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Serving The Chicagoland Area Since 1998


ServiceMax Blog

What Do Those Odd Smells Coming from My Furnace Mean?

There are a number of ways that furnaces send signals that they’re experiencing malfunctions or are in danger of breaking down. Strange noises, elevated bills, drops in air flow, and uneven heating are all warnings that a furnace should receive attention from repair experts—the sooner, the better.

Another common kind of warning sign is unusual smells coming from the room vents whenever the furnace is running. Some indicate minor issues, while others will need to have HVAC technicians on the job fast to keep the furnace from shutting down. Here are some of the more common strange odors from a furnace and what they may mean.


A furnace’s air filter can start to develop mold growth (a reason that you should always allow a filter to completely dry after cleaning it before it gets put back in place) leading to this unpleasant smell. Make sure you regularly replace or clean the filter to prevent this from happening. The smell of mold may also indicate gaps in the ventilation system where the ducts are starting to draw air in from closed-in parts of the house.


Dust and other debris will start to build up inside the ducts of the furnace’s ventilation system, and when the blower comes on they will be wafted out the vents. Usually, the dusty smell won’t last for long, but if it continues you should have professionals take a look.


A burning odor coming from a furnace when it turns on for the first time during the season usually means there is dust along the heat exchanger and it’s burning off. This is usually harmless and nothing to worry about. However, acrid electrical burning smells often mean that a motor is overheating and will soon burn out. This is something you need to worry about, since it may mean the blower is in danger of shutting down. Call for repairs right away.

Malek Heating & Cooling is here to help you with evaluating and repairing your furnace in Evanston, IL. We’ve served the Chicagoland area since 1998.

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