Ventilation guidelines for mold prevention and air quality

Proper ventilation is essential for maintaining indoor air quality and preventing mold growth, even during inclement weather or freezing temperatures. Regular air exchange helps reduce moisture buildup caused by breathing, which is particularly problematic in winter.

When ventilating during rain, fog, or snow, the relative humidity inside the room will decrease once the incoming cold air is warmed by the building's heating system. This is because warmer air has a higher capacity to hold moisture than cold air.

To prevent walls and furniture from cooling down unnecessarily, experts recommend 'shock ventilation' (Stoßlüften) rather than leaving windows tilted open. Recommended durations for air exchange depend on the outside temperature:

- Below 0°C: Approximately 5 minutes. - Between 0°C and 10°C: Approximately 10 minutes. - Above 10°C: Approximately 15 minutes.

Frequency should be determined by the moisture load of specific rooms, with kitchens, bathrooms, and bedrooms often requiring more frequent ventilation than less-used areas.