Cooling ceilings instead of air conditioning, is it sensible?

I do not know the "other" system. But I know the problem of the German summer: the humidity. If the system cannot reduce it, it can at best serve as a supplement to the traditional air conditioning.

Thank you, that confirms my initial suspicions. I think we’d rather stick with the classic air conditioning, like we currently have here in the house. In summer, doors are often open when visitors are around and people are coming in and out. Especially then, you might want to specifically cool down if you have let in heat. And I really like the humidity control of our air conditioning. Building without air conditioning is out of the question, especially since we have already gotten used to the increased quality of life. In light of the latest report from the [Weltklimarat] (which got somewhat overlooked because of the war), I think the climate-relevant days will also increase. :/

I need to bring this topic up again. We are currently planning. We have discarded chilled ceilings for now; instead, the central ventilation system is to be installed in the house again. Additionally, my husband still wants an air conditioning system. We are now considering how to size it. In the old house, we had a Mitsubishi outdoor unit of 7100W with 3 split units. One in the upstairs hallway for the entire upper floor, one downstairs in the living/dining/kitchen area, and another one downstairs in the office.

The old house has 152 m² of living space, and that was sufficient. That won’t be enough for the new house with 215 m², right? Are there air conditioning systems that work through the ventilation system installed in the house? That would be cost-effective because the ventilation grilles are in every room anyway. But I have read that the low airflows are not sufficient for proper air conditioning. So, do you have to go with split units after all?

So how important it is to you to have many indoor units, you have to decide. For me, one per floor with open doors is enough. But the power is definitely too high. Why should you have more cooling capacity than heating load? A 5 kW heat pump is enough to bridge a delta-T of 30°, so why do you need 7 or more for a delta-T of 10°? In new buildings, a 2.5 kW unit in a central location should be completely sufficient. It can then run nicely for 12-24 hours at 250 watts and the whole house remains comfortable. Just like with heating, you also want to avoid cycling with air conditioning units.

So how important it is to you to have many indoor units, you have to decide. One per floor with open doors is enough for me. But the performance is definitely too high. Why should you have more cooling capacity than heating load? A 5 kW heat pump is enough to bridge a delta-T of 30°, so why would you need 7 or more for a delta-T of 10°? In new buildings, a 2.5 kW unit in a central location should be completely sufficient. It can then run nicely for 12-24 hours at 250 watts and the whole house stays comfortable. Just like with heating, you want to avoid cycling with air conditioning as well.

Can you name systems that work like this? Maybe also in combination with a controlled residential ventilation system?

Uh - single split air conditioning unit, just normal.

It has nothing to do with the [Kontrollierte-Wohnraumlüftung].