Avoiding mould in the home

You will find the following content in our article:

Mould in the home can make you ill
How mould develops
Mould and humidity
How to avoid mould in the home
Control humidity with the air-Q

There are different types of mould, some of which are suspected of being particularly dangerous (e.g. black mould). So far, there are no limit values for the respective mould contamination, as it is unclear from which concrete concentration of mould spores in the air a health hazard exists. Nevertheless, mould in the home should generally be avoided.

Mould in the home can make you ill

Mould in the home can cause various complaints. For example, the inhaled spores as well as accompanying symptoms of mould(VOC gases caused by decomposing organic material) can cause allergic or irritant reactions or aggravate already existing diseases - especially those of the respiratory tract. The symptoms are non-specific and range from burning eyes, headaches and joint pain to inflammation of the mucous membranes as well as respiratory problems and gastrointestinal complaints. To avoid this, mould in the living space should be removed as quickly as possible for hygienic and health reasons. Better still, mould should not be allowed to develop in the first place.

How mould develops

ool infestation with mould can occur in both old and new buildings. The fungus only needs heat, water and organic material. The latter can be found everywhere; for example, wood, wallpaper, plaster, paste or even dust can serve as a breeding ground. Mould indoors is almost exclusively a winter problem. The warm heating air creates optimal conditions for mould. The basic problem is that people often do not air their rooms regularly because of the cold temperatures. Due to the breathing and exhalations of people, plants and animals, the air humidity in the interior then increases. Perfect climate for the harmful spores.

Mould and humidity

It becomes critical when the humidity in the room is particularly high. Water now begins to condense on the outside walls, windows or window frames, for example. The reason for this is the very different temperature distribution in the room. While the temperature in the middle of the room is a pleasant 21 degrees, it is often a few Kelvin cooler near the window or directly on the wall. This has an effect on the humidity. Although the absolute air humidity is the same everywhere in the room (9.16 g/m³ in the example below), the relative air humidity can quickly rise to the condensation point (see also dew point). This causes condensation to form.

Table mold growth as a function of temperature and humidity

Mould growth can often occur in the bedroom in particular. This is because it is usually the coldest room. In addition, the humidity of the room increases strongly at night due to the exhaled air. Due to the lack of air exchange, condensation can form on cold surfaces, such as the windows. Mould also develops quickly in the kitchen. Here, cooking or washing up causes water vapour to develop. This generally increases the humidity in the room. If there are large temperature differences between the different rooms of a flat, this can also promote mould in the cooler rooms. Aquariums or plants also contribute to an increase in humidity. Since they continuously release water vapour into the air.

How to avoid mould in the home

Proper heating and ventilation are essential to avoid mould. You should air generously after showering, bathing, cooking or ironing. This draws the water vapour outside. It is best to open the windows completely and ensure good ventilation for five to ten minutes. If possible, you should also refrain from drying laundry in the living rooms. If this is not possible, ensure that there is a regular supply of fresh air. When placing furniture, make sure that radiators are not covered. Only in this way can the warm room air always circulate well in front of the cooler outer walls in order to avoid cold-heat bridges (i.e. places where the dew point can easily be reached).

So the higher the humidity, the better the conditions for mould. Accordingly, the air humidity should always be controlled, especially in winter. The maximum limit is 60 percent humidity. If the air humidity is below 60 percent, you prevent mould infestation as much as possible. Nevertheless, the relative humidity should also not be too low to prevent the mucous membranes from drying out (see blog article on minimum air humidity).

Control humidity with the air-Q

By measuring the air humidity throughout the day, humidity peaks become visible. This allows you to take countermeasures and thus prevent mould. This can be easily done with simple hygrometers or even easier - the air-Q. The air analyser continuously monitors and records all measured variables such as humidity, temperature and also air pollutants. In the air-Q, the absolute humidity is determined with very high accuracy by a sensor for the relative humidity. From the measured value, the air meter derives the absolute humidity with pinpoint accuracy.

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