An Aggressively Passive Approach to Energy-Efficiency

I was born in Darmstadt, Germany, so it was especially exciting to read about a revolution in home-building taking place in the city.  The homes rely on “passive” heating, a creative and resourceful approach to the energy crisis. The NYT reports:

The concept of the passive house, pioneered in this city of 140,000 outside Frankfurt, approaches the challenge from a different angle. Using ultrathick insulation and complex doors and windows, the architect engineers a home encased in an airtight shell, so that barely any heat escapes and barely any cold seeps in. That means a passive house can be warmed not only by the sun, but also by the heat from appliances and even from occupants’ bodies. […]

“The myth before was that to be warm you had to have heating. Our goal is to create a warm house without energy demand,” said Wolfgang Hasper, an engineer at the Passivhaus Institut in Darmstadt. “This is not about wearing thick pullovers, turning the thermostat down and putting up with drafts. It’s about being comfortable with less energy input, and we do this by recycling heating.” […]

Buildings that are certified hermetically sealed may sound suffocating. (To meet the standard, a building must pass a “blow test” showing that it loses minimal air under pressure.) In fact, passive houses have plenty of windows — though far more face south than north — and all can be opened.

Inside, a passive home does have a slightly different gestalt from conventional houses, just as an electric car drives differently from its gas-using cousin. There is a kind of spaceship-like uniformity of air and temperature. The air from outside all goes through HEPA filters before entering the rooms. The cement floor of the basement isn’t cold. The walls and the air are basically the same temperature. […]

Passive houses need no human tinkering, but most architects put in a switch with three settings, which can be turned down for vacations, or up to circulate air for a party (though you can also just open the windows). “We’ve found it’s very important to people that they feel they can influence the system,” Mr. Hasper said.