Sonya Newenhouse practices what she preaches; She founded Madison Environmental, a green consulting firm, and now is putting her name to use by building and selling the NewenHouse, described as "superinsulated, sustainable, small kit homes that are furnace free, even in cold climates." The first NewenHouse was built a few years ago and was certified Passivhaus, German style in 2011.
Tafline Laylin of Inhabitat toured the house recently and did a slideshow; it's nice to see so many interior shots of what looks like a very comfortable home. It should be, sitting in a tub of 12" of expanded polystyrene foam below grade and surrounded by 16" of cellulose insulation above.
Like so many Passivhaus designs, it is simple and boxy. As one reviewer noted, "There are many reasons for this. First, the “cube” nature maximizes the ratio of volume to surface area, creating the most space per square foot of wall (where heat is transferred.) Second, it maximizes construction efficiency, few corners means fewer dollars." It also has the classic big windows facing south to maximize passive solar gain. The polished concrete floor provides the thermal mass to store that heat after the sun goes down.
Unlike many Passivhaus designs, it's quite small at 1100 square feet for three people. Sonya told Mother Earth Living: . "More space means more stuff, and I’m trying so hard to simplify my life."
Newenhouse had planned on selling the NewenHouse in kit form in three sizes starting at 600 square feet and up to 1000 square feet, emphasizing that these are half the size of most new American homes. Because Passivhaus limits the energy use per square foot, it's actually harder to build small. However Sonya tells Inhabitat that "it’s a no-brainer that a smaller house uses less energy.” She says she is " trying to bring together three movements: the green building movement, the small house movement and the sustainable- or simple-living movement."
Passivhaus is all about energy (hence the teensy windows on the sides) , but there is a lot more going on here, including the use of healthy materials, sustainably harvested wood, rainwater collection, salvaged materials and clever storage, all for about $175 per square foot.. That's impressive.
Some specs from Passive House consultant Carly Coulson:
Space heating demand: 11.4 kWh/m²a (3.61 kBTU/ft²a)
Primary energy demand: 104 kWh/m²a (32.9 kBTU/ft²a)
Blower door: 0.51 ach50
Wall U-factor: 0.09 W/m²K (R-63)
Slab U-factor: 0.10 W/m²K (R-57)
Roof U-factor: 0.06 W/m²K (R-94)