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Can This Man Reinvent Concrete?

Posted March 26, 2014 5:06 PM by Alex Wilson
Related Categories: Energy Solutions, GreenSpec Insights

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.

Our Green Home Cost a Lot, But Yours Doesn't Have To

Posted March 19, 2014 11:51 AM by Alex Wilson
Related Categories: Energy Solutions, GreenSpec Insights

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.)

Safe, All-Electric "Induction" Cooking: Try This At Home

Posted March 12, 2014 12:14 PM by Alex Wilson
Related Categories: Energy Solutions, GreenSpec Insights

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.

Heat Pump Water Heaters in Cold Climates: Pros and Cons

Posted March 5, 2014 11:41 PM by Alex Wilson
Related Categories: Energy Solutions, GreenSpec Insights

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.

Picking a Water Heater: Solar vs. Electric or Gas Is Just the Beginning

Posted February 26, 2014 5:31 PM by Alex Wilson
Related Categories: Energy Solutions, GreenSpec Insights

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?

When Weatherizing Increases Radon

Posted February 24, 2014 10:50 AM by Peter Yost
Related Categories: BuildingGreen's Top Stories

Air sealing and other energy retrofits in our homes can raise or lower radon levels. The only way to know is to test.

This blog post first appeared on GreenBuildingAdvisor.com.

Will this be on the test? With radon, the correct answer is always Yes. Photo: National Institutes of Health. Image is in the public domain.We are always trying to avoid unintended consequences of our best efforts to improve home performance. A good example of this is radon gas and air tightness levels in homes during energy retrofits. How are the two levels related, and what can we do about it?

Airtightness and radon levels

There are five main factors that drive radon levels in homes:

Insulated Vinyl Siding: Worth the Extra Cost?

Posted February 20, 2014 1:50 PM by Peter Yost
Related Categories: BuildingGreen's Top Stories, GreenSpec Insights

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

A weather-resistive barrier combined with insulated vinyl siding had some visible, qualititative results on thermal performance in a new industry study. Image: Vinyl Siding Institute.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:

Commissioning Our Home's Heat-Recovery Ventilator

Posted February 18, 2014 7:08 PM by Alex Wilson
Related Categories: Energy Solutions, GreenSpec Insights

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.

4 Resources Help Draw the Shades on Poor Window Performance

Posted February 15, 2014 1:53 PM by Peter Yost
Related Categories: BuildingGreen's Top Stories, GreenSpec Insights

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.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.

How We Chose Our Heat-Recovery Ventilator

Posted February 12, 2014 11:06 PM by Alex Wilson
Related Categories: Energy Solutions, GreenSpec Insights

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.

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