Plot in View, Which House Provider is the Right One?

Depends, if you move from Görlitz to Munich it might make sense.

I highly doubt that you would find any company that does that. Keywords here are warranty, structural engineering, etc. Different plot of land, possibly different structural engineering, and so on. Pipes would have to be partially cut off, roof uncovered, and so on.

And more... the screed needs to be removed, new one laid, I suppose the tiles/bathroom won't survive the move intact, the sealing must be restored, etc.. in the end, you have quite an expensive shell.

Ok, transferring the FH is not recommended for the average person. The FH planner said one of the installers had done it, he does it every day and can of course also do it more easily once in reverse order.

How can I compare the heating costs in a Kfw55/40 house with a rental apartment with a gas boiler? And: does solar thermal energy make sense together with controlled residential ventilation or from what number of people could that work?

What does solar thermal energy (warm water) have to do with controlled residential ventilation (air)?

According to a provider, there is a large water storage tank that is heated by the heat pump of the [Kontrollierte-Wohnraumlüftung]. I wonder if and from when the use of solar heat additionally makes sense.

According to a provider, there is a large water storage tank that is heated by the heat pump of the controlled residential ventilation. I wonder if and from when the use of solar heat additionally makes sense.

That is then definitely not a controlled residential ventilation, but an exhaust air heat pump (e.g. Nibe 750, as discussed in other threads, look it up in the forum...). In principle, solar thermal is not very effective/does not pay off, since you only get warm water when you need it little. When it is really cold, only the particularly expensive modules, which are installed on a house wall accordingly (due to the low angle of the sun), make any difference.