Air intake in light well?

Exactly, that's what I meant! The orange ones. ops:

If I carry out at the currently planned location, with a 3% slope the pipe at the suction point would be only about 20-30 cm below the ground. But that should be enough, right?

Why so much slope? For the smooth pipe, at least one percent and that’s good.... I would find that too little if there was a path there. Otherwise ok.

Okay, fine.

Did you also run that through the floor? Pipe diameter?

Instead of an expensive intake tower, I was simply thinking of a gray HT pipe with a roof vent cap on top.

Have been sucked in through the gable

if the controlled residential ventilation is to be installed in the basement, can it still draw air through the gables? the controlled residential ventilation would be located in the basement facing the street, which is the southeast side, and the front door is there, outlets there would not be visually appealing and it is also the sunny side. on the left is the terrace on the southwest side, on the right the carport, also unsuitable for intake due to exhaust gases. on the northeast side of the basement there are living rooms because of the hillside location. so either diagonally through the basement to get a north-facing intake and through the northwest gable. is that much more expensive (more pipes to lay, longer intake paths)?

It's not nice...

First long distances, then you need a lot of space, because these are 160 mm pipes - possibly two if it also goes out over the roof. Plus the pipes for the three floors... that adds up. We planned generously and it already got tight for us with 3 floors.