passive houses

The importance of air-tightness is the basic elementary for passive houses.

The air in the air-tight house is same perfectly sealed than a blew up paper-bag.

In order to minimize heat loss , the air exchange with exterior is done by controlled ventilation through an heat-exchanger. Uncontrolled air leaks are best avoided.

Another reason is the passive house standard makes extensive use of insulation which usually requires a careful management of moisture and dew points^. 

This is achieved through air barriers, careful sealing of every construction joint in the building envelope, and sealing of all service penetrations.

Favorable air conditions in the house:

• air exchange 0,3 to 0,5 times per hour

• fresh air supply minimum 30 m3 per person and hour

• temperature between 20 and 27 celsius

• 30-60 % relative humidity in the air

• CO2 maximum 1000 ppm

• radon maximum 50 Bq/m3