Extractor fan - need to vent outside

Discussion in 'Electricians' Talk' started by Kel, Sep 10, 2019.

  1. Kel

    Kel New Member

    Hi everyone,

    I'm hoping I could get some advice please.
    Due to the layout of my kitchen, my extractor fan ducting may need to take a scenic route...

    Hopefully the pictures attached will help to explain.
    The ducting can't go to the left as the conservatory is in the way.

    The fan in the kitchen backs on to our (unfinished) downstairs loo. The plug socket you can see is for the kitchen fan.

    My thoughts were, could the ducting be fed to the false roof in the downstairs loo and linked up to the extractor fan in the loo which vents outside?

    The duct vents down as can be seen boxed in and follows through to the cupboard under the stairs.

    The space from the toilet fan to outside is approx 4m. So from the extractor fan, maybe another .5 metres?!

    I open windows in the dining room as much as possible but it only can do so much. A lot of the condensation ends up in the conservatory, I have a dehumidifier in there but it isn't enough.

    My only other alternative is to buy a wall mounted dehumidifier to sit on top of the kitchen cabinet and feed a hose and feed it through the bathroom fan duct to outside.

    I have no experience in any trade, I just read a lot of forums and like to be imaginative to get what I need!! My husband is quite handy but more than happy to pay for someone to do this, just need someone with a bit of imagination too, which has proved difficult.

    Any help and advice would be amazing!
    Thank you.

    I'll post the above and add photos shortly when I've worked how to do this.
  2. Kel

    Kel New Member

    Phew... That was difficult...

    Photos attached.

    1 - current fan we don't use as just recirculates and is very noisy.

    2 - conservatory

    3 - ceiling of downstairs loo. The plug for the kitchen fan can be seen.

    4 - ducting from loo to cupboard and outside.

    Thanks again and great for your advice and ideas!

    Attached Files:

  3. CGN

    CGN Well-Known Member

    Difficult to get the entire picture, but run through wall into ceiling void in toilet and out through external wall. Keep it separate to your loo extractor.

    Or through wall(lower down) and box it in as tight as possible to loo ceiling and then out external wall to save breaking through into the ceiling. Could use rectangular ducting to keep it ‘low profile’.

    One of those jobs that is easy if you’re confident in your ability to patch in plasterboard. You may be able to do it without any patching with a bit of cunning.
    Last edited: Sep 10, 2019
  4. Alan sherriff

    Alan sherriff Member

    Most extractor fans are noisey and often a cosmetic unit why not to save hastle and not getting rid of fumes install a charcoal filter one and then you will see how often you use it
  5. Kel

    Kel New Member

    Thank you both. I'll take a look later at CGNs suggestion.

    I've already installed the charcoal filters but regarding the steam generated, it's not doing anything but circulating around the room.

    Does anyone know the difference in efficacy of an external vented extractor and a dehumidifier?

    Would the extractor have difficulty being vented almost 5m? I don't think it could be vented out any closer than the loo fan as that's where the conservatory ends.

    The temperature is starting to drop and the issue with condensation in the dining room and conservatory is going to start to bother me again.

    And daft question, but would it be a plumber or electrician I'd need??

    Thanks again for your input, it's saving me many hours of thinking about it!
  6. Bazza

    Bazza Well-Known Member

  7. DIYDave.

    DIYDave. Well-Known Member

    Just some general thoughts;

    Do some research on extract fans and check data on exhaust rates, you need one with a really decent performance as your vent run is 5m +

    Realise you have fan in place but is it suitable for this installation ? Good looks are cosmetic and although important, performance is what you need to look into

    Also duct size - many are now 125mm, better performance than the smaller 100mm size - more air flow

    Try to minimise bends, although not easy in your situation and use rigid duct, either round or rectangular as opposed to cheap flimsy flexi duct (as in your pics). The more bends, reduction in airflow and increase in noise

    The smooth walls of the rigid duct give much better air flow with less resistance when compared to the flexi stuff with all those nooks and crannies to also collect grease

    Really think someone needs to look at this on site and discuss options with you

    Most things can be achieved but may take more work / more destruction / more making good / more ££ / but as long as you get there in the end

    Check duct length with manufacture of fan for compatibility although shortest route is always gonna be best :)

    Good luck

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