Performance specification for a Passive house in the UK and Ireland

Space heating energy demand:
Total energy demand for space heating and cooling  Less than 15 kWh/m2/yr

Total energy consumption:
Total primary energy (source energy for electricity and etc.) consumption (primary energy for heating, hot water and electricity) must not be more than 120 kWh/m² per year.
Low energy refrigerators, stoves, freezers, lamps, washers, dryers, etc. are essential in a PassivHaus.

Building envelope air-tightness:
Air leakage (n50) through unwanted gaps and cracks in the building fabric must be less than 0.6 times the house volume per hour under negative and positive pressurisation.

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%).

Super-insulation:
All components of the exterior shell of a PassivHaus are insulated to achieve a U-Value minimum 0.15 W/m2K

Energy-efficient window glazing and frames:
Windows should have U-values not exceeding 0.80 W/m²K  for both glazing and frames. This requires the window frame to incorporate insulation and the glazing to be triple.

Solar Heat Gain Co-efficient through the glazing should be at least 50%:
The Solar Heat Gain Co-efficient (SHGC) is provided as a guide, it can be adjusted for glazing on different facades. This can help either reduce heat loss on sheltered sides/ north facing glazing, or alternatively help to reduce the likelihood of overheating when specified in conjunction with other features/strategies (please note that the SHGC of a window usually decreases as the U-value improves).

Southern orientation and shade considerations:
Passive use of solar energy is a significant factor in PassivHaus design and may reduce heating load substantially. It is desirable to have larger windows on south elevations and smaller windows on northern sides.

Please note that the following information is for guidance only, compliance with the PassivHaus standard must be assessed using the PassivHaus Planning Package ( PHPP software ).  The PassivHaus Institute also has an informative checklist which outlines the typical process undertaken to achieve PassivHaus.