After all the posts, I feel like I’m suffocating in a KFW55 house without controlled residential ventilation. :-D
nah, first the breathing masks will come out of the ceiling, don’t worry. You just occasionally read about it.
If the general contractor starts to act up or demands excessive prices, does that mean the whole trade has to be removed?
It’s not a separate trade to achieve a KFW standard. The individual materials make it up, and the energy consultant can tell you WHAT you can do to make it sufficient. Of course, it makes sense to implement things from which you personally benefit even without KFW. I wouldn’t recommend just chasing after KFW.
What would be a “reasonable” price for a 125 m2 semi-detached house in the northern Ruhr area?
For sale? It depends on what has been planned so far and what you can/should/want to do additionally to achieve it. Then the general contractor tells you what each additional cost is or whether/how it’s possible. For us it was completely trouble-free, elsewhere I sometimes read unpleasant things about it, so you have to ask—especially the energy consultant! Depending on the federal state, it also makes sense to ask consumer advice, there’s even free and very good advice from the energy consultant.