Bathroom Exhaust Vent.. Air Inlet?

[DD716TED]

I live in a manugactured home and have been fighting dust problems for several years now... The electric furnace draws its air from a tiny fresh air inlet vent (solenoid controlled) that is located directly above the furnace air filterand the majority of the air that the furnace requires is drawn from what is inside the house... Since the bathrooms seem to accumulate the most noticable amounts of white dust, is it possible that the furnace is sucking outside air back thru the bathroom exhaust vent.. I have checked the bathroom fan units and the flapper valve in them seems flimsy at best. Is this a common problem in manufactured homes? Is there any sort of filter that can be installed in these vent fans? Suggestions? Dusty

[HayZee518]

you can try using an open neoprene filter used in airconditioners. this product looks and feels like a grey foam sheet. maybe you can use it behind the bezel cover on your vent/light.