Cost calculation for gas heating instead of geothermal heat pump kfw 55

Hello,

Until a week ago, I was planning to use a ground source heat pump for our new building (approx. 175m²). After sitting down with two heating engineers and both advising against the ground source heat pump with the same arguments, furthermore, someone has shut down their ground source heat pump due to too high electricity consumption, I am now back to a gas heating system.

Now my question is, what do I have to fulfill in my new building so that I can meet the KfW 55 criteria with the gas heating system. I have read a lot, but it is still not really clear to me.

Planned are: triple glazing, underfloor heating, appropriate insulation of roof and walls, chimney (I think that is irrelevant for that, right?)
Do I have to insulate the floor slab?

Would that possibly be enough for a KfW 55 house or what else would I have to do to achieve this?

Thank you
Regards
Daniel

What kind of arguments are those?
For me (and other users here), various ground source heat pumps (brine with deep drilling, direct evaporator) run quite satisfactorily.
With KfW 55 and gas (use forum search!), additional technology (e.g. ST) is needed that actually doesn’t deliver much.
If a ground source heat pump consumes too much electricity, then that is rather a disgrace for the person who planned and commissioned it, because something must have gone wrong. Because precisely operating costs are (compared to the costs for source development) THE strength of ground source heat pumps.

Both heating engineers have independently said that electricity prices will rise significantly in the next 3-4 years and therefore the higher purchase price is not worthwhile as many say/claim. I also considered installing a photovoltaic system on the roof, but both advised against it. It is not worth it for the heat pump because it does not need much in summer and there is not really any sun in winter.

What does Technik and especially ST mean?

What anyone says about heating engineers is secondary. Just like that blanket spin doctor from [wp].

What matters to me is only a cost calculation. Do it and you'll gain clarity!

Cost calculation always based on the individual case ... ?

We are faced with the same question. The plan was exactly the same (single-family house, ~170 sqm, without basement, Kfw55, clinker facade, triple glazing, fireplace, underfloor heating).
So far, without exception, everyone (architects, energy efficiency consultants) has advised against a ground-source heat pump. That really makes you think.

Cost calculation always based on the individual case ... ?

Of course.