Heating and ventilating properly in winter: dry air, no mouldy corners

Burst ventilation, not tilted windows

In winter a tilted window is the worst option: it cools the wall around the window but barely exchanges the air. Better: open the windows fully two to four times a day for five to ten minutes, ideally with a cross-draught. This lets the moist air escape without cooling down walls and furniture.

The key moments to ventilate

• In the morning after getting up: most moisture builds up overnight.
• After a shower or bath: ventilate straight away and keep the bathroom door closed so the moisture does not spread through the home.
• After cooking: use the extractor hood and briefly air with a cross-draught.
• When drying laundry indoors: ventilate more often, or better still, use the laundry room.

Heating properly, including unused rooms

Letting rooms cool down completely does not pay off: cold rooms absorb moisture less well, and heating them up again costs more than keeping a moderate temperature. Guide values: living areas 20 to 21 degrees, bedrooms 17 to 18 degrees, no room permanently below 16 degrees. Keep doors between warm and cool rooms closed, otherwise the warm, moist air condenses in the cool room.

Keeping an eye on humidity

Ideally, relative humidity should be between 40 and 60 percent. A simple hygrometer costs little and shows whether your routine is right. Misted-up windows in the morning are a warning sign: ventilate more often.

Preventing mould before it appears

• Place furniture a few centimetres away from outside walls so the air can circulate.
• Wipe window frames and seals dry regularly and do not leave condensation standing.
• Treat the first dark spots on silicone joints early, before they take hold.
• If mould keeps coming back despite proper ventilation, inform the property management, as the cause often lies in the building.