Repayment grant KFW 261 - experiences?

Serial renovation and WPB are capped cumulatively at 20%. I also seriously doubt that you are renovating serially there. Have you already looked at the conditions for this?

Serial renovations refer to energy-efficient building renovations carried out using modular prefabricated elements. These can be insulation elements for facades and roofs – but also parts of the technical systems, such as heat pump modules. Compared to conventional building materials, these elements can be assembled on site with significantly reduced time expenditure. The word "serial" here does not refer to the renovation itself, but to the manufacturing process of the materials used.

If you – for example as a housing association – want to renovate a multi-family house or even a row of identical residential buildings, this can be particularly worthwhile.

I understood the information sheet from KFW as follows: 15 % Kfw 70NH 10 % WPB Bonus 15 % SerSan

You can really forget about serial renovation. You can, for example, take a look at something like that at LEG. It's called Renowate. Then you'll know what it actually means.

Oh, okay, thanks! Then without serial renovation and with a 25% repayment grant. Does anyone of you have experience with the difference between KFW 55 NH and 70 NH? Is 55 NH much harder to achieve? Or much more expensive?

Does anyone of you have experience with the difference between KFW 55 NH and 70 NH? Is 55 NH much harder to achieve? Or much more expensive?

Depends...
In principle, it is neither a big effort nor a large additional cost. BUT: If you, for example, don’t have a basement, you have a problem insulating the floor appropriately – or you simply give up about 20 cm of ceiling height (or more) during reconstruction, or you spend a lot of money on VIPs to build more flat.
I myself took the 55 route and apart from thicker insulation (where the additional cost is manageable) I didn’t have to make any major contortions – ending up slightly above KfW 40 in the end.

Or is each invoice for an eligible measure checked individually and then a 40% grant is paid out on it? (Simply put: New windows 15k, 40% grant on that, = we get 6k back for the windows). Or how does that work? What happens if you get a 120,000 loan and not all of the paid measures are eligible?

The 120,000 may only be used for eligible costs described in the KfW information sheet. Proof of this must be submitted to the processing house bank. The repayment grant is credited to the outstanding loan amount after 2 years. So you will not see any of the money directly.

For the application with KfW, you need a confirmation for the application (BZA) from an energy consultant. For the calculation of the efficiency house, he needs plans of the house and the planned extension/basement, showing details such as size, current wall thickness and material, window areas, etc. However, you will not be the only ones under time pressure regarding the house purchase without meeting the requirements for a KfW application. I would actually speak directly with the bank here.

So, what is possible according to the development plan

Is it possible to have two residential units on the semi-detached house plot?

Two residential units could be created,

So, what is possible according to the development plan and what we would like to have, we know exactly. Cubic extension in timber frame construction attached to the existing building, two stories. The entrance area and the living room should be downstairs, and upstairs two children's rooms and a small bathroom.

Where did the second residential unit go in that list?

We are working with 3 small children

I can’t imagine that you want to give up 190 sqm?! All five of you can definitely make good use of that.