Hole for fan - What size?

Thanks to all of you for the helpful answers!

From a construction perspective, I probably wouldn't have thought that much. However, the issue of sound decoupling is an important point. I don't want these things to be so audible. explained it a bit more thoroughly, so I also got some background information. I thought that was not bad.

I probably wouldn’t have thought too much about the construction aspects.

Isn’t the installation manual the crucial thing? That’s the first thing you look at.

Hej, we are men. First do, then look

So...
1. I strongly deny the accusation of being a bot. I just put a little effort into writing.

2. The instructions state a drilling diameter of 160/162mm. However, this is really tight, because a) you can't compensate for any inaccuracies in the drilling (slope, ...), and b) there is no further possibility for sound decoupling, since otherwise the pipe would be directly connected to the masonry. Otherwise, you would have the option to create an additional airtight buffer zone with preferably well foam, which has a significantly noise-reducing effect.

... the manual simply does not state 160/162 mm. copied the decisive excerpt from the installation manual from , which can be found on the Luftbude website, with the specific drilling diameter specification, as this was requested. In general, I recommend reading this installation manual in its entirety.

2. The manual states 160/162mm

The manual is attached above as a screenshot. 180mm. It's easy to read.