Huge problem with condensation on the window

The problem with the cloths and wiping is that afterward you also dry the cloths inside the apartment and thus release the moisture back into the apartment. The [Kärcher Fenstersauger] is really a cool device.

By the way, we have the same problem in our apartment. However, the building was constructed in 2000. We already tried a very, very consistent approach for a week and nothing changed regarding the moisture on the windows. However, we also have very high ceilings and no ventilation options under the ceiling at the top. What I want to say with this: theoretically, it might be a question of ventilation, but practically, it cannot be solved by window ventilation.

It does not necessarily have to be just the heating and ventilation behavior, although that is absolutely popular with landlords. Our house is not heated at all in the basement (no heating present), but we are there almost all the time, cooking there including the resulting humidity. At temperatures around 15°C and humidity above 60% and rare ventilation, there are absolutely zero problems with moisture. Yes, the windows fog up daily, especially in the morning, but from outside. This has been going on for the third year now - without any mold or water anywhere. The first year with insulated glass windows and without insulation, the second with insulation, and the third with insulation and triple-glazed windows. Before that, in the rental apartment, we had just as wet windows as the OP, always properly heated/ventilated by the book and everything nicely moldy. Especially behind furniture on exterior walls (where it was already legally established that an apartment in which you cannot place furniture against exterior walls without causing mold is not suitable for residential purposes. The tenant is under no circumstances obliged to move the furniture away from the exterior walls. Solution: rent reduction!). Back then, a few experts were sent to prove that we were to blame, but it turned out that the insulation of the house was patchy and cracked and that we had done everything correctly. We simply solved the problem of the moldy dump by moving out. Because it was completely unlikely that anything would be renovated there. Therefore, I would also recommend such a measuring device. If there is mold or condensation at normal temperatures (20°C) and normal humidities (around 50%), something is wrong with the apartment.

Hello,

It doesn't necessarily have to be only the heating and ventilation behavior, although that is absolutely popular with landlords.

Which is because it is true in over 90% of cases

I would be very surprised if it were different for the OP; because if it were different, more tenants would have the same problems with running water at the mentioned locations.

Rhine regards

So as a tenant, I would always first measure with a hygrometer before getting on the landlord’s nerves. Because in case of doubt, they will definitely come by with such a device and set it up for measurement. In our case, it was the facade/dormer; surface temperatures of 10° were measured on the moldy exterior wall, while the room was heated to 20°. Behind the wardrobe, there was a streak of mold, sharply limited along the edge, showing that the mold boundary ran exactly along the dormer connection. That was so clear that there were no further discussions.

What temperatures do you have in the apartment now? It should already be better with the fogging...

Hello again! I have carefully read your comments, bought the hygrometers for the living room and bedroom, and have been measuring everything properly since Friday. For the last three days, we have set the heating to 3 in every room and left it like that. We have constantly kept an eye on the temperature and humidity and, as before, ventilated three times a day (max. 10 minutes, this time with all windows wide open, and in between we locked the cats in the cat basket).

The temperature now always ranges between 20 and 26 degrees. Early in the morning after getting up, the humidity is 60-67% (the max value once reached at night was 74%). We turn the heating off, ventilate for 10 minutes, close everything, turn the heating back on to 3, and so on... Afterwards, the humidity is below 50% and rises very slowly until it reaches 60-65% again in the evening. Is this correct now? When should the first effects become noticeable? So far, not much is noticeable, only a single pane in the living room stays nicely dry; the others and especially the balcony door are still a disaster.

Here you can see the left pane dry and the door acting like Niagara. Why is that?



I also want to say that I already wanted to contact the landlord two years ago, but unfortunately, I have no decision-making power here myself. I think I might try for another week to ventilate and heat the apartment properly and conscientiously. But what if not much changes? Should the housing company decide then? If this is all just our fault, then we have to swallow it. Something has to change anyway.