What Should You Do If Your Furnace Creates a Burning Smell?

Closeup photo of family feet in woolen socks lying next to fireplace

That first time furnace burning smell may be reminiscent of the first crisp, Louisville, KY winter morning. The first time you turn on your heater, dust burns off. However, if that furnace burning smell continues throughout the season, there could be a problem with your HVAC unit. Burning plastic odors, the scent of burning dust, or a rotten eggs smell coming from your furnace could mean your system needs repairs.

Fortunately, burning smells from your furnace don’t always mean significant problems with your gas HVAC system. In fact, you may be able to do some simple DIY repair and troubleshooting to eliminate the smell. Read this article to learn how to troubleshoot bad smells coming from your furnace, and when to turn to professional HVAC contractors for help. Here at Jarboe’s Plumbing, Heating & Cooling, we are only a call away.

What Does A Normal Furnace Smell Like?

Your air conditioner works in tandem with your furnace, as both systems use the blower motor indoors within your furnace cabinet. As your furnace sits dormant during the year, a fine layer of dust can build up within the system. The very first time you turn on your furnace, you may notice a burning smell as your system physically burns off this fine layer of dust and dirt. This smell is normal, not harmful, and shouldn’t last longer than an hour.

Other smells, however, are not as harmless. Anytime you smell a rotten eggs smell in your home, it could be caused by a natural gas leak. If you smell natural gas, turn off your furnace and report the issue to your utility company right away. Leave your home until the issue is resolved. If you smell mold or mildew, there may moisture accumulating in your ductwork or somewhere within the HVAC system. When coupled with the heat from your furnace, mold can grow and affect your indoor air quality. Mold growth should be removed professionally, as it can be dangerous and impact indoor air quality.

What Is Happening When Heaters Smell Like They Are Burning?

Unfortunately, if that first time of the season smell lasts, there could be a deeper problem at fault. Anytime you smell a burning odor coming from your furnace on an ongoing basis, the following issues could be to blame, and you may need professional repair.

The cause of burning odors coming from your heater include:

Dirty Air Filter

Air filters are essential for protecting both your indoor air quality and the delicate components of your home furnace. As you use your air conditioner and furnace throughout the year, the air filter screens fine particulates like dust, dirt, hair, and pollen. Over time, the filter can become clogged, allowing dust and grime to blow back into your system, perpetuating a dirty smell. When your system burns off dust at the start of the season, a dirty air filter can cause the smell to stick around.

To prevent bad odors from staying in your home, replace your furnace filter according to the manufacturer’s instructions printed on the front package of the filter. As a general rule of thumb, filters should be checked every few weeks and replaced as soon as they look dirty, which can be as often as every month for homes with a large family or multiple pets.

Blower Motor Overheating

Inadequate air flow can cause big problems for your furnace. When enough air can’t enter your system due to duct blockages, a dirty air filter, or closed vents, your furnace may work harder than it needs to in order to pull in air, which can stress and overwork the blower motor. Heat can also become trapped within your furnace, which can damage delicate components like sensors and heat exchangers.

Anytime your furnace accumulates too much heat, a limit switch may trip within your system, turning off your furnace until the unit cools down. Sometimes, the furnace will also create a burning smell if it gets so hot that it overheats. If this occurs, walk through your home to ensure that all vents are open and all air return ducts are unobstructed. Check your air filter and replace it if necessary.

If you have had recurrent problems with an overheating blower motor, it may have created a dangerous problem within your furnace. Heat exchangers can become cracked when subjected to high heats, which can allow carbon monoxide to leak out of your furnace and into your home. Contact an HVAC professional to have your system inspected and repaired, especially if you can’t find an obvious cause of the problem, such as a dirty air filter.

Singed Wires

Modern gas heaters are controlled by thermostats and electrical connections. While these systems are designed to be incredibly safe, improper installation, physical damage to the wiring, and even power surges can damage the wires that relay messages within your furnace. When wiring becomes damaged, the protective insulation can melt off of the wiring, sparking a fire. A smell of burning plastic can mean damaged electrical wires. Always take electrical burning smells very seriously and consult with a professional HVAC technician as soon as possible.

Contact Us for Heating Repair

Anytime strange odors are emanating from your furnace, we are here to help. Call Jarboe’s Plumbing, Heating & Cooling for help finding and correcting smells coming from your HVAC system. We can help with everything from professional tune-ups to spotting and resolving challenges with your ductwork.

Subscribe for Savings and Tips in Your Email!