Kfw contract / House modification for an existing contract

KFW is relatively unconcerned as long as the *independent* energy consultant takes responsibility for everything, the information at the beginning and end match, the certificate confirming the achievement of the requested efficiency level is provided at the end, this also corresponds to the truth, and you keep the documents for at least as long as the funding lasts.

KFW has no idea what your house looks like in detail; it only knows the information on the form. No plans, no calculations, nothing.

So the information from the first Kfw online confirmation differs from the new one, for example, the heated building volume or the enclosing surface area... because it is a different house type now.

It is important that all conditions of the KfW continue to be met. Housewives, form, etc. do not play a decisive role at first. Of course, you should not have applied for 100m2 of living space and now build 500m2. In the end, no one from the KfW will come by. What matters is that the energy consultant is on board and gives their approval, as they must certify the proper execution afterwards.