Upgrading bathroom extractor fan

[sennajc]

Hi there,
I have an in-line (I think axial) extractor fan in the bathroom. 100mm diameter located above the ceiling ducted to the external wall about 2-3metres.
The fan is almost useless as the room is always very steamed up after a shower. The fan barely holds a tissue when completely covering the vent!

I want to upgrade but think that it will be very difficult to install through a 100mm hole - not sure if a replacement will fit through?? For this reason, I was thinking of installing a surface mounted fan?

Can you advise please:
1) is it possible to work through a 100mm hole to replace the in line fan and if yes, what would you recommend?
2) What surface mount fan would you recommend and do I need to remove the inline fan ( I guess so!).

All thoughts appreciated!!

BTW...room is c. 12 cubic metres.

Thanks.

 

[muggles]

You just need a better inline fan

 

[MJN]

Whatever you end up doing you're going to have to access the existing fan i.e. to remove it if fitting a surface mount fan or to replace it. I'd suggest the latter and, given the length of ducting, your only viable option here is a centrifugal fan. An axial fan simply cannot overcome the pressure drop hence it'll just sit there spinning in a stall and having virtually no effect at all.

I can highly recommend the Manrose CDF200T e.g. from TLC or, cheaper but harder to link to(!), part number 18223 from BES. It's cheap (~£35), works extremely well over long duct runs, runs very quietly and has an adjustable run-on timer.

Mathew