ᐅ Very wet windows overnight.

Unfortunately, you forgot the attachment?

frauherrmann schrieb:
As mentioned, heating a lot doesn’t really work because the heating system eventually reaches its limit and then needs to "recharge." This often results in the room cooling down since it can no longer be heated.

This is also your main problem, as already explained. You can see the consequences on the windows. It’s just basic physics.

Heating along with ventilation is the only solution. The moisture simply has to be removed to the outside.

All the heating and ventilation won’t help if the windows are poor quality. You can’t heat away cold glass, and you shouldn’t try to either (energy saving issue). If the windows are drafty and air leaks through, you should contact the landlord. You can also measure the surface temperature of the glass with an infrared thermometer. If it’s too low, the dew point is being breached and condensation will form.

It’s also useful to buy an inexpensive humidity meter.

When I lived in a rental place, we had the same problem: the landlord kept repeating the usual advice about airing and heating properly, but unfortunately the indoor humidity was below 50%, usually around 42%, so it wasn’t tenant misuse. The windows were soaking wet with puddles on the windowsill. The puddles even appeared in the frame, and everything got moldy. The issue was simply bad quality windows that were poorly installed.

In this house, we have exactly the same heating and ventilation habits, and the windows also fog up: but on the outside! Inside, everything is completely dry.

If the property develops mold even though the indoor humidity is fine, a rent reduction is justified!

@frauherrmann External links are prohibited according to the admin...

,@Elina You’re right, under 50% humidity. Once this level is reached, you can proceed with further steps.

Yep... off-topic, Elina...

As far as I have read, the original poster doesn't know anything about the humidity yet. First measure it, then you can proceed.