KfW funding residential building grant 461

Good evening, does anyone know which documents need to be submitted to the KfW regarding the "Wohngebäude Zuschuss 461"? So far, I have only read on the KfW website about energy efficiency experts who have to provide the "Bestätigung zum Antrag (BZA)" and the "Bestätigung nach Durchführung" or that these documents need to be "uploaded." When buying an apartment, one surely also has to submit the purchase contract, right? Or possibly other documents? Thank you in advance for your response.

The confirmation of the application (BZA) is sufficient for submitting the application. If the application is submitted personally as an individual or a married couple, no document needs to be uploaded at all.

Doesn't one have to prove "at some point" whether or what one, for example, has bought?

Without a completed purchase and confirmation of the energy-related construction costs by the developer, the energy efficiency expert will probably not issue the confirmation after completion in order to be able to apply for a payout.

I applied for the grant on Monday. You only need the confirmation of the application (BZA), which the energy efficiency consultant provided, as he submits an application beforehand.

I also called the kfw. We are building the house as a married couple. The employee said it is sufficient if one person submits the application. Then both don't have to identify themselves later.

The information is unfortunately only semi-correct. The application should be submitted for the correct owner or acquirer and not just for one of them. A change is not possible afterwards and the processing must be based on the currently existing commitment.