ᐅ Location and Installation of Ventilation Intakes and Exhausts

The installation of our LWZ 180 will be completed soon. Two flexible ducts were routed from the utility room to the attic. From there, the supply air duct is supposed to be routed through the soffit, and the exhaust air duct through the roof (via a metal collar that will be integrated into the roof and then fitted with the photographed cover).

According to the ventilation installer, the cover with a perforated grille will be installed perpendicular to the roof slope (meaning the grille faces upward toward the ridge and downward toward the eaves). I am concerned that rain might enter the exhaust shaft through the grille in the cover.

How should the penetration of the building envelope be executed? Are there standard solutions for this? Is fresh air intake through an outlet in the soffit acceptable?

That should not be a problem... provided the attic is not an uninsulated cold roof or the pipes are insulated...

It is a cold roof. The pipes are flexible ducts, which I believe are also minimally insulated.

Do you see any problem with rainwater potentially entering through the covering?

Is the unit itself located in the utility room? Why then is the ducting routed through the roof? A cold roof is generally not ideal. At least the unit should not be placed there. However, for the pipes in front of the unit, this might not be an issue.

The unit is mounted on the opposite wall (interior wall) from the window (exterior wall) in the utility room. There is practically no space around the window (due to the ring beam, roller shutter box, etc.) for a core drill hole.

Hmm, I’m not an expert. I’m not sure if such a long run is okay or if it affects performance. I can’t say anything reliable about the grille either, but I would have the same concerns as you. Maybe ask again. It doesn’t always help, I know, many people try to talk you out of your doubts – but they don’t have to live with the consequences.
Are you sure you understood correctly why not put the grille at the bottom? Because then the warm air can’t flow upwards as easily?