The Many Burning Smells You Can Smell from Your Furnace

A furnace’s job is to provide heat through fire. However, it’s a different story if there’s a burning smell that comes directly from the furnace itself. If you detect a burning smell from your furnace, it’s usually a burning plastic or an overheated blower motor.

The smell of burning plastic isn’t necessarily a cause for alarm. Many modern furnaces have plastic parts that can melt, but this doesn’t necessarily mean that the heat exchanger or blower motor needs to be replaced. This is something that you do need to look into, but it isn’t an emergency. If you have a burning smell from your furnace, this is typically a sign that it’s overheating. In this case, you need to turn it off immediately. While it’s certainly possible, it isn’t always a sign of a blocked vent. In some cases, a blocked vent can cause a furnace to overheat. The smell can be a little more pungent when there is already a blockage in the vents.

This article will list the possible causes of why your furnace emits a burning smell, so read on below to find out why they happen.

Burning Plastic

Burning plastic is caused by one of several conditions. Typically, the smell of burning plastic is caused by the plastic melting down into the furnace unit. In some cases, it also happens when plastic is deliberately stuffed into the ductwork or vent. Plastic bottles, like milk jugs, are often the culprits in this case. Other sources of plastic can include toys, plastic bags, and plastic grocery bags.

Burning Dust

Dust is a common problem with furnaces, and its smell can be difficult to discern from burning plastic. The smell of dust burning is an acrid, smoky odour that’s almost like burnt toast. If you notice your furnace emitting this odour, turn off your furnace and call Legacy Heating.

Clogged Furnace Filter

When a blower motor is clogged, it exerts itself more, causing it to overheat. If you want to protect your family from the potential hazards of a failing furnace filter, it’s recommended that you buy a quality furnace filter from a reputable manufacturer. Also, make sure to change the filter regularly, as the manufacturer recommends. If your furnace or air conditioning system is more than 10 years old, talk to Legacy Heating and Cooling’s repair professionals to know if it should be replaced.

Electrical Burning

A furnace automatically turns off by itself if it starts to overheat, but there are instances where the safety feature gets turned off. If this happens, the risk of an electrical fire increases and can arise in your home. Have an HVAC specialist check the burning components in the furnace if you notice an electrical burning smell in your vents.

Smell of Gunpowder

When your furnace’s circuit board overheats, it will give off a smell that’s very similar to that of gunpowder. You need to turn off your furnace immediately and call Legacy Heating and Cooling to inspect and repair the problem with your furnace. Do not turn your furnace back on until the HVAC professional gives you the all-clear.

The Smell of Oil or Smoke

If you’re using an oil furnace, it often gives off smells similar to the smell of smoke or burning oil. In these types of furnaces, you’ll want to replace the filters with ones designed to eliminate overheating from occurring.


If you smell any of the scents mentioned above, you’d do well to contact Legacy Heating and Cooling as soon as possible. You should also turn off your system until the repairs are complete because fire can catch on quickly if you leave it as is.

Legacy Heating offers top-quality services for furnace repair in Edmonton. We believe every home should have a well-maintained heating and cooling system for maximum comfort, and our HVAC professionals will take care of your home systems for you. Contact us today to learn more!

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