The Passive House concept, invented in Germany, is starting to take root in the US. Passive houses are super-insulated to the point where they don't need a furnace and can be heated with a toaster. Despite their air-tight construction, they continuously move fresh air into the house through heat-recovery ventilators, which take heat from stale air on the way out of the house and use it to heat up incoming fresh outdoor air.
We wrap up in wool sweaters to keep warm in winter. Why not extend the same courtesy to our drafty, energy-gobbling homes?
The "super-insulated" house got its start in Canada in 1977. The Germans followed up in 1991 with an improved version by eliminating the furnace altogether. They called it a "passive house," which quickly caught on in their chilly climate.
This revolutionary concept has only recently spread to the United States, where it is gaining devoted followers among green building enthusiasts.
"The irony is that we knew about this (Canadian) house in the 1980s," says Mike O'Brien, residential green building specialist for the city of Portland. "Everybody at the time thought it was overkill. But now our energy bills have caught up with us and we're ready to hear about it."