Air heat pump or use gas and solar?

Are you the client, or is it a developer project?

I am the client.

So the thermal insulation certificate must definitely be available as of today, correct?

Sure. Do you have your building permit? Do you remember that in the application there is a box to be checked confirming compliance with the energy saving ordinance? Do you know that this box is linked to the calculation that must be submitted to the building authority upon request? Therefore, this calculation must be there and with you.

For the thermal insulation certificate, it says "will be submitted after the start of construction".

The GÜ does not provide any calculations. The architect once sent me the heating load calculation and according to his own statements, he got into trouble with his superiors because an energy consultant found a suspected error in it, which I then forwarded.

I am basically convinced that building with a GÜ was the right decision; but when it comes to heating / building services engineering, you definitely face the disadvantages of this model.

As a big fan and staunch advocate of building with an architect, I have to say that this does not necessarily have to be related to the GÜ model. A highly questionable error culture can also be found abundantly in other trades and also among architects (in the latter case I am NOT speaking from experience, as I am still fully convinced I got the right one). Instead of being grateful that the error was detected early and thus significant costs and trouble could be saved later, the reaction is completely incomprehensible. Well, self-righteous idiots exist everywhere – across industries. [emoji6]

For the thermal protection verification. I would assume she will only create it once I approve this "Konstrukt" now.

That the thermal protection certificate must already be available at the building permit stage was not the case with us at least. It came comfortably half a year later and is still subject to changes that arise during the construction progress (specifically: two sandwich exposed concrete walls are dropped and replaced by masonry because the dirty elements have a 2-month delivery time). I believe it is not as big a deal as it is made out to be. However, once the place is standing, you should be able to present the certificate. How such a document formally looks and whether a general contractor is obliged to hand over these planning documents is uncertain. Intuitively, I would also assume that all plans related to the construction (working plans, heating load calculation, etc.) eventually pass into the hands of the builder/customer. That this does not necessarily have to happen as automatically and self-evidently as intuition suggests was shown to us by an expert who at the time reviewed a “Stadt und Land” contract for us and urgently recommended including a clause that ensures exactly this handover. He must have had his experiences and reasons...