How Do I Know If Fire Smoke Got Into My HVAC System?

The most obvious sign is a smoky smell that comes back every time the blower runs, even after airing out the house. You might also notice a thin gray film on surfaces near vents, or dark streaks on the air filter. These are clues that smoke particles have settled inside the ductwork.

Another clue is visible soot around the supply registers or the return air grille. If you have a central system, check the filter slot and the blower compartment for gray or black dust. Any of these signs means the system needs professional attention.

• Smoky odor when the system runs
• Dark or gray stains on the air filter
• Soot around vents or the return grille
• Gray film on walls or furniture near registers
• Burnt or smoky taste in the air

Do not run the HVAC system until you have checked for obvious soot or heavy smoke damage. Running the fan can push smoke particles deeper into the ductwork and make the problem worse. Turn off the system at the thermostat and the breaker if you can.

Change the air filter if you see any dark staining. That simple step can reduce the spread of particles. But keep in mind that the filter only catches some of the smoke; the rest may stay in the ducts and need professional cleaning.

Professional duct cleaning is often the way to remove smoke particles, but the cost depends on the size of your system and the amount of contamination. It typically ranges from a few hundred to over a thousand dollars, depending on those factors. Ask the pros for a clear explanation of what they will do.

After cleaning, replace the filter and consider upgrading to a higher-efficiency filter to catch future particles. If you have had a fire, also check your policy to see what is covered. Policies vary, and your insurer decides what is covered.