Proper Ventilation to Prevent Mold

Black spots on the walls are often a sign of mold. This is more than just a visual defect; it is a defect. Mold is harmful to your health and is associated with a variety of diseases. In the long run, fungal infections can also damage structures. To prevent the formation of mold, reducing humidity is an effective measure. Proper ventilation and heating usually prevent mold in your home. The key is optimal air circulation in the individual rooms and adapting the ventilation behavior to the outdoor temperature.
What causes mold to form on walls and in the corners of rooms? How can you prevent moisture in your home? If mold appears, how should you ventilate and heat the room to eliminate it? You can find all the important information on this topic in this article.

How to prevent mold with proper ventilation

Mold is a fungus that needs heat and moisture to grow. Mold thrives especially easily at room temperature with a relative humidity above 60%. The more humid the air in the room, the more likely black mold spots will appear. To reduce humidity in your home and prevent mold from forming, you need to ventilate regularly.

Mold: a hazard to your health

The Federal Environment Agency warns in a guide that staying in a room with mold infestation can have consequences. Airborne mold spores have a particularly strong impact on the respiratory tract. Asthma patients are particularly susceptible and experience more severe symptoms. But runny noses, coughs and respiratory infections are also often associated with moldy walls. If you live under moldy blankets for a long time, the incidence of allergies is also suspected to increase. The guide recommends reducing the humidity in the room to minimize the health risks caused by mold.

Proper ventilation and heating to prevent mold

Reducing humidity is the most effective way to prevent mold growth. Open the windows for ventilation and replace the moist air in the room with dry air from the outside. Frequent ventilation is the best option because the room will not cool down too much. On the other hand, tilted windows only allow very slow air exchange and cause the temperature of the wall near the window to drop too much.
The better the air circulation, the faster the indoor air will be exchanged during rapid ventilation. A duration of five to ten minutes is usually optimal. Turn off the heating when ventilating to save on heating costs.

How to effectively reduce humidity through ventilation

Proper ventilation means that the fresh air outside contains less moisture than the dirty air in the room. This happens when the outdoor temperature is lower than the indoor temperature: Since cold air can hold less water than hot air, it is drier at the same relative humidity.
While you can always ventilate in winter to reduce humidity and thus prevent mold, the higher the outdoor temperature in summer, the more moisture there is in the air that enters the apartment during ventilation, which poses a danger. If the fresh air in the house cools, humidity increases and quickly forms on the walls and window panes. In summer, ventilate when it is coolest outside, i.e. late at night or early in the morning.

How often do you need to ventilate to prevent mold

Everyone increases humidity by breathing, and household activities such as showering and washing also contribute to increasing the humidity in the air. The Federal Environment Agency calculated in a guide that a family of three emits approximately 6 to 14 kilograms of water per day. In order to get the humidity out of the house, you have to ventilate about seven times a day.

Proper ventilation starts with the furnishing of the room

Good air circulation is a prerequisite for effective air exchange during shock ventilation. This is why wide open windows are preferable to tilted windows. You can further increase the air exchange rate by opening the inner doors and windows of the apartment. Ventilation is particularly fast if the windows on both sides of the house are open. Through so-called cross ventilation, it is enough to replace the indoor air with fresh air in a short time.
However, it is also necessary that the air exchange is not hindered in the room. So, always draw the curtains when drying! It is better to place large pieces of furniture a few centimeters away from the walls and ceiling so that air can still circulate between them. Since the coldest surfaces in the home are most likely to be affected by moisture and mold growth, you should avoid placing larger cabinets on the outer walls, but place them on the side of the room inside the house.

How to heat correctly when mold appears

Basically, the higher the room temperature, the lower the humidity. In order to keep the indoor climate in the apartment dry and thus prevent mold growth, it helps to turn up the heating a little.
Avoid letting individual rooms get cold even if they are not used during the day! In most homes, the bedroom has a lower temperature than the rest of the home. But if warm air flows from the living area into the bedroom and cools down there, it increases the humidity. For example, if your living room has a relative humidity of 50% at 20°C (which is in the optimal range), then in a bedroom at 16°C, air with the same moisture content will have a humidity of 64%. This is already above the recommended maximum and should be avoided to prevent mold from forming.

Wet corners are harder to ventilate

Even if the room is properly heated and the humidity is below 60%, moisture can condense in certain areas of the outer walls. If certain parts of the wall are cooler than the rest of the room, the local air temperature drops and the relative humidity increases until the water finally condenses.
In rooms with radiators, the walls are only heated indirectly by the room air. The worse the air circulation in the room, the colder the hard-to-reach parts, such as the corners of the room, will be. As a result, corners are often the first to be affected by moisture and mold.
If there is mold in the corners of a room, ventilate and heat it properly by simply opening the windows briefly to prevent the walls from cooling down again. Avoid turning the heating down too low during the day, as the walls and corners will only warm up slowly if they are otherwise exposed to moist air for a long time. Instead, heat continuously to avoid the risk of mold forming.

How to properly adjust ventilation to the characteristics of the structure

Condensation often appears on poorly insulated window panes, as they quickly release heat to the outside. Similarly, shutter boxes and other fixtures can also cause thermal bridges, which are the areas with the highest humidity in the room and are therefore most susceptible to mold. If you cannot provide better insulation, ventilate especially frequently and heat the interior a little.
If you move into a new building, the walls may not be completely dry yet. To prevent mold from settling, you must first intensify heating and ventilation. In this case, increased ventilation does not mean opening windows longer, but opening them more frequently during the day. Up to two heating periods may be required until all components are dry and the humidity in the new building returns to normal.

Ventilate during periods of high humidity to prevent mold formation

Certain activities, such as cooking or showering, release a lot of water into the air in a short period of time. Large amounts of moisture can quickly settle in cooler parts of the home and promote the formation of mold stains. Ventilate immediately after completing the activity to allow outdoor moisture to peak. During this period, keep the inner doors closed to prevent the spread of moist air to other parts of the apartment.
If possible, move clothes to dry outdoors in the summer. Since damp laundry can cause humidity to build up over time, you should increase the room temperature.