Costs for geothermal drilling - Is it worthwhile in our case?

Different funding criteria apply for existing buildings and new buildings. Therefore, there are many (all?) air-to-water heat pumps listed there that would be eligible for funding in existing buildings but not in new buildings.

Therefore, it would be very interesting if you or someone else manages to achieve that in new buildings as well.

Good point, I was not aware of that at all. However, the offers from HLB explicitly included a note about the eligibility for funding in new constructions. I will check that again as soon as it is current. At the moment, I am hoping that the excavation will start on Monday... [emoji51] But thank you again for the hint!

Standing in the table is already good, but in my opinion, the annual performance factor must still be proven after one year. However, that can be looked up.

In new buildings, an annual performance factor of 4.5 must be achieved. Anyone can verify this for their system with the annual performance factor calculator.

With an air-to-water heat pump, it is not possible to receive funding even with good systems in single-family houses according to our heating engineer. I also did some calculations online and it is definitely not possible in southern Germany. In the north, maybe, as different outdoor temperatures are allowed to be assumed here.

Calculate the savings from the drilling against the additional costs.

New air-to-water heat pumps also still work at -20 degrees, just with a COP of 1.8-2.

For us, the drilling would have paid off at the earliest in 25 years.

From a purely economic perspective, one can usually do without a brine-water heat pump, unless there is really only a small additional cost of a few thousand euros. However, from five figures onwards, the calculation probably no longer works out.

But it's not just about heating. "Cooling" in summer, aesthetic reasons (no device in the front yard), and the green thumb can also play a role.

From a purely amortization point of view, the air-water heat pump is certainly advantageous.

Thanks for the note about eligibility for funding, I really thought that would be a given [emoji6]