But install a controlled residential ventilation system?

I once turned off the central controlled residential ventilation in my new building for two hours and was surprised at how bad the air seemed to me, I already felt uncomfortable. Then I quickly turned it back on and now hope that it doesn’t fail. I don’t think I could manage that by ventilating myself. The house is of course also accordingly airtight, but that has to be the case with practically every new building.

Due to my work, I am often at customers' sites where I have installed a decentralized ventilation system. Often, I can really smell the before/after comparison after a short time (1 - 2 months) during a follow-up inspection. You can also often feel that the humidity has decreased. The good air that gradually develops as a result can really be easily smelled. Customers then also say: "If we had known this earlier, we would have decided on it much sooner!"

Thank you very much for the many opinions. I now have the answer from my BU: The structural engineer says that for the installation in the concrete ceiling, it must be thicker and there is indeed the risk that the pipes will be drilled into later. So in any case, the floor structure would increase.

For this reason and due to time pressure, we will forego the ventilation system. The BU, by the way, states that he builds relatively few houses with a ventilation system and has not had any bad experiences with it so far. Acquaintances have also built with him both with and without [Kontrollierte-Wohnraumlüftung] and have no problems whatsoever, and they only report positive things about the air quality. Of course, they haven't had any so far either, which is certainly a difference. But we haven't had any either.

Hello Uwe, statements from the past are deceptive... back then houses had more holes. On the other hand: if it really gets too stuffy for you later, you could still install decentral devices... Best regards

Hello Uwe, Statements from the past are deceptive... back then houses had more holes. On the other hand: if it really gets too stuffy for you later, you could still install decentralized devices... Best regards

Do you mean the one of my acquaintance? He moved into his house last year, same manufacturer, same wall structure

I also don't know if giving up the [Kontrollierte-Wohnraumlüftung] is a good solution, although I am basically against [Kontrollierte-Wohnraumlüftung] for various reasons.

We built a prefabricated house with [Kontrollierte-Wohnraumlüftung] in 2008. For certain reasons, we turned it off in 2013/2014 and the air quality almost instantly deteriorated. In our guest WC, in the bathroom, and at the roof windows, mold formed on the window frames within a very short time.
If we had built a prefabricated house a second time, we would have opted for a decentralized ventilation system. However, we built a solid house and have only installed decentralized ventilation in the bathrooms and the utility room. The air quality in our solid house (without insulation) is significantly better without ventilation than before in the prefabricated house after the ventilation was turned off.

If I were you, I might consider whether a decentralized system could be an option. You don't have to lay complex piping in the floor for that.