Mold near ac registers, air sealing problem?
Thesporky123
| Posted in Energy Efficiency and Durability on
I see what I believe is mold near most of the ceiling-mount AC registers. The house is a two story townhome in the tropics (Cayman Islands) and currently rented out to tenants, so I don’t have a lot of detail.
The home has two air handlers, both in an unconditioned vented attic. The AC units are \~10 years old and have had reasonably regular maintenance. The AC is typically set at 70-74.
I didn’t see signs of mold in other areas (e.g. bathrooms, kitchen, on ceiling near duct runs), it just appears near the AC registers. What might be causing this?
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Replies
It might also just be dirt.
If it's mold, I'd suspect the cool A/C air is cooling off the ceiling (and, to a lesser extent, the wall) in the area of the vent to a low enough temperature to condense some water out of the air. Condensation on the ceiling and wall, if present often enough, can encourage mold growth. I'd try adjusting the louvers in the vent to direct the cool air down a bit and away from the ceiling to limit the problem, then clean what's on the ceiling and see if conditions improve over time.
Bill
Thank you, Bill! I figured perhaps that was the case, or that maybe the duct boots are not well sealed and humid air from the attic is being pulled into the conditioned space from a reverse stack effect and that is supplying the moisture to condense where it is cold from the throw of the AC registers.
I appreciate yiur insight.
Dan