KfW energy calculation with cooling heat pump

I'll join in here. We had also considered cooling the house in the summer using controlled residential ventilation. A system from Zehnder was recommended to us for this purpose, which is supposed to cool through an additional feature. It's apparently called Comfocool. Has anyone had experience with it?

And does it make sense to pre-install the appropriate lines for an air conditioning system (split) so that you can retrofit air conditioning units later without much effort/cost? Or is that nonsense and should rather be done together with the installation? Perhaps technology will change and the lines will become "outdated"?!

The cooling capacity of a controlled residential ventilation system without "real" cooling units is rather homeopathic. Every window that lets even a little bit of sun in immediately ruins the modest effect for you. For effective cooling or (also heating), the volume flow of a normal controlled residential ventilation system is far from sufficient. You are only slightly reducing the intake temperature and distributing that small amount with a gentle breeze throughout the house. I would take care of the split system right away; otherwise, after the first summer in the house, you'll start again. For example, we planned a 3-split system with the bedroom, living room, and study. It can then be excellently operated with the solar power generated at the best sun time, if you wouldn't need it anyway. Cooling through the floor already brings a bit more (although mostly just cold feet), a cooling ceiling is a little better. However, nothing replaces a unit that actively produces cold and does not just reduce heat a little.

which is also supposed to cool through an additional feature. I think it’s called Comfocool. Has anyone had any experience with it?

It is a cooling coil with brine/water. But it doesn’t help much because the maximum air volumes for the whole single-family house are around 300-400 cbm, whereas for active cooling about 800 cbm per 30sqm is required. You can do the rest of the math yourself. The star up there is simply quite strong and there isn’t much you can achieve with a controlled residential ventilation system. But it does a very good job ventilating the house. Every device has its purpose and generally it fulfills very well the purpose for which it was designed.

I would think straight away about active cooling and at least have the lines installed. You don’t need to be afraid, no, these will not become obsolete. It’s only two copper pipes, a 5x1.5 NYM cable, and a condensate connection per indoor unit.

I would immediately think of active cooling and at least have the lines installed. You don’t need to be afraid, no, these will not become obsolete. It’s just two copper pipes, a 5x1.5 NYM cable, and a condensate connection per indoor unit.

Two copper pipes per indoor unit that are then routed to the location of the outdoor unit? The condensate connection must then be installed with a slope to the next wastewater connection point? We are also currently considering having the appropriate preparations made. With our current attic apartment, we are quite resilient, but you never know.

Yes, two pipes per unit from A to B + NYM for power supply and control. For multisplit, you have to distinguish because there are different procedures: either all B's to A or from A to B to C to D or from A to the distributor and from there then the B's are served.

But you can't go wrong if you only lay (pre-install) from A to B, if necessary even multiple times. The costs remain about the same.

A = outside
B,C,D = inside

Condensate then with slope either directly out through the wall/roof or into the next HT pipe (of course with a siphon).

According to our heating engineer, that doesn't make sense. Cooling should be done better through the controlled residential ventilation - but preferably through an air conditioner.

That is not entirely correct. It does reduce a few degrees. I have several acquaintances who confirm that. However, it is of course not comparable to an air conditioner. We are having a Bosch ground-source heat pump with cooling function and additionally a controlled residential ventilation installed.