How many degrees of heat loss per night is "normal"?

No, we had to move in due to time pressure. The proper heating system will be installed in week 47/48.

You can live well like this for one month. The house heats up quickly and since we have an open space above (gallery), the bedroom upstairs is also warm, but only for a short duration. But of course, the heating system will be installed next week.

With experience, I thought that surely someone has already tested how many degrees their house retains overnight.

I will take a look at 3:00 PM right away.

Your house gets cold as quickly as it warms up... Mass is not heated, only air

We currently still live in an unrenovated apartment from the 70s ([single-family house], although we only live on the 1st floor) and almost exclusively heat with our wood stove at the moment. The residents on the ground floor do the same. We also heat roughly from 4 PM to 10 PM and usually have around 23 degrees in the living room. The next morning, when the stove has gone out overnight, we generally have about 17 degrees in the living area. So we are not doing much worse than your new building, which in my opinion is only because the stove heats only the air and that cools down quickly. Therefore, I think this is normal so far. In the bedroom, we have the heating on overnight (regular radiators, oil heating).

No, we had to move in because of time pressure. The proper heating will be installed in week 47/48.

I will have a look at 3:00 pm right away.

There are passive houses that manage without average heating systems, you also have a solid wood house (I’m not really familiar with that), plus this wood stove... but you will also have a concrete screed, right? How did you get rid of the moisture?
If the plan is to heat only with the stove, it will also have to be stoked in the morning...

The other thing: time pressure does not apply!
A house that is occupied is considered accepted – and that without heating! For me, that is a serious legal mistake. It’s not about a door that hasn’t been installed.
If you have to leave the apartment, there are other options.
Besides the question of who was to blame, there are possibilities for temporary housing.
Just accepting the house like that, without a heating system installed, is a no-go for me.

Couldn’t pipes burst?
We’ve had severe subzero temperatures with snow for 10 days now...

But as already said above, like other users: it’s not surprising that the temperature in the house cools down in the morning.

I wouldn’t know in which law it says that you have to install a heating system? Accordingly, I could also move in with a wood stove if I wanted to. Which pipes are supposed to burst? We have 17 degrees in the house at the lowest point. Nothing will burst.

We don’t have screed. Our floor slab consists of concrete, where the underfloor heating is integrated. A "Schwedenplatte."

The construction was dry from the beginning.

In short: since only the room air heats up quickly with you, it cools down just as quickly. It would be different if you properly heated through sometimes; then the materials would also warm up and would retain the heat longer according to their material properties.