese drywall has been linked with indoor air quality problems, while concerns have cropped up around waste from coal power plants and its links to drywall.

Domestic manufacturers are quick to point out that gypsum board manufactured in the U.S. has not been linked to indoor air quality problems, but potential leaching of heavy metals and biocides included for mold resistance are among the issues that need to be addressed more thoroughly by the gypsum board industry.

Synthetic gypsum and mercury

Synthetic gypsum is created from a byproduct of flue-gas desulfurization (FGD), a process coal-fired power plants use to limit emissions. Although the chemical process that captures FGD gypsum is different from the physical collection of fly ash and bottom ash, which is more likely to pick up heavy metals as a matter of course, mercury and other heavy metals are showing up in synthetic gypsum--and, as a result, in our buildings.

In 2010, the U.S. Environmental Protection Agency (EPA) released a study of total content and leaching values of heavy metals in synthetic gypsum, which found that these chemicals could have leaching values of up to 550 times the level for safe drinking water. Total content, on the other hand, never exceeded a measurement of 100 ppm--a difficult feat considering that 100 ppm is the threshold for disclosure in the most rigorous green chemistry programs. Further, gypsum board commonly achieves indoor air quality certifications, such as Greenguard Children & Schools, suggesting that drywall is not a problem for indoor environmental concerns.

Gypsum becomes poisonous gas in the landfill

However, when drywall reaches landfills--and it does so in vast quantities, as it constitutes about 15% of all construction and demolition debris--it can leach these toxic chemicals into groundwater. And in the anaerobic conditions of landfills, bacteria convert gypsum into hydrogen sulfide, a poisonous gas.

Unfortunately, post-consumer gypsum board is commonly diverted from landfills to be used as a soil amendment in agricultural settings. If we have restrictions to prevent these toxic chemicals and heavy metals from being spewed into the air by power plants, is it really a good idea to add them straight into our soil?

Fungus among us vs. biocides on our insides

As if heavy metal content weren't enough, biocides are commonly used in mold-resistant products because paper-faced gypsum can develop mold if not installed properly. When gypsum is used as a soil amendment, moisture in the soil causes these toxic chemicals to leach into the earth as well.

Raising the standard for drywall

Fortunately, the industry is beginning to address these issues. Steps are being taken to develop an Environmental Product Declaration (EPD) for gypsum board (see "The Product Transparency Movement: Peeking Behind the Corporate Veil," EBN Jan. 2012). Although ULE's 2010 standard based on life-cycle analysis hasn't had the kind of adoption GreenSpec would like to see, many paths toward healthy building materials--and healthier gypsum board in particular--are being explored.

Buyers can use market pressure to encourage this shift--and avoid including toxic building materials in your building projects--by following these steps:

  • Choose domestic: Regulations in the U.S. maintain minimum safety standards for gypsum board, and domestic drywall has not (yet) been linked to the Chinese drywall debacle.
  • Avoid waste: Look for gypsum products with post-consumer recycled content, and avoid waste during drywall installation at the construction site. GreenSpec lists domestic manufacturers that have made strides in post-consumer content.
  • Avoid indoor air quality problems: Select Greenguard- or ULE-certified gypsum board to ensure a healthy interior. GreenSpec lists domestic manufacturers that are certified to indoor air quality standards.
  • Specify inert products: Wet paper-faced drywall is a perfect medium for mold growth, making any biocides included in drywall for mold prevention just a Band-Aid. If you're serious about mold prevention, particularly in settings or locations (like the first floor in a flood-prone area), specify non-paper-faced drywall, like the fiberglass-faced products listed in GreenSpec.

Keep your eyes open for new data in the drywall industry. Send us any tips you might have, and let us know your opinion in the comments below.

2012-03-14 n/a 10129 German Innovation in Solar Water Heating
With the SECUSOL drainback solar hot water system, the heat exchanger coil in the tank doubles as the drainback tank. Photo: Wagner & Company. Click on image to enlarge.
I was in Boston last week for the annual Building Energy conference, sponsored by the Northeast Sustainable Energy Association. Each year this conference provides an opportunity to connect with friends and colleagues, catch up on leading-edge building design, and learn about product innovations in energy conservation and renewable energy.

I was amazed to see the large number of European companies represented in the conference trade show, with most of the leading innovation in windows, biomass heating, and solar energy seeming to come from Germany.

The product that I found most exciting this year was a unique, drainback solar water heating system, SECUSOL, from the German company Wagner & Company, which is one of Germany's oldest, though not largest, manufacturers of solar water heating systems. Wagner products are represented in the U.S. by Wagner Solar, Inc., of Cambridge, Massachusetts. Before describing what makes the Wagner SECUSOL so exciting, a few words about solar thermal systems are warranted. Over the past few years, solar electricity (photovoltaics) has garnered most of the attention in the renewable energy world. But solar thermal systems, which can include both solar water heating and solar space heating, are often significantly more cost-effective.

Most solar water heaters include flat-plate collectors through which water or a water-glycol mixture is circulated. "Closed-loop" systems have the collector filled all the time, and a pump circulates the fluid from the collectors, where solar heat is absorbed, to the tank, where a heat-exchanger coil transfers that heat to the stored water.

Other systems have an open "drainback" loop. When the sun is shining and the controller tells the pump to turn on, the water or water-glycol solution is pumped through the collectors, and when the sun goes down at night (or power is lost), the fluid in the collectors drains back to a drainback tank. This drainback configuration has the advantage of preventing the collector fluid from getting too hot if the electric pump fails or electricity is lost.

The Wagner SECUSOL system is the latter type of solar water heater, but with several significant distinctions:

Drainback design without a separate tank

Most drainback systems have a separate tank that has to be plumbed into the system. In the SECUSOL system, an oversized heat-exchanger coil in the storage tank serves as the drainback tank--so one component serves two key functions.

Elegant housing

A single housing contains the well-insulated 66-gallon or 92-gallon storage tank, the controls, and the circulation pump (situated beneath the tank and accessible through a hatch). This configuration means that the single unit, which is not much bigger than a standard water heater, contains everything except the collector(s) and a back-up heating element.

Quick-mount fittings

The plumbing lines that circulate the glycol heat-transfer fluid through the collectors and heat exchanger coils in the tank are pre-insulated flexible copper, and they connect with compression fittings. This avoids the need for soldering, speeds installation, and reduces the risk of installer errors.
Wagner's flat-plate solar collectors are among the world's most efficient, with 96% transmissivity of the glass and a selective absorber surface. Photo: Wagner & Company. Click on image to enlarge.

Pre-programmed controls

The controls that tell the pump when to turn on and off come pre-programmed, speeding installation.

High-efficiency collectors

The Wagner EURO C20 AR-M flat-plate copper collectors are among the highest efficiency collectors available. They feature extremely high light transmissivity (96%), a selective coating on the absorber plate, and nearly 2-1/2 inches of mineral wool insulation in the back of the collector. They can be installed flush to the roof or on a racking system, which is also made by Wagner.

Back-up heating element

A second heat exchanger in the insulated tank allows a back-up electric heating element to be installed. In this way, the single tank can provide a family's entire water-heating needs. When solar energy is adequate, the electric element isn't needed, but when there isn't enough solar, the family has hot water.

Easy, rapid installation

The various innovations with Wagner's SECUSOL solar water heating system enable it to be installed rapidly and efficiently. A skilled installer can install two complete systems per day, according to Wagner Solar, which is remarkable. This helps keep the total cost down. Tyler Plante of Wagner Solar, Inc., in Cambridge, told me that systems are typically installed for between $7,500 and $8,000.

Wagner also produces some elegant solar space heating systems with packaged components and easy integration with conventional or pellet-fuel heating equipment. More about active solar space heating in a future blog.

Wagner Solar introduced Wagner products to the U.S. market in late 2010 and has installed slightly over 100 systems to date through the East Coast, but mostly in Massachusetts, according to Plante. The company is currently expanding its dealer network. Here's a link to the Wagner Solar listing in our GreenSpec database (requires log-in). This is one of the standout products among more than two dozen packaged solar thermal entries that we include in GreenSpec.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. To keep up with his latest articles and musings, you can sign up for his Twitter feed.

2012-03-13 n/a 10130 Eleek: Lighting That's Eco-Friendly Even When It's Off

Eleek strips miles out of its supply chain and carbon-intensive steps out of its manufacturing. That's good for the embodied energy of its cast aluminum luminaires and other hardware.

Wait a minute. Weren't we criticizing Eleek and its cast aluminum hardware in this blog a few weeks ago? We were--and that sparked a dialogue with one of our readers that led to more discussion with the company, in turn leading us to change our minds, and apologize to them for the rough treatment.

You might think we would have been in love with product lines with 100% post-consumer recycled content, and in a lot of cases (insulation, for example) we would be. In metals, however, high levels of recycling are the norm, and there isn't enough recycled aluminum stock to go around, so buying a recycled aluminum product may still stimulate demand for more mined aluminum. That led us to ask a while back if some recycled content claims should have an asterisk. Also in an energy-consuming product like lighting, the efficacy of the light source is arguably the most important sustainability metric, all other things being equal.

That leads us to Eleek--a company doing a lot to differentiate itself and its products from business-as-usual. First, its products: Eleek is making beautiful hardware with some processes that we think result in products with reduced embodied energy (tailor-made for meeting the 2030 Challenge for Products).

Its products are all made in Portland Oregon, and 80% of the supplies come from within 50 miles of the shop. Most notably, Eleek's Masa cabinet hardware line is made of 100% post-consumer scrap sourced from Portland's ReBuilding Center, a building materials reuse center located less than a mile from Eleek's shop. (See for more.) This means that aluminum scrap collected in the Portland area goes directly to Eleek's foundry to be melted into new products. That cuts out the thousands of miles that scrap normally travels to China and back and also cuts out the melting of scrap into pellet--the commodity that is normally sold to foundries like Eleek's for making products.

Eleek co-owner Sattie Clark emphasized to me that Eleek is primarily a lighting company, however, offering a variety of interior and exterior cast aluminum luminaires. Like the Masa line, these use aluminum scrap, often but not always from the ReBuilding Center. It wouldn't make sense to pair Eleek's luminaires and their reduced embodied energy with electricity-guzzling halogen or incandescent lamps, but with LED or fluorescent lamps, you'd have a winning combination.

Like many product manufacturers, Eleek has a website sporting a Sustainability page, but items they discuss there are unlike many other companies'. Eleek is a B Corporation--the 'B' is for 'benefit.' According to the B Lab website, B Corporations:

  1. Meet comprehensive and transparent social and environmental performance standards;
  2. meet higher legal accountability standards;
  3. and build business constituency for public policies that support sustainable business.

In contrast, conventional corporations are legally obliged to maximize value to shareholders, above all else. We tend to think that corporate transparency is good for the environment, and it's exciting to see a company that seems to be doing well with this ethic.

2012-03-13 n/a 10092 Tape It? Seal It? Glue It? Sealing Weather Barrier Seams

Lots of building products offer some help in keeping air, water, and heat in our buildings, but without attention to the joints, you lose critical continuity in your barriers.

NOTE: Read this whole series here.

To keep out the weather, don't head for the stickum first. Take a page from the lobsterman's book and use weatherlapping, overhangs, and mechanical fasteners. Photo: KGBKitchen on Flickr.

In just about every climate in which we live and build, the number one job of any building envelope or enclosure is environmental separation. Keeping water, air and heat in or out of buildings can make them more resource-efficient, durable, and safer for occupants.

The number-one difficulty or challenge in environmental separation is continuity of our air barriers, drainage planes, and insulation layers, particularly at penetrations, transitions and margins of building assemblies.

Many of us jump straight to adhesives, sealants, tapes and membranes to achieve barrier continuity, but there are strong reasons to employ three strategies: weatherlapping, mechanical fastening, and then selective, task-specific use of sealants and the like.

Basic Storm Gear: The Weatherlap

We need look no further than the storm gear of any fisherman to understand this strategy. From brimmed hat to boots, many overhangs, drip edges, and healthy, gravity-honoring overlaps shed bulk water down and away from the fisherman.

In buildings, weatherlaps are the foundation of bulk water barriers and should not be ignored. Many buildings suffer from lack of overhangs, poor flashing details, and similar issues. However, these fundamental protections may not be sufficient if the wind blows hard enough or the structure stands tall enough for even small wind pressure to push or suck water over weatherlaps against gravity. And managing both air and heat requires more than the weatherlap.

Reinforcement: Mechanical Fastening

When the weather gets nasty enough, the fisherman's weatherlaps may be reinforced with cinches, belts, and hook-and-loop fasteners. Secure all of these tightly enough, and physical sealing can achieve continuous or nearly continuous contact of one barrier element to the next, keeping water out even as the wind pulls and pushes at each overlap.

In buildings, we can pin down the exposed edges of our barriers with fasteners, gaskets, and rigid bars or cleats, rendering the overlaps physically sealed, or nearly so. On tall commercial buildings or very exposed low-rise residential buildings, mechanically fastening or "trapping" the exposed edges of our barriers should be routine.

The writer air seals sash pockets in his home after sash replacements.

Sealing the Deal with Chemistry

Sealants and adhesives (along with materials that make use of them, like tapes and membranes), rely upon surface chemistry to "stick" one material to another to make a barrier. Unlike weatherlapping and mechanical fastening, the quality of the bond or "stick" is dependent on the nature of the underlying materials, as well as the conditions of application: usually the ideal is clean, dry, and moderate in temperature.

We use an incredibly wide array of these materials to make our barriers continuous, but how do we know which ones to use and in what combinations with the various sheet goods that make up the fields of our barriers?

Defining the Options


Adhesives are chemical compounds whose sole purpose is to join two substrates--to be "sticky." Their performance is mostly related to the strength of the bond achieved between two substrates. Adhesives are strictly two-dimensional in function; they are not exposed.

Adhesives are classified according to how they cure--physical hardening, chemical curing, pressure-sensitive--and their chemistry--water-based, solvent-based, and two-part reactive. The ability of an adhesive to manage stresses--temperature range, application temperature, ultraviolet-light exposure, expansion/contraction, moisture (bulk water and vapor), and time--can be related to both curing and chemistry. The environmental profile of each adhesive can also relate to curing and chemistry.


These materials are meant to span gaps between two building components; they are formulated to adhere to the substrates on each side of the gap. They have lower strength than adhesives but greater elongation, or elasticity. Their primary function is to seal, to keep air and water out (or in). Their function is a three-dimensional one; they are very often exposed.

Sealants are classified as one-component, two-component, or sealant tape. They are also categorized by chemistry: acrylic, butyl, latex, polysulfide, polyurethane, and silicone. As with adhesives, the performance properties and environmental profile of a sealant is often tied to its chemistry.


Mastics are adhesive materials that do not "dry out" but instead remain pliable during their service life. They are generally a pretty heavy consistency, airtight, and waterproof. Mastics are typically troweled or smeared, making them a "flat," thin, three-dimensional application. Typical applications include HVAC ducting, roofing, and foundations.

Putties and caulks

These materials are strictly fillers, meant to span gaps but not provide air or water sealing. Many of us in the industry use the terms caulk and sealant interchangeably, but chemists and manufacturers like to make a distinction between filler materials and true sealants.

These definitions may seem basic and self-evident, but how many times have you seen a sealant being used as an adhesive, or the reverse? I can't tell you the number of flanged windows I have installed applying a bead of sealant to the backside of the flange, compressing the sealant to a flattened smear during installation--per the manufacturer's directions. Yet, this treatment eliminates any three-dimensional bead configuration of the sealant, treating it like an adhesive!

Stay tuned for Part 2 in this series: Matching Performance Properties to Application.

And for a head start on an enclosure system with appropriate--and continuous--weather-resistive materials, GreenSpec's guidance on weather-resistive barriers is a great place to start.

2012-03-06 n/a 10064 A Tale of Two Material Safety Data Sheets (MSDS)

Not all MSDSes are created equal. Because what they are required to report is minimal, manufacturers take very different approaches to how much they disclose.

Looking for better information on chemicals of concern? An MSDS can be a good place to look. Then again, it can be a really bad place to look. Click for a PDF of the full non-information. (We took out the company name; they DID include that much!)

One of the first tools we use in product evaluations are Material Safety Data Sheets (MSDSes, or MSD Sheets). These data sheets, required by the U.S. Occupational Safety and Health Administration (OSHA) for all products, are designed to address occupational safety and provide a bare-bones assessment of the chemical hazards in a product. The problem is that what manufacturers are required to report is minimal, so disclosure levels are all over the map.

If you're looking for useful information to distinguish the health and safety of different products, the lack of data can be so frustrating as to be almost comical.

It was one of these comically useless MSDSes that prompted this post. GreenSpec products editor Brent Ehrlich emailed me with an MSDS attached, saying, "I was curious about [Name withheld]'s claims, so I decided to check out the MSDS. It's a beautiful piece of non-information. Poetic in its near complete absence of substance."

This got us on a roll with the good, bad, and ugly of MSDSes.

The Good: Full Disclosure

This MSDS for Gorilla Wood Glue (PDF) is short, to the point, and includes the full list of ingredients in the product and how much of each is in there.

This is all too rare--and that's part of the impetus behind one branch of the transparency movement we've talked so much about lately--including things like International Living Future Institute's "Declare" label and the Health Product Declaration.

The Bad: No Disclosure

Well, the aforementioned MSDS (pdf) really takes the prize. There is no information in it whatsoever, other than that the legal requirements for an MSDS don't give one much to go on. All we know here is that there are no reportable hazards at reportable levels, but whether or not there is anything that is an emerging concern, or lower levels of a hazard, cannot be determined.

A better contrast to the Gorilla Wood Glue MSDS, though, would be something in the same category, like the MSDS for Titebond's Original Wood Glue (PDF). Titebond provides no ingredient information: they don't have to, because there are again no reportable hazards at reportable levels. There is some indication from section 15 on the MSDS that there are hazards in the product--including at least one Proposition 65 chemical (a chemical that prompts a mandatory health warning in California), but these ingredients apparently haven't reached an amount requiring Titebond to tell us what they are.

The Ugly: Interpreting what you get

Here's the interpretation game we play. Lets first pretend that these products are otherwise equal, and that we're just trying to determine which is safer. Which do we choose?

Step 1: Who is hiding less?

We have one MSDS that doesn't disclose any ingredients, but has some warning indications that imply hazards are present, if below reportable levels. We have another MSDS that spells out all ingredients, with a list that includes known carcinogens and other hazards, but these are all far below reportable levels.

The MSDS rules only require a carcinogen to be disclosed if it makes up 0.1% (1,000 ppm) or more of the product by weight, and another health hazard to be disclosed if it makes up 1% (10,000 ppm). In contrast, the most rigorous system in use in the USA, the EPA's Design for Environment program, requires reporting of all intentionally added ingredients plus known residuals (trace amounts of chemicals impurities) down to 0.01%, or 100 ppm.

Here's the ugly part: In the MSDS with better disclosure, all of the listed hazards are below 100 ppm. The non-disclosing MSDS could have up to 999 ppm formaldehyde, for example, but the company just didn't not bother to tell us. If this were all I had to go on, I'd use the product with better disclosure because it's hiding less.

Step 2: Add your own chemical screening

Lets take a second look, using the Pharos Chemical and Material Library (member link), an easy way for non-chemists and non-toxicologists (i.e. most of us) to assess which chemicals are known hazards. That's where we find the hazards listed on the MSDS with better disclosure. A bunch of the main ingredients are listed in Pharos with no hazard info; that means they aren't on any of the exhaustive set of hazard lists that Pharos keeps track of.

Does that mean they're safe?

Not necessarily--it could mean they're simply less-known, less-tested chemicals, but it's still a good first step. Some of the other ingredients have an NJTS number, and these aren't listed in Pharos either. NJTS stands for "New Jersey Trade Secret" and is one of a variety of terms and lists used when an ingredient isn't disclosed because it's a trade secret. OSHA has a bunch of rules about when that is or isn't allowed, along with requirements on how the hazards of trade secrets should be disclosed.

Step 3: Demand better information

One possible next step would be to harass Titebond for more detailed information (something GreenSpec does on a regular basis--and which gets increasingly effective the more times they get asked, and the bigger the customers and projects demanding that info).

You could also harass Gorilla Glue for more proof of the hazardous or nonhazardous properties of trade secret ingredients. It's worth a try, and the more we all try, the more luck we'll eventually have (or manufacturers will just get tired of it and fill out a comprehensive Health Product Declaration).

So which product do you choose?

Let's say you didn't have any luck getting more info, so you're back to basing your decision on these two MSDSes (or trying to find an alternate manufacturer who will give you more info). Again, the one without disclosure could contain the same hazards at much higher amounts, so, somewhat counterintuitively, I'd go with the one that tells me what to watch out for.

It is of course rare that two products are exactly equal other than the MSDS. There may be cost or performance differences you are familiar with or myriad other concerns.

For reasons that don't have much to do with the MSDS, we haven't accepted either of these products into GreenSpec. Before even looking for what is in a product, the GreenSpec team typically checks for what is emitted from the product. With adhesives, whether flooring adhesives or general construction adhesives, GreenSpec looks first for products that both have low VOC content and are certified to California Section 01350 or other more stringent emission protocols.

Then we start looking for products that take the next step with greater transparency on ingredients and minimization of hazards. I could go on ad nauseum about the challenges with emissions testing, particularly for wet-applied products, and how we're making the best of the info we have, and where a better understanding of performance might change our assessment method further--but that's a topic for another post.

The main point of all this back-and-forth is to make it clear that at the end of the day, what you see on an MSDS is not necessarily what you get. It's worth understanding the ramifications of what you don't see, particularly when comparing products with more and less disclosure.

2012-02-29 n/a 9963 Cost-Effective Window Attachments: A Practical Guide

With so many types of window treatments available, including awnings, shades, storms, and shutters, it's hard to know which one is right. GreenSpec can help.

Awnings are a traditional way to control solar heat gain in the American South. Blocking gain is more effective than dealing with the heat after it comes into the building. However, awnings aren't the best product for every window in every climate.

Most window attachments are chosen with aesthetics in mind--probably in part because picking the right awnings, shades, shutters and other attachments for their performance characteristics hasn't been simple in the past.

In collaboration with BuildingGreen, publishers of GreenSpec, Lawrence Berkeley National Lab (LBNL) has been doing modeling, field-testing, and lab testing to develop standards for window treatment performance. Different types have different strengths, including glare control, thermal performance, and even security, so choosing a particular window attachment depends on your priorities. While performance is likely to be the foremost concern for most people, some products use materials with environmental health and safety concerns.

With the exception of window film, there is no performance standard to measure window attachments, so we eagerly await the results of LBNL's work. In the meantime, we've handpicked a number of manufacturers and products to list in GreenSpec that we consider best-in-class. In selecting these listings we looked for companies emphasizing strong performance and offering solid performance information (including some companies collaborating with LBNL), and companies with well-thought-out, innovative, and well-detailed products.

Read on to learn more about how to choose products that won't harm you or the environment.


The main advantage of awnings is that they block the light before it comes through the window, preventing glare, heat gain, and damage from UV-rays, while fully maintaining the view to the exterior. Keeping direct sunlight off your windows keeps solar heat gain out--which is a more effective strategy than trying to keep the solar heat after it has hit or entered the window. For times when you want the sun's heat, retractable awnings are available.

GreenSpec lists four awnings product lines. Awnings can cost several times as much as other window treatment options, so keep that in mind when shopping around.

It is common practice to treat exterior fabrics with fluorocarbon-based coatings for durability. Fluorocarbons are considered potentially hazardous to the environment and human health, so GreenSpec encourages both consumers and manufacturers to look for alternatives.

Exterior Sun Control Devices

Exterior roller shades, roller shutters, and solar screens are other options that block direct sunlight before it enters your home.

Roller shades are opaque or translucent, and when rolled down do not afford a direct view of the exterior. They are also commonly treated with PVC coatings, and GreenSpec encourages the market to find alternatives. Roller shutters provide lighting conditions closer to blackout and can also provide security and hurricane-resistance.

Solar screens are panels or roller shades and are designed with openness factors to allow direct views, even while covering the window. As with awnings, thermal performance primarily comes from preventing direct sunlight from entering through the window. Based on strong performance, innovation, and other factors, GreenSpec chose 23 products to list here.

Exterior Storms

Low-e, airtight storm windows provide a significant layer of thermal performance on the exterior of the window. They also afford direct views to the outside. Most exterior storm manufacturers use metal frames, although PVC frames with superior thermal performance are available.

In both cases, GreenSpec has concerns about the product composition--aluminum because of energy intensity, PVC because of life-cycle health and environmental concerns--but reducing energy use and good performance is the trump card. With that in mind we list six exterior storm products with good detailing and low-e coatings that can help bring an entire window up to near-high-performance levels.

Interior Window Panels

Interior window panels, like exterior storm windows, contribute to thermal performance and air tightness. Sometimes called "interior storm windows," these usually have frames made of aluminum, although magnetic strips and PVC frames are available. While some options can be moved up and down, many are fixed in place and limit window egress. Do not use these options in fire escape locations.

GreenSpec lists eight companies here, all of which pay attention to airtightness and usability.

Window Film

Surface-applied films and seasonal flexible film kits provide reduced solar heat gain and increase the thermal performance of windows. Seasonal flexible film kits are primarily used to reduce convective and conductive heat loss through windows. For seasonal kits, aesthetics and short service life are downsides, though ease of installation and relatively low cost are upsides.

Surface-applied films, primarily used to reduce solar heat gain, can be compared using NFRC ratings, and from among these GreenSpec chose seven to list.

Interior Window Treatments

Blinds, curtains, drapes, shades, and quilts offer some thermal insulation, glare control, and solar heat gain control, although direct sunlight comes through the window before hitting the shade. Cellular shades, offering superior thermal performance, and interior solar screens, featuring PVC-free fabric since durability is less of a concern on the interior of the window, are both attractive options.

With an emphasis on strong thermal performance data--when we could find it--GreenSpec lists 20 products in this area, including products such as light shelves that extend the reach of daylight to the interior.

Window Restoration

Our approach in creating this guidance has been to try to answer the question, "How can we make our windows work better?" In many cases, window restoration should be among your first choices. Proper truing and gasketing can drastically improve airtightness and make windows easier to open. Lead paint management is important to consider in the case of older windows. GreenSpec chose five reputable window restoration firms to list.

So...What's Your Answer?

The proper choice for window attachments varies from case to case--there is no one-size-fits-all answer.

Depending on the problems you face, your financial constraints (keep in mind that springing for a pricier window attachment may come with a quicker return on investment), and your design preferences, each option has its own benefits and drawbacks. For a more detailed exploration into each of these areas, as well as some representative listings, please see the appropriate GreenSpec section.

Comprehensive guidance is also available in our EBN feature article, "Making Windows Work Better." (As with most of our feature articles, BuildingGreen members can get continuing education credits for reading it and taking a short quiz.)

2012-02-22 n/a 9961 Making Renewable Energy Work Better: "Swarm Power" Cogeneration

There's a lot of talk about how renewable energy like solar and wind can't ramp up to meet our energy needs. What we need are creative solutions to that challenge, like distributed cogeneration.

This image is a screen shot from a LichtBlick video demonstrating how distributed cogeneration can take up the slack when wind and solar energy sources are not producing power.

I just got off the phone with Ralph Kampwirth, at LichtBlick in Germany, who told me about a system his company now has up and running to provide power to the grid exactly when it's most needed, while at the same time providing cheaper heat and hot water to German homes.

While we don't like to tease our readers too much with products you just can't get here, sometimes it's heartening to see what's possible if creative minds, engineering, and policy come together. This is the case with LichtBlick's EcoBlue CHP system.

Free, grid-tied heat and power

EcoBlue natural-gas-powered combined heat and power (CHP) cogeneration plants were developed through a partnership between Volkswagen and LichtBlick, and are produced by Volkswagen exclusively for LichtBlick. LichtBlick installs the units in homes, where they provide 100% of heat and hot water while supplying power to the grid. LichtBlick maintains ownership of the system, takes care of all of the maintenance, and controls each unit's operation wirelessly from a central location.

GreenSpec has long looked at cogeneration (CHP) systems that work at the single-building scale because the efficiency benefits from using the heat generated from power production are dramatic; Volkswagen estimates the EcoBlue provides 40% energy savings over conventional, separate, heat and power production.

However, most of these systems are designed to operate whenever there is a need for heat, with electricity either used locally or returned to the grid when it's produced. LichtBlick's "SchwarmStrom" or "Swarm Power" plan reverses that. According to Kampwirth, "It's easy to store heat and expensive to store electricity, so we run the CHP system when electricity is needed and store heat in water."

Cogeneration for demand-response

LitchBlick runs each unit for the number of hours needed to ensure the hot water storage system can provide 100% of heat and hot water needs. That's the way most building-scale CHP systems operate.

What's different is that the LitchBlick central office uses wireless control to time each unit's operation for the hours when they anticipate the highest demand (and highest price) on the electricity market. The market price on the German electricity exchange varies every 15 minutes. Right now, LitchBlick interprets the pricing data from one day to assess when to operate each unit the next day, which works pretty well, although according to Kampwirth, they're already looking into systems that will allow more real-time control.

Scaling cogeneration to the megawatt level

It's this approach that makes LitchBlick's model a breakthrough for increasing the percentage of renewable energy in the grid: it makes for a scalable, distributed power supply that can provide for peak power needs and balance the irregularly generated power provided by renewable energy systems like solar and wind. This works much the same way that we hope the smart grid will eventually work with demand-response in the U.S.

LitchBlick's goal is to ultimately install 100,000 units in Germany, which according to LitchBlick would produce 2,000 MW of electricity--what LitchBlick describes as the capacity of two nuclear power plants. Right now LitchBlick has 400 units installed, and is installing 10 more every week.

Why not here?

So why can't we get this in North America? In Germany, new renewable energy generators are encouraged. According to Kampwirth, electrical network providers are required to accept their electricity, and EcoBlue also gets a government subsidy for power produced. Also, the market price of electricity is generally higher than in the U.S., so this kind of innovation makes sense for an entrepreneurial green energy company like LitchBlick.

I look forward to the day when we see more of this kind of creativity made in America. This is only likely to happen if we establish policies to encourage it.

See this brief video on how the EcoBlue "Swarm Power" system works.

2012-02-22 n/a 9919 Dual-Flush Toilets Shouldn't Be a Crapshoot

Which flush is which? Dual-flush fixtures should be better at making it obvious.

Editor's note: Thanks to Evan Dick for this guest post. Evan is a former writer from BuildingGreen and now works at the Center for EcoTechnology in Massachusetts.

The adage "If it's yellow let it mellow, if it's brown flush it down" might be an acceptable water-saving solution in some households, but certainly doesn't meet our expectations for cleanliness in more public throne rooms. Enter the dual-flush toilet, invented in 1980 by Bruce Thompson, an Australian working for bathroom products company Caroma. Dual-flush toilets have a full-flush option for solids and a partial-flush option for liquids. Each flush represents a measured and appropriate response to the waste-removal needs of the moment.

Unfortunately, flush controls on some models make it difficult to know which flush is which. Most of these toilets are in more public facilities, and getting busy, distracted people to understand and use the green design features we implement is a tricky problem, as we discussed in our recent feature on occupant engagement.

Confusing instructions

I used to get regular treatments from a Community Acupuncture Clinic in Tucson, Arizona.  Not wanting to be distracted during my treatment, I almost always used their restroom. The toilet was equipped with a perplexing dual-flush handle, and no instructions except a circle split down the middle, with one semicircle fully filled in and the other semicircle halfway filled in. This circle was located at the pivot point of the handle.

I was never sure which flush I was choosing.  Other models I have seen come with arrows or with stickers that can be placed on the tank to add further instruction.

Another type of lever uses a dual-action approach, where the main lever has a smaller lever within it that moves separately. The small lever moves independently for the half flush, and the large lever activates the full flush. However, because moving the large lever will also move the small lever, users can also find this confusing.

Pushing my buttons

While levers are common for dual-flush conversion kits, new dual-flush toilets are usually equipped with a push-button system. While these shiny chrome circles divided into two buttons look nice, they too fail the clarity-of-use test.

One side is usually larger than the other, representing the larger flush, but the size difference is slight enough that further instruction is often required. Some systems use equal-sized buttons with decals identifying which side is which. This is adequate, but could be problematic if the decals come off and are not replaced.

The most straightforward button system consists of two separate buttons, each manufactured with a full or half-full circle to direct the user. 

Potty training needed?

Maybe other folks are better potty-trained than I am, but an informal office survey found that other BuildingGreen employees had experienced similar confusion, with both the handle- and the button-controlled varieties.

The handles and buttons used for dual-flush toilets do important work and save water. That water savings should not be compromised by confusing design. If you have one of these toilets, simply adding an instructional sign, or making sure that markings on the controls are clear and well maintained should be enough to direct users to the right flush.

Looking for guidance on the most efficient dual-flush and regular-flush toilets? GreenSpec's listings of commercial toilets go a step beyond minimum federal standards, both in water efficiency and flushing performance.

2012-02-16 n/a 9918 Scraping the Surface of Exterior Paint Prep

For wood siding, preparing the surface is as important as the paint itself. Here are some factors to look for, or fix, to help that next paint job last.

Premature paint failure is often caused by poor preparation.
Even before you choose an exterior paint product, it's important to learn a bit about what makes paint stick--or not. For background I sought out a few paint prep tips from an expert, Bob Cusumano, president of Coating Consultants and past president and current technical director of Painting and Decorating Contractors of America.

Get the lead out

According to Cusumano, "You first have to consider whether or not there is a previous coat of lead paint." If you have a house that was painted before 1978, there is a good chance that there's lead in the paint.
Lead can cause serious neurological and other health issues, especially in the young, but "a lot of architects don't understand the implications of lead regarding cost and the required steps in the preparation process," he says. If there is lead paint present, there are significant environmental and legal ramifications, and up to three times as much cost.
Lead removal is a complicated issue, so look for more information from us in the future, and from EPA's guidelines. For now, let's assume there is no lead.

Some prime considerations for old clapboards

What is the integrity of the wood surface? Wood with rot caused by exposure to moisture, the sun's ultraviolet (UV) rays, pollution, or other factors will not hold paint well and will need to be cleaned, repaired using an epoxy filler, or replaced.
In some cases there, might even be rot lurking underneath reasonably sound paint. Cusumano recommends probing the surface of the wood with a small sharp knife. It will sink in if there is rot underneath, and the paint won't last long.
But before replacing the wood and repainting you should figure out what caused the damage. Problems such as poor flashing that allow moisture in behind the clapboards should be fixed or you'll run into even larger problems down the road. Mold or mildew need to be cleaned off, too, and the area thoroughly cleaned. If not properly treated, the fungi will just grow back through the paint, and if not properly rinsed, the paint will blister off.
  • How well are the existing coats adhering? "Every coat of paint you apply over what is already there applies more weight and stress," said Cusumano. Adhesion tests will determine if the coatings are going to hold. If the paint is ok, then you can go over the top. If not, the paint has to be removed, hopefully through simple scraping. An adhesion test, where a paint is applied, allowed to cure, and t