smoke smell from furnace

Smoke Smell From Furnace: What’s Causing It?

When you turn on the heat and notice a smoke smell from the furnace, it’s normal to feel concerned about a serious problem with your heating system. As the most trusted HVAC contractor in Tucson, our Eazy Breezy Heating & Cooling team receives many calls from homeowners worried about smoky odors from their heaters. 

If you smell smoke when you run the furnace, call us at (520) 207-0334 to have a technician investigate the problem. If you suspect gas leaks, call 911 and leave your home immediately for safety. Otherwise, keep reading to learn the most common furnace odors and their causes and how to solve—and prevent—unpleasant heating odors. 

Musty Smells 

One of the most common and normal reasons for furnace odors is dust buildup on components like burners and heat exchangers. The first time you turn on the furnace after the summer, accumulated dust burns off and creates a musty or smoky smell that typically goes away after a few hours. Scheduling a furnace tune-up and cleaning before the heating season can help keep it from happening.  

“Something’s Burning” 

If, after a few hours, there’s still a smoke smell from the furnace, it just smells like something is burning, or the smell appears suddenly, you may have a clogged air filter. Blocked air filters cause blower motors to work harder than usual, which can cause overheating and a burning smell. If the odor doesn’t go away after you change the filter or the current filter is clean, the burning smell may be from an electrical issue that requires immediate attention to prevent a fire.

Burning Plastic

The smell of burning plastic from the furnace could indicate a foreign object, like a toy, caught in the HVAC system. It might also mean something inside the furnace is malfunctioning. In either case, to prevent toxic fumes and further damage, call for an inspection and repairs.

Burning Oil 

An oily odor from the furnace is most often a sign that it’s time to change the oil filter. A dirty oil filter can cause overheating and damage to the furnace. Changing the filter should solve the problem, but if it doesn’t, turn off the furnace to prevent a fire and call an HVAC professional for help. 


A gunpowder or firework-type sulfurous odor is usually a sign of an overheated blower motor or a damaged circuit board. In either case, turn off the furnace to prevent further damage and schedule furnace repairs. 

Call Us for Help with Furnace Problems  

When you have concerns about a smoke smell from the furnace or any other HVAC issues, call our professionals at Eazy Breezy Heating & Cooling at (520) 207-0334 for prompt, professional, and affordable service. We can also help prevent furnace problems with regular maintenance and tune-ups to ensure critical components are clean and in good working condition. If we determine it’s time for a new home furnace, you can trust us to help you select the perfect model and provide reliable and efficient installation.

Contact Us

Eazy Breezy Heating and Cooling can provide you with regular tune-ups for both your furnace and air conditioner in your Tucson home. We’re professionals, so we’ll always provide you with the best service possible. Don’t wait another day before getting the routine maintenance you need–call us today!

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3710 S Park Ave #705
Tucson, AZ 85713

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