Your opinion on my financing offer is requested

Yes, you can combine the 153 with others and would thus get a maximum, I believe, of €150,000 KFW. But as I wrote, I had read that incorrectly above *shame on me*

Regarding the stated €50,000, I have little concerns about the remaining amount after 10 years.

Ok, then everything is fine :)

Hello everyone,

after I had another appointment with my financial advisor today, I now have new figures available.

Ing-Diba 177,000 euros effective 2.07% 15 years repayment 1% 449.88 euros annuity
KfW 50,000 euros effective 1.00% 10 years repayment 2.97% 165.42 euros
Wohnriester building savings 122,500 euros 15 years 299.34 euros savings

Outstanding debt Ing-Diba 15 years approx. 146,000 euros will be repaid through building savings 122,500 euros
further 14 years approx. rate 420 euros until full repayment
about 23,000 euros remain. I think I can live with that.

Outstanding debt KFW 36,000 will be repaid after 10 years

I am still not 100% convinced by Wohnriester, but the concept sounds good.

I always miss similar concepts here, therefore I write down my concept as detailed as possible. Maybe this will help other readers

Whether this solution is the best for your needs and situation, no one can tell you exactly. Besides, there will be no "best" solution because no one can look into a crystal ball.
Have you received an effective interest rate from your financier for the entire financing?
If you can come to terms with the idea of Riester and are aware that costs will arise in old age or that you won't be finished like maybe others at 55 years, 60 years, or 65 years, then you can do it that way.
As already stated in the first post, there are many who rely on Riester because of the subsidies from the state. Personally, I cannot come to terms with the idea of paying a monthly residential pension in old age or paying a large lump sum. Therefore, Riester is ruled out for me from the start.
What I haven't fully understood yet is whether you want to repay or refinance the remaining amount at Ing-Diba with a new / already existing home savings contract or how this was intended? So you pay off your Ing-Diba loan for almost 30 years, and when you are done with that, you start repaying the Riester (the Wohnförderkonto). Just as a note...

You can repay the €177,000 at 2.07% fixed for 15 years with 3% amortization (monthly rate is about €750), after 15 years there remains about €80,000 outstanding debt, even if the interest rate is then 5%, you will finish in another 12 years. All without special repayment. With an annual special repayment of €4,000, you will be completely finished in 15 years (with €177,000). Just as another option.

What remains from Ing-Diba not covered by the Wohnriester contracts (about 25,000) I will pay off, if everything goes according to my plans, by selling a single-family house which I own together with my sister (she is building the planned two-family house with us). This sale will also pay off the KFW loan. Should we not sell this house, we still have the rental income to partly cover the installments for the remaining KFW and Ing-Diba loans.

Regarding Wohnriester: I prefer to take advantage of Wohnriester now and have a tax burden in old age instead. Now that I am still young, I need the money more than in old age. At least I hope so. But I think it's really a matter of attitude.

Thank you very much for your suggestion. Of course, I checked it immediately. It is definitely a good option. The only disadvantage here is that no one knows what will happen to interest rates in 15 years. Although I do not hope that interest rates will be at 6% then. In addition, after 15 years I will fall to an installment of 420 euros with Wohnriester, and that for sure. Furthermore, my Ing-Diba + KFW installment is only 615 euros at the beginning. I definitely have to pay these 615 euros per month. With the Wohnriester contracts, as far as I know, it is a bit more flexible. I have to pay a certain amount per year, but if a few months become very tight, I can also skip a payment once in a while. Of course I don't want to do that, but who knows.