Single-family house with 2 residential units for KFW funding

When I am bored, I ask KfW whether you can apply for the 297 (owner-occupation) for two residential units.

You can ask for anything.

Owner-occupation for the primary residence and the secondary residence? "I live in the first unit, I sleep in the second one" Hehe

for me as a single man with a girlfriend

... the question is therefore (negatively) settled whether a release granny flat makes sense for the children.

If it's only the insulation under the floor slab, for example, I don't think that will definitely eat up the interest advantage.

You are thinking too short, the granny flat also needs, for example, a separate balanced ventilation circuit.

Sorry, that’s nonsense – then I would just write it exactly like that in the application according to reality and see whether it really doesn’t matter and whether this does not contradict the actual purpose of the funding.

Yes, it totally doesn’t matter who lives in it. The residential unit is funded, not the usage or the resident. Sucks, but that’s how it is. But it rarely makes sense, because you have to build a real second apartment. So it sucks just as much for a single-family home use – it ruins floor plans, costs roughly as much as the funding provides, and each one also costs taxpayers money.

When I am bored, I ask KfW whether you can apply for 297 (owner-occupied) for two residential units

Then the answer comes that the application does not ask about the usage. You can save yourself the effort and use your time better.

Yes, it totally doesn’t matter who lives inside. The housing unit is subsidized, not the use or the resident. Crap, but that’s how it is.
But it rarely makes sense, since you have to build a real second apartment. So it’s just as crap for a single-family home use – messes up the floor plans, costs about as much as the subsidy provides, and every single one is also taxpayer money.

Then the response is that the application does not ask about the use. You can save yourself the effort and use your time better.

Thanks. That was exactly my thought too.

Regarding construction costs KFW55 to KFW40... Since I want to do a lot myself, it might actually pay off... If it's only the insulation under the floor slab, I don't think that will definitely eat up the interest advantage.

1. Problem 1: "If I do a lot myself, it's cheaper," or "The provider has KFW40 as standard": you pay for it anyway. Additionally: The more you do yourself, the trickier it can become to prove that you meet the requirements. 2. Interest advantage: For loan terms >10 years (which is realistic), there is currently an interest advantage of roughly €7000 over the term with KfW 297/298 compared to my regular bank. Some providers claim that amount just for the perimeter insulation (!) on the floor slab of a 150m² house. (Of course, if you outsource the floor slab, which is a really bad idea, you can get the perimeter insulation for €2500-3000. But with all the general contractors I dealt with last year, the perimeter insulation alone was somewhere in the range of €6000-8000.) Achieving monolithic construction KFW40 is also associated with higher costs than simply making cheap ETICS a bit thicker in other construction methods. With 2x KfW 297/298, you still won’t cover the additional costs for the second housing unit by far, even if you integrate it optimally into the floor plan. That is not achievable for a ballpark €7000.