Mold in air ducts does happen in Marietta, but far less often than a sales pitch implies: it usually begins at the cold, wet indoor coil, its drain pan, or a supply duct sweating in a hot attic or damp crawlspace, and it only needs professional removal once real growth is confirmed and the moisture feeding it has been stopped.
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Six boxes, about thirty seconds. You pick when to be called back, and that is when the phone rings.
Or call (943) 271-6154Plenty of dark dust inside a duct only looks like mold. The EPA says only an expert can make a positive determination, that a tape sample sent to a lab can settle it for roughly $50, and that homeowners should ask any contractor claiming mold to show it to them.
NADCA's 2021 ACR standard sorts indoor mold into three conditions taken from the IICRC S520 standard. Condition 1 is the normal background of settled spores in every Cobb County house. Condition 2 is spores spread from a growth site elsewhere. Condition 3 is actual growth. Only the last two are reasons to clean.
Mold needs water, and in a Marietta air conditioner the water comes from the coil, which pulls moisture out of the house all through the long humid cooling season. The EPA calls condensation near the cooling coils a major factor in moisture contamination, and it treats standing water or debris in a drain pan as a problem needing immediate attention.
The EPA adds that an oversized unit short-cycles and removes moisture poorly, and that ducts in unconditioned space must be sealed and insulated or they will sweat. That describes a lot of local houses: air handlers in vented attics, supply runs across crawlspaces, and returns that were never leak-tested because the house went up before Georgia began requiring duct tightness checks in mid-2011.
The EPA's brief guide to mold gives the first step plainly: do not run the heating and cooling system if you know or suspect it is contaminated, because the blower can carry spores through every room. If a pan overflowed or a duct got soaked, dry the wet materials within 24 to 48 hours, which is the window the EPA gives for preventing growth. Then check indoor humidity with an inexpensive meter. The EPA and University of Georgia Extension both put the target below 60 percent, and ideally between 30 and 50.
Hard metal ducts with surface growth can be cleaned under negative pressure, with the debris leaving the house through a filtered collector. NADCA's standard says remediation should follow IICRC S520 alongside its own cleaning rules.
Fiberglass duct board, internal liner and flex duct insulation are different. The EPA says wet or moldy insulation should be removed and replaced, and NADCA recommends the same for porous parts with Condition 3 growth. A quote that promises to clean moldy duct board in place deserves a hard question.
The coil gets wet cleaning. Under the ACR standard, any suspect microbial growth on a coil or drain pan calls for Type 2 wet cleaning, not just a vacuum pass, and the pan and condensate line should drain freely when the job is finished. That work is covered on the HVAC coil cleaning page, and the duct side of it under air duct cleaning.
Chemical treatment is where mold jobs get padded. The EPA notes that no biocide is currently registered for use in internally insulated duct systems, and that research has not shown these products to work in duct cleaning. Any antimicrobial belongs after mechanical cleaning, never instead of it. The EPA also says duct sealants should never be sprayed over wet liner, over actively growing mold, or over debris.
NADCA's post-job cleanliness check confirms surfaces are free of loose debris, and the standard says it does not determine microbial contamination. Visibly clean is not a mold clearance; after extensive growth, an independent indoor environmental professional should confirm the result.
Three patterns account for most of the real cases here. Attic air handlers on second floors, where a slow condensate drain lets the primary pan stay wet for weeks. Crawlspace ductwork, especially flex duct lying on bare soil or uninsulated metal that drips through August. And the older homes in the city's historic districts, where central air was added long after the house was built and the runs pass through crawlspaces and closets that nobody inspects. In each, the leak or drainage problem is the real fault, and duct sealing and repair is what stops the mold from returning.
Ask to see the growth from inside the run, and whether a lab sample was taken. Ask the contractor to name the moisture source and how it will be fixed, which components will be replaced rather than cleaned, and whether any chemical used is EPA-registered for that surface. Then compare the total with the sourced ranges on the pricing page. A same-day mold finding that multiplies the bill is a reason to slow down.
Mold in Air Ducts If the answer here points at a repair, call (943) 271-6154 with the address and what the job is, and ask for the price before anything is booked.
Call (943) 271-6154Upfront pricing · No obligation · Local Cobb County technician