Bathroom extractor replacement

[endecotp]

Dear Experts,

The extractor in my en suite has never been very effective; I have to leave it on for most of the day to clear the moisture from a morning shower. I've considered various possible reasons for this:

- There's a fair length of flexible duct to the outside (about 4m I think).
- The fan itself is possibly not very powerful.
- There is insufficient gap under the door for replacement air.

But while I've been pontificating about the root cause, the fan has been working hard and has now died. Now that I have it off the wall I can see that it is a Silavent SDF100HT; it's a 100mm axial fan whose spec claims 80 m^3/hr at zero pressure and max pressure of 16 Pa.

With it off the wall I can also see that the flexible duct immediately goes around a sharp bend.

So, I need to replace it - presumably with something more powerful. But maybe actually more power isn't going to help if the problem was really the duct or the lack of gap under the door.

Also this is a mains powered fan. Should I replace it with a low voltage one? It is at ceiling level above the bath/shower and easily within reach while I am standing under the shower - I think zone 2. So IIUC mains is OK, but maybe 12v is "best practice"?

Thanks for any suggestions.

Phil.

 

[riveralt]

That fan you have is only suitable for up to 2 metres of ducting - though I would always try and avoid sharp bends whatever the length allowed.
You will need a centrifugal fan for zone 1 or 2 either in-line or surface mounted.
12v or 230v not really the issue - don't think there is a best practice.
You do need a good air flow into the bathroom as well.

 

[Iggifer]

Until you get round to shaving some off the bottom of the door, just leave it ajar during the day?

Solid 4" waste pipe is an option to avoid the turbulence in flexi ducting if you can get it in there

 

[endecotp]

I actually did some experiments with various amounts of ajar to try and see if that was a significant factor. The results are not very conclusive. I was also considering fitting a vent in the floor instead; I want to avoid having to also increase the gap under the bedroom door.

I could replace the ducting when I re-decorate the hall, but that won't be soon.

But as the fan has now died the priority is to replace it. If anyone can recommend any particular models that would be great. The volume of the room is about 11 m^3 and it would be great if it would fit in the existing hole without having to get access to the ducting.

Any views on humidistats?

 

[EFLImpudence]

The extractor in my en suite has never been very effective; I have to leave it on for most of the day to clear the moisture from a morning shower. I've considered various possible reasons for this:
- There's a fair length of flexible duct to the outside (about 4m I think).
- The fan itself is possibly not very powerful.
- There is insufficient gap under the door for replacement air.

4. Your house is unduly humid due to your activities which will not be cleared by a fan.

Leave the windows open and go on holiday; there will be no condensation when you return.

http://www.envirovent.com/home-vent...89gYn6hzkSZ7eYiFYVp7N5aMMRD5nFSLfwRoC_6bw_wcB

http://www.envirovent.com/home-vent...ondensation-problems/condensation-prevention/

 

[endecotp]

No, quite the opposite actually (measured).