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Bathroom extractor fan

Discussion in 'Electrics UK' started by Bigtree, 20 Sep 2020.

  1. Bigtree

    Bigtree

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    Hi all, not sure what category would be best for this?

    I currently have an extractor fan in my bathroom, the type that is a light as well (if you know what I mean)

    despite having this I am getting some spots of black Mold on my ceiling.

    is there a better type of fan that I could get that would offer better extraction?
     
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  3. JohnD

    JohnD

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    yes.

    But to choose one, we need to know more

    Do you find the fan a bit noisy?

    Is your old one mounted in the ceiling, and does it have a 4-inch duct in the loft that takes the steam out through an external wall? Do you have access to this duct?

    is it in a shower cubicle?

    Is it the main light of the room? or just a dim gadget?

    Does it turn on when you operate the light switch?

    Does it run on for some minutes after you turn out the light?

    Is the fan directly above a fixed bath or shower?

    How high is the fan above floor level? To be precise, is it more than 2250mm above floor level? Or less than 2250mm?
     
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  4. Bigtree

    Bigtree

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    Ermmm.........standard ceiling height :D I’ll try to find a tape measure :D

    thank you so much for replying
    (y)
     
  5. Bigtree

    Bigtree

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    Not quite sure why my reply looks like that??

    my answers are below each of your questions
     
  6. Taylortwocities

    Taylortwocities

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    Some points and questions.

    If you get a bit of paper and put it over the fan inlet above the bath, does it stick strongly to the inlet?

    What is the size of the room in metres?
    H X W X D

    Is the bathroom door a really snug fit (you may need to take a slice off the bottom of the door, or otherwise enable enough air to get in to the room, otherwise the fan won’t work efficiently.

    You obviously need a timer fan that runs on for a time (maybe 15-20 mins) after the light goes off.

    Many of the cheap in line fans are hopeless. There are some good ones out there, but let us know the room size and can make some suggestions.
     
  7. JohnD

    JohnD

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    As it has a 4" duct in the loft, a very good solution would be to put a "ducted inline fan" in the loft, in the duct. Your old one may do that but is probably a weak, frail little thing. Because the duct, especially in flexible convoluted hose (currugated) slows the airflow, you need a more powerful than average fan. As TTC says, the size of the room is relevant.

    A typical cheap fan has a nominal flow around 80 cubic metres of air per hour, but it might be less. As you already have a problem with mould we'll look for one that is two or three times as powerful. These better quality fans have ball-bearing motors and (surprisingly) can be quieter than your old fan as well as more powerful.

    It will be much better to have a fan with timed run-on after you finish in the bathroom and turn the light off. As they are so quiet this will not be a nuisance. However it will require a minor change to the wiring above the ceiling. Do you feel competent to do that, or will you need an electrician?

    It will also be best to check the insulation in the loft. If it is gappy or thin, parts of the bathroom ceiling may be cold, and this will also promote condensation.

    if the fan goes in the loft, the ceiling height will not be critical. But it is important for a fan that's inside the bathroom.

    Your new fan will not incorporate a light. If this is important, you can have an extra light fitted at the same time.

    if you mount your new fan on a piece of ply or other rigid board, with a piece of carpet underlay on the bottom, and screw that to the joist, it will reduce any vibration.
     
    Last edited: 20 Sep 2020
  8. JohnD

    JohnD

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    Does your old fan look something like this?

    [​IMG]

    or this

    [​IMG]
     
  9. Bigtree

    Bigtree

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    Thank you for all of your information.

    the first picture is like mine.

    the insulation is definitely in need of a top up too.

    do you have any recommendations for a replacement?
     
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  11. Taylortwocities

    Taylortwocities

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    Yes I do. Provide the answers to my questions in post #5 and can provide some guidance.
     
  12. Bigtree

    Bigtree

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    sorry......I missed your reply. Im all tucked up in bed now but I’ll get the answers tomorrow after work (y)
     
  13. Bigtree

    Bigtree

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    Hi, once again, so sorry for the delayed reply.
    The room is 2.7m x 2m

    the door is ‘an average fit’ (ie a normal small gap all around, doesn’t catch anywhere)

    with regards to the paper test.......not really! It’s more noise than power!!!!
     
  14. Taylortwocities

    Taylortwocities

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    You don't have any/much air flow. Start with investigating why. Maybe the duct is blocked, or the flap doesnt open, or theres a heavy suitcase sitting on the duct in the loft.
    Is air flow better with the door open? Cut a 4" diameter hole in the door, or find another way to get air in.

    Once you've explored all that, it is likely that the fan is too weedy to do anything. Cant tell you about a possible replacement without knowing the answers to the Q's in #5.

    This will need sorting too

    Does it run on for some minutes after you turn out the light?

    no, it’s purely operated with the lights
     
  15. JohnD

    JohnD

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    a decent gap under the door would be much less unsightly.

    I'd start by thinking that the inherent weediness of that fan type is responsible. Corrugated flexible duct adds a lot of drag to the airflow.
     
  16. Taylortwocities

    Taylortwocities

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    I wasn’t being entirely serious there!

    Yes, but even a rubbish fan should hold sheet of paper reasonably well.
     
  17. Bigtree

    Bigtree

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    No wayyyy.......not serious?

    ive just hacked a letterbox sized hole in the door......much to the wife’s dismay
     
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