How do you prevent mold through proper ventilation?

Poorly ventilated homes not only spread an unpleasant odor. There is also a risk of mold growth. This can affect the health of residents and damage the fabric of the building. It is therefore particularly important to ventilate correctly in winter. You can find out what you need to look out for in this article.

How does mold develop?

Especially in winter, large areas of mold can quickly form in living spaces. If temperatures are low and the façade is poorly insulated, the exterior walls cool down rapidly. Moisture contained in the warm indoor air then settles on them, creating ideal conditions for mold spores to grow and enter the interior of the home via the air. This can happen imperceptibly even before condensation is visible. However, if you air your rooms regularly, heat them slightly throughout and do not allow them to cool down too much, you can counteract this effect.

Regular air exchange through shock ventilation

The basic recommendation is to air rooms four times a day. If you are not at home during the day, do this in the morning and evening. However, depending on the number of people in the rooms and their size, they should be ventilated much more frequently if possible, especially in times of coronavirus.

The windows should not just be tilted and opened a crack. Instead, experts recommend airing the room four times a day. This involves opening the window wide so that the air can be exchanged as much as possible. Cross-ventilation is particularly efficient. This involves opening opposite windows to create a draught.


How long should you ventilate?

How long the windows should remain open depends on the outside temperature. If there are large temperature differences, such as in winter, it is usually sufficient to open the windows wide for five minutes. In spring and fall, it should be 15 minutes and in summer, when the indoor and outdoor temperatures are largely the same, 30 minutes. If it is very hot outside, ventilation should take place in the early morning and late evening. This ensures that no hot, humid air enters the home.


Particular thoroughness required in damp rooms and bedrooms

In the bathroom and kitchen, humid air should be replaced as soon as it is created. It is therefore advisable to air the room thoroughly immediately after bathing, showering or cooking. Even if laundry is dried in the home, it should be aired regularly to remove the saturated air to the outside.

People also constantly release moisture into the air around them while they sleep. It is therefore important to ventilate thoroughly in the morning. In principle, it is also possible to sleep with the window open. However, this causes a lot of heat to be lost in winter, which increases heating costs.

Ventilate frequently, even in new buildings

In new buildings, residents should ventilate too much rather than too little. This is because there is still a lot of moisture in the walls from the construction phase, which is slowly released into the room air over about 2 years. If you do not ventilate sufficiently, you run the risk of mold growth. Residents should also ventilate more frequently after replacing windows or insulating the facade of an old building. The particularly tight windows prevent the previous slight but constant exchange of air.


Ideal indoor climate with the help of ventilation systems

In addition to regular ventilation, there are other ways to ensure a constant exchange of air. These are particularly important in heavily sealed buildings such as passive houses, where there are practically no gaps through which outside air can penetrate.

Powerful ventilation systems, such as those available in a wide range from Lunos, are used here. They permanently extract stale air from the bathroom and kitchen and blow fresh air into the living room and bedroom. The windows do not need to be opened. If you use a heat exchanger, you can even save energy. The heat energy stored in the exhaust air is transferred to the fresh supply air, which significantly reduces energy consumption.


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