Apartment renovated - unpleasant smell?!

Doors are all clean and we also cleaned them again before moving in because of dust, etc. I would say I have a good nose and cannot identify the window as the source of the smell... that is actually the problem everywhere, you don’t find a spot where it smells strongly.

Could it be that mice have hidden somewhere? Due to your renovation work, they cannot get out and are now slowly rotting away?

Could it be that mice have hidden somewhere? Because of your renovation work they can't get out and are now slowly decaying?

But it would have to be quite a nest if the whole apartment smells. What about the heating? Are all the pipes sealed? Could there be a leak? Heating water can also smell terrible when it leaks.

Floor: Laminate was laid on a stone floor. Only vinyl in the kitchen.

Was a vapor barrier foil laid underneath? If not, the laminate could be "wet" from below (previously you would probably notice swelling damage on top). Or a marten / raccoon and its "prey" in the attic? (you would hear it loudly at night... if it is still alive). Or: defective silicone seal on a shower tray (possibly above you?) and water is finding its way....

A vapor barrier is only necessary if the screed has not yet fully dried. Therefore, in old houses, one can usually do without a vapor barrier. It is only possible that so much water has entered the screed, or even underneath it, through cleaning that it now smells. How was it cleaned and when was the floor installed?

I don't think it is dead animals; that smells different and much worse.

A silicone seal on the shower tray could also be the cause, but then it should primarily occur in the bathroom.

We have the feeling that when we turn on the heating, it gets worse. The same with the clothes; when it is cool, they smell less than when you sit in a warm room.

The house had problems with the wastewater, but everything was basically resolved by the drain cleaner. The smell smells musty, old simply, I don't know how to describe it.. musty, like sometimes at old grandmas' when the apartment is not well ventilated

I would take a close look at those two points.

Is this an old house with a [Sanmelgrube] for the wastewater? Maybe a ventilation valve is broken? I would look in that direction, especially if you say there is a smell coming from there.