Price difference ceiling heating/floor heating

Yes, just as you imagine it. Outdoor unit on the flat roof and distribute the necessary number of indoor units throughout the house.

The ceiling is ideal for cooling. Nowadays, almost every modern office building is air-conditioned this way. When heating, you have to make sure the ceiling temperature does not exceed 35 degrees. Otherwise, you get headaches.

Is he right!!!! But in the single-family house sector, I personally find it unpleasant because it feels unnatural. It's certainly a matter of taste; I would rather advise against it: -> underfloor heating + air conditioning

At least one conventional air conditioning unit is usually needed for dehumidification anyway (otherwise the ceiling cooling switches off too early due to condensate formation). Therefore, I agree with the majority opinion here. The underfloor heating could be supplemented by concrete core activation.

For the air conditioning units (indoors), have a drainage system with a dry trap installed directly by the plumbing so that the condensate does not have to be pumped away. And of course, plan the drillings and slots for the [KM] lines in advance.