ᐅ Sizing of Air-to-Water Heat Pumps for New Construction

Hello everyone,

we are planning a prefabricated house using timber frame construction. It will have 180 sqm (1,937 sq ft) of living space with underfloor heating, and about 230 sqm (2,475 sq ft) of usable area.
So far, the offer included an air-to-water heat pump from Daikin (Altherma 3R, formerly Rotex HPSU compact Ultra).

Now it seems that this unit might not have enough capacity (?) and as an alternative (additional cost around 4,000) we have been offered a "Wolf heat pump CHC Monoblock 10/300-35".

The Daikin is available in the 4-9 kW version—would that really be insufficient for this size? And what do you think about this offer?

I have the energy-saving regulation heat protection certification and a renewable energy heat law document available, if any information from those is needed.

Thank you very much!
Best regards

You need the heating load calculation for the house, or the room-by-room heating load calculation.
If you have the energy saving regulation (EnEV) document, you can anonymously share it here.
How far along are you with your project, if you already have the energy saving regulation (EnEV) document?

Pixelsurium schrieb:

Wolf heat pump CHC Monoblock 10/300-35

That’s quite a powerful unit in terms of output. I can hardly imagine needing something like that for a timber frame house.

And having a minimum modulation limit of 4 kW is actually pretty bad.

That’s why, as @T_im_Norden already mentioned... please share some details about the house and its location.

What is the design outdoor temperature (standard reference temperature) for the area?

If it turns out that the capacity of the first heat pump is insufficient, there must be a calculation. Have you seen it or even been given a copy?

Yes, please show the calculations; 4–6 kW should be sufficient.

Lumpi_LE schrieb:

Yes, please show the calculations, 4-6 kW should be sufficient

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