Suitable heating system for new construction - how to choose?

Hello everyone

we are currently taking the next steps towards owning our own home.
We have now looked at some prefabricated houses and spoken with several sales consultants from various providers.
From this, we have created our top 5 list.
Now I would like to contact these 5 companies with our floor plan and the standard we desire.
In this way, I hope the list will shrink by 2-3 providers once I have received the first offers.

In my inquiry, I want to roughly state what we imagine. KFW55, KFW40, or KFW40+ is initially not so important, it will be one of these.
Our floor plan does not differ much from the standard floor plans of the prefabricated house providers. Square 8x10 or so...
So that I can compare the 5 offers somewhat equally, they should all be as similar as possible.
Therefore, I would like to specify the heating system.
Now the question is what is the right one....
I suspect this is partly a matter of philosophy?
Possible options are air-to-water heat pump or air-to-air heat pump or geothermal water-to-water heat pump.
I guess most have one of these three designs combined with solar on the roof.

My first thought was as follows.
Air-to-air heat pump, since we also have automatic air exchange in the house here and ventilating would be less or not necessary at all.
Now I have learned that all KFWx houses are so airtight that an automatic ventilation system is almost always included.
So that argument is no longer valid.
Nevertheless, I still find the air-to-air heat pump topic interesting.
We also want to have a wood stove installed in the living room. With an air-to-air heat pump, the room air is circulated throughout the house and I could benefit from the heat of the wood stove in the whole house, right?
Maybe even work with heat recovery, which is usually included.
Then there would also be the advantage with the air-to-air heat pump that if it ever gets too warm, we can install a fixed air conditioning unit somewhere in the house and the whole house benefits from it?
Because the automatic cooling that comes with those systems is usually not as good as promised.

Is it true that air-to-air heat pumps cannot provide hot water? Then a second system would be needed just for hot water... More costs again, two systems to maintain and space lost.
In the forum, I mostly see only air-to-water heat pumps, so probably underfloor heating. That seems to be the most popular system. Is there a special reason for that?

The most effective seems to be geothermal in combination with the heat pump. Then I also have underfloor heating, right?
Actually, we did not want underfloor heating, but while writing this, I am convincing myself towards geothermal or air-to-water heat pump...

How did you make your decision and why?
I somehow don’t fully trust the salespeople yet because they want to sell whatever makes more money, right?
And since I am not technically knowledgeable in this topic at all, I hope for your experience.

Best regards
Andreas

What exactly are the questions that are still open? The internet is full of experiences. Why don't you want underfloor heating?

I have now searched the Internet for hours/days. I was hoping for some reviews from here. How did you make the decision and why for one and not the other. Why no underfloor heating, I can't really say exactly, it's more of a feeling, so not really tangible.

So that I can at least somewhat compare the 5 offers, they should all be as similar as possible.

Well, I wish you good luck! If you really want to be able to compare the offers, then they have to be the same, ergo you have to specify ALL details. But hardly any general contractor would agree to that, and you would probably need "technical assistance" (an architect) for that.

Possible options are air-to-water heat pump, air-to-air heat pump, or geothermal water heat pump.

Sure? It’s not without reason that nowadays an air-to-water heat pump is most often regarded as standard. Geothermal energy has to be geologically feasible in the first place (do you already have a specific plot of land?) and an air-to-air heat pump is rather something for passive houses. Accordingly, even from your three top candidates, one might practically remain through natural selection.

You can find more details, for example, at :D

Unfortunately, I can only report from limited personal experience. Radiant heat is the most pleasant heat; the sun gives us radiant heat. In principle, underfloor heating also works according to this principle of radiant heat, additionally, the floor is heated and then also emits some convective heat. This makes underfloor heating quite comfortable. Theoretically, you can also cool with underfloor heating and a heat pump; the effect is rather negligible in terms of cooling capacity, but at least you have a cooler floor barefoot in summer. (= Assumption) I see two disadvantages of underfloor heating: It is a very sluggish system, and individual room control makes little to no sense. Air-to-air heat pumps heat the air, which usually also makes the air very dry. Personally, I cope very poorly with dry air (-> heating in the car in winter). This would be an absolute exclusion criterion for me. Even though an air-to-air heat pump is probably by far the cheapest option in terms of price. (Price is, in my opinion, absolutely the only advantage of air-to-air heat pumps)

I would also read some experiences, the whole internet, including here, is full of them.
Regarding your specific points:
An air-to-air heat pump only makes sense in a zero-energy house, otherwise it consumes too much electricity and is uncomfortable.
With a heat pump (air-to-water heat pump or geothermal), you need a surface heating system. The most cost-effective is underfloor heating, but wall or ceiling heating also works.
Where does the aversion to underfloor heating come from? In a normally used single-family house there is no reason against it or for something else like radiators.
The most economical is KFW55 + air-to-water heat pump + photovoltaic, but with the current subsidies for KFW40+ there is probably not much difference anymore. For everything else you need personal reasons.