Huge problem with condensation on the window

Dear forum members,

I hope you can help me a little with my problem. I have been living with my boyfriend in a rented apartment for three years. Already in the first autumn/winter, I was amazed by the incredibly fogged-up windows. As soon as the temperature drops, such a large amount of condensation collects that it simply trickles down onto the floor. First of all, we ventilated the apartment intensively, every day for a long time despite the cold outside, but that didn’t help much. Last year my boyfriend came up with the brilliant idea to sleep with the window open in winter, so we got to enjoy some peace and an extra 1300€ in heating costs... This year the problem is of course back; my boyfriend is staying out of it now, he doesn’t want to talk to the landlord because he’s afraid of possible costs for inspections. I can’t do it myself because I am not on the contract and besides that I don’t know anything about the law (I’m a foreigner studying in Germany). My boyfriend says I should just stack more cloths on each window and on the floor. But I’m running out of those too! So can someone help me? What else can I do? Is it our fault that the windows look like this? Can the landlord charge us for repair/inspection costs? I took a few photos this morning that better illustrate my daily routine (really every day and night it looks like this):

Bedroom:



Here you can see how terrible the mold problem in the bedroom is, although we have used special remedies against it:


Kitchen:



Balcony door in the living room:



We also have a window in the study that comparatively stays dry... Why is that?

I am asking for any tips. Have a nice day!

Maszka

Hello,

how is your apartment ventilated? Decentralized, e.g. by window rebate ventilators for drafts and electric fans in the bathroom for exhaust air, or centralized, e.g. by controlled residential ventilation?

How old is the house?

klblb

Opening the windows for a long time is rather ineffective because the apartment cools down and cold air cannot hold as much moisture. Better to open everything briefly (5-10 minutes) but more often.
Have you ever placed a hygrometer? If yes, what does it show (before and after airing)?

Even in our new building, which still needs to dry out, we don’t have nearly as much moisture on the windows.
There must be an incredible humidity level in your room. The only question is where it comes from.
If I interpret this correctly in the background, you are probably also in a new building block with a flat roof. (Apartment approx. on the 4th floor).
Do the neighbors and the head tenant have the same problem? Perhaps the flat roof or a pipe is slightly leaking, causing the walls to soak up water?
Are there any water stains anywhere? Are the neighboring apartments even occupied?

In any case, this is not normal and should urgently be clarified with the landlord (assuming proper airing).

Unfortunately, I don’t know that. I looked in the rental contract for any information but didn’t find anything. The building was built in 1965. You estimated everything pretty well. It is an apartment block with a flat roof, 4th (top) floor. All apartments are occupied, the neighbor below us also has problems with condensation but not as severe. We ventilate three times a day, the windows in the bedroom and living room are wide open, in the bathroom and kitchen they are only tilted (because we don’t have a cat net there) for 10-15 minutes. Heating is continuous only in the bathroom and study, the rest as needed. Could that be the cause? I have looked around everywhere and luckily found no water stains. Oh, we haven’t measured the humidity yet, I have now ordered a measuring device and will get back to you as soon as I have results.

Hello,

The bathroom and study are constantly heated, the rest as needed. Could that be the cause?

If you are serious, you shouldn’t be surprised! In an apartment/a house, all rooms should be heated to at least 18°C continuously. Your apartment doesn’t even stand a chance to handle the moisture generated by you – through breathing, cooking, bathing – let alone the temperature difference between outside and inside. That’s how mold develops; you can also save yourself into an early grave ....

If I were you, I would quickly change my heating habits, use mold remover, and after the walls have dried out, redecorate the whole place BEFORE the landlord finds out and/or you get sick.

Rhine greetings

Had to learn it the hard way too... Same problem, rental apartment from the 70s with the nice aluminum frames.
Year 1 hardly heated, hardly ventilated -> mold
Year 2 hardly heated, lots of ventilation -> mold
Year 3 heater turned up full when I got home, lots of ventilation -> no mold but horrendous heating costs
Year 4 heater on permanently from November to April also at night (level 2-3/5) or replaced by electric controllers -> all good, no moisture and always nice and warm

Keep in mind: If the room has "charged up" and the walls are warm, you need MUCH less energy to keep the room temperature comfortable.
Everything else is nonsense both in terms of living comfort and energy efficiency.

In new buildings, ventilation/extraction systems are usually installed nowadays, so that working people also have a chance to ensure air exchange.