KfW 261 if the developer has already applied for funding

Ah ok. But the lady from KfW explained it differently to me. I was already looking forward to it. Can you read about it somewhere? I can't find anything about it at all.

Just google BEG WG guideline. Under point 8.8 on page 10, the combination with the old EBS products is explicitly excluded.

Just write an email to KFW with exactly this question. This is not so much about the combination of old and new funding but about whether the construction of an efficiency house by the developer can receive funding and then, when buying the same house, funding for the buyer is possible.

If they then reply to the email that this is possible, I see no reason why you shouldn't apply for it. But this email should be kept safe...

whether the construction of an energy-efficient house by the developer can receive funding and then whether funding for the buyer is possible when purchasing the same house.

The clear answer will be "No".

Thank you for the info. In my youthful recklessness, I searched in vain for this information on the KfW website. That is exactly what I have just done. I am curious about the response. I will get back to you.

The clear answer will be "No."

Yes, then the OP has it in black and white from the KfW.

Thanks to everyone for the comments. Unfortunately, I still have not received a written response to my question. Since it is now becoming urgent, I have once again contacted the KfW hotline. The caseworker I spoke to this time confirmed to me – as many others here have – that an object can only be funded once. It's a pity, because we had relied on the statement of the first caseworker. Now we just have to rethink. The request to the bank has been sent.