I don't have to justify that; a look at the KfW's requirements profile is completely sufficient.
Maybe it would be helpful for some to know exactly what you see with just one look. I claim that statement is false.
The 20 homeowners were not only all against controlled residential ventilation, but most of them also did not know the requirements and conditions of the KfW. It always went something like this. Building professionals: "KfW 55 is not worth it. You don't even need to think about it! It costs that much! You then definitely need a ventilation system." Us: "No, we don't need that, but we want it anyway." Building professionals: "Oh, you want it anyway? Are you crazy!? It will just mold away on you. All the germs and all the dust. But then you also need solar thermal." Us: "Our local heating is powered 100% by renewable energies and is therefore positively rated by the KfW. We also don't need solar thermal." Building professionals: "Aha... Well, let's see what the energy consultant says." That unsettled us quite a bit the first two times because we thought they were right—they are professionals in the construction business after all, unlike us. Then we sought confirmation and dismissed those two companies as unsuitable. Until we eventually realized that subsequent appointments went similarly. It annoys me that all these people just parrot something they once overheard somewhere. And that at a time when information is so easily accessible. That's why it also annoys me a bit when you write "That's just how it is, I don't need a reason."
@TE: You can reach the KfW info line at the following phone number: 0800 539 9002 Or ask an energy consultant. Both should confirm that controlled residential ventilation is not mandatory for KfW 55 and 40. It CAN be necessary if the rest of the insulation and heating technology is not already sufficient. The overall package counts.
