What annual consumption should be specified in the electricity contract?

No, that applies from moving into the finished house.

Exhaust air heat pump is like roulette, unless it is a [Passivhaus]. I would plan some buffer. Especially because hot water is probably also supplied via it, there is a chance that the heat pump turns into a pure electric heater.

Well, only hot water is prepared via the exhaust air pump. The underfloor heating is supplied by the air-water heat pump. Therefore, I will first try to operate the exhaust air pump in eco mode (heating element is not used).

Better to have a few kW more and be happy about a back payment than too much. It also depends on which region you are in and how cold it gets.

Well, only hot water is prepared via the exhaust air pump. The underfloor heating is supplied by the air-water heat pump. Therefore, I will first try to operate the exhaust air pump in eco mode (heating element is not used).

True, I overlooked that. But why do you have a separate exhaust air pump for domestic hot water? That doesn't make any economic sense at all?

Hm, whether this makes economic sense I might be able to tell you after a few winters ;)

This combination is what the developer offered in all the townhouses, so we couldn't have chosen anything else. Naively, I think that the outdoor unit only has to provide the 35 degrees flow temperature for the underfloor heating in winter, and the exhaust air pump, which receives the heated air, can work more efficiently.