Very wet windows overnight

Good morning!

Since this is my first post here, I hope it ended up in the right subforum...

I haven't done any construction myself, but I hope to find some ideas about the cause of my problem here. It is really stressful...

Now to the problem: Especially in the cold season, my windows get completely covered (see pictures/video below). They become really wet overnight, you need 1-2 large towels just to dry them.
Additionally, of course, the water first collects at the bottom edge, creating the perfect basis for mold.

During the day and in the morning, ventilation is done frequently and for a long time, but that doesn't change anything. The windows don't feel particularly sealed either; especially on stormy days, you can feel a draft at the edges.

What causes this? Is it an insulation problem? Are the windows to blame? Or the walls? Unfortunately, I’m really not an expert on this...

Thank you very much in advance for your answers!

You are to blame; you ventilate incorrectly and heat too little.

Please measure the indoor air and change your ventilation behavior.

How do you ventilate properly? Should I leave the window open overnight so that you are really frozen in the morning?

Apart from that, the heating here is electrically operated by night storage, which means it has limited heating power and costs a lot of electricity.

Room air was measured here about a year ago, as far as I remember the humidity was quite high, but I don't have any number in mind anymore.

I air out several times a day with windows wide open, not just tilted. Especially in the morning and evening. The windows are closed overnight. The problem does not exist all day long, only in the morning. In what way is this incorrect ventilation behavior?

First, get a moisture meter. Then always try to stay below 50%, which can only be achieved if the heating is on and the room does not cool down. When I hear [Nachtspeicher], it will become difficult and expensive.

How big is the room? How many people sleep there? How far away are the kitchen/bathroom?

I still need to get the measuring device, but I am quite sure that the humidity is rather between 60-80%, at least at night. Heating a lot, as mentioned, is rather not possible because the heater also gets exhausted after a while and then has to "reload" again, so it often happens that the room cools down because it simply cannot be heated anymore. The room (the video shows the windows in the kitchen) is about 14m^2 in size, and there are three of us here. The bathroom borders the kitchen on one side.