Poroton 36.5 or 42.5 Perlite or MW

That's what the gut says, not the mind ;).

I would rather do without another small thing and install a decentralized ventilation system. €350 per unit and only one power cable as well as core drilling. That should always be included in new buildings.

But decentralized ventilation is also a terrible crutch, completely unsuitable for a single-family home. OK, in the bathroom, but otherwise? These things get dirty, are noisy, not particularly nice from the outside and inside, heat exchangers are not effective (in winter there's a cold draft), and the air exchange doesn't work properly. Also not centrally controllable. As I said, it's really a crutch—better to install nothing and save the money!

But decentralized ventilation is also a really bad crutch, completely unsuitable for a single-family house. OK for the bathroom but otherwise? The things get dirty, are noisy, not particularly nice on the outside and inside, heat exchangers are not effective (in winter it feels cold) and the air exchange does not work properly either. Also not centrally controllable. As I said, it's a real crutch, better to install nothing and save money!

??? Then you have never seen, heard, or used such a device. I cannot confirm that in any point (design is subjective). No more dirt than central (just in more places), heat exchanger very effective, no drafts at all, air exchange works and is controllable/adjustable. Even central control is possible including integration with a pressure monitor for the chimney.

Bookstar, don't fiddle around, you talk about decentralized ventilation like a blind person talks about color. It works excellently here with us.

I had it for years and that is my experience. I also have acquaintances who only put up with it because it is rubbish. Our systems were from Meltem. Lunos is said to be even worse. I rather believe that people with decentralized systems have never enjoyed a central device. Apart from the price advantage, decentralized systems really only have disadvantages.

It is also no longer state of the art for single-family houses; such systems are almost only installed in multi-family houses.

oh yes, the thing can’t be quiet at all, I mean the fan sits right in the wall next to you? how ridiculous is that please? It’s obvious that it must be rubbish.

Then the parts get dirty inside/outside/housing, that is really insane. You don’t have that with a central device. In every room you have holes, when it’s windy it whistles through, etc.

I now have a central ventilation system which is also planned 2x in the new project. Decentralized is out of the question for me.

Yes, I get a bit emotional because builders are reading along here and they should simply be spared from such mistakes. Decentralized ventilation in single-family houses are absolutely avoidable "planning errors," just like unfilled bricks.