KfW40 house offer with AWP and controlled residential ventilation, is it any good?

I think that with these values a ground source heat pump becomes too expensive.

Yes, that is true for deep drilling. A trench collector would still be an option: similar costs due to subsidies and with own effort during installation. A somewhat nicer technology, consumption slightly lower again.

This is what was stated on the homepage.

You need the H't value of the house. You are missing windows, floor, thermal bridge allowances. In the end, approximately another 1,x kW will be added. One way or another, 4kW is sufficient if the controlled residential ventilation is installed – and probably otherwise as well – but then no longer computationally. Inform yourself for the planning of the underfloor heating.

That is what was stated on the homepage.

Yes, U-value of the walls 0.148
The HT value for Crinks-Tool is something completely different.
Should be between 0.25 and 0.3 for the house.

Ah ok thanks for explaining. But even with 0.3 everything is still acceptable. Instead of 1500 W transmission load, you then come to 3000 W accordingly. Controlled residential ventilation is desirable, as the property borders the A3 motorway to the west. According to the "Geothermieportal" of NRW, a ring trench collector is apparently not possible on the property (No. 231). The casual statement about it is "too shallow".

Can you actually calculate the electricity consumption from the "total heating load"? With an estimated 12,000 kWh of heat, you would be at around 800 euros per year for gas (just as a comparison) and for electricity at 4000 kWh at just under 1000 euros with the heat pump rate, and with "normal" electricity at a little over 1000 euros. Or is the calculation wrong?

Only roughly. But KFW40 for 120sqm is 12000 way too much, also with a heat pump you don’t have a factor of 3 but rather 4, so 3000 kWh. Also, with gas there is the chimney sweep added. 120 sqm, with the described house, no exposed location, no major shading and normal heating behavior is probably more like 7000 kWh. So about €450 gas including basic fee + about €100 chimney sweep. Electricity would also be about €450, but without additional costs.