Germans Slash Energy Use With 'Passive' Houses

A revolutionary house design from Germany keeps inhabitants warm in winter with about as much energy as it takes to run a hairdryer, the New York Times reports. The "passive house" is sealed with ultrathick insulation. A central ventilation system exchanges warm air from inside with cold air from outside with 90% efficiency, keeping the house warm with heat from the sun, appliances and even occupants’ bodies.

By recycling heat, the homes use only about a twentieth the energy of houses a similar size and in Europe, cost only around 5% more to build. Governments are working to get the design adopted across Europe and architects are exploring adapting it to American construction methods. "This is a recipe for energy that makes sense to people,” said a California architect building one of America's first passive houses. “Why not reuse this heat you get for free?” (More house stories.)