Air-to-water heat pump sizing in new construction

I am currently still working on hydraulic/thermal balancing access and trying to minimize cycling because it simply isn't cold enough yet to push the system to its limits. And yes, we do have controlled residential ventilation, but not from Vaillant

Didn't you have a controlled residential ventilation system with WRG? Because ventilation loss is fully included there.

17x2 pipe is better than 16x2.

I understood that too. But better in relation to what? Do I then need less volume flow? Less supply? Less pipe?

Didn't you have a controlled residential ventilation system with heat recovery? Because there is a ventilation loss stated there.

If you meant me, then yes. No idea what the energy consultant calculated there and what the heating engineer then took from that calculation as a basis for my design. I don't care either, I just want him to agree to the small heat pump now. :) Let's see what Vaillant suggests for my needs. As long as it stays with the Arotherm plus, it can only be the 75 because of the funding eligibility. My heating engineer also doesn't really want to install the split units, since he wants to switch to R290 in the future.

Larger pipe diameter mainly means less pressure loss, the pump has to work less. 16 or 17 can both fit, that also depends on the calculation.