I'm doing it all myself so there is no real "mandatory", contractors will do it properly of course and by the rules (at least they should, but I sometimes wonde

I'm doing it all myself so there is no real "mandatory", contractors will do it properly of course and by the rules (at least they should, but I sometimes wonder how careful they are taping all small holes on the inside of the insulating layer with aluminum tape, etc). People doing it themselves, I feel, just put mineral wool everywhere. Quite unwise, I hear some alarming stories. But I really spend a lot of time reading and thinking. I am insulating my roof, insulated the ceiling. But CO2 buildup is very rapid in the living room now, even though there are 2 large ducts in the wall leading directly outside (easily >1500 PPM while cooking and the 4 of us in the room). So I'm looking at installing stuff like this now: [0]. Imo such things are very necessary and I feel that many people "modernizing", insulation their own house are inviting a lot of issues. [0]: https://blaubergventilatoren.de/en/series/vento-expert-a50-1-w https://blaubergventilatoren.de/en/series/vento-expert-a50-1...