The most recent blogs at Green Building Advisor

Making Healthier, Greener Foam Insulation

Posted on January 10, 2013 by Alex Wilson in Energy Solutions

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 (XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation.) 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.

An Innovative Net-Zero Solar Decathlon House

Posted on January 9, 2013 by Allison A. Bailes III, PhD in Building Science

Twelve years ago, I discovered the Solar Decathlon. I was a new physics professor at a small university in Georgia, and I'd received a packet from the US Department of Energy describing the competition. It was set to have its first run in 2002, so I tried to figure out how to get involved and put together an entry. We didn't have design or construction programs, however, and the physics department that I was in was one of the most dysfunctional groups of people the world has ever seen.

Insulating Window Shades

Posted on January 8, 2013 by Marc Rosenbaum in Guest Blogs

One of the technologies I have tried in my house is an insulating window shade with side tracks. I got four Ecosmart cellular shades from Gordon Clements at Gordon's Window Decor. One is translucent, and the other three are blackout shades, achieving that by using aluminum foil inside the cells. Because the foil is reflective to radiant heat transfer, these shades have a higher insulating value than the translucent version.

Nostalgia for the Hippie Building Heyday

Posted on January 4, 2013 by Martin Holladay in Musings of an Energy Nerd

A discredited theory of embryonic development held that “ontogeny recapitulates phylogeny” — in other words, that the the developmental stages of an embryo (its ontogeny) mimic the stages of evolutionary development experienced by the species (its phylogeny). One piece of evidence supporting the theory: in early stages of development, a human embryo has a tail.

What I’m Hoping for in the New Year

Posted on January 3, 2013 by Alex Wilson in Energy Solutions

With snow gently falling as the holiday season winds down, I find myself reflecting on the New Year and what we might hope for. World peace of course, and solving the poverty conundrum would be great.

But what about energy and the environment? Here are some thoughts:

A UL-Listed Carbon Monoxide Alarm May Not Protect You

Posted on January 2, 2013 by Allison A. Bailes III, PhD in Building Science

Don't judge a book by its cover? That certainly applies to what may be the best protection against carbon monoxide poisoning you can buy. The two best carbon monoxide monitors, the CO Experts monitor and the NSI 3000 from the National Comfort Institute, don't have the approval from Underwriters Laboratories (UL) that so many manufacturers crave. There's a good reason for that.

Passive House Certification: Looking Under the Hood

Posted on January 1, 2013 by Roger Normand in Guest Blogs

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the 20th article in a series that will follow their project from planning through construction.]

What’s Happening to All the Green Building Programs?

Posted on December 31, 2012 by Carl Seville in Green Building Curmudgeon

Green home certification programs are starting to reach a level of maturity. At the national level, LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. has established itself as the national industry leader, at least from a branding standpoint. NAHB’s National Green Building Standard (NGBSNational Green Building Standard Based on the NAHB Model Green Home Building Guidelines and passed through ANSI. This standard can be applied to both new homes, remodeling projects, and additions. ) has a growing following but, in my opinion, is still struggling to gain broad industry acceptance.

Framing and Air-Sealing Tips for High-Performance Walls

Posted on December 28, 2012 by Martin Holladay in Green Building Blog

In three new videos produced by Oregon builder Hammer & Hand, lead carpenter Val Darrah explains how he keeps air sealing in mind as he frames the walls for his current project, the Pumpkin Ridge Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates..

Val explains why he prefers to use a router rather than a saw when he cuts out window openings in the OSB sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. . He also shares his method of building window bucks out of 3/4-inch plywood.

Heat Loss from Air Is No Big Deal, Right?

Posted on December 27, 2012 by Erik North in Guest Blogs

No, it’s a huge deal. The photo (right) is of air streaming through recessed lights in a cathedral ceiling.

I often and exhaustively speak about air sealing as if it were a universal good. And it is, right up there with brown ale and Avengers movies. My audit customers often look confused when I address their insulation questions by bringing up air barriers and air leakage. I mean, “Why are you talking about air leaks when I asked about the insulation?”

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