Oh man... actually don’t want to digress, but ok, just briefly, then please BTT. It is (or rather we are in the process of) a renovated old building. Calculation was at 7.9KW. An 8KW would be too tight, the 9KW was almost the same price as the 13KW, especially since a 45% BAFA subsidy also plays a role. Availability is also uncertain for anything between 8-12. At least the large one was immediately available except for the outdoor unit. In addition, it has higher efficiency at cold temperatures, meaning the supplementary heating or the "heating element" only starts at (now I have to estimate because I don’t remember exactly) -10°C, with smaller units it starts earlier. Furthermore, the system should also be able to cool in midsummer, which smaller ones probably can’t or at least not with this efficiency. All this information comes from the consultation with my plumber. I felt very well advised by the plumber, I also know him personally and consider him a competent partner. I don’t think he’s trying to take me for a ride, otherwise he won’t get a beer at the housewarming party.
