What to Do Before Running the System Again
Keep It Off
Running the blower spreads soot from the returns into every room.
Call Your Insurer
Smoke cleaning is often part of a fire claim; ask before you hire anyone.
Replace the Filter
The filter catches soot during the fire. Bag it and throw it out.
Have the System Inspected
A technician checks the ducts, blower, coil and insulation for soot.
How Smoke Spreads Through Ductwork
Return vents pull room air back to the air handler. During a fire, they pull smoke with it. Soot settles on the blower, the coil and the inside of the ducts, then blows back out every time the system starts. Fine soot particles also stick to fiberglass liners and flex duct.
What Gets Cleaned and What Gets Replaced
| Part | Usual outcome |
|---|---|
| Sheet metal ducts | Clean under negative pressure |
| Blower and coil | Clean |
| Flex duct with soot inside | Replace |
| Duct board and insulation | Replace if soaked or stained |
| Filter | Replace |
The EPA's duct cleaning guide says duct insulation that gets wet or moldy can't be cleaned effectively and should be replaced; soot-soaked insulation is usually handled the same way. The full equipment-side job is described on the HVAC duct cleaning page.
Does Duct Cleaning Get Rid of Smoke Smell?
It removes the soot that carries most of the smell from metal ducts and equipment. Smell that has soaked into flex duct, insulation, carpets or drywall stays until those are cleaned or replaced. Masking sprays don't remove it. The odor removal page covers smells that remain after cleaning.
Wildfire Smoke and Your HVAC Filter
Wildfire smoke drifts into Northern Virginia some summers. The EPA advises a high-efficiency HVAC filter, such as MERV 13, or as high a rating as your system fan and filter slot can handle, fitted snugly so air doesn't leak around it. Ducts rarely need cleaning after outdoor smoke alone; a fresh filter usually does the job.