Assessment of financing project and budget accounting

I am a bit surprised that the heating system was replaced after 15 years and the windows after 25 years. Both usually last significantly longer. What do you want to replace the gas heating with now? Follow the heat pump craze?

Since KFW is only slightly cheaper, I wouldn't do it. You won't save €4,000 in 10 years, but you will have no choice among banks for refinancing in 10 years.

but you have no choice of banks for refinancing in 10 years

Can you explain that in more detail?

Can you explain that in more detail?

Few banks agree to a second charge in the land register and then not on good terms. You are forced to take the bank that finances the rest. Cancelling the main loan after 10 years does not fit the timing either because of the notice period and staggered disbursement.

I am a bit surprised that the heating system was replaced after 15 years and the windows after 25 years. Both usually last much longer. What do you want to replace the gas heating with now? Following the heat pump craze?

Probably a gas condensing boiler. Possibly in combination with solar. However, I am not very familiar with the topic yet.

According to our advisor, the KfW loan is treated as equity by this bank.
Without KfW, we would be well above 4%.
After 10 years, KfW offers a new deal. You can accept it or repay the remaining amount with a new loan from another bank.
After the 10 years, you are flexible.

I would definitely make sure that with the regular loan you have the option to change the repayment rate. We can do this once a year for free. That is very generous. But at least two or three free changes are worth "gold".

Without KfW we would be well above 4%.
After 10 years, KfW offers a new deal. You can accept it or repay the remaining amount with a new loan from another bank.

I financed at 3.8% last year and since then interest rates have fallen. Well above 4 is definitely too expensive.
As already mentioned, few banks go into the second rank in the land register and then not under good conditions.
If the KfW amount were smaller, you could repay it with a home savings loan, but almost 100,000 is too high for that.