Is the KFW 153 confirmation mandatory after conducting the Blower Door Test?

The blower door test is not explicitly stated, but there is a passage that the contractor must provide all necessary documents to the KFW. Accordingly, this also includes the document "Confirmation after completion," where the blower door test apparently is mandatory. That is exactly what concerns me, that the blower door test was not done, and no efficiency expert was on site.

But it may be that you have to commission the BDT yourself. I would ask about that with the GU/BU.