Air-to-water heat pump sizing in new construction

If he meant 30°C supply flow, then that should mean the floor would be that warm. What goes into the heating pipes cannot be controlled. He would have completely misunderstood everything we have discussed (and documented) so far.

I find this statement alone shocking from a general contractor. I mean, okay, he doesn’t carry out the trade, but you should at least know a little bit about everything related to building a house if you offer it commercially.

A construction manager always refers me directly to his heating technician. He also wants to do about 35° supply flow for me, I’m not yet sure how to make him understand that I want it differently. He’s the type who thinks he knows everything better and that what is said in internet forums is nonsense.

Is there actually any source besides the relevant forums regarding low supply flow and laying distances? So that I might be able to convince him with it?

Thanks and regards

Tolentino

Yes, physics textbooks say exactly the same thing.

Order a heating load calculation including the design calculation of the underfloor heating with your desired supply temperature and then hold the calculation right in front of his nose... You don’t need to mention that you commissioned the calculation online

You pay, so you dictate what you want.

So I have the calculation in front of me. Apparently, we bought "bad" walls. A supply temperature of 30°C is not possible. According to the calculation, the required heating output is missing in several rooms. Interesting how much the brickwork and the many windows conflict with our desired temperatures. I don't think our neighbors with ETICS have similar problems.

Presumably, the floor heating will now be designed with 33°C - even then, the bathroom is still critical and must either be heated electrically or I persuade my heating engineer to install wall heating.

Fortunately, both my general contractor and the heating engineer have already installed wall heating. The heating engineer didn't sound enthusiastic and didn't want to comment on the additional costs, but I take that as a good sign.

Yes, that is not uncommon at all. There are situations where underfloor heating reaches its limits, regardless of whether you reduce the spacing, etc. The rooms do not mathematically achieve the required heating values, for example due to the number/size/type of windows, and also because of the wall construction, etc.

Then other approaches have to be taken, or wall heating systems used, edge zones installed, insulation values improved, and so on.

However, theory is sometimes somewhat different from practice, and it may be that later, when living inside, the temperatures are perceived differently and are sufficient for the individual. Especially since we rarely have -20°C here. Although that is usually not a problem with proper execution.