Very wet windows overnight

well, even if the information comes across as rather sparse, you can piece together quite a bit. an electric night storage heater indicates a really old place and he is a tenant. (frau hermann, but male gender - huh?) then he says that the heating doesn’t properly warm up the place, because the heating gives out beforehand and heating with electricity is anyway pretty great. since the water still clings to the window, that clearly indicates that the windows are still the coldest spot and thus also stone old.

factually, there is only one solution: move

alternatively: run the totally messed up heating around the clock, which will really please the electricity provider.

maybe check what moisture you bring into the house. wet laundry and not ventilating after showering are both extremely bad for cold unheated old building rooms. if the moisture isn’t your fault (breath air doesn’t count as your own fault^^), the place is simply beyond saving. then better move into something newer. definitely make sure the heating is any good. with central heating in large multi-family houses that is usually the case rather than in small individual apartments. otherwise, check out the heating. the best and cheapest is still your own gas boiler in the apartment. you then contract directly with the gas supplier and can take advantage of newcomer bonuses and such and don’t have to pay for others, as is usual with oil, for example.

ps: what did you study for teaching certification?

Hello Mrs. Herrmann,
I do not see the situation as bleak as many previous speakers!
1. I have lived with a storage heater for over 10 years; it always depends on how you control it! I really did not have excessive heating costs, although it was always warm. Costs were not higher than in comparable apartments with oil heating. It was no different in our entire house.
The trick is simply not to control it at the room thermostat, but at the radiators, since the fan consumes the most electricity. So in the coldest winter, I set about 3/4 power at my radiators so that the storage units heated up properly and were well charged. Then only the night electricity is used. If the radiators become too cool during the day, they naturally compensate with expensive day electricity! The hot parts then made the room nice and warm.
I did not set much at the room thermostat so that the fan does not turn on. Through movements in the room, warm air is distributed well in the room. Doors always open and close occasionally, so there is air movement.

2. But ventilation is really important! The house I lived in (built in 1974) already had newer windows, but over time they were replaced again, which made a noticeable difference! I ventilated twice daily (full-time employed) with a draft for about 15 minutes each time, and normally that was fine. In the coldest winters with severe frost, I had slight moisture on the older windows (about 1 cm at the lower edge of the panes), which I always wiped off in the mornings with a towel and that was fine. Draft ventilation is really important, meaning you open all windows fully at the same time! (and very important: fix the doors, otherwise it will bang!).

If you are not noticeably introducing moisture in one place (boiling water in an open pot without external venting, showering, ...), you should then have no problems. Otherwise, it could really be due to the too old windows that simply become too cold.
Best regards
Tanita

The OP wrote something about 60-80%, which is simply way too much.

Yes, that is too much. But he wrote "is guessed," not "is measured." You can guess a lot. A simple measuring device for 5 euros is definitely a good investment, then you know for sure. But the dew point can simply be an insurmountable problem. At 20° room temperature, which can be considered reasonably heated in winter, and 50% humidity, which would be optimal for health (dry mucous membranes, etc.), the dew point on cold window panes is already reached at just under 9 degrees. That can easily happen with old windows. In the past, we had frost flowers on the inside of the panes (by "in the past" I mean 35 years ago when I was still a child :D).