ᐅ Air-to-Air or Air-to-Water Heat Pump?

Hello,

I am currently planning my construction project for an urban villa (KfW40+) with about 140m² (1507 sq ft) plus a waterproof basement.

I have four prefabricated house companies (timber frame construction) to choose from, all of which have different opinions regarding the heating technology.

A water pump is the only option that makes sense, that much is clear. Everything else does not seem reasonable.

However, I am undecided between a Proxon system (air-to-air) and an air-to-water heat pump.

The Proxon heating system has a somewhat poor reputation, based on what I have read in various other forums.

Are there any experiences or tips regarding the heating technology? What are your recommendations? Is it also possible to have the heating system installed externally by a heating company and exclude the prefabricated house provider? Has anyone had experience with this? What are your general experiences or approaches with prefabricated house companies regarding heating technology?

I would appreciate any advice.

Kind regards

Simon

Well, which is the better heat transfer medium, air or water? That already gives you the answer...
The opinion about the air-to-air heat pump doesn’t come out of nowhere.

Your prefab home provider probably offers an air-to-water heat pump for an additional charge if the standard package includes an air-to-air heat pump. Why do you want to subcontract that externally? Later on, no one will want to take responsibility when it comes to warranty issues, and they will just blame each other.

The same applies to your basement thread, by the way. Unless you have external tradespeople from private contacts whom you trust and who will not let you down.

I would also prefer not to outsource externally. Having everything from a single source is always better, but I think it will also be more expensive.

Air-to-air heat pump is standard, and air-to-water heat pump is available at an additional cost, exactly!

I have often read about outsourcing the basement.

The question is how risky this really is, or what the likelihood is that something might go wrong?

If you plan early enough and schedule the civil engineering company properly, this shouldn’t be a problem, right? For a basement costing around 70,000, you could probably save up to 10,000 here?

Basically, it’s an external service. The basement contractor is usually a subcontractor when working with a general contractor. You always work with those you know and can rely on. We also have a waterproof concrete basement, and honestly, I can’t imagine where you’d see savings of €70,000 and €10,000 there. The €70,000 savings often mentioned mostly refer to the finished basement—meaning walls, plaster, screed, heating, tiles—not just the basement construction itself. That is estimated at around ±€40,000. Now you can consider whether the suggested €4,000–5,000 savings calculated proportionally are worth the extra stress. That’s up to each person, but I find it a bit risky for someone without experience to source, negotiate, and coordinate basic trades. But maybe you’ll be lucky.

A prefabricated house supplier sent me an offer from a basement subcontractor.

This offer, including an external staircase, amounts to 66,000 (66k). It only covers the basement itself, including walls, screed, etc., but no heating.

That is quite a substantial amount. Another prefabricated house supplier quotes me the basement as an additional cost to the slab foundation roughly between 30,000 and 40,000 (30-40k).
I am a bit confused about where these price differences come from.

Currently, I have requested a quote from Glatthaar with the same floor plan and various specifications, and I am now curious about what price I will get here.