Why Does My Furnace Smell Like Burning?

Heating and cooling services are only a call away with Fast Air Repair!



Smelling something burning at home is always a frightening experience, especially if it's ongoing and you can’t seem to pinpoint the source. Sometimes, that distinctive odor comes from your heating unit, which is a cause for concern. 

Why does my furnace smell like burning plastic or paper? Furnaces emanate a burning smell for quite a variety of reasons, from clogged filters to excess dust. Learn more below from Fast Air Repair, the HVAC service experts in Ocala, Florida.

6 Reasons Your Furnace Smells Like It's Burning

There are several possible reasons your furnace could let off burning smells. Below are six of the most common factors behind a furnace’s burning smells that should let you know it’s time to call a professional:

#1: Clogged Air Filter

Blocked air filters put excess strain on the blower motor, and this overheated blower motor then emits a burning smell. Your blower motor works harder when the filters are dirty because it's trying to push air through debris and fluff. You can avoid this issue by regularly checking the air filters on your heating unit and replacing them or cleaning them if they’re clogged up. 

Scheduling a yearly furnace tune-up also helps because clogged air filters are one of the many things your HVAC technician will check during the appointment. The team might remove the dirty filter and replace it with a brand-new one or clean it if it’s a reusable type.

#2:  Plastic That’s Burning

If your furnace smells like burning plastic, it may be exactly that. Items like bottle caps and small children's toys sometimes find their way into these heating units, and foreign objects melt. 

Notably, this reason for the smell of burning plastic needs some caution. The fumes given off by burning plastic could be harmful to your family's health, so it needs prompt resolution. Don’t wait to call an HVAC professional like Fast Air Repair when you notice a burning plastic smell coming from your furnace.

#3: Overheated Circuit Board 

Why does my furnace smell like burning gunpowder? If you detect something similar to gunpowder, you may be looking at an overheated circuit board after a power surge or when moisture enters your HVAC system.

You should consider an overheated circuit board an electrical emergency that significantly increases the risk of a fire on your property. When you smell gunpowder around your heating unit, turn off the furnace immediately and contact the HVAC professionals. Do not turn on your furnace again until your HVAC technician gives the go-ahead.

#4: Burning Electrical Components

Your furnace contains a safety feature that powers itself down when it begins overheating. If this safety feature malfunctions, it increases the risk of an electrical fire. If you smell burning, it may be these electrical components, and it is an emergency for the safety of your home and family. 

When you smell burning due to electrical elements within your furnace, contact your local HVAC team immediately.

#5: Overheating Oil

Oil furnaces will sometimes give off the smell of burning oil or even smoke. This happens when the oil inside the furnace gets too hot. 

If you smell burning oil or smoke within your home, schedule an emergency appointment with an HVAC professional.

#6: Dust Accumulation

Dust accumulation is one of the most common causes of a burning smell coming from your furnace, especially when you first use your furnace in the fall or winter months. Long periods of no use accumulate dust in and on the heating unit. When you turn the furnace on after a while, the unit heats this dust, which creates the burning smell. 

Fortunately, dust burning is not a cause for concern. The smell usually dissipates within a few minutes. However, if you find this smell bothersome every winter, there are measures you can take to prevent it, such as:

• Keep your heating system clean throughout spring and summer.
• Sweep the area surrounding the unit regularly.
• Get furnace maintenance twice a year.

Why does my furnace smell like burning when I've already been using it for several hours? In this case, contact an HVAC professional. A prolonged burning smell indicates something more serious.

What Other Furnace Smells Should You Look Out For?

While burning smells are surprisingly common, they're not the only type of smell a furnace emits when something is wrong. Two other odors arise from an ailing heating unit: sulfur and mold.

“Rotten Egg” or Sulfur Smell

Beware of a "rotten egg" or sulfur smell coming from your heating unit. In general, this foul odor indicates a dangerous gas leak.

Natural gas has no odor, so furnace manufacturers tend to add an artificial scent to it as a safety precaution. When your furnace leaks gas into your home, it will emit a nasty sulfuric smell, alerting you to the issue. Since gas leaks are serious concerns, you’ll need to call a professional fast.

If you suspect a gas leak in your home, follow these steps:

• Turn off your furnace.
• Do not light any open flames within your home.
• Evacuate all people and pets from the building.
• Alert your local fire station.
• Call an HVAC technician for an evaluation.

Gas leaks place all inhabitants at risk of carbon monoxide poisoning. Call 911 immediately if anyone is experiencing these symptoms of carbon monoxide exposure: 

• Nausea
• Vomiting
• Dizziness
• Lethargy
• Rapid heart rate
• Fainting

One way to protect your family from these gas leaks would be to install a carbon monoxide detector. These devices will detect the presence of carbon monoxide at home even when there's no odor, keeping you all safe and sound.

Pungent Mold or Mildew Odors

The second odd furnace smell that needs attention is one of mildew or mold. Moldy smells are always linked to moisture somewhere within your home, and most homeowners first think of water leaks, not heater issues. However, the reality is that your heater creates steam and, in turn, moisture. 

When too much moisture accumulates within parts of the heating system, it promotes mold growth. So, units giving off a moldy smell need professional cleaning and, in some cases, an entire reworking of the ductwork. Faulty ductwork traps wetness inside the unit, so changing it could help prevent the issue and keep unhealthy mold growth at bay in your home.

Fix Common Furnace Issues with the Help of Fast Air Repair

Addressing odd furnace smells or HVAC malfunctions isn't easy. Most of these issues require skilled hands and professional experience. That's why they're best left to professionals like Fast Air Repair. 

At Fast Air Repair, the team understands the importance of having a working furnace, even in Florida. Our winters aren't the coldest, but there's still enough chill in the air to make your home feel uncomfortable without a reliable heating system. That’s why our local contractors go above and beyond when it comes to HVAC repairs, ensuring your home's comfort all year round.

From furnace repairs to air conditioning installations, Fast Air Repair is a leading provider of HVAC services throughout the Ocala area. Our commitment to quality care and customer service means countless residents choose our team for their heating and cooling needs! Why not ask us more about your own systems, including questions about what causes black furnace filters and anything else you’d like to know?

Why does my furnace smell like burning plastic or gunpowder? Don’t wonder too long if you want a safe and secure home. Contact Fast Air Repair in Ocala, FL, at 352-290-7968 today!