A recent New York Times piece explains the secrets of a passive house:
A so-called passive home like the one the Landaus are now building is so purposefully designed and built — from its orientation toward the sun and superthick insulation to its algorithmic design and virtually unbroken air envelope — that it requires minimal heating, even in chilly New England.
Where possible, passive construction maximizes window and facade exposures toward the southern sun. Thick walls and abundant insulation are also cornerstones of the process.
Walls in a typical American home might be about six inches thick and insulated with fiberglass batting. The walls of the Landaus’ new home are nearly three times as thick — a citadel of insulation and tape-sealed construction intended to keep the cold at bay and to prevent costly heat from slithering out through cracks, holes and other imperfections common to conventional construction.
And more than a foot of rigid foam insulation sits between the earth and the concrete slab forming the Landaus’ basement.
Fresh air is continuously pulled into the house, and stale air pushed out through a sophisticated mechanical ventilation system that can serve double-duty as a heat saver: some of the thermal energy being carried by the exhaust air is transferred to the intake air, minimizing heat loss.
As for preventing pipes from freezing, the Landaus will rely on two heat sources — a wood-burning stove on the main floor and electric radiant floors in the bathrooms. When the house is occupied, the wood-burning stove is capable of heating the whole house. When no one is home, the electric radiant floors can maintain a minimum temperature throughout the house to avoid plumbing disasters. To heat water, the family will depend on solar thermal collectors on the roof.
Wringing out every last ounce of energy efficiency isn’t especially economically efficient:
Although the final price tag on the Landau home is yet to be determined, Mr. Landau’s back-of-the-napkin estimate in June was $200,000 for site work like installing the foundation and a septic system, digging a well and bringing power to the site. Another $200,000 would go to Bensonwood for the shell, and roughly $40,000 to ZeroEnergy Design for its design and consulting services.
The balance — an additional $110,000 for interior components like bathrooms, finishes and appliances — would bring the total to $550,000, although Mr. Landau recently suggested that his own exacting standards might drive up the costs quite a bit more.