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

Once again regarding the heating load of the building. Are these values correct?

KFW-60 houses: approx. 50 W/m²
KFW-40 houses: approx. 40 W/m²
Passive houses: approx. 15 W/m²

For my house from the offer, that would mean:
7500W/122sqm = approx. 60W/m²

or calculated differently:
KfW40 house = 40W/sqm x 40W = 4.8kW
where I already find the 40W quite high and would rather tend towards 30W/m² = 3600W or less than half of the offer.

I think I will inquire again there and ask why the value is so high and, on the other hand, whether an air-to-air heat pump can also be obtained.

Forget the flat-rate calculations and for now also what comes from the home companies. Read up a bit more and give the companies appropriate specifications.

For orientation: we have a calculated heating load of 3.9x kW with 150m² without an allowance for domestic hot water. The house is somewhat worse than Kfw 40, region somewhat colder. The actual measured heating load for us last winter was a maximum of 3kW including domestic hot water.

Search for "Crinks Heizlast Tool" online. The tool is simple and sufficient for estimating the total heating load.

Unless your house is somehow special (in shape or glass areas), you come to a heating load of 3-4kW. You don’t need to calculate much more than that, because you probably won’t find a heat pump with correspondingly lower or exactly matching capacity. More important is the calculation of the underfloor heating.

Therefore the advice:
1. definitely a deeply modulating heat pump, not oversized (max 6kW, preferably less)
2. normal air-to-water heat pump, absolutely no exhaust air or ventilation combo device
3. floor heating planned for a maximum of 30° at standard outside temperature. Possibly wall heating in the bathroom.
("Room-by-room heating load calculation" with your desired temperatures per room)
4. and the usual: no buffer tank, no bypass valves, no individual room control at the latest when moving in

If you implement this, then that’s half the battle; if not, you have room for surprises in consumption.

why the value is so high and, on the other hand, whether you can also get an air-to-air heat pump.

No, you want an air-to-water heat pump, not an air-to-air heat pump! It is better that you calculate the total heating load for selecting the heat pump yourself; everything else will be pointless. By the way, the Energy Saving Ordinance calculation/energy certificate will differ, just file it away. Insist on the smallest model and on receiving the room-specific heating load calculation early, so that you can check it yourself in time. I would try to clarify the latter in your position.

Thanks again boxandroof! Of course, air-to-water heat pump (the abbreviations can get confusing quickly )

It is a "standard shoebox" house. So nothing special.
I used the Crinks tool and fed it with the data from the offer, as well as the advertised U-value (0.148) from the manufacturer of the FH (the roof is a bit better at 0.133).
Key data:
Standard outside temperature -12°C
H'T: (transmission heat transfer coefficient) 0.148 W/(m²·K)
Desired average indoor temperature: 22 degrees
A: (envelope area) 300m²
Ve: (heated gross volume) 440 m³
Maximum number of residents: 4 people

The values are already very interesting and significantly lower.
Central controlled residential ventilation with heat recovery
Transmission load: 1510 W
+ Ventilation load: 193 W
+ Domestic hot water load: 400 W
= Total heating load: 2103 W

Decentralized controlled residential ventilation with heat recovery
Transmission load: 1510 W
+ Ventilation load: 483 W
+ Domestic hot water load: 400 W
= Total heating load: 2393 W

Window ventilation or controlled residential ventilation without heat recovery
Transmission load: 1510 W
+ Ventilation load: 966 W
+ Domestic hot water load: 400 W
= Total heating load: 2876 W

I think with these values a geothermal heat pump will be too expensive.

H'T: (transmission heat transfer coefficient) 0.148 W/(m²·K)

What kind of house is that supposed to be?
I consider that very unrealistic.

That is what was stated on the homepage.