When its cold out my bath exhaust fan gets noisy. Is there a reason for this, and how can it be prevented?
Attic mounted, unit and duct are well insulated. Unit has been cleaned.
You cleaned the unit, but have you greased it? Fans that I have installed in the past have made note to make sure to grease bi-annually. I don’t think anyone really does though. Sometimes that’s all they need, other times the bearings are shot and it’s time for a new one.
Sounds like your back draft flap may be stuck or broken. if broken then obviously replace it and if just stuck you will have to inspect the area and try and find the reason for it sticking. Simple fix.
you need new one for sure.
it means its really old and should be changed!