Burning Smell from Furnace: Causes and Solutions

Have you noticed your gas furnace smells like burning? This isn’t uncommon, but it can be alarming when it happens. Fortunately, you can prevent a furnace burning smell with preemptive solutions. 

This blog post will explain the causes of a burning smell from the furnace, and the different odours you might encounter. Keep reading to learn what to do when your heater smells like burning.

Why Your Furnace Smells Like Burning

Coming home to a burnt smell from a furnace is disconcerting. The smell can mean various things, and it’s best to get to the bottom of it immediately. Below are some potential causes of a burning smell from your heater. 

Clogged Furnace Air Filter

If the air filter is clogged, it can restrict airflow, causing the furnace to overheat. This leads to a burning smell coming from the furnace. Replacing the filter should resolve the issue.

Burning Oil or Gas

If your oil or gas furnace smells like burning oil or fuel, it could indicate a leak, malfunctioning burner, or improper combustion. All of these are critical issues that require immediate attention.

Overheating Components

A burnt smell from the furnace interiors might indicate  internal components, like the blower motor, are overheating due to mechanical issues or a clogged furnace filter. If the smell persists, it’s important to turn off the furnace and call a technician.

Image Source: Canva

New Furnace Smells Like Burning

It’s usually not a cause for immediate concern when your new furnace smells like burning. When a furnace is first used, dust that has accumulated on internal components, such as the heat exchanger or burners, often burns off, producing a temporary odour. 

This is common during the first few uses and typically disappears within a few hours. However, if the smell persists or becomes stronger, it could indicate other issues, such as overheating parts or an electrical problem.

Read more: The Ultimate Guide to Buying a New Furnace

Types of Furnace Burning Smell and What You Should Do

With the winter season approaching once again, it’s a good time to give your furnace a quick test run to make sure it’s ready to keep your home warm. Below are some types of a furnace burning smell to pay attention to.

Electrical Rubber Burning Smell

If your furnace smells like burning rubber or overheated electrical components, it could be an indication of an electrical issue. Over time, the furnace’s wiring may deteriorate, leading to exposed or damaged insulation. Additionally, an overheating blower motor can produce a strong burning odour, often due to poor maintenance or blocked airflow.

Most modern heating systems are equipped with safety mechanisms that shut them down when they overheat. However, if the furnace continues to run despite overheating, it could signal a malfunction in these protective features. If you detect a furnace burning smell, it’s important to turn off the furnace immediately and contact an HVAC technician for repairs.

Rotten Egg or Natural Gas Smell

A strong rotten egg smell is a serious warning sign of a natural gas leak. Natural gas itself is odourless, but utility companies add sulfur compounds like t-butyl mercaptan to help detect leaks by giving off that distinct, sulfuric “rotten egg” scent. Prolonged exposure to leaking gas can cause health issues such as dizziness, nausea, or even suffocation.

If you smell gas, turn off the furnace immediately, vacate your home, and call both your gas company and an HVAC professional. Avoid using any electrical devices or open flames until the leak is addressed.

Burning Plastic Smell

If your furnace smells like burning plastic, a foreign object, such as a plastic bottle cap or part of the furnace itself, may have gotten stuck inside. As the plastic melts, it produces harmful fumes that can circulate throughout your home.

Inspect the furnace for any obvious obstructions, and remove them if possible. If the smell persists, the cause may be an overheating component or an electrical issue. In either case, turn off the furnace and contact a technician for a thorough inspection.

Mouldy or Musty Smell

A musty odour coming from your furnace may indicate moisture issues around the unit, possibly from nearby standing water or excess humidity. Failure to regularly change the air filter can also contribute to dampness in the system, which leads to mold growth and a furnace burning smell. 

While minor musty odours may dissipate on their own, persistent smells could signal mold in the furnace or ductwork. To address this, it’s best to call an HVAC professional who can inspect the system, clean the affected areas, and ensure proper moisture control.

Image Source: Canva

Burning Dust or Hair Smell

Don’t worry if your furnace smells like burning dust when you turn it on for the first time after months of inactivity. A short-lived furnace burning smell is completely normal. Dust that has settled on the furnace’s heat exchanger and other components burns off quickly, resulting in this odour.

If the furnace smells like burning hair, it could be due to the accumulation of hair, pet fur, and dander inside the unit. To resolve this, clean the furnace’s surface, vacuum the vents, and replace the air filter to prevent further build-up.

Prevent a Furnace Burning Smell With These Tips

A burning smell from your furnace is preventable with proper care. Follow these simple solutions to avoid odd odours and extend the lifespan of your heating unit.

Regularly Replace the Air Filter

A common cause of a burning smell from a furnace is a clogged air filter. When air filters become blocked with dust and debris, they restrict airflow, causing the furnace to overwork and emit a burning odour.

To avoid this, replace your furnace filter every 90 days, or more frequently if you have pets or live in a dusty environment. Regular filter changes should be part of your routine HVAC maintenance to keep your system running efficiently.

Read more: Best Furnace Filters for Allergies

Check for Gas Leaks

While a rotten egg smell indicates a natural gas leak, other dangerous gases, like carbon monoxide, are odourless and invisible. Carbon monoxide leaks can be hazardous and difficult to detect without proper equipment.

Installing a carbon monoxide detector is essential for furnace safety. It will alert you immediately if there’s a leak, allowing you to take action before experiencing symptoms like dizziness, nausea, or headaches.

Clean Exterior Surface Before Turning It On

If your furnace hasn’t been used in a while, it’s important to clean it before turning it on. Dust, pet hair, and debris can collect on the unit’s exterior, and when the furnace heats up, these particles can burn off and cause a furnace burning smell.

You can clean the furnace surface yourself by wiping it down and clearing the surrounding area. For a more thorough cleaning, consider hiring an HVAC professional to service the unit before the heating season begins.

Image Source: Canva

Call an HVAC Technician for Maintenance

Annual furnace maintenance, ideally before winter, is crucial for preventing issues that lead to a burning smell from the furnace. An HVAC technician will clean the system, check for worn or damaged components, and make necessary repairs. 

This proactive approach ensures your furnace runs smoothly and provides warm air without any strange smells.Routine maintenance keeps your furnace in top condition, extends its life, and maintains a comfortable, odour-free home.

Heater Smells Like Burning? There’s Only One Company to Call

When your furnace smells like burning, it’s best to turn to a trusted professional who can sort out the issue quickly and efficiently. Ontario residents trust LG Home Comfort’s certified experts with all their HVAC concerns. Leave your furnace burning smell to us.

We offer professional same-day or next-day installation, maintenance, and repair services, with 24/7 emergency support. Get a quote today to make sure that your furnace is in top condition for winter!