KfW stop! Energy consultant wants his money!

Yes, it is ridiculous. You are being made a fool of here! You get a loan (150,000) and would receive 18,750 as a repayment grant with an interest rate of > 2%. If I now finance part of it here and the rest at the bank where I still got 1% interest, do you think that helps?

Actually, you can already tell from the sentence that you haven't dealt enough with some matters. You should be able to calculate that 150,000 € - 18,750 € at a 2% interest rate is better than 150,000 € at a 1% interest rate. A very simple example without builder X making any repayments:

150,000 € - 18,750 € = 131,250 €
10 years interest rate of 2% = 159,993.02 €

150,000 €
10 years interest rate of 1% = 165,693.32 €

After 10 years you still have a difference of 6,000 €. The faster you repay the KfW loan, the greater the difference.

Actually, you can already tell from the sentence that you have not dealt enough with some matters. You should be able to calculate that €150,000 - €18,750 at a 2% interest rate is better than €150,000 at a 1% interest rate. A very simple example without builder X making a repayment:

€150,000 - €18,750 = €131,250
10 years interest rate of 2% = €159,993.02

€150,000
10 years interest rate of 1% = €165,693.32

After 10 years, you still have a difference of €6,000. The faster you repay the KFW loan, the greater the difference.

Believe me, I know what I’m doing and can also calculate, just as I also know that you pay less interest if you repay faster. Nevertheless, I am much better off with my bank.

... think about it.

1. We did not conclude a contract with him for 5800,-, but he had demanded 4600,- for his complete service. 2. He offered that we first transfer 1000,- and if his previous service is no longer usable due to the KfW stop, he would reduce the invoice (1000,-)!

Believe me, I know what I'm doing and I can do the math too, just as I also know that you pay less interest if you pay back faster. But despite everything, I am much better off with my bank.

That may be. But then it's not about the amount, but about the flexibility and other factors...

1. We did not conclude a contract with him for 5800,-, but he would have demanded 4600,- for his complete service.

You wrote: "(Preparation for the application) 1200,-, for the entire construction supervision he would have demanded 4600,-." Construction supervision and preliminary work are two different things for me, and therefore I thought a total of 5,800€.

2. He offered that we transfer 1000,- first and if his previous service is no longer usable due to the KfW stop, he would reduce the invoice (1000,-)!

Reducing to or by 1,000€ is the crucial question. Have you now received a final invoice? How much is it? Basically, according to VOB, he could bill for the services provided and claim lost profit for canceled services.

... and claim lost profits for canceled services.

Question from a non-businesswoman: At the tax office or with the client? What is more advantageous for the energy consultant?