Humidity in basement apartment

Proving a tenant "incorrect ventilation" is likely to be relatively difficult. As far as I know, the tendency in case law is that normal ventilation should be sufficient. If moisture still accumulates, the wall is not insulated enough. Imposing a sort of ventilation plan on tenants is practically impossible today. Unless the tenant is willing.

Never tilt the windows. Open all windows at least 3 times a day and create a draft. The room temperature must be at least 19 degrees, so a cold sleeper will have problems here.

Again and again this myth.. funny that we have NEVER had problems with mold. We NEVER air shock ventilate and like to dry laundry inside (makes the air so nice and humid).

No sorry.. but that's just rubbish! To cause mold yourself... you really have to be very stupid..

That would mean the apartment is practically unrentable or you have to mess around every time someone doesn't cooperate.....

He doesn't heat in the summer.

You can't blame him for that. Who does that anyway
But don't let it cool down in the spring - not from 0 to 100 - that is something one can understand...

Good luck!

Well, in summer he doesn't need to heat, he already has over 19°, but warm air carries a lot of moisture and that has to be regularly removed. You will notice it at the latest when you get [Estrich]. And yes, tenants are very, very demanding, that was also a reason to sell my [etw].

I have now told him about the shock ventilation three times a day. I hope he will do it.

But he was not pleased about not putting the windows on tilt anymore.