I spend winters in our double wide in Florida. I've been running the AC off and on for the last 4 weeks. I just started to get a mildew/mold odor from the cold air return when the unit isn't running.
Is there anything I can do? Or do I just need to call a qualified AC firm?
Metallic Musty Odor from Cold Air ReturnNEW by: Anonymous
I have the same problem with the cold air return odor. In the master bedroom, a dull, metallic, dusty odor comes from the cold air return. To prove it, I covered it with plastic and the odor is gone, although now it is coming from the air return directly below the bedroom. A heating guy who performed the pressure test in our home said we had to seal the top of the air return shaft since the odor was being pulled from the attic, but this absolutely is not true. My husband caulked the top of the return, and we checked the attic which is odor free and dry. Odor is worse on a warm humid day and more apparent when it seems to ooze into the room without the furnace or AC on. I can also smell this terrible odor which gives us a headache, in other rooms, but not as strongly as the bedroom. Could it be an old or rusty duct system or from adjoining walls? I don't think it is a dead animal or mold problem. It has been there for years and years and nobody can discover the source of the problem.For sure, it is in the cold air return duct which runs between wall studs.
Nov 22, 2010 Rating
Mildew and Mold Smell by: Dadan
Just to me sure I get this. You only get the mildew and mold odor from the return vent. While the central ac unit is off? You have to get close to the return vent to smells it right?
This odor could be coming from your return vent surround wall or the return duct is touching against ground.
When was the last time the evaporator coil was clean or it pans under neither the evaporator coil? But, I doubt the evaporator smell. If the evaporator coil smells, it should have spread to the entire house, not just the return vent.
You could also check to make sure there is not mold or mildew built near the evaporator drain.
