Technician checking the furnace for any burning smell

Why Your Furnace Smells Like Burning

It’s that time of year again: the furnace is constantly running, and the smell of burning is in the air. For many people, this is a worrying circumstance since a burning scent always signals the beginning of a fire. Although, this isn’t always the case. The furnace smells like burning may be natural, anticipated, and innocuous.

But what’s causing it? How can you fix it? In this article, we’ll explore the possible causes of a furnace that smells like burning and offer solutions to help you get your home back to normal.

Burning Smell Cause #1: The Oil Furnace

If your furnace is oil-powered, then it’s likely that the burning smell is simply due to the furnace igniting. It is normal and not cause for alarm.

To confirm this is the issue, look at the furnace itself. If there’s a small fire burning within the furnace, then that’s the cause of the smell. If you don’t see any flames, then it’s likely another issue.

Burning Smell Cause #2: Dust Accumulation

If your furnace is powered by electricity or gas, the burning smell is likely due to dust accumulation on the furnace’s heating elements. The dust burns off when these elements heat up, causing that familiar smell.

You’ll need to shut off power to the furnace and remove the access panel to clean the heating elements. Use a vacuum attachment to remove as much dust as possible from the furnace, being careful not to touch the hot parts. Once you’re done, replace the access panel and turn on the furnace.

Burning Smell Cause #3: Clogged Air Filter

Usually, all a furnace needs to stop emitting a burning smell is a new air filter. When the filter is blocked, the blower motor needs to run harder, raising its temperature.

The overheating causes a burning odour to emerge as the filter tries to continue to push air through it. Additionally, a blocked filter lets a lot of dirt build up on the furnace’s heat exchanger. This dirt can also cause a burning smell when it starts to burn on the furnace, burning off and emitting a burning smell as the furnace warms up.

To clean or replace the furnace filter, first, turn off the furnace. Then, locate the filter inside the furnace and remove it. If it’s disposable, throw it away and insert a new one. If it’s reusable, wash it with soap and water, let it dry, and put it back in the furnace. Once you replace the filter, you can turn on the furnace.

Burning Smell Cause #4: Wiring Issues

If the furnace smells like burning plastic or metal, then it’s likely that there are wiring issues inside the furnace. It could be due to a loose connection, frayed wires, or something else.

You and your family are in danger of an electrical fire if this safety mechanism isn’t operating. If you smell burning electricity from your vents, get an HVAC expert to look for burning electrical parts.

Burning Smell Cause #5: Gas Leak

It could be a gas leak if you smell a burning odour from your furnace but can’t find the source. It is a severe issue that you need to address immediately.

If you think you may have a gas leak, switch off your furnace and evacuate your home, and call the gas company or an HVAC expert. Do not turn on any lights, appliances, or anything else that could create a spark, as this could ignite the gas and cause an explosion.


If your furnace smells like burning, don’t panic. In most cases, it’s not a sign of an impending fire. However, if you can’t identify the smell’s source or are concerned about your safety, be sure to call an HVAC professional for help. Furnace Repair Toronto can help you with any furnace-related issues you may be experiencing. We will be able to quickly identify the problem and get your furnace back up and running safely.