Ventilation

Indoor air quality takes top priority in planning a building, so planning passive houses also involves the requirements of health-promoting building. The goal is to minimize pollutant immissions and damage to health. If possible the Pettenkofer threshold of 0.1 % v/v CO₂ should not be exceeded. This leads to a requirement of 30 m³ of fresh air per hour for each person at normal levels of activity.

Controlled ventilation systems help to increase comfort and ensure hygienically satisfactory indoor air. In addition, heat recovery via a heat exchanger can save energy. The following parameters are prerequisites for a ventilation system appropriate to passive houses:

Heat recovery rate η_WRG,eff ≥ 75 %
Intake air temperature > 16.5 °C to ensure comfort
Electrical efficiency pel < 0.45 Wh/m³
Ventilation device largely leak-free
Noise level in living space < 25 dB(A)

EXAMPLE BOX

Air distribution in a plus-energy building. Upper floor (above) and ground floor (below) (source: Benjamin Wimmer, Architekt Nürnberg)