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During the heating season, in particular, mold can quickly become a problem. Mold requires moisture to grow, and during the winter months, in particular, insufficient moisture is removed from the home. Residents themselves produce a lot of moisture (for example, through sweating, showering, bathing, drying clothes, and breathing)—up to twelve liters per day. But temperature and the presence of a breeding ground also promote mold growth. So what can be done to nip this process in the bud?
Infographic: Moisture Production in a 4-Person Household
Mold Prevention: Know the Cause and Act Early
If you want to stop mold before it spreads, you first need to understand how it develops. As shown above, three factors are crucial: humidity, temperature, and nutrients.
Moisture isn’t even necessary for condensation to form. Just 80 percent surface humidity or 65 percent indoor humidity is enough for mold spores to develop. Moist air condenses in cold spots in rooms (known as thermal bridges). But it also happens quickly in places like window sashes or balconies. Particularly problematic are areas in homes where air circulation is poor, such as behind cabinets, curtains, or even under flooring.
Besides humidity, mold thrives in temperatures between 15 and 30 degrees Celsius. Surfaces aren’t particularly important. Concrete, cement, wood, drywall, and wallpaper can be just as much of a breeding ground as paint or plastic.
Video: Preventing Mold
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Simple tips to prevent mold
It’s important to remember that normal air always contains some mold spores. However, they only pose a danger when their concentration rises above a certain level. Nevertheless, it’s important to prevent spores from settling on indoor surfaces and spreading. This can only be achieved through proper ventilation and heating.
Ventilation, in particular, is often ignored in winter. This is because many people fear it will lead to too much heat being lost and wasted. However, it’s more a matter of regularly opening the windows fully for five to ten minutes. Ideally, open opposite windows and interior doors to ensure full air exchange. To minimize heat loss, reduce the power of your radiators during this time .
Inclined ventilation, on the other hand, often has the opposite effect. Heat is lost unnecessarily, and rooms cool significantly during the day. This not only requires more energy to reheat the rooms, but also leads to an excessive temperature difference between the cooled surfaces and the heated air. In such cases, moldy patches often form around windows.
But proper heating shouldn’t be neglected either. This is because warm air absorbs more water molecules than cold air. The decisive factor here is the type of room and how long people spend in it. In living rooms, an average temperature of 20 to 22 degrees Celsius is recommended. Other rooms can be slightly cooler.
Preventing mold with mechanical ventilation systems
In older buildings, air exchange occurred naturally through leaks, such as in wooden windows. However, this is increasingly changing. This is because every renovation ensures that as little heat energy as possible is lost through leaky windows, sashes, or doors. However, this doesn’t mean that renovation should be abandoned; rather, ventilation must be adapted to the new conditions. Impact ventilation should be performed more frequently during the day to remove moisture to the outside. New buildings are also becoming increasingly airtight. Ventilation is particularly important here. However, in many cases, this cannot be done manually, as residents are at work, university, or school during the day. Controlled mechanical ventilation offers a suitable solution.
How do ventilation systems prevent mold?
Controlled mechanical ventilation ensures a constant, healthy indoor climate and a sufficient supply of fresh air without heat loss. Thanks to integrated heat recovery, it’s even possible to recover heat from exhaust air and use it for heating. Mechanical air exchange also ensures moisture is removed from the inside of the home to the outside. Another form of protection is provided by filters in ventilation systems, which prevent dirt and particles from entering the room via the outside air.
Thus, both decentralized ventilation systems and centralized mechanical ventilation systems protect against mold growth not only by limiting the symptoms or consequences of infestation, but also by preventing its causes.
