Bathroom extractor fan ineffective at clearing moisture

googler

Place the photo on a photo-sharing site such as Photobucket, then use the direct URL as a link from here.

googler

How much room is there above the door? Is there a fanlight there? If there's room, perhaps an open fanlight or louvred fanlight above the door?

Cameron1983

This is a link to the photo http://i305.photobucket.com/albums/nn236/HUKDCameron1983/fan.jpg

apologies for the rubbish image; my flat is the 2nd to right on the lower level, with the bathroom one room 'further away'. The window above and left has a black grilled pipe to the left of it (poor quality image), but I would estimate it to be somewhere between 5-10 metres in length to the bathroom fan.

Theres not a lot of room above the door, and I would feel more comfortable sawing into an old door than the wall; I'll maybe just try to plane a bit off the top of the door and saw a bit off underneath....:mad:

I emailed a few companies and was recommended:
http://www.justfans.co.uk/sp-td160-mixvent-100mm-p-298.html
http://www.epicair.co.uk/100mm-recessed-bathroom-extractor-wall-ceiling-fan-with-timer-p-159.html

and this tool: http://www.tlc-direct.co.uk/Technical/Ventilation/Ventilation4.html which would work out at needing something to provide at least 42 litres/second removal.

Thanks for all the above replies!

gmgmgm

You have a couple of problems, but none of them are impossible to solve.

Firstly, the fan needs to work pretty hard to push all that air outside and through such a thin pipe. So while the current fan will probably do the job, it will take longer than a more powerful fan.

You certainly need to run this fan for a long time. If it has a timer, I'd set it to an hour at least and see how it goes.

You should only have a tiny gap from the bathroom into the rest of the house - ie so dry "house air" can come in to replenish the air the fan has pushed out. So the door should be only slightly ajar (a few mm) or left shut if there is decent gap at the bottom of the door. Certainly don't leave the door open when showering- you'll just make your house damp.

A humidity sensor fan would be the best solution really; they start at about £30 for a basic one. The more powerful the fan you get, the less it will be on...

googler

I couldn't make anything out from the photo, sorry - but I still think there's mileage in using a smoke match to determine how much air is getting pushed to the exit point.....; also the exit grille may have moveable shutters on it to allow airflow out, but prevent air flowing in. If these are stuck, that will be preventing the fan from reaching its full potential; the only to determine this is set the fan running, possibly also with a smoke match, and observe the outside grille with binoculars or similar. The only way to unstick them if they're not moving is to shin up a ladder, I fear.....

CLAPTON

how long do you leave the fan on after a shower?

Cameron1983

The timers set to about 15 mins. The fans left on til the moisture clears after showers though which takes a while. Im probably going to buy a continuous flow centrifugal fan, perhaps the one linked to by dampdaveski. It seems the centrifugal ones are best for long ducts which this one appears to be. I'll try to shave a bit off the top (or bottom) of the door to ensure theres about 1cm gap for air inflow. Hopefully this will sort it. Not sure which centrifugal ones are best, or the difference between a standard one and an inline one though.

I'll maybe try the smoking match trick to check the pipe actually works first....

Thanks for above replies

googler

If all else fails, you may want to invest in a Dehumidifier......

jamesd

Before shaving anything off the door, just try leaving it open by 1cm to 5mm. That'll let air into the room while the fan is operating. If it works then you'll know that the shaving will be helpful.

Cameron1983

Update; Have managed to significantly improved inflow ventilation by removing a raised 'step' from infront of the bathroom door which appears to have been put in as part of draft proofing the flat by the previous owners (obviously now realise not a good idea!)

Have had a good look at Nuaire products, but the only concern about the Genie MX is, given its a continuous trickle fan with a boost, it states it operates at 30 dba sound level... after googling this, it appears this is the sound level of a quiet office - does anyone know if this is the boost sound level or the trickle level? Would the noise from the continuous trickle level get annoying? Otherwise it looks like a good bet.