# Hear a Banging Noise from Bathroom Fan When its Windy



## KUIPORNG (Jan 11, 2006)

would it be as simple as outside exhausted cover is loose up or got part broken... did you check?


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## wjk7320 (Sep 12, 2007)

Everything is new---we recently put new siding on---the soffits have the vinyl covering with vent holes---the soffit covers are new.


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## NateHanson (Apr 15, 2007)

There's probably a damper flap somewhere in the vent (usually at the outside louver), and that will clap open and closed, especially if you have a window open somewhere in the house.


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## Ron6519 (Mar 28, 2007)

As Nate said, there is another flap on the fan where the vent hose is attached. You don't hear it when the fan is on because the fan is holding it open. If the soffit vent is working correctly, it shouldn't be letting too much air back into the hose to effect the fan flapper. Is this a dedicated soffit vent?
Ron


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## wjk7320 (Sep 12, 2007)

Yes---its a dedicated soffit vent---the flaps hang down at an angle and are closed when the fan is off----it does sound like the flap from the fan is being opened and closed when it is windy outside---how can I stop the flap from making this noise....?


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## wjk7320 (Sep 12, 2007)

Would caulking around the soffit vent cover help? (might it prevent air from flowing up into the ducting causing the fan flapper to move and make noise?)


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## NateHanson (Apr 15, 2007)

See if closing the bathroom door makes a difference.


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## wjk7320 (Sep 12, 2007)

Still happens when the door is closed....


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## KUIPORNG (Jan 11, 2006)

You should lift the fan cover to check if the noise is indeed from the fan flag first... this is a malfunction fan then if this is the case in my opinion...


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## Ron6519 (Mar 28, 2007)

The noise from the flapper is from air leaving the house, not air entering it. Air is not coming in the soffit vent. 
I'm not really convinced the soffit vent is functioning properly. If the flapper is in place on the soffit vent it should preclude air movement in the duct to the fan. If wind is blowing outside, past the soffit vent, it's possible it could draw the soffit flapper open. But it would take a sustained wind to also effect the flapper on the fan.
How close the the soffit vent is the fan?
Easy experiment. Immobilize the vent flapper and see if the fan flapper, well, flaps.
Ron


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## mcvane (Mar 19, 2007)

Our bathroom fan makes a similar sound on very, very windy days. I'm thinking it's just the fact that there is a natural air pressure point which causes the noises that you cannot do anything about. I think if you were to go to the roof and cover up the air vent (which is not to code I would think), the noises would disappear.

In fact, when in the washroom, we can clearly hear the voices of kids playing basketball on our dead end street, which echoes through the bathroom vent. I think this is as design?


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## wjk7320 (Sep 12, 2007)

I've tried immobilizing the soffit vent flaps and the fan flapper still flaps when its windy...I think this is because the openings to the soffit vent are exposed directly to the wind and some wind leaks into the duct and causes a backdraft....any way to correct this?


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## Ron6519 (Mar 28, 2007)

As I said before, it's air coming out of the duct that causes the fan flapper to move, not air going in. You can try adding another flapper at the end of the duct,before it's attached to the soffit vent. Or trying a different design in soffit vents.
Ron


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