Eligible costs for heat pump

You don't need the confirmation from the property developer for the pure application. In my opinion, you also don't need it if you are building with a general contractor (GU). With the GU, you get the offer from the heating installer. Afterwards, in my opinion, you need an (approximately) matching invoice + 19% VAT and then upload it.

Property developers are such special cases.

We didn't send anything with that. Only the annual performance factor calculation (from the WOLF homepage). For the application, we still specified the GU and as the total the maximum possible funding amount (€50,000). We didn't even have an offer because at that time the GU's heating installer was not even decided yet (they have 2-3 and take whoever has time). The application went through without any inquiries.

That is interesting :)

So I could simply apply for 15% hot water generation. That also gets me just over 4.5.
They can't do more than reject it ..

Short question about the approval period: The commissioning of the system must take place no later than 9 months after the notification of the funding approval notice.

An extension can be requested informally (by email) before the deadline expires.

Does anyone know by how many months the deadline will then be extended? Unfortunately, I couldn't find anything about it in the information sheet... :/