Passive house (Passivhaus)
A rigorous building performance standard, developed in Germany in the 1990s, achieving very low heating demand through insulation, airtightness and heat-recovery ventilation.
The Passivhaus standard was defined by Wolfgang Feist and the Passivhaus Institut in Darmstadt, with the first building completed in 1991. It is performance-based and verified using the PHPP energy model. Core criteria for the Classic level in cool temperate climates:
- Space heating demand ≤ 15 kWh/(m²·a) of treated floor area, or peak heating load ≤ 10 W/m²
- Airtightness n50 ≤ 0.6 air changes per hour at 50 Pa
- Primary energy renewable (PER) demand ≤ 60 kWh/(m²·a) for Classic
- Overheating frequency (above 25 °C) ≤ 10% of hours
Windows U_w ≤ 0.80 W/m²K (triple glazing)
MVHR heat recovery efficiency ≥ 75%
Thermal bridges ψ ≤ 0.01 W/m·K
For comparison, typical existing European housing uses 100–250 kWh/(m²·a) for heating, so a passive house uses roughly 75–90% less. The low peak load (10 W/m², about 1 kW for a 100 m² home) means heating can be delivered via ventilation air or a small heat pump. Higher tiers, Plus and Premium, add renewable generation requirements; EnerPHit is the retrofit variant with relaxed limits (25 kWh/m²·a). Construction cost premiums are commonly reported at 3–10% over code-built buildings.
Related terms
All terms →- U-value
The thermal transmittance of a building element: heat flow in watts per square metre per kelvin of temperature difference (W/m²K). Lower is better.
- Thermal bridge
A localised area of a building envelope with significantly higher heat flow than its surroundings, caused by geometry or more conductive materials.
- R-value
Thermal resistance of a material layer or assembly, its ability to resist heat flow; the reciprocal of U-value. Higher is better.
- Heat pump
A device that uses a refrigeration cycle to move heat from a cooler source (air, ground, water) to a warmer sink, delivering 2–5 units of heat per unit of electricity.
- Energy Performance Certificate (EPC)
A standardised rating of a building's calculated energy performance, typically on an A–G scale, required in the EU and UK when buildings are sold or rented.