Air-to-air or air-to-water heat pump?

Good day,

I am currently planning my construction project of a city villa (KfW40+) with approximately 140m² + waterproof basement.

I have 4 prefabricated house companies (timber frame construction) to choose from, all of which have different opinions on heating technology.

A water pump is the only thing that comes into question, that is clear. Everything else makes no sense.

However, I am torn between Proxon (air-to-air) and air-to-water.

The Proxon heating system has somewhat of a bad reputation, as I gather from various other forums.

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

I am grateful for any tips.

Best regards

Simon

Well, which is the better heat carrier, air or water? That already gives you the answer... The opinion about the air-to-air heat pump does not come from nowhere.

Your prefabricated house supplier probably offers an air-to-water heat pump for an additional charge if the air-to-air heat pump is included as standard. Why do you want to outsource this externally? Afterwards, no one wants to take responsibility when it comes to warranty, then one shifts the blame onto the other.

And the same applies to your [KellerThread] by the way. Unless you have external tradespeople whom you trust from private contacts and who won't let you down.

I would of course also be reluctant to outsource externally. Everything from a single source is always better, but I think that this will also be more expensive.

Air-to-air heat pump as standard and air-to-water heat pump for an additional charge, exactly!

I have read quite often about outsourcing a cellar externally.

The question is how risky the whole thing is, or how high the chance is that something will go wrong here?

If you plan early enough here and plan the civil engineering company accordingly properly, this should not be a problem, right? With a cellar costing about 70k, you can certainly save up to 10k here?

Basically, it is external. The basement builder is mostly a subcontractor for a general contractor. You always work with those you know and can rely on. We also have a waterproof basement made of watertight in-situ concrete, and honestly, I lack the imagination of where you see €70k and €10k savings there. The €70k being propagated here mostly refers to the finished basement. So walls, plaster, screed, heating, tiles, and not just the basement builder's service. That is estimated at around +/- €40k, now you can reflect again and consider whether the suggested €4-5k savings calculated proportionally are worth having more stress than necessary. It’s up to everyone personally, but to solicit, negotiate, and coordinate basic trades as an uninformed person seems a bit daring to me. But perhaps you will be lucky.

A prefabricated house provider sent me the offer of a basement subcontractor.

Here the offer with exterior stairs amounts to 66k. This only concerns the basement, clear walls, screed, etc. However, no heating.

That is quite a substantial amount. Another prefabricated house provider offers me the basement as an extra cost to the floor slab roughly between 30-40k.

I am a bit confused as to where these price differences come from..

I have currently inquired with the same floor plan and various specifications at glatthaar and am now curious about what price I will get here.