Newly built single-family house KfW55 standard - How to heat?

I'm totally with you. Personally, I would also prefer gas. However, in most new development areas – like ours – unfortunately no pipelines are being laid anymore. So the only options left are the air heat pump, air-water heat pump, or the ground-water heat pump...

or liquid gas.

In my opinion, you will have massive costs. Electric underfloor heating means a 1:1 conversion of electricity into heat. Especially in small rooms, you don't even have enough surface area to implement it. The heat output is also limited due to the surface temperature.

If your provider promotes the concept, they will surely have built other houses with it. Ask for references and talk to the homeowners.

With the approximately €30 per month you calculated, you can supply the entire house including hot water with a heat pump.

In my opinion, you will have massive costs.
Electric underfloor heating means a 1:1 conversion of electricity into heat.
Especially in small rooms, you don’t even have enough surface area to implement this.
The heat output is also limited due to the surface temperature.

If your provider promotes this concept, they must surely have built other houses with it.
Ask for references and talk to the homeowners.

Good idea. I will definitely bring that up in the next conversation.

With the roughly €30 per month you calculated, you can power the whole house including hot water with a heat pump.

True. My calculation doesn’t convince me either...

If you have to save, better leave out 4 sqm than do such nonsense...

We don’t have to. It’s about developing a concept.

But isn’t it also the case with a gas heating system, air-water heat pump, or brine-water heat pump that I have to heat the bathrooms temporarily, right?
And because of the inertia of the water-based underfloor heating, I can’t manage that without an additional heat source. That leaves me only an additional electric heater or an infrared heater here as well, right?

If you like to have 26° in the bathroom and 18° in the next bedroom, then yes. You should say goodbye to that in a low-energy house, then you won’t have that problem.

If you like it to be 26° in the bathroom and 18° in the bedroom next door, then yes. You should say goodbye to that with a low-energy house, then you won’t have that problem.

It's about a constant 21 degrees in all rooms and temporarily 2–3 degrees more in the bathrooms in the mornings/evenings for female well-being.