ᐅ Single-family house with two housing units eligible for KFW funding

Hello everyone!
I am still in the middle of planning a single-family house (approximate base dimensions 10 x 8.80 m (33 x 29 ft)).
The KFW advisor suggested that we might consider having two separate dwelling units so that we could qualify for a total of €200,000 under KFW terms…

What might a floor plan look like that would be accepted by KFW as two dwelling units but can still be used as a single-family house in practice?

The plan is for a monolithic construction house with, of course, a photovoltaic system, heat pump, and controlled mechanical ventilation.
What additional work would roughly be required to achieve KFW40 standard in order to benefit from the KFW terms?

I would really appreciate any input.

I would just try searching online with the keywords: "How can I cheat without getting caught." Aside from that, this idea from the "advisor" (instigator) is simply nonsense from an economic and planning perspective; was he previously involved in the traveling sales business?

I also looked into this topic but decided against it because the KfW 297 doesn’t offer particularly favorable conditions either.

However, the following points need to be considered:
- separate lockable access
- bathroom
- possibility to install/connect a kitchen

Feel free to add to this, but I believe it is also stated in a KfW document.

Regarding achieving "KfW40" standard, we also built monolithically with 42.5 T7 bricks, insulation under the slab, and thicker insulation on the top floor ceiling.

I also knew someone in my circle of friends who bragged about receiving double funding but lives alone with his wife in the house. The emphasis is on "knew." I find that more than unfair – to put it politely.

After all, these subsidies are government funds coming from taxpayers’ money – including mine.

If you can’t afford a single-family house built to KFW40 standard with only one subsidy, then build smaller or buy an existing property.

As far as I know, KfW40 standards do not come for free. The additional costs, whatever they may be, are somewhat supported by subsidies but are not fully compensated.

We should quickly dismiss the consultant’s suggestion, because a) there is no such thing as a second dwelling unit without cost, and b) it is not lawful to consider a subsidized fake dwelling unit as legitimate. That person is c) committing an offense.

So, anyone who still wants to look at themselves in the mirror, be part of decent society, and simply create living space for themselves and their family should build according to their means and bank account.

ypg schrieb:

As far as I know, KfW40 doesn’t come without extra costs. The additional expenses, no matter how high, are partially supported by the subsidy but not fully covered.

For our prefabricated timber frame house, I did a detailed cost analysis. Essentially, the subsidy almost exactly matches the costs for the KfW40 standard (around 50,000 Euros, ventilation included, in our case), which is quite reasonable. It’s also important not to forget the initial 5 years of repayment-free period.