Cooling with heat pump via underfloor heating?

May I ask how much the air conditioning cost? Did you build with Viebrockhaus?

No, with a construction company that mostly operates in the northern region. I think we paid about 5000 for the air conditioning. The preparation for something like that should not be underestimated; because of the condensate water, substantial pipes had to go through the walls.

Preparation for something like this should not be underestimated; because of the condensation water, solid pipe sections had to go through the walls

This is very individual. Sometimes it's only 1 meter of hose that is routed through the sloping roof/wall to the outside. It depends on the installation location and form factor of the system.

I just spoke with our prospective neighbor yesterday because he is unsure whether an air conditioning system should be prepared or not. My advice: If it is not completely ruled out to install a unit at some point, he should definitely at least provide the condensate lines. This only costs a small additional charge, but with reasonable effort, it will no longer be visually appealing to implement later. If I take these items from our offer, we are talking about roughly 1200 EUR gross. Depending on where your drains are located, you might even save a few meters.

So we are building Kfw 40+ and definitely want an air conditioning system. We would have 60sqm open space and 20sqm work/bedroom to cool on the ground floor and on the upper floor three rooms of 18sqm each and one room of 12sqm. Our construction company mentioned something like 20-25k for everything. One unit in each room. But the company does not install it themselves; they would also source it through a subcontractor. This subcontractor is known for his pharmacy prices. We have now contacted several companies ourselves and are waiting for offers. I'm curious... In the open space, for example, I would like a ceiling outlet and no unit on the wall. But this will probably be difficult to impossible due to the statics / delicate ceiling.

Everything is possible if it is planned early enough. For a ceiling cassette, however, I would rather increase the room height and use a suspended ceiling. Then you also have plenty of space for all kinds of other lines.

For our system with a similar size (although "only" with normal wall units), we will definitely stay well under 20 K, which also seems to be a good price for the models used compared to some nationwide (Internet) providers.

We have an increase in space, which would basically be negated by the implementation of an attached ceiling. Let's see what the detailed planning of the offers says...