This article is only available to GBA Prime Members Start Free Trial Already a member? Log in A few weeks ago, my wife and I went on a short hike with our college-age son. As the three of us drove to the trailhead in Norwich, Vermont, we passed a construction site. “Looks like a zero-energy house,” I observed. The sign out front read, “Prudent Living Homes.” I decided to get more information on the house and return later to try to talk with the builder.I called up Prudent Living Homes, and the owner of the company, Paul Biebel, agreed to meet me at the site. When I showed up a few days later, two carpenters, Gary Castellini and Maynard White, were working on exterior details.The house in Norwich is a custom three-bedroom home measuring 2,500 square feet. The home’s 13-kW photovoltaic (PV) array should produce enough electricity on an annual basis to more than meet the home’s electrical needs.The foundation consists of perimeter stemwalls surrounding a slab on grade. (The design originally called for a basement; however, once the excavator started digging the foundation hole, a natural spring bubbled up — one that no amount of drainage pipe was likely to defeat. The team decided to switch gears and build on a slab.) Insulated concrete forms (ICFs) from Nudura were used for the stemwalls; additional rigid foam installed on the exterior side of the ICFs increased the R-value of the walls to R-22. A 4-inch-thick horizontal layer XPS (rated at R-20) was installed under the slab. (See Image #2 at the bottom of the page.)The R-45 double-stud walls are 12 inches thick, and are insulated with dense-packed cellulose. (See Images #3 and #6 at the bottom of the page.) The roof is insulated to R-60.Paul Biebel, owner of Prudent Living Homes in Windsor, Vermont, has been building homes since 1976. “I’ve… Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.