Air-water heat pump current consumption and data

Do you have a ventilation system?

If no explanation is found by next winter, it might be interesting to take a look with a thermal imaging camera (maybe borrow one somewhere?).

Yes, we have one, but still a balcony door is left open for about 30 minutes (because of the cat or for airing). Also, when cooking, we ventilate everything thoroughly, etc. We simply love to throw open doors and windows when needed, even if it costs some energy.

However, the pump only runs about 3 hours or so, which is manageable.

Actually, right now is the perfect weather for air-water heat pump + solar + battery: AT > 6*C, so no energy-consuming defrosting processes, heat pump regularly draws the battery almost empty for heating purposes (we have felt a maximum of 13 *C AT here for weeks), still enough solar yield for direct use and battery charging (12.8 kwh) due to the long daylight even without direct sun, little ineffective feed-in to the grid. Only the lots of money for terrace and garden felt purely pointless...;):mad:

If there is no insulation yet, that does not help me.

Yes, it does. An uninsulated house is just as "good" as your insulated house. So the problem with you is not the heat pump, but the house itself.
Who knows how "good" your house really is and not just nicely calculated on paper.

I think your house is fine. We have Kfw 40+ and the heat pump still runs every day. Room temperature 22 - 23 degrees. It has been windy for weeks, sometimes strong, outside temperature between 1 and 15 degrees and it is almost always overcast, so no solar gains. No idea how you are supposed to manage without heating under these conditions.

What did the Bowerdoor test show?

Likewise here, during the day 12-16°C AT, little sun, at night down to 4°C. So far there have been one or two days without heating, otherwise it heats about 3 hours a day plus hot water preparation. KFW 40 with blower door test just above passive house level.