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.

Few others are thinking about energy audits and weatherization, but now’s a good time.

Weatherization should target the biggest air leakage sites.
Image Credit: U.S. Department of Energy

Wait a second. Spring has barely sprung, and you’re saying we need to start thinking about energy audits already? What’s up with that?

There are several reasons why now is a good time not only to focus on energy auditing and weatherization—not only for your clients, but also for your own home.

Weatherization professionals have some time

Because spring is a time when few homeowners are thinking about heating bills and how to bring them down, it’s a good time to find energy-performance contractors who can do that weatherization work.

Those energy-performance contractors who do general construction work may be gearing up for the summer building season, but for those limited to energy audits and weatherization, now is a good time.

Panelized construction, meticulous attention to energy detailing, and a sophisticated computer design system put Unity Homes at the cutting edge of home buiding.

A Unity Homes wall section at the company's Walpole, NH factory. Click to enlarge.
Photo Credit: Alex Wilson

In my blog last week, I provided a little background on Tedd Benson and his evolution that led him to found Unity Homes. This week, I’ll describe some of the features that set Unity Homes apart from both standard home construction and other panelized and manufactured home production.

An emphasis on energy performance

A top priority for Unity Homes is energy performance. The homes have R-35 walls and roofs that vary from R-38 to R-48—depending on the roof spans. (Longer spans require deeper rafters (made from engineered I-joists) with room for more insulation.)

Unity’s R-35 wall does better than some nominally rated R-35 walls, because thermal bridging through the framing is minimized. The wall system uses 9.5-inch-deep I-studs, so there isn’t a lot of higher-conductivity wood.

Tedd Benson's latest initiative to reinvent home building—with lower-cost panelized construction

Wall panels being fabricated at Unity Homes' Walpole, New Hampshire factory. Click to enlarge.
Photo Credit: Alex Wilson

A few weeks ago I spent a half day with my good friend Tedd Benson learning about his new company Unity Homes. Yhis Walpole, New Hampshire company is on the cutting edge of home building today, with its focus on energy performance, building science, green building, and (relative) affordability.

This week I’ll describe some of Tedd’s work that led to the creation of Unity Homes, and next week I’ll go into more detail about this new company and the state-of-the-art green homes he and his team are cranking out.

For those not familiar with Tedd, he is responsible—more than anyone—for the emergence of the modern timber framing movement some four decades ago. Initially to save money, Tedd and his brother Steve used timbers salvaged from old barns in 1973 to build a workshop in Alstead, New Hampshire for the fledgling Benson Woodworking Company that they had launched a year earlier. (Steve died tragically in a car accident in 1974, and Tedd and his wife Christine continued the business.)

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.

Växjö, Sweden embraced the U.N's Agenda 21 and is now a model of sustainability

Växjö Energi AB's wood-chip-fired CHP plant. My host is standing in front of a large steam turbine. Click to enlarge.
Photo Credit: Alex Wilson

My blog last week about Kansas and efforts to outlaw any mention or promotion of sustainability was so depressing (to write as well read) that I needed to find a more uplifting sequel. I needed to remind myself—and readers—that even if some politicians in Kansas don’t want to make the world a better place for their children and grandchildren, that’s not a universal attitude.

There are lots of towns, cities, and countries around the world where planning for the future is a priority and whose sustainability stories are truly inspirational.

I’ll report here on one of those places: Växjö, Sweden (the approximate pronunciation is “VECK’ shuh”), which is often called Europe’s greenest city. Five years ago I had the good fortune to spend a few days in this municipality of 85,000, with an urban core of 60,000.

Fear of Agenda 21 fuels a bill to ban sustainability planning in the state of Kansas

The Konza Prairie in northeastern Kansas.
Photo Credit: Bill Johnson

I love many things about Kansas—from the tall-grass prairies in the Flint Hills where I’ve hiked through rolling hills overlooking grazing bison to the dramatic waterfowl migrations in the Cheyenne Bottoms region in the western part of the state. But a bill currently in committee in the Kansas Legislature makes me wonder whether these natural treasures will be around for future generations to enjoy. Reading about this legislation simply left my jaw agape. At issue is whether the Kansas legislature should outlaw anything that even remotely encourages sustainability planning.

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.

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.

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.