But you have to have decided how you want to execute it when you submit the Kfw application.
Yes and no. You state how you achieve your energy level. You can also easily deviate from that, especially if you choose better technical implementations. Controlled residential ventilation instead of opening and closing windows. Geothermal energy instead of gas. Etc.
Central systems have been tested for decades and earlier myths have been massively disproven. But like everything on the internet, such conspiracy theories are impossible to kill.
Every 2 to 3 hours, the air must be ventilated for good air quality. Just the fact that I want to sleep at night and not always have the window tilted open in winter made it clear to me that it basically doesn’t work without a ventilation system.
No clay plaster or other hocus pocus helps against Co2.
Once again, for you , there are only right and wrong. Take off the blinders.
Many paths lead to a good feeling in the house. A well-adjusted and constructed controlled residential ventilation system is one of the ways. Those who don't like that have other options available. No conspiracy – just facts and measurable for doubters or particularly interested parties, humidity in %, CO2 in ppm, etc.
Those who don't like that have other options available.
I find the example from with the fresh air at night very expressive. The note about long-term experience is also appropriate. In this case, he is not saying that everything else is rubbish :)