ᐅ Is an additional €30,000 for geothermal heating worthwhile? Any experiences?

Hello everyone,
I would really appreciate your collective expertise here. Here’s the situation: We are currently building a turnkey semi-detached house with a basement through a developer in NRW. It’s a KfW 55 energy standard house, including subsidies.

Now we are faced with the question: Should we switch from gas (standard) to geothermal energy? According to the developer, the additional cost is about €30,000. The city unfortunately does not approve air-source heat pumps. It’s a long story, and we cannot change that. Our thoughts so far:
- Gas at this time of year... better not
- €30,000 surcharge: ouch!
- It’s too late to switch to KfW 55 EE, so we will probably only get the “old” KfW 55 subsidy. The higher subsidy for renewable energy would certainly have helped. However, the KfW hotline said this “upgrade” to renewable energy will not negatively affect our promised 55 standard loan (meaning: if you deviate significantly from the application, tough luck). Can anyone confirm this? The final approval for implementation is quite different.
- Would it make sense to install gas now and then switch to geothermal in 1–2 years with a different subsidy? That way, it might be possible to get a 30% grant, which is currently not available. It sounds crazy, but with these prices, we are considering every idea.
- Any other suggestions?

Thank you very much!

A ground probe is definitely worth it in the northern regions; given the geopolitical situation, I would avoid gas – and installing gas first only to convert in 1-2 years never makes financial sense; the savings from the ground probe cannot be that high.

Wow... I can't really help you much with that. I didn’t even know that air-to-water heat pumps can be outright banned!? What’s the reasoning behind that? I’m familiar with geothermal restrictions because of water protection zones, etc.

30,000 is really a significant amount. Think about it. You could end up paying an extra 1,000 per year on gas for 30 years, and only then would you break even... So, installing gas would be the last thing on my mind, but given the circumstances, it might be worth considering.

Are you actually building with a developer or a general contractor? So, are you buying the complete finished property including the land from the developer?

P.S.: I’m still curious about the exact reason why air-to-water heat pumps aren’t being approved!

Are we talking about a detached house of approximately 300 m² (3,230 sq ft) or a semi-detached house of about 150 m² (1,615 sq ft)?

With an additional cost of 30,000 € (Euros), it’s unlikely that gas heating includes underfloor heating, right?

Maybe only outdoor heat pumps are prohibited? There are all-in-one combo units designed for indoor installation!

NBN2022 schrieb:

- It’s too late to switch to KfE55EE, so unfortunately we will likely only receive the "old" KfW55 funding—the higher subsidy for renewable energy would have helped, of course --> however, KfW stated on their hotline that this "improvement" regarding renewable energy does not negatively affect our approved 55 credit

You ONLY have to build to 55 standard, but you can improve as much as you want—even up to passive house level. That doesn’t matter. You just must not do worse.

NBN2022 schrieb:

The city unfortunately is not approving an air-source heat pump.

Why? What is the legal basis? At most, it might be in the development plan / local zoning plan.

NBN2022 schrieb:

According to BT, the additional cost is about €30,000.

What exactly is included in that? If an underfloor heating system for gas is already included, then that surcharge is quite exorbitant.

NBN2022 schrieb:

- Is it sensible to install gas first and then switch to geothermal energy with a different subsidy after 1–2 years? Then you could get up to 30% subsidy on the flow temperature, which is currently not possible anywhere. It’s crazy, of course. But with these prices, we consider all ideas.

You should definitely pursue that idea further. However, the underfloor heating must already be designed for heat pump temperatures. Maybe a later conversion to an air-to-water heat pump with indoor installation could also be possible?

P.S. Who checks your heating system to ensure it is either geothermal or gas?

P.P.S. The extra cost seems too high to me. With it, despite rising gas prices, you can probably heat until the gas boiler replacement without being more expensive than with the brine-to-water heat pump.