Why Is There a Burning Smell Coming From My Furnace?

A burning smell coming from your furnace after turning your heat on for the first time that season can be cause for concern, although it is fairly normal. However, if you’re noticing this burning smell throughout the entire winter, then it could indicate a more serious issue. Additionally, if you’re noticing the smell of burning plastic or another electrical odor, then you might require a furnace repair. 

What Causes the Burning Smell From My Furnace?

There can be many reasons why your furnace is producing a burning odor, and the causes may vary. Some smells aren’t cause for concern, while others are. Here are a few common answers as to why you’re experiencing a burning smell from your furnace.

Dirty Furnace Filter

If you notice a looming dust-burning smell throughout the entire day, not just right after you turn it on, a dirty furnace filter is probably the source of the odor. A dirty or clogged air filter can restrict airflow, causing the furnace to overheat and then produce a burning smell.

Changing the filter often is crucial for proper airflow in the home and preventing the burning smell from your furnace. 

Overheated Blower Motor

Without proper airflow in the home, your furnace blower motor can overheat, causing a burnt smell. This particular issue commonly occurs due to poor air movement, which a dirty filter or a blocked vent can cause. If your motor overheats, the furnace will typically shut down to allow the internal components of your furnace to cool down.

When this happens, it’s wise to check and change the furnace filter if needed and do a thorough walkthrough of your home to ensure no vents are closed or blocked. These precautionary steps should be followed every year before turning on your furnace because when your blower motor overheats, the internal components of your furnace can be damaged. 

Excessive heat coming from your furnace can cause the heat exchanger to crack, thus causing a carbon monoxide leak within your home. For this reason, your furnace is equipped with something called a limit switch, which is responsible for sensing high heat temperatures and turning off the unit when they occur, but this could cause the system to become stuck and prevent it from turning back on. 

Melting Plastic Wire Casing

Typically, an issue with the wiring or electrical connections within your furnace will cause a smell of burning plastic. This is due to the electrical wiring burning off its insulation, which can cause significant damage if not addressed as soon as possible.

It’s standard practice for technicians to check these components of your heating system during your annual professional maintenance check prior to the cold weather. 

Foreign Objects 

Before getting too concerned about the maintenance of your furnace and the safety of your home, simply check your ductwork and vents to ensure that there isn’t anything unusual in there. More common for homes with floor vents, it can be easy for a child or a pet to drop something into a vent accidentally. Signs like a burning smell or restricted airflow could be due to a foreign object in the ductwork of your home. 

Fried Circuit Board

Another common burning smell associated with your home’s HVAC system is the smell of gunpowder or fireworks. This is commonly due to a fried circuit board. A fried circuit board is past the point of fixing on your own, so it’s best to turn off your furnace and call a professional before you turn it back on.

Oil Furnaces

Oil furnaces tend to produce a burning oil or smoky aroma. This isn’t always an indication of a malfunction as long as your air filters aren’t clogged. But, it’s important to note that if your oil furnace is continuing this burning smell after you first turn it on, these toxins are being continually released into your home, which can lower your indoor air quality.

At Total Comfort, we understand the importance of having a trusted and reliable contractor for any of your furnace needs. Our team of experts is trained and experienced in providing furnace installation and repair services to homeowners in the greater Minneapolis area. Contact us today to learn more about our services and how we can help keep your home comfortable and safe from furnace hazards.