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Bathroom fan louder since insulation installation

Hi there,

We live in a 1950s ranch in New England. The bathroom is small and has a Nu-Tone fan, probably 15-20 years old. It ran perfectly fine until we had blow-in cellulose insulation added to the attic. Having only lived here a short while and never spent a great deal of time up in the attic, I can't recall if the ductwork was bendy or rigid, and now it is buried in the insulation. While I appreciate this is the right way to run the ductwork (that is, under the insulation rather than on top of it, as it was before), I am concerned that the fan has gotten crazy loud since the stuff went in. Any ideas? Might the ductwork have collapsed, or is the motor just aging?


Re: Bathroom fan louder since insulation installation

The exhaust ducts go in TOP of the insulation, not under it. Most use a flex duct so it probably has collapsed. Was teh fan assembly protected from getting insulation into it?

Re: Bathroom fan louder since insulation installation

Not that I'm aware of. I poked around with a mop handle to find it but had no luck.

Re: Bathroom fan louder since insulation installation

If the insulation has caused the vent to collapse, it will block airflow which will increase the loudness. Turn on the fan, then check the vent outside to see if air is coming out. If none is coming out, or it's coming out wimpily, it's probably blocked.

One other thing to check is the damper on the outlet of the fan housing. You may need to remove the blower and motor from the housing to access the damper. Sometimes you'll get a buildup of greasy dust that causes the damper to stick.

While you've got the fan apart, give it a good cleaning. Don't get the motor wet; just use a vacuum. If the impeller (fan blades) can be removed from the motor, wash the impeller. Lubricate the motor bearings with a light oil such as 3-in-1. Just a tiny drop on each bearing is sufficient.

If that doesn't resolve the issue, your best bet is to just run a new exhaust duct.

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