In short: AC mold in Tampa usually starts in the air handler, where the coil sweats all day and the drain pan holds water, then spreads into the supply plenum and nearby ducts. Cleaning the air handler and the duct runs closest to it typically costs $2,500–$7,500, as an estimate, and the job isn’t finished until the reason it was wet is fixed.
Why Tampa AC systems grow mold
An AC here runs most of the year, and every hour it runs it pulls water out of the air across the evaporator coil. That water is meant to drip into a pan and drain outside. When the condensate line clogs with algae, the pan overflows; when the system is oversized, it short-cycles and never dries the coil; when ducts run through a hot attic with gaps in the insulation, they sweat on the outside. Each one leaves a wet surface in the dark, with dust for food.
Signs it’s in the system
- A musty smell that gets stronger a minute after the AC kicks on.
- Black spotting on supply registers or the ceiling around them.
- Water on the floor of the air handler closet, or a rusted drain pan.
- Indoor humidity that stays above 60% even with the AC running.
What the cleaning involves
We isolate the air handler, clean the cabinet, blower and coil housing, replace or treat the drain pan and clear the condensate line. Accessible duct runs are HEPA cleaned; duct board or flex duct with growth inside is replaced rather than cleaned, because it can’t be cleaned reliably. Where the cause is an AC design problem, such as an oversized unit, we tell you what to ask your HVAC contractor for.
Price guide
| Job | Estimated price | What drives it |
|---|---|---|
| Air handler, coil housing and drain pan | $2,500–$7,500 | Unit size and access |
| Replacing affected flex or board duct runs | Priced per run | Length and attic access |
| Mold in the closet around the unit | $1,200–$3,000 | Drywall removed |
Estimates only. We look inside the air handler before pricing, because the visible vent spotting doesn’t show how far it has gone.
AC & air duct mold: common questions
Is it safe to run the AC with mold in it?
Short term it is usually better to keep humidity down than to switch it off, but get it looked at quickly. Running a contaminated system keeps moving spores through the house.
Can UV lights fix it?
A UV light at the coil can slow regrowth once the system is clean. It doesn’t remove mold that is already there and does nothing for the ducts.
Do you replace AC units?
No. We clean the system and document the cause; a licensed HVAC contractor handles repairs or replacement.
Last reviewed October 8, 2026.