KfW Funding Climate-Friendly Residential Building from March 2023

And what markup does the bank still add here? The tooltip explicitly states that the effective annual interest rate shown here does not include any costs of the bank.

I wanted to come back to my question. The 0.7% for the 25 years is not what I have to pay in the end. Do you know approximately how much the bank adds on?

I assume that means basic debt costs. For us, the nominal interest rate on the website was also what we paid. Banks earn differently on promotional loans. might be able to say something about that

[*]no heat generator based on fossil energy or biomass

How does this count if you do not have your own heat generators but are compulsorily connected to a district/local heating system that produces its energy with fossil energy or biomass?

For us, the bullet loan would be especially worthwhile, even with very high additional costs. Lower interest rates on the bank loan, 10 years to specially repay/invest the savings, according to my repayment plan Excel, the granny flat with 2x funding almost becomes attractive again.

Yes, heating networks are like electricity. It comes from the pipe and is automatically green ;)

Here we go... if I once calculate these interest rates against the current Dr.-Klein best interest rates of 3.71% over 10 years, the place with KfW 40 can be about 29,000 euros more expensive than without, so that it pays off. For everyone who easily reaches 40, certainly nice.

I have now calculated this exactly again with an example. The financing requirement in the example amounts to 450,000 EUR and for simplicity I assume 4% interest, 2% repayment, 2,000 EUR special repayment in the first 10 years and thereafter 5,000 EUR special repayment. This leads me to the following numbers:

Variant 1
==========
Loan: 450,000.00 EUR, Interest: 4.00 %, Repayment: 2.00%, Special repayment: 10 years 2,000.00 EUR - thereafter 5,000.00 EUR
Rate: 2,250.00 EUR
Remaining debt: 0.00 EUR
Total interest: 243,288.60 EUR
Total term: P22Y8M
Total special repayment: 80,000.00 EUR
Costs: 693,288.60 EUR

The costs now mean the total costs consisting of loan amount and interest.

Against this stands the variant from bank loan + KFW 297. To compare properly, I calculate with a monthly total installment from both loans, which is equal to that in variant 1. KFW loan 100,000 EUR for 10 years at 0.7% interest and 3.66% repayment (that should be the calculated repayment for a term of 20 years). The rest then at the conditions mentioned above via the bank.

KFW 297
=======
Loan: 100,000.00 EUR, Term: P10Y, Interest: 0.80 %, Repayment: 3.66%
Rate: 371.67 EUR
Remaining debt: 61,908.98 EUR
Interest: 6,509.38 EUR

Bank
====
Loan: 350,000.00 EUR, Term: P10Y, Interest: 4.00 %, Rate: 1,878.33 EUR, Special repayment: 2,000.00 EUR
Remaining debt: 221,112.85 EUR
Interest: 116,512.45 EUR
Special repayment: 20,000.00 EUR

These are now the first 10 years in variant two, so that one comes to the same rate. The special repayment of course only applies to the more expensive bank loan. Afterwards there remains a residual debt which is then financed further under the same conditions as variant 1 and with the same rate.

Bank follow-up financing
==========================
Loan: 283,021.83 EUR, Interest: 4.00 %, Rate: 2,250.00 EUR, Special repayment: 5,000.00 EUR
Remaining debt: 0.00 EUR
Interest: 68,104.58 EUR
Special repayment: 54,126.41 EUR


In comparison, I then obtain an interest advantage of 52,162.19 EUR for variant 2 compared to variant 1. That is already a considerable amount. Now one must see, however, that a KFW40+ house probably costs one or the other euro more than if I, for example, build "only" KFW55 standard. If I assume 30,000 EUR additional costs and calculate the variants again (this time with 480,000 EUR in variant 2), I come to the following numbers:

Difference in interest variant 1 to variant 2: 9,335.77 EUR
Difference in costs variant 1 to variant 2: -20,664.23 EUR


The interest advantage has shrunk, but is still there. However, in the end I still have additional costs of about 20,000 EUR that I have to bear.

And I also find the total costs for the construction project interesting. If I now assume that I still have to invest 100,000 EUR equity capital into the house (i.e. 550,000 EUR total just for the place, which, according to my last conversations with the prefab house manufacturers, is quite realistic for 150 sqm) and have already acquired a cheap plot of land for 100,000 EUR (we live in the countryside), then I end up with total costs of almost 900,000 EUR. And that means I have already put in 200,000 EUR equity and can afford a monthly rate of 2,250 EUR plus special repayments (with a 30% rule that means a net household income of 7,500 EUR). After the construction boom of recent years, that can only lead to a deep crisis in the industry because these are sums where one must already belong to the better middle class.

The additional costs strongly depend on your base. Ventilation with heat recovery? Does the building envelope just meet KfW55 or already with some buffer? What extra effort needs to be made? Just a slightly thicker stone or, like some prefab builders, do you then build a second frame? Does the prefab builder of your choice even still offer KfW55 walls? How important is it to you what your wall consists of (Styrofoam is cheap and achieves that more easily).

On the other hand, I consider all these optimizations practically irrelevant. 750 million are planned, 100k per housing unit. That makes according to Adam Riese 7500 housing units to be funded. If you are still getting offers now, you probably do not belong to the funded ones.