According to my research, you need to fully ventilate your house by opening the windows 10 times a day for shock ventilation.
Better to spend 10,000 euros more.
Yes, it was more about the floor plan but now about windows. Controlled residential ventilation is behind us, so we decided against it and I don't really want to discuss it, but thank you anyway for your opinion.
Two-leaf doors would indeed leave very little glass area - one should be aware of that. We have 150 width two-leaf and I was shocked at how little light they provide. About 25 cm of glass area is lost in the middle. The standard windows with 100 cm width (800 euros cheaper) would have been worth considering. But you’re always wiser afterwards...