Air-to-water heat pump sizing in new construction

Yeah, the 75/6 can do that too. It just seems more efficient on paper.

Search for vwl75/6 A yields 6 results, the page of Vaillant from Austria with the data sheets

I have not checked the annual performance factor

Searching for vwl75/6 A results in 6 hits, the page from Vaillant Austria with the datasheets

I usually don’t make a fool of myself when googling

I hereby officially retract my statement :D But now I at least have a datasheet. Thanks for the hint. There I also find the max. volume flow you found. Unfortunately, it doesn’t really help me. 5.4 kW min sounds already quite a lot when I actually only need max 6... I have to find where the optimum between volume flow and low power is. Heizi either installs Vaillant or Daikin/Rotex. Daikin outdoor units have unfortunately been visually rejected by my wife. So I somehow have to find a suitable Vaillant for me. :rolleyes:

So, I have the feedback from the engineering office regarding the smaller Vaillant. He increased the supply temperature from 33 to 33.5°C and the return from 29 to 28.5°C, so the spread from 4 to 5 K.

Now the volume flows are lower and the small 75/6 A from Vaillant can deliver the volume flow.



Let's see how I can optimize this in the long term. It almost feels like an old building with 34°C supply temperature when I compare the benchmarks here with you. Our building shell with gable and bay window plus the many floor-to-ceiling windows really seems to make a big difference. But I am hoping for solid solar gains in practice, so that I can reduce the supply temperature over the years.

It's just a shame that I can't get the small 55/6, which would be perfect for our heating load, above the annual performance factor of 4.5....

In the list of eligible items, the 55 is included. Arotherm plus VWL 55/6 A 230V S2