Windows sweat on interior seals during cold outside temperatures

In principle, it is good that it condenses on the windows and not on the walls.

How warm are the rooms and are you sure the measuring device works with the humidity?

The rooms are relatively warm. At least 20 degrees, even 22.5 degrees in the bathroom. I have 3 measuring devices, which all show roughly the same, except for 1-2% (including 2 different types). Therefore, I assume that they display approximately correctly. It is certainly better at the window than at the wall. The exterior walls are also relatively warm due to the wall heating. However, the wood of the windows certainly does not go very well with the water. It is annoying to have to dry the windows twice a day. In winter, you can practically not go away for a few days without hiring someone to dry the windows to prevent unsightly stains or even damage to the windows.

but after 3 years you have little chance to make a claim

Why? 5 years warranty...


Does it just look like that in the photos, or do the sashes have no seal? In my understanding, there should still be an (inner) sealing layer between the sash and the inner frame profile. In the photos, you can only see the outer sealing layer.

The water seems pretty clearly to be condensation to me. That should normally not penetrate in such quantities all the way to the outer seal if the window were properly sealed.

Sweating. Well, it just condenses when warm air meets cold surfaces.

While reviewing the photos, I also thought that there somehow seem to be fewer rubber seals and sealing lips than on mine. Whether this is a warranty case will be decided by the examination of the offer; if what was ordered is delivered, then this is not a defect. In my opinion, the fact that YOU and I have no building physics knowledge about windows simply does not count! Whether you can refer to incorrect advice, I cannot say.

There is already an additional seal running around the wings. Can this be seen in the pictures? Is that okay?

Well, the spot where it condenses on the window is obviously colder than it should be, or faulty warm, moist air reaches this spot. At 22°C in the bathroom with 56% humidity, the dew point at the window is 12.8°C. In my opinion, your window installer is definitely responsible, the windows simply have a defect. Buy yourself an infrared thermometer, those cold bridges can be identified quite easily with it.