Passiv Haus (Passive House)

A “new” construction style coming out of Germany creates houses that barely need energy to run. They don’t even have heating systems. In the dead of winter they might need a little space heater but that is is. What is the secret?

Insane amounts of insulation, triple pane windows, fanatic air sealing, smart solar design, good air circulation and efficient appliances.

Here is a list from their site:

Compact form and good insulation:
All components of the exterior shell of the house are insulated to achieve a U-factor that does not exceed 0.15 W/(m²K) (0.026 Btu/h/ft²/°F).

Southern orientation and shade considerations:
Passive use of solar energy is a significant factor in passive house design.

Energy-efficient window glazing and frames:
Windows (glazing and frames, combined) should have U-factors not exceeding 0.80 W/(m²K) (0.14 Btu/h/ft²/°F), with solar heat-gain coefficients around 50%.

Building envelope air-tightness:
Air leakage through unsealed joints must be less than 0.6 times the house volume per hour.

Passive preheating of fresh air:
Fresh air may be brought into the house through underground ducts that exchange heat with the soil. This preheats fresh air to a temperature above 5°C (41°F), even on cold winter days.

Highly efficient heat recovery from exhaust air using an air-to-air heat exchanger:
Most of the perceptible heat in the exhaust air is transferred to the incoming fresh air (heat recovery rate over 80%).

Hot water supply using regenerative energy sources:
Solar collectors or heat pumps provide energy for hot water.

Energy-saving household appliances:
Low energy refrigerators, stoves, freezers, lamps, washers, dryers, etc. are indispensable in a passive house.