Heating load calculation 10.3 kW, is a 9.5 kW air-to-water heat pump sufficient?

Whether the lower modulation range fits, you can find out from the datasheet. The modulation range at different operating points should be indicated there. The lower limit at A7 (7°C AT) would be interesting. Then you can estimate how well the heat pump fits during the transition period. At A-7 you can estimate whether the performance is sufficient in winter or whether the heating element needs to be activated early. Also check the heating load calculation carefully, which room temperature was assumed, does it meet your wishes... Was a room-by-room heating load calculation created with the parameters of your house?

Many thanks first of all for your quick help and responses. That already helps me a lot for the next conversation with our heating engineer. As soon as I have more detailed information, I will get back to you.

It starts at 2.6, could work since modulating.

I also find the heat pump with 10kW oversized for the QM, but you’re paying the expert, he should know what he’s doing.

I also find the heat pump with 10kW overdimensioned for the sqm, but you pay the professional, he should know what he's doing.

I wouldn't trust that blindly when it comes to heat pumps...

So, I just received a letter regarding the annual performance factor calculation. If I read it correctly, it is "only" 8.1 kW?

Performance factor Cop (A-7/W35 / A2/W35 / A7/W35): 3.3 / 4.31 / 5.12
Nominal power in kW (A7 / W35): 8.1

Overall annual performance factor: 4.61