Costs for heat pump, water, and electricity

Hmm, your problem now is that the consumption on the general meter is 779 kWh, while your heat pump shows an electricity consumption of 810 kWh. That means you effectively cannot calculate any communal electricity because the heat pump believes it already consumes more. The fact is, you need a separate meter for the heat pump. Just wait and see what the electricity bill shows for the communal electricity.

You are right. I just read the values from the heat pump and the main meter again today for testing. Even in this case, the heat pump shows a higher power consumption than the main meter. What could that possibly be due to? Otherwise, I guess it means waiting and drinking tea until the bill arrives.

Well, the meter in the heat pump is often not super accurate, but normally it counts less rather than more. However, the power consumption is also too high just for the hallway light (in case the meter does not actually count the heat pump consumption). Asking an electrician would be my next option; he has to know exactly what is connected to the meter and might also be able to measure how much the heat pump really consumes.