Airing the basement in winter

How do I ventilate the basement properly in winter?

Especially in the cold winter, we shy away from having the windows of the house open for a long time. This is because we are reluctant to exchange our comfortably warmed room air for the icy air from outside. But regular and correct ventilation is nevertheless necessary to prevent mould growth, among other things. The cellar is particularly susceptible to this. Due to its location in the ground, it is usually the coolest room in the house. The low temperature in turn increases the humidity. This is why basement rooms are particularly susceptible to mould growth. To counteract this, especially in winter, we have summarised the top tips for you.

6 tips for airing in winter

Relative humidity can be measured with a hygrometer. It should only be ventilated when the absolute humidity outside is lower than inside.


As a rule, the humidity content of the air should not exceed 50 percent in winter to avoid mould growth. However, air that is too dry irritates the mucous membranes.


Richtig lüften heißt auch richtig heizen. Die ideale Temperatur liegt laut Umweltbundesamt in Wohnräumen zwischen 18 und 22 Grad. Auch bei Abwesenheit sollte die Raumtemperatur nicht unter 16 Grad sinken.


When airing, the heating should be off. Make sure that the heating is always off when airing. Even if it is only for ten minutes, a lot of energy is lost.


Short bursts of airing with a wide opened window for five to ten minutes ensure that the air in the room is sufficiently exchanged and yet the masonry does not cool down.


Wenn Sie den Kellerraum auch als Wohnraum nutzen, empfiehlt es sich 3-mal am Tag zu Lüften. So haben Sie sowohl ausreichend Frischluft im Raum und halten dennoch die Raumtemperatur.


Ventilating against humidity in the basement

Unlike in living spaces, the optimal humidity depends on the use of the basement area. If it is used as a living space, such as a hobby room, party area or even a living space, then the humidity should be between 40 and 60 percent. The ambient temperature should be around 20 degrees to create a pleasant room climate. Cellars that are not used as living space but only for storage can have a higher humidity of 50 to 65 percent. Often the basement is also used as a washing and drying room. A lot of moisture is released during the washing and drying process, which could lead to mould growth even faster if the basement is not ventilated properly and irregularly.

Another criterion for an optimal room climate and mould prevention depends on the year of construction of the building. Today's houses are also better insulated in the basement area than houses built before 1970, as these still meet an older standard. These basement areas often have higher humidity and are more susceptible to mould growth. Therefore, it is particularly important to have a good air exchange in these houses without introducing new moisture from the outside.


Maintaining ACO cellar windows correctly

Only use mild, ph-neutral cleaning agents in diluted form for cleaning!

Never use sharp objects, scouring agents or aggressive cleaning agents (e.g. cleaning agents containing vinegar or acid), as these can attack the corrosion protection of the fittings! When cleaning, make sure that no water runs into the fitting. After cleaning, dry the hardware thoroughly and lightly oil the surface with an acid- and resin-free oil by wiping it with an oil-soaked cloth.

Your windows/window doors are equipped with a high-quality SIEGENIA fitting. In order to maintain its smooth running and perfect function for as long as possible, we recommend that you carry out the maintenance and inspection work described below at regular intervals (at least once a year or more frequently, or every six months in school and hotel buildings, near the sea or in areas where drifting sand is to be expected).

Grease or oil all moving hardware parts and all locking points. Use only acid- and resin-free oil or grease for this purpose. For the moving parts in the window sash, a spray grease is advantageous, which you spray into each opening of the fitting. Then move the hardware several times to the intended switching positions until the grease is distributed. Wipe off excess oil/grease from the window frame. Then grease the striking plates in the window frame with a stiffer grease (consistency class 2 according to DIN 51818) at the points where the locking pin engages in the striking plate. Our maintenance grease, which you can order from SIEGENIA under the material number ZXSXO 120-093010, is particularly suitable for this purpose.