1. Introduction
The first passive houses have been built in Germany and are inhabited since 1991 (Feist, 2006). Two
countries are ahead in terms of realizations (Lang, 2009): Germany (>10000 PH) and Austria (> 5000
PH). Then follow Switzerland and Belgium with a few hundred PHs and only a few built in different
countries.
The PH standard is defined only in terms of energy performances. The way to achieve these
performances matters little. In central Europe, for housing, the criteria for being passive are:
• The annual heating requirements must be less or equal to 15 kWh/(m².year)
• Air leakage measure at a P of 50 Pa – n50 - must be less or equal to 0.6 ACH (Air Changes
per Hour) according to (EN 13829, 2000).
• Primary energy must be less than 120 kWh/m².
• Overheating within the building (> 25 °C) must be less or equal to 5 % of time.
For non-residential buildings, there is also a criterion related to the annual cooling requirements which
must be less or equal to 15 kWh/(m².year). Then one must pay attention to effective sun protection,