How to finance buying a house?

Sorry, but I don't quite understand your way of thinking :confused: Now once again very slowly. Bank and KfW run for 10 years, 2 home savings contracts are taken out in the amount of the outstanding debt and mature after 10 years. Then we pay back the loan portion of the two home savings contracts for another 5 and 12 years respectively. I hope now it can be understood.

Ah now I understand. Thank you.
That means you are now paying part into the loan (1) and part into the building savings contract (2). After 10 years, then only the building savings loan.
And that is cheaper than paying the full monthly amount (1+2) into the loan from the start and thus having less outstanding debt?