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What Is The Burning Smell Coming From My Furnace

A technician conducts regular maintenance on a furnace

As furnaces and heating systems rest throughout the spring, summer, and fall, dust particles typically settle within the equipment and parts tend to age and break. When winter arrives and the cold outdoor air creeps in, you’ll want to fire up your furnace to keep warm. You may notice your heater producing a burning smell. But is what you smell normal or a more serious issue?

While a burning smell can be unnerving at first, it doesn’t necessarily mean there’s an emergency. Generally, it’s completely normal when a heater produces a burning smell when first turned on. In most cases, this odor should dissipate within an hour or so. If you notice the smell persisting, it’s essential to understand the warning signs.

Let’s explore the most common burning smells, what they mean, and what you can do.


Dust-Like Burning Smell

When a furnace is inactive for several seasons, dust and dirt particles can build up inside your furnace and ducts. This dusty, burning smell coming from your gas furnace should go away within an hour.

What to do:

If the burning smell doesn’t fade within an hour of turning on the heating system, it may be time to check your air filter. When an air filter gets overly dirty or clogged, the blower motor works harder and may overheat, causing the burning smell you’re experiencing. If replacing your filter doesn’t work, give the Cates Heating and Cooling team a call to inspect your system.


Moldy/Musty Burning Smell

If you smell a moldy, musty scent after turning your furnace on for the first time in months, there is likely one of two causes. You could be smelling a dusty filter; if that’s the case, the smell should subside rather quickly. The second cause could be a buildup of mold in your filtration system, which is a much larger problem and would need to be addressed by a professional. Mold smells hamper indoor air quality, and mold is unhealthy to breathe in for an extended time period.

What to do:

If you’re still noticing the smell after an hour, installing a new filter is a good idea to be safe. If the scent lingers, the issue will likely require professional services to eliminate mold growth within the furnace or air conditioning unit.


Plastic Burning Smell

If you’re experiencing a plastic or crayon-like scent from your furnace, there are several potential causes. This smell could mean a foreign object got too close to the furnace or even ended up inside of it. Vents tend to be mystery tunnels for children, and dropping things inside can be very tempting! If you are confident this is not the case, a burning plastic smell could indicate something more serious, like a scorched wire.

What to do:

Electrical burning smells and burning plastic odors need to be taken seriously. If your furnace smells like burning plastic, turn it off right away and call an expert. Cates Heating and Cooling is here to evaluate your heating system and ensure your family is safe.


Rotten Eggs Burning Smell

A “rotten egg” sulfuric smell is added to gas to alert you. This smell could mean a cracked part or a failing pilot light ignitor within your heating system.

What to do:

If you notice a rotten egg smell coming from your furnace, immediately turn off the system and get everyone out of the home. Contact your utility company or the fire department immediately, because inspection and repair is necessary before turning the system back on. 


How Cates Can Help

Maintenance is key in avoiding a dangerous furnace situation. Schedule annual maintenance with Cates Heating and Cooling professionals. Our team will clean your unit, switch out your filter, and check each component to ensure your system stays up and running to keep your family comfortable all year long.

Contact us today to book an appointment for Cates HVAC servicing. We offer financing and maintenance programs, so you can conveniently get a complete care maintenance schedule and avoid unplanned breakdowns or burning smells.

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