Looking for a cooling solution. Underfloor cooling?

We were / are in a similar situation: finished last year, KfW40, but timber frame. Our energy consultant told us that air conditioning is not possible with KfW40. However, we had the installer and electrician prepare the house so that later, quite uncomplicated, an air conditioner could be retrofitted in the upper floor and the living room. And we could also use passive cooling, but we have refrained from that for the time being. As I wrote recently in another thread, we were very positively surprised this summer by what can be achieved with shading and cross-ventilation. Temperatures are not bad. It will probably be more the humidity that will make us reconsider air conditioning....

Addendum: with us, the electrician and plumber only coordinated after the former had already finished. He then came by briefly for the necessary wiring, it was no big deal.

Our energy consultant told us that air conditioning is not possible with KfW40.

Yes, it's nonsense to the power of 10 again... but that's just how it is. You are allowed to have the device installed for heating, even with a subsidy. But if you want the same device again for cooling, of course, that's not possible.

Probably yes. And of course, 3k more in a project with a total budget of 550k (all in with kitchen, land, additional costs...) is not huge. On the other hand, I just once again have the feeling that the planning costs are running away...

I can well understand that. It is always easy to talk about "relations" when it comes to individual trades. In the end, however, it is the total sum that matters, and that is usually not insignificant. A few thousand more here, a few thousand more there... Ultimately, it is more about the principle and weighing the cost/benefit ratio. And the latter will probably be best achieved with a normal split air conditioning system, as already discussed in the other thread.

Maybe you just get a climate specialist to come, if they even have time before Christmas :( and discuss the project on site? Ultimately, even with full glazing, there will be possibilities to run the corresponding pipes through the adjacent rooms? What about the floor plan at the bottom? Is the shown section oriented according to the cardinal direction?

The floor plan is not aligned, but the top of the plan corresponds to NNW. Although now I’m also wondering if you are even allowed to install such a device, since the house comes as close as the minimum 2.5m to the boundary. At the bottom of the plan, on the right, there is the study for my girlfriend and at the very bottom, the two bedrooms; no air conditioning will be installed there (or I’ll move into the house alone...). And yes, the ideal solution would probably be proper consultation, but there won’t be enough time for that before I have to decide. Planning beforehand would of course have been even better, but air conditioning was never a priority for us and I’m still not really sure if we will actually need it. It’s just a bit cooler up there. That’s why a retrofit solution alone would actually be the most convenient; I just don’t know what that would cost financially.