House construction, KFW70, approx. 150m², which heating? Gas/air-water heat pump?

Hello, we want to start building a home this year. For various reasons, we want to work with a provider where we have everything from a single source. At the moment, we are deciding between Fischer Bau and Helma.

About our house: We are 95% sure that it will be the house according to the attachment (Attachment: image comes from the provider Fischer Bau).

We would like to achieve KFW70. No basement, underfloor heating throughout the house, shutters throughout the house, additional towel heater in the bathroom, clinker bricks, Grüppel hip roof. The plot is located in a village, roof surface (with dormer) probably south-southeast.

I have been looking and reading about all topics of the house building project for a while now. So far, I was also impressed by the air-to-water heat pump. It seems to me to be a good and secure heating system that already looks somewhat into the future. The more I dealt with the air-to-water heat pump, the more negatives also appeared.
Our two providers each proposed a gas heating system with solar in their basic offer. However, in response to my inquiries, both also offered an air-to-water heat pump with ventilation and exhaust heat recovery.

In any case, I am currently very uncertain about what the right heating system for our house is. Many statements about the air-to-water heat pump, such as that they are very loud and inefficient, come from the years 2010-2012; I don’t know if that is still current. Gas is basically not bad either, a solid heating medium with mature technology.

I hope I can get a few comments and suggestions here on how to best proceed. I think ventilation/exhaust is important today because houses are very tight and you can/never ventilate as often as you should.

But gas? Solar? Air-to-water heat pump? I am somehow overwhelmed with information and I can’t really find any independent/unbiased opinions.

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Hello,

I have edited your post to add the link; please observe the forum rules. Thank you!

Best regards from the Rhineland
Building Expert

Unfortunately, I could not find the button to edit the post. Here is an addition regarding the heating system we were offered by one provider. We will receive the second offer on Saturday.

Vaillant solar-gas compact unit with condensing technology, auroCOMPACT VSC S 206/4-5 150 with 150 liter stratified storage tank and 2 flat collectors with a gross collector area of 5.02m² VFK 145V, including complete accessories for the solar station and the solar device Auromatic 560/2.

Before selecting a device, a heating load calculation should be available (although it can already be roughly estimated - especially if they are model houses). There is initially little against gas and solar - you can even achieve KFW70 with them (provided the rest is right).
If you compare the heating costs of an air-to-water heat pump with gas, it may well happen that gas comes out cheaper, as does the investment cost. The advantage of an air-to-water heat pump is that you are independent from gas and do not need a line - but even with a line, gas heating is often still cheaper than the air-to-water heat pump.
By the way, the air-to-water heat pump is not really more ecological - unless you produce the electricity yourself or it is very, very efficient.
Furthermore, the air-to-water heat pump is significantly more susceptible to planning errors - if it is incorrectly dimensioned, if the underfloor heating is installed incorrectly (e.g., too far apart), etc., it quickly becomes expensive (I will explain shortly).
If the KFW70 house only becomes KFW70 with the air-to-water heat pump (and the insulation is not right), I would advise against it from my gut feeling - the heating system partly relies on heating little or working with very, very low flow temperatures (every degree costs efficiency). If the heat losses of some rooms are too high, for example, if 6 m of windows with a Ug of 0.9 and a Uf of 1.3 are installed in the living room and then the underfloor heating has a 20 cm pipe spacing, the air-to-water heat pump will struggle and will switch on the heating element in deep winter and then money burns away.
What I recently read is that frequency-controlled air-to-water heat pumps are supposed to perform very well - also inform yourself in this direction.
Take a look at the pink forum, where the types of heating are discussed up and down every day. The wrong heating system does not exist - it always depends on the building you are constructing, the location of the building, the usage, the quality of the planning, the preferences, etc.

Solar? Solar thermal for hot water or photovoltaics for electricity? Probably solar thermal ...

Ug? Uf? Pink? (preferably by private message, I only know a green (?) forum, ah, the vastness of the WWW ....)

From the gut:
- Central ventilation with heat recovery (for the feel-good climate)
- Underfloor heating with gas condensing boiler
- Solar thermal supporting hot water generation

Have a price quoted for that. Have a comparative price quoted for an air-water heat pump. Then report back here

I can say very clearly that air-water heat pumps are always more expensive than the gas/solar thermal variants. But your short summary Bieber is, I think, what has appealed to me more since this week. Classic, mature gas technology with hot water support from the sun and then additionally (unfortunately, no one offers this as standard) the ventilation with heat recovery.

For the ventilation, there is one option with "holes in the wall" and a proper system from Vaillant.

Which would you rather recommend?

It's not entirely clear. There are also air-to-water heat pump units for just over 3,000 euros – they just aren't usually offered to you. Generally, that's true of course. Question of belief. So they'll probably recommend a central system to you – quieter, nicer, usually better heat recovery, possibly more energy-efficient, etc., but you have non-visible pipes in the house where rats, spiders, and martens breed.