In summer, the fungal spores that give rise to mushrooms find the ideal conditions they need to spread. It’s hot and humid, and not just on humid days. Warm air can hold more moisture than cold air. That’s why you need to be careful about ventilation in summer, especially in cool basement rooms.

Basement of a house – Source: spm
Ventilate the basement well in summer
If the basement smells musty, it makes sense to ventilate the rooms on hot days. However, this can make the problem worse. This is because warm, moist air from outside condenses on cooler basement walls, bringing additional moisture into rooms. Therefore, you should only ventilate when the outside temperature is at least five degrees Celsius lower than the floor temperature.
This bottle test shows when you can vent
Also, the outside air must be drier than in the basement. You can easily try this: put a bottle stored in the basement in the open air. If the bottle becomes foggy, it is not recommended to ventilate the cellar.

Open windows at night – Source: spm
open windows at night
In summer, it’s generally best to open windows only during the coolest hours of the evening, night, or morning. To prevent mold growth, you should also air-dry your clothes. A positive side effect: clothes often smell fresher. Even after showering, you need to make sure that moist air is sucked out and does not enter other rooms.

Mold on the walls – Source: spm
You should know that mold is dangerous
Fungal spores in the house are dangerous. They not only cause respiratory problems such as dry cough or asthma, but also skin irritations and flu-like symptoms. The spores can even trigger dizziness and memory or speech disturbances.
The health hazard doesn’t just come from visible mold stains on the wall. Invisible mold spores fly through the air as fine dust particles and are inhaled by humans and animals. Therefore, when removing mold, it is important to equip yourself with respiratory protection, gloves and safety glasses.
Mold in the home can have a number of causes, from poor ventilation to design errors during construction. If construction defects such as thermal bridges, damaged insulation or leaks in the pipes are the cause of dampness in the home, a specialized company must do it.