In winter you are always faced with the dilemma: the apartment should be nice and warm and comfortable, but without ventilation there is a risk of mold and bad air. To prevent this, there are a few things to consider.
Mold can quickly form in apartments in winter. The low temperatures cool the outer walls, the moisture in the warm room air then condenses on the cold wall - a tasty breeding ground for mold. You can counteract this with proper ventilation.
In general, you should open the windows two to four times a day. However, this rule of thumb does not necessarily apply to every room.
The humidity in bedrooms tends to be higher than in other rooms because we release a lot of moisture through breath and sweat while we sleep. The Federal Environment Agency advises that the window should ideally be left open all night. If that is too cold for you - especially in winter - you should ventilate intensively immediately after getting up. Means: Open the windows fully for five to ten minutes and let in fresh air.
On the other hand, continuous ventilation with a tilted window is counterproductive. The necessary exchange of air is hardly possible, instead the apartment cools down slowly and energy is wasted. The following applies: the colder it is outside, the shorter you should air the room. Between December and March, windows should not be open for more than ten minutes.
Depending on the decor, it can also quickly get damp in the living room. Plants or wet laundry increase the humidity. At the latest when water droplets form on the window panes, forced ventilation is necessary.
Thanks to numerous water sources, the bathroom and kitchen are the wettest rooms in the house - and therefore a paradise for mould. That's why you should open the window more often here than in other rooms. It is best to air the rooms for a few minutes with the window open after each shower or cooking.
Cross ventilation ensures a particularly effective exchange of air in the home. To do this, you open the windows in opposite rooms and the room doors at the same time when you ventilate the room. This creates a draft through the entire living space.
Irrespective of whether it is for intermittent or cross ventilation: the heating should definitely be turned off during the air exchange. Otherwise valuable energy is wasted.
