New single-family house construction | Selection of the "right" heating technology

I calculate roughly like this. Gas heating including solar and connection 6000 compared to air-water heat pump. KfW does not interest me. Operating costs estimated by BU, gas 1000 per year. Electricity for the two of us now 850,- per year. 1850,- plus 50 euros chimney sweep equals 1900,-. Air-water heat pump, gas zero, chimney sweep zero. Electricity, yes, if cold winter, then 2400,- per year, if mild winter, then only 1800,-. On average over the years, the air-water heat pump is not cheaper in operation than gas, only it is more expensive to purchase. Both systems need to be maintained, because it would be unfair to say one breaks down and the other does not. That is left aside. If I could now reduce my electricity consumption of the pump by say 400,- per year through Photovoltaics, which would be possible, it would look better. Unfortunately, the Photovoltaic system will again cost several thousand in investment. So, nothing gained except expenses. Karsten

Why do you always come up with these absurd numbers? 2400€ electricity, such nonsense. We already understood that you prefer gas, but let’s drop the dramatics.

Drilling over 100m requires another approval instance, yes. That means two more forms that the drilling company submits. No drama according to our provider, this is only dealt with as an imaginary limit on the internet.
Having only one borehole is both more effective and efficient, I’d get a consultation on that again.
I had set Bafa at 5000, most heat pumps are now sg ready and then there’s a 500€ load management bonus.

Without heating load and knowledge about the expected extraction performance at the location, the target depth is just a shot from the hip.
We were offered 60€/m plus 300€ for the container. Including house entry, practically connection-ready for the heating engineer.

I can already tell that I actually need to delve even deeper into the subject than before.

Apparently - but to some extent I was aware of this - you really must not accept anything without scrutiny and cannot simply trust anyone in this industry.