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Mold RemediationAir Duct & HVAC Mold Removal Cost Calculator
Mold in your air ducts and HVAC system spreads spores to every room it serves, so it needs specialist cleaning of the ductwork, coils, and air handler. Enter the affected area for an estimate.
Air duct and HVAC mold removal typically costs $2,000–$6,000, often around $25–$35 per square foot of affected system because ductwork, coils, and the air handler each need cleaning or replacement. Whole-system contamination with duct replacement runs higher.
How this calculator works
We price the affected system area at a higher per-square-foot rate that reflects specialist duct and coil cleaning, then add duct cleaning and post-job testing. Badly contaminated ductwork is often replaced rather than cleaned, which pushes toward the high end.
What changes the number
- Ductwork can sometimes be cleaned, but heavily contaminated runs are usually replaced.
- The evaporator coil and air handler are common mold sites and need separate attention.
- Running the system spreads spores house-wide — shut it off until remediated.
- A humidity or condensation problem at the unit must be fixed to prevent recurrence.
Air duct and HVAC mold removal cost by affected system area
At the calculator’s default $30/sq ft plus $450 for duct cleaning and post-job testing. "Affected system area" means the surface area of the ductwork, coils and air handler that needs treating, not your home’s floor area. The single biggest swing is whether contaminated runs can be cleaned or have to be replaced — porous flex duct is almost always replaced.
| Affected area | Typical range | Midpoint estimate | All-in per sq ft |
|---|---|---|---|
| 50 sq ft | $1,658–$2,730 | $1,950 | $39.00 |
| 120 sq ft | $3,442–$5,670 | $4,050 | $33.75 |
| 250 sq ft | $6,758–$11,130 | $7,950 | $31.80 |
| 500 sq ft | $13,132–$21,630 | $15,450 | $30.90 |
| 800 sq ft | $20,782–$34,230 | $24,450 | $30.56 |
Frequently asked questions
How much does air duct mold removal cost?
Air duct mold removal usually runs about $2,000–$6,000, depending on how much of the ductwork, coils, and air handler is affected and whether contaminated duct runs can be cleaned or must be replaced. Enter your affected area above for a tailored estimate.
Can mold in HVAC be cleaned or must ducts be replaced?
Light contamination on hard surfaces can be cleaned; porous or heavily contaminated flex duct is usually replaced. A pro will assess which runs are salvageable.
Is HVAC mold dangerous?
It can be — the system distributes spores to every room, so symptoms are often house-wide. Turn the system off and have it assessed before running it again.
Should HVAC ductwork be cleaned or replaced when it has mold?
Hard-surface sheet metal duct can usually be cleaned and treated. Porous flexible duct and internally lined duct are normally replaced, because the mold is inside the material rather than on it and cleaning cannot reach it. That single determination is most of the difference between the low and high ends of the range above.
How do I know if there is mold in my air ducts?
The two reliable signs are a persistent musty smell that gets stronger when the system kicks on, and symptoms that affect the whole household rather than one room. Visible growth at the supply registers or on the evaporator coil confirms it. Dust in the ducts is normal and is not mold.
Can I run the HVAC system while waiting for remediation?
Turn it off. A contaminated system distributes spores to every room it serves each time it cycles, which turns a localised problem into a whole-house one and enlarges the job you are about to pay for. Use portable heating or cooling until it has been assessed.
Does duct cleaning prevent mold from coming back?
Only if the moisture is dealt with. Mold grows in HVAC because something is wet — usually a condensate drain that is not draining, an oversized unit that short-cycles without dehumidifying, or duct running through a humid crawl space or attic without insulation. Clean ducts in a wet system are moldy again within a season.