Geothermal heat pump single-family house 200m² underfloor heating kfw55 - setting/optimization

then something is wrong here...
Warmwasser 4.2??

I can't quite believe that now: our heating is probably not super-duper optimized because with such a ridiculously low consumption, I somehow lack the motivation for it. Nevertheless, since commissioning, we have a COP of 4.2 for hot water, 5.9 for heating, and 5.6 mixed.

Including electricity for the heating pump and control of the heat pump? Your values are similar to mine. But I am currently reading that the distribution through heating must be included. And that is about 35W alone for the heating pump (which runs at subzero temperatures) for me, 25W standby for the heat pump, ERR+-valves and the other pumps + heating pump that run during heating even draw 255W. That means I continuously have at least 25W, the heating pump runs at 35W, about 15% at outside temperatures above 5°C and 100% below 5°C, and about 6 hours a day there are 255W more. Roughly, that is 2kWh on heating days (rather more), 0.7kWh on summer days, and probably about 1-1.5kWh in passive cooling mode. That naturally lowers the COP significantly. Especially for hot water.

I have now roughly estimated consumption values for the parts that run on the household electricity. This lowers the COP for hot water from 3.8 to 1.9 and for heating from 6.1 to 4.1 -> very sobering. For 5 months of hot water and 1 month of heating, this currently results in a COP of about 3.3 -> trending upwards. It will probably really be the case that I have to be happy if I end up at 4 after a year. That was the expected absolute minimum. But we'll see, there is certainly some potential for improvements. However, I never expected the heat pump to draw so much from the household electricity in standby and for the pumps during operation. That's about 500 kWh per year.

But I would never have expected that the heat pump in standby and for the pumps in operation still draws so much from the household electricity. That's about 500 kWh per year.

You don't have to look at it that way. The consumption for this "ancillary equipment" only appears high because the building's energy demand is low and the heat generation is efficient.
In the end, only the electricity bill matters and not the values on the way there.
Of course, I can understand the desire for optimization, but you don't have to take it to the extreme. I have 40€ heating costs per month (195 sqm, 4 people) – how much time should I invest in 5% optimization potential?

The bottom line is only decided by the electricity bill and not by values along the way. Of course, I can understand the desire for optimization, but you don’t have to take it to the extreme. I have €40 heating costs per month (195sqm, 4 people) – how much time should I invest in 5% optimization potential? Fundamentally, of course, absolutely correct. For me, it will probably also come out at around €40. It’s less about the money for me. I always hope that besides the concern of eliminating large consumers, everyone also looks to see if there are small savings potentials among the small consumers. For example, heating mainly runs in winter, and exactly then there is little yield from photovoltaics. From a climate perspective, it makes sense to look exactly there to see what else is possible. – but yes, one simply should have built a 150sqm house instead of a 200sqm house. That would be more sustainable.

I find it baffling how such values are reached inside the house. Yesterday, because we forgot, both floor-to-ceiling windows in the bedroom were tilted, and we still had "only" 19° in the bedroom. Just two adults lying in bed produce about 400 watts, which should noticeably increase the temperature in any new building after 6-8 hours.

The ventilation system alone already tends to keep the temperature relatively "steady" inside the house, or don't you have one?