Photovoltaic system air-water heat pump - profitability single-family house KFW55EE

you have to see it more positively, almost 100% of the photovoltaic yield in winter goes directly into heating ;)

in 2021 we had 29% self-consumption without much optimization, with a 9.2kWp system.

I believe we are now over 50% with our 4.55kWp system. But we are working from home, optimizing kind of "lari-fari" (turning on the washing machine / dishwasher when the sun is shining), and our IT continuously consumes a lot of electricity.

Why is the percentage so important to you? I mean as a number?

Self-consumption determines profitability today. It is useless if you produce tons of kWh that are fed in at 7-8 cents while you pay much more for your own electricity.

Mmh, I dare say that it is smarter to operate a 10kwhp with 30% own consumption than 4.8 with 50%. It is clear that as much as possible should be self-consumed.

and continuously consume a lot of electricity through our IT.

Ahem. Charging 2 laptops + say 2 flat screens each at 20W amounts to about 1 kWh per 10-hour workday. Or which “IT” is being referred to here?

Ahem. Charging 2 laptops + say 2 flat screens each at 20W amounts to about 1 kWh per workday of 10 hours.

Or what kind of "IT" is being talked about here?

4 screens, 2 developer machines with several IntelliJ instances open (building the project is like blowing air), plus coffee machine, external audio interface for XLR mic, router, access points, air conditioning in summer. When the work PCs shut down, the gaming PCs start up with 1000W and 800W power supplies.
It all adds up, together with the "other" household electricity.