Installation of controlled residential ventilation - in the ceiling or outside?

Chases are also not necessary for us, as the pipes run under the screed.

Thanks again for all the answers.

: Why is installing INSIDE the ceiling easier? And am I wrong in thinking that in case of maintenance, it is more difficult to access cables that are not inside the ceiling?

@ Kazazi

Because the pipes are "simply" laid on the formwork or the lower reinforcement. It goes super fast and easy. What maintenance do you mean? If proper filters are used, the pipes stay clean forever.

Ah, thanks. I meant the (hopefully unlikely!) case that something actually happens and you have to get to the pipes. A craftsman from my circle of acquaintances just told me a story where children got open a ventilation opening and fed it with marbles, for example....

That is why I would not want to have them on the floor, besides marbles there is, for example, the 1.5-liter bottle of cola that someone (hopefully accidentally) poured in there, or the cat that found no other place...

When laying pipes in the ceiling, they must also be taken into account in the structural analysis.

The installations in the floor represent (according to the information provided to us) a more cost-effective option. It is better to install supply and exhaust air in the ceiling (ideally during the masonry/floor pouring, subsequent core drilling in the shell construction is possible but expensive). With supply air in the floor, you have more work at the latest when laying the flooring. And the bottle of cola should also be an argument!