KfW Funding Climate-Friendly Residential Building from March 2023

2025-09-30 09:27:51

Hello everyone,

we want to build a KFW 40 QNG house and have applied for the loan through KFW 300 220k€ applied for, 0.18% eff. (Allianzbank) term 10 years full repayment, we don't need more.

Additional costs compared to KFW 40 without seal approx. 11k€ incl. 2000€ buffer and 1500€ contribution from the developer.

I have read most of the posts and have to say that many write that it is not worth it because it is too expensive and so on, unfortunately always from members who have not built a QNG and did not intend to do so, etc.
Is there really anyone here who has built a QNG house and could roughly describe how complicated the whole thing was or is?
The energy consultant said, don't worry, it’s the same house as KFW 40 just with a seal :)

Thanks in advance for the answers

Greetings from Buxtehude

You can calculate the whole thing. Just compare the interest rates and calculate the savings for 10 years. Some house companies want 8-10k extra, which definitely is not worth it for a single dwelling.

2025-09-30 19:12:22

Evening,

220k for 0.18% approximately 1700€ interest with a 10-year term. 2050€ repayment, (full repayment)
House price kfw 55 approx. 350k€
Kfw 40 approx. 15k surcharge
Kfw 40 including QNG approx. 25k surcharge.
Kfw 55 is therefore approx. 25k cheaper, we don’t want to build it but just as calculation.
Which loan is cheaper?

Bring it on if you have an idea.
Maybe I’m making a mistake.

Regards

2025-10-01 06:17:29

Evening,

220k for 0.18% approx. €1700 interest with a 10-year term. €2050 repayment, (full repayment)

Always bring it on if you have an idea.
Maybe I'm making a mistake.

Regards

There is no mistake in that.

As mentioned: Due to the salary limits, only very few people who build a house nowadays can take advantage of KFW 300.

Therefore, only KFW 297/298 remains. Until recently, interest rates for terms >10 years fluctuated just below 3%. Therefore, it is not worthwhile.

With KFW 300, especially if it can be repaid within 10 years, it looks different.

2025-10-01 08:27:05

Kfw 55 is therefore about 25k cheaper, we don't want to build it but just as a calculation.

Then it gets very tight. A regular loan of 220k with 3.5% interest, also fully amortized over 10 years, is cheaper than the 25k surcharge. So you pay less interest than with KfW + surcharge. And if you then consider that with KfW 55 you would only have to finance 195k, you are already almost 5k cheaper over 10 years. BUT: Of course, that means only a "bad" house in terms of energy efficiency. The higher the surcharge and the lower the interest rate differences of the nominal rate, the more it shifts in favor of KfW 55. And vice versa. Simple math. Difficult decision, since the more expensive house is also of higher quality.

2025-10-01 11:59:39

195k€ KFW55

[TH]During the fixed interest period:[/TH]
[TH][/TH]

[TH]3.51 % *[/TH]

[TH]0.00 Euro[/TH]


Monthly installment amount:	1,923.84 Euro
Annual installment amount:	23,086.08 Euro
Annual effective interest rate:
Total installment payments:	230,842.27 Euro
Included interest payments:	35,842.27 Euro
Repayment payments made:	195,000.00 Euro
Includes special repayments:	0.00 Euro
Outstanding debt:

220k€ KFW 55

[TH]3.51 % *[/TH]

[TH]0.00 Euro[/TH]

Monthly installment amount:	2,170.48 Euro
Annual installment amount:	26,045.76 Euro
Annual effective interest rate:
Total installment payments:	260,437.62 Euro
Included interest payments:	40,437.62 Euro
Repayment payments made:	220,000.00 Euro
Includes special repayments:	0.00 Euro
Outstanding debt:

So where do I pay less interest with a 25k€ surcharge?

220k€ QNG

[TH]During the fixed interest period:[/TH]
[TH][/TH]

[TH]0.17 % *[/TH]

[TH]0.00 Euro[/TH]


Monthly installment amount:	2,052.97 Euro
Annual installment amount:	24,635.64 Euro
Annual effective interest rate:
Total installment payments:	221,702.73 Euro
Included interest payments:	1,702.73 Euro
Repayment payments made:	220,000.00 Euro
Includes special repayments:	0.00 Euro
Outstanding debt:

Someone has to explain this to me.
I would save on the house price, but the interest eats it all up, so I always pay more than 220k€ except with QNG.

Or someone has to explain to me where I am making a mistake; for me it counts to pay back as little as possible to the bank.
Regards

2025-10-01 19:15:14

170,000€ KfW 40 without QNG and the additional 40,000€ through a regular loan?

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KfW Funding Climate-Friendly Residential Building from March 2023

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