Extractor fan through insulated plasterboard

[rreanor]

Hi,

I've put in a shower cubicle in what used to be a room with just a toilet.

I was originally going to put an extractor fan directly on the outside wall, however this would mean cutting a hole in the insulated plasterboard that i've installed in this entire room due to it not being that well insulated. I've heard though that cutting into PIR board can create cold spots.

The alternative is to put the fan on the adjacent cubicle (internal) wall, however this would mean a 90 degree right angle bend before it goes out through the external wall in the utility room adjacent to it.

Does a 90 degree angle reduce the effacacy of an extractor fan? The total distance from the fan to the outside will be less than a foot in either scenario.

Attached is a sketch.

Thanks,

 

[conny]

People talk about cold spots when you cut through insulation but, in my opinion, if you cut through and make the ducting a snug fit through the board, the cold spot will be minimal. It's not as if a few mm of uninsulated wall/board is going to cause a big problem surely?

 

[^woody^]

Cutting through insulation for a fan won't create a cold spot, it creates ventilation.