Vaillant Arotherm Owners Thread

1.5kW at -3C? Almost passivhaus?

My heat loss survey was 5.4kW at -2.5C

You can read all about my design and how we sized it here:

and a shorter summary here:

I will be very interested to see the heat meter trace from the 3.5kW unit. Just to see ‘how low’ it can go, in terms of electric in and heat out.

The 3.5kW is the smallest unit on the market I think. but I have heard it’s just a downrated 5kW unit. The ‘golden’ doc suggests there isn’t much difference in the ‘floor’ of both 3kW and 5kW units. It’s more than that the smaller unit can’t reach as high.

Yeah, it’s on 65%
I had to leave it here as I had issues with my heat meter when I ramped the flow rate up.