Is a surcharge of 17,000 common for KfW55?

I know that the conditions of the KfW are not optimal. The thing is, we expect a larger one-time payment in the next 1-2 years and could completely repay the KfW loan with that.

If the surcharge stays at 17k, we wouldn’t build a KfW house either. We would rather save that.

The starting point is about 200 sqm of living space plus 60 sqm hobby room in the basement in Bauhaus style, built with Poroton bricks without ETICS.

I have to correct the heating; it will be an air-water heat pump, probably with a ground collector. They only calculated with district heating because we want to contract the heating ourselves.

With another general contractor, the surcharge was about 12,300, but that even included wood-aluminum windows instead of plastic ones.
Therefore, I am now a bit skeptical whether the price is justified.

Is the basement within the heated envelope? That can be expensive. Is district heating also considered in the Energy Saving Ordinance? And I am not familiar with flat roofs. But I think that as good insulation as possible should be installed there.

The basement is heated. At least partially. I think district heating was considered as the heating source.

Given the size of your house, I definitely see the surcharge as justified. It's already a considerable size. For more information, one would have to look deeper into the details. Especially where the 17k€ is going into.

Are you far enough along in the planning to submit the KfW application before mid-April? Free special repayments will no longer be available from then on.

Planning is complete. But thanks for the hint, I hadn't considered that at all. They probably want to prevent refinancing the KfW loan on better terms after receiving the 5,000.