Passive Houses

The current economic gloom can be especially painful in these cold winter months, as the nighttime chill means higher heating bills for most of us. But for the inhabitants of Darmstadt, a town in central Germany that has pioneered passive heating, there are no drafts or cold tile floors. Taking advantage of a revolution in building design, homes there can stay cozy and warm using the amount of energy needed to run a hair dryer.

As explained in today's New York Times, architects of these so-called "passive homes" use ultrathick insulation and complex doors and windows, essentially encasing the home 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. An ingenious central ventilation system exchanges warm and cold air with 90 percent efficiency.

Passive houses cost only about 5 to 7 percent more to build than conventional houses in Germany. And their popularity is quickly spreading beyond German-speaking countries, with the European Commission promoting passive-house building and even the United States Army considering passive-house barracks. Still, there are difficulties to consider - climate and geographic location are variables, and both residential buildings and sprawling homes are difficult to insulate and heat, making adoption in the United States more tricky.

(Photo courtesy of the Passivhaus Institut)