If you’ve noticed that your furnace smells a little funky, or perhaps even like something might be burning, this could be an indication that there’s an issue with your heater. A furnace “burning” smell is very common the first time you turn on the unit at the beginning of the cold season, but if you notice that the smell errs on the side of burning dust or even burning plastic, it could signal an issue with the internal components of your furnace. Here’s what to do.

The Furnace Combustion Process:

Your gas-powered furnace is essentially the head chef of the cozy atmosphere-making process in your home. The combustion process involves a series of coordinated steps that (when performed without issue) result in a comfortable heat in your home.

Consider the gas valves as like the “conductor” in your home, regulating the natural flow of gas and channeling everything into the combustion chamber. Once the gas has entered, the ignitor then takes up its spot and generates a spark which can ignite the gas and transform it into a controlled flame. You can imagine this pretty similar to how a spark would ignite a campfire.

The burner becomes the focal point. It offers a platform for the flames to thrive, so as the gas flame engulfs the burner it elevates the temperature. The heated burner becomes a source of warmth for the entire process.

The blower fan then comes in, kicking into action and directing air over the heated components. Heated air then circulates through the heat exchanger. The warm air emerges and is distributed through the ductwork, offering comfort to your entire household.

Why does my furnace smell like it’s burning?

Your furnace involves a burning process, so to some degree the scent of “something burning” is actually rather normal. However, if the scent persists throughout the season, or it smells strongly of dust burning or even plastic burning, it could indicate an issue.

Here are some common reasons why a furnace might produce a burning odor:

Dust Accumulation

If your furnace has been dormant for a while, dust and debris might have settled on the heating elements. When you turn the furnace on, the burning smell could come from this accumulated dust burning off. This should dissipate after a short period as the system heats up and cleans itself out.

Clogged Air Filters

A dirty or clogged air filter can restrict airflow and cause the furnace to overheat. This overheating can lead to a burning smell as the system works harder to circulate air.

Blocked Vents

Restricted airflow due to blocked vents or registers can cause the furnace to work harder, potentially leading to overheating and a burning smell.

Foreign Objects

Sometimes, objects like papers, leaves, or even rodents can find their way into the furnace, leading to a burning smell when these items come into contact with the heat source.

Oil Leak

For oil furnaces, an oil leak can cause a burning smell. This is a serious issue that requires immediate attention, as leaking oil poses both safety and environmental risks.

Electrical Issues

Electrical components within the furnace, like wiring or motors, can become overheated, resulting in a burning odour. This should be addressed promptly to prevent potential hazards.

New Furnace

A new furnace can produce a slight burning smell during its initial use. This is often due to the heat exchanger or other components curing and adjusting to the first few heating cycles.

As you can see, some of these issues involve an easy remedy or are typical and to be expected given the context and circumstances. However, some issues require the intervention of a professional, as the diagnosis of the problem can threaten the safety of your household. If you’re still unsure, call a technician.

What to do if your furnace smells like it’s burning:

If your furnace smells like it’s burning, and you’re certain that it isn’t due to your furnace simply starting off for the season or the traditional smell of “furnace burning” that doesn’t signal an issue, then follow along for these three steps:

Turn off the furnace.

As a precaution, make sure to turn off your furnace. Find the furnace’s power switch or breaker and shut off the power supply ASAP. This prevents any potential issues while you can safely investigate the source of the burning smell.

Check for obvious issues.

Once the furnace is turned off, visually inspect the area around the furnace. Look for any visible signs of debris, foreign objects, or blocked vents that could be causing the burning smell. If you feel comfortable, also examine the furnace's interior for any visible damage or signs of overheating.

Call a professional tech.

If you cannot identify a simple cause for the burning smell or if the smell persists after you've taken initial steps, it's essential to call a professional HVAC technician. An experienced technician can thoroughly inspect your furnace, diagnose the problem, and perform any necessary repairs. Avoid attempting to repair the furnace yourself, as it can be dangerous and may void any warranties.

Is it bad if your furnace smells?

So, in summary, is it bad if your furnace smells? It can be, but the scent of a furnace “burning” is very common for the beginning of the season. Pay attention to the details and the context. If you notice a burning scent persisting, intensifying, or even being accompanied by other issues (such as smoke or strange noises) then it’s likely time to contact an HVAC technician to diagnose and then address the issue.

Is a smelly furnace something you’re dealing with? If so, Home Aire Care is available 24/7/265 days a year including after-hours, weekends, and holidays! Schedule an appointment with a certified HVAC technician today to make sure your heating system is working properly and safely for your home!