That is why proper ventilation is so important

Poorly ventilated flats not only smell unpleasant, they also have an increased risk of mould growth. Therefore, it is important to carry out a regular air exchange in order to remove pollutants and moisture. In this article you will learn what is important.


Preventing mould

Especially in the cold season, mould can quickly form in living spaces. When temperatures are low, the exterior walls cool down - especially in insufficiently insulated houses. The moisture contained in the warm indoor air then condenses on the cooled walls, where mould spores find optimal growth conditions - and without any visible or tangible condensation.

This is particularly problematic because spreading mould poses a serious health risk that can lead to a wide variety of allergies and respiratory complaints. Accordingly, conscientious prevention is of great importance.


Ventilate every room properly

As a general rule, pollutants and humidity should be removed at the point of origin if possible and already during or shortly after their formation. Depending on the room, some special features must be taken into account.

Sleeping rooms:
If possible, bedrooms should remain completely open or at least tilted open throughout the night. However, since ventilation for several hours is problematic, especially during the winter months, intensive shock ventilation with wide-open windows is recommended immediately after getting up.

Living room:
Humid air should also be regularly removed by airing the living room. This is especially true if there are many plants and other sources of moisture (e.g. clothes horse) in it. Here, too, it is advisable to open the windows fully for 10 - 15 minutes at regular intervals, ideally creating a draught through other rooms.

Kitchens and bathrooms:
Large amounts of moisture are regularly released in utility rooms such as kitchens and bathrooms. This is especially the case after cooking, showering and bathing. In such cases, intensive shock ventilation is recommended every time. If there are only limited ventilation possibilities, it is essential to remove water from floors and walls.

The outside walls of basements are often cold, which can lead to moisture from the warm outside air condensing on them, especially in summer. This can lead to the formation of mould. Especially in the summer months, the cellar should therefore not be ventilated during the day, but at night or in the early morning hours.


Notes on ventilation

In order to make the air exchange as efficient as possible and to reduce the risk of mould, a few things should be considered. The following aspects should be mentioned in particular.

Keep interior doors open:
It is important to keep the interior doors open during shock ventilation, especially if the windows on the opposite side of the facade are open. This creates a draught that leads to a much greater exchange of air. Bathroom and kitchen doors should remain closed, however, to prevent moisture and odours from entering the rest of the flat.

Do not leave windows tilted open all the time:
If the windows are tilted open for a long period of time, this drastically increases energy consumption and heating costs. In addition, only a small amount of air is exchanged. Therefore, ventilation should only be carried out as needed.

Remove building moisture through increased ventilation:
Both in new buildings and after renovations, building moisture can occur for some time. The decisive question here is how much moisture has penetrated the building fabric during plaster and screed work. Due to the type of construction, there is more building moisture in solidly constructed buildings than in lightweight buildings.

Particularly in the initial period, the building moisture must be removed from the building through increased ventilation of all rooms. Basically, you can assume that this process will take 1 - 2 years. During this time, one must also reckon with higher heating costs.

Check ventilation habits after flat renovation:
After renovations, a problematic moisture situation can occur. This is especially the case if new windows have been installed and the exterior walls do not have sufficient thermal insulation.

In these situations it is important to adapt the ventilation behaviour to the new conditions and to ventilate more frequently. To constantly monitor the relative humidity in the rooms, it is best to use a hygrometer.

Be careful when drying laundry:
If you do not have a balcony, you must dry your laundry indoors. Regular ventilation or a tilted window is recommended to ensure a constant exchange of air. If possible, laundry rooms and drying rooms should be used.


Notes on the use of ventilation systems

Since building envelopes are being built ever tighter and most people are not at home during the day to exchange air, ventilation systems are being used in more and more households. In order for these to do their job properly, regular maintenance is required, just as with heating systems. Special focus is placed on sufficient air exchange and proper cleaning.

Depending on how heavily the air is contaminated with dust, grease, etc., cleaning should be carried out two to four times a year and the filter should be changed about once a year. Otherwise, germ contamination may increase.

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