Sonya Newenhouse, the founder of the green consulting company, Madison Environmental, is putting theory into practice through building the so-called NewenHouse, which is a prefab sustainable, passive house. The home is also Passivhaus certified. According to her, the house is superinsulated, furnace-free and functions well even in cold climates.

Sonya’s NewenHouse was built Wisconsin, and it measures a modest 1100 square feet, which is still enough to house her family of three. It is shaped like a cube, and while most of the windows are tiny, it does also have several large ones that face south to maximize the passive solar gain of the home. The home rests on a foundation made up of a 7” monolithic slab, which is placed inside a 12” thick pan of expanded polystyrene foam insulation. The flooring is made of polished concrete floor, which gives enough thermal mass to store the heat. The walls are insulted with 16″ cellulose insulation.

In building the home, only sustainably harvested wood and salvaged materials were used. The home also features a 1200-gallon water collection tank on the roof, which will provide water for the garden. All told, the home cost $175 per square foot to build, which is modest indeed.




The space heating demand of this passive house is 3.61 kBTU/ft²a, while its primary energy demand is 32.9 kBTU/ft²a. The walls are insulated to a rating of R63, the slab has a rating of R57 and the roof has a rating of R94.

Sonya plans to begin selling the NewenHouse plans as kits in three sizes, ranging from 600 square feet to 1000 square feet. These are pretty small homes, and, since Passivhaus limits the energy use per square foot, it’s actually harder to make them small. But for Sonya, living sustainably is about downsizing too, which is one of the main reasons the NewenHouse kits are smaller than they could be.