Air-to-water heat pump sizing in new construction

Hello everyone,

we are planning a prefabricated house in timber frame construction. 180 sqm living space with underfloor heating. About 230 sqm usable area. So far, the offer included an air-water heat pump from Daikin (Altherma 3R formerly Rotex HPSU compact Ultra).

Now it has apparently emerged that this is not sufficient in terms of performance (?) and as an alternative (extra cost about 4000) we are being offered a "Wolf heat pump CHC Monoblock 10/300-35".

The Daikin is available in the 4-9 KW version, is that really not enough for this area? And what do you think of the offer?

I have the energy saving ordinance thermal insulation certificate and a renewable energy heat law available if information from these is needed.

Thank you very much!
Best regards

You need the heat load calculation for the house, or the room-by-room heat load calculation. If you have the [Energieeinsparverordnung], please upload it here anonymized. How far along are you with the project, if you already have the [Energieeinsparverordnung]?

Wolf heat pump CHC Monoblock 10/300-35

That's already quite a powerhouse in terms of performance. I can hardly imagine that one would need that for a house with timber frame construction.

And anyway, 4kW as the lower modulation limit is actually terrible.

That's why, as already said... tell us something about the house's data. And where the house is located.

What standard outdoor temperature is assumed.

If it turns out that the performance of the first heat pump is not sufficient, there must be a calculation. Have you seen it or even been given it?

Yes, show the calculations, 4-6 kW should be enough

Yes, show the calculations, 4-6 kW should be enough

...but please not one that only modulates between 4 and 6 kW.