It is only about the household electricity because wrote in post #226:
Well, with the (hopefully) repaired heat pump, we currently consume about 25 kWh per day. Of that, an estimated 12 kWh are household electricity and the rest (12-13) the heat pump. We don’t know exactly, but in the old house, we last had about 12 kWh on average electricity/day.
Therefore, I am somewhat reassured regarding electricity consumption.
Currently, we still heat with oil (Buderus). Hot water also comes from there. The heating system will eventually be replaced. So far, it has been running without any problems. Nevertheless, I already had a gas connection installed because it was free. However, the CO2 tax will come starting in 2021. Therefore, I am not yet quite sure about the next heating system, possibly pellet(?). "Our" installer said there would soon be a new refrigerant for air-to-water heat pumps that would increase efficiency so that they wouldn’t necessarily have to use electricity for backup heating even on particularly cold days. Long cold periods are common in our area. When others are already working in their gardens, we often still have snow or at least it’s not yet possible to think about the garden due to the temperatures. A year ago, I had a cost estimate made for a ground-source heat pump plus solar on the roof. It took some time until the offer came. When I finally had it, I knew why. It comprised about 50 pages and each page was supposed to cost on average €1,000! Installation work was not included and would have been five figures again. I didn’t read it that precisely anymore because €50,000 plus 1X,000 € for a heating system – even with funding – is beyond reason for me. And I think I still remember that – contrary to my wish – only an air-to-water heat pump was included in the offer. I am also considering first getting a gas heating system and waiting to see what happens in the heating technology sector. Gas boilers don’t last forever either and according to my energy consultant, I could still "survive" with a gas boiler for now. I took that as a compliment ...
Heating is another project anyway :)