Bathroom Fan with 4.5m ducting?

[ChrisKingston]

Hi,

To get to the outside wall I have a 4.5 metre straight run through the ceiling void and am looking for a fan that will still give good ventilation for a smallish shower room.

Most of the axial ones seem to only stretch to 3 metres. I've looked at the inline ones which can handle the longer run, but I don't want to have to put an access panel in the ceiling. An exterior one that sits in the external wall is also not ideal because access to the outside is pretty tricky too.

Is there any other way? My best idea so far is fitting an inline very close to the intake (not advised) and putting a large enough grille on to be able to get into it that way.

Any ideas or tricks I'm missing?

Thanks,
Chris

 

[riveralt]

You will want something like this.

Don't forget the condensation trap.

http://www.free-instruction-manuals.com/pdf/p3133389.pdf

 

[JohnW2]

To get to the outside wall I have a 4.5 metre straight run through the ceiling void and am looking for a fan that will still give good ventilation for a smallish shower room.

Other people's mileage may vary, but I have bog standard extractor fans running over that sort of distance and performing fine.

The one thing I would suggest is that you use solid ducting for most of the run. If you use anything like that length of flexible corrugated ducting sitting on a ceiling, the noise will drive you mad!

Kind Regards, John.

 

[Lectrician]

I would always go for rigid duct on lengths like this for efficiency, not noise.

Rigid duct will allow a fan to perform far better at extraction than the ribbed flexi duct.

Condensation trap required only if you cannot give the duct a fall to the outside.

For anything with this length of duct, a centrifugal fan should ideally be used.

 

[TicklyT]

You can give the extractor fan an easier and more effective life if there is adequate ventilation allowing fresh air into the room.

Without ventilation, even the worlds largest fan would extract exactly nothing.