Real estate financing building savings contract - What interest rate lock?

Hello,

I have a question regarding financing. My girlfriend is getting a house as a gift from her parents and we have to pay off her brother. According to the appraisal, 200,000, so 100,000 to pay her brother. I would then pay the 100,000 and would also be listed in the land register or would then be co-owner.

Since we have about 80,000 equity and want to keep about 20,000 of that as security, there are 60,000 left that we want to use. I would therefore like to take out 80,000 for the house or the renovation. Since the house will also need a new heating system and new windows in the next few years, I am planning an additional 23,000 here which I would finance through a KFW loan.

Now my question(s): I have already obtained or have 3-4 offers. The cheapest so far is from Interhyp with a 20-year fixed interest rate at 3.13 Price Indication Regulation Variants with building savings contracts were also offered to me... What do you think of this? So 10 years of repayment and savings phase etc. I have always indicated or calculated a monthly rate of around 450-480 euros. Which fixed interest period should I choose and for how long?

What are your experiences with Interhyp?

I have not thoroughly checked everything 100%. 100K€ purchase price - 60K€ equity = 40K€ financing the remaining 40K€ of your financing are renovation costs that are now incurred? Heating and windows are not included and will come later? I have only calculated the 80K€ loan with 3.1% interest once. There you are at 480€ installment and finished repaying after 18 years. So it would make no sense to take out such a long fixed interest period. With 15 years fixed interest you should be about half a percent lower. Unless the KFW also has to be served from the 480€. One question arises for me, however. Does it not make sense to consider the house purchase and the renovation including windows and heating as a total project? Otherwise you might have 2x costs for registering the mortgage and so on. Bausparvertrag Bauspar contracts can be worthwhile under certain conditions, but they do not have to be. Advantage Bauspar contract - long interest rate security, - payments can be completely suspended temporarily in extreme cases, whereas with an annuity loan at least 1% must be repaid. Disadvantage Bauspar contract - closing costs 1% of the savings contract sum - in the savings phase, the credit balance is saved with a low interest rate, while higher interest rates apply for the suspension of repayment loan. For a Bauspar contract to be financially worthwhile, the closing costs and interest disadvantage in the saving phase must be offset. Therefore, a Bauspar contract will only be worthwhile if it runs for a very long time and interest rates rise sharply in the future. If early repayments are expected, the overall term will shorten and the Bauspar contract will be less beneficial.

I need 80,000 to pay off the brother. 20,000 are planned in 2-5 years to renew the heating and windows (as of today I still have almost a full tank - 6,000 liters of oil) the 80,000 through the bank and the 20,000 through KFW