Is the total budget for the construction project realistic?

Thanks for the info. Understood. But the insulation could also make a difference in the basement, whether I build 40+ or 55/40, right? Did you take that into account with the 10,000?

Adding a controlled ventilation system later will probably be much more expensive and complicated than including it right away during the new construction if I want to have it anyway. Or?

Yes, I have taken that into account. You will get a bit more insulation under the floor slab and on the sides of the WU walls. Instead of 14 cm, it will be 16 or 18. It’s not a big deal. The labor cost remains the same. Ventilation is best done centrally, I would recommend it anyway from a comfort perspective. It costs about 15,000 euros.

Okay. Then maybe one more question. I’m not really convinced by air heat pumps. The delta for heating/cooling is quite large. Therefore, my ideal scenario, provided that the property and the ground allow it, is to use a ground source heat pump. In my view, it is much more efficient. Can you tell me what the price difference between the two options is? With the ground source heat pump, it is apparently the installation with earthworks that makes up the additional costs?

Air-to-water heat pumps have their drawbacks, no question. Nevertheless, they are by far the most commonly installed. Simply because they are cheaper.

With geothermal energy, the question is how you tap into the energy source. As a borehole, area heating in the garden, or trench collector.

Back then, we had the problem that most heating companies were not knowledgeable. The borehole is usually offered, but depending on the soil and federal state, it costs about 10,000 to 18,000 euros. That is also approximately the additional price for an air-to-water heat pump. However, you can also apply for funding; I believe there is 4,000 from the BAFA.

We also decided on geothermal energy with deep drilling and are very happy with it so far. If yes, make sure where the drillings are done, because 1. they are hardly ever found again and 2. you should be careful not to plant the Christmas tree or build the well exactly there later. However, there must be enough space so that the drillings are not too close together. But the heating technician will explain and plan this for you.

We also have a brine heat pump in our house. It will be the same in the planned new house construction. The heating is very efficient, low-maintenance, requires almost no space, and is therefore virtually "invisible".


BAFA funding is currently as follows:
(Quote from the BAFA homepage)
Heat source earth and water
The innovation subsidy amounts to 100 euros per kilowatt of installed nominal heat output, but at least:

[*]4,500 euros per system for all heat pumps with the heat source geothermal energy, with simultaneous geothermal probe drilling
[*]4,000 euros per system for all heat pumps with the heat sources geothermal energy or water