What must be observed for the ventilation of the building?
Health and comfort for the residents are the important goals of any planning. In particular, excellent air quality is essential for this. Good air quality can only be achieved if “stale” air is regularly replaced with fresh outside air. Opening windows twice a day is not enough. Comfort ventilation adjusted to the fresh air requirement is therefore indispensable in every passive house. A regular, secure and sufficient exchange of air in the cold season is only possible with targeted comfort ventilation – this also applies to very ordinary new buildings.
Without comfort ventilation, sufficient air exchange in newly built apartments can only be attempted by regular impulse ventilation: To achieve an air exchange rate of about 0.33 times, the windows would have to be fully opened for 5 to 10 minutes at least every three hours – even at night! In reality, much less ventilation is used in practice.
The air quality is correspondingly poor and the danger of high humidity increases. Because we have no direct perception of the quality of the air in the room and cannot estimate the amount of fresh air actually supplied through open windows, it is difficult even for a specialist to achieve a “just right” exchange of air through window ventilation.
If too little ventilation is provided, the air quality is poor and there is an increased risk of condensation.
If too much air is ventilated, the air becomes too dry and excessive energy consumption occurs.