Depending on where you live, you may not have to rely on your furnace or other heating units all year. In many areas around the United States, seasonal changes require that you shut off your heating system for a while. But, after sitting dormant for several months, you may notice an unpleasant burning smell coming from your vents. This is likely due to dust that has settled on the equipment. After a few moments, the smell should subside. If the smell is prolonged or occurs more frequently, you may need to consider other causes.

If you have found yourself in this situation with an unpleasant furnace smell, there could be several reasons for a burning smell. While some of the potential causes for the smell could be serious, other reasons aren’t as big of a deal. If you have found that you have to ask, “Why does my heater smell like burning?”, you will need to troubleshoot a few things. You may even need the assistance of an HVAC professional. Let’s look at why your heating system might have a burning smell.

Dust on the Furnace


Perhaps the most common cause of a burning smell coming from your heating system is dust buildup. As discussed, dust can settle on your equipment when it is not used during the spring and summer. When this happens, you may notice a burning smell the first time you turn it on. The dust will burn off and often circulate an odor for a few minutes around your home. The good news is that this is not a big deal, and the burning smell should dissipate when all of the dust has been burned off. However, if the smell lingers and doesn’t disappear or reoccurs frequently, you may need to contact an HVAC professional to have your equipment serviced.

Objects or Debris in the Heating System

In some situations, objects like toys or debris could have found their way into your equipment or ductwork. If the burning smell is more like melting plastic or rubber, something is likely in your system. If you have central heating with various vents, you can try to pinpoint the smell in a specific room or area to help locate the source of the problem. If you can’t locate the issue and the problem frequently occurs, you may need to contact an HVAC professional to get to the bottom of the smell.

Dirty Air Filters


Regular air filter changes and furnace maintenance are key to preventing burning smells and other issues from developing within your system. Dirty filters and air vents in your system could create a foul smell when the heat is on. As the system tries to force air through a dirty filter, it could push contaminants and other substances into your system and create bad, burning smells. Poor air filter maintenance could cause mold or mildew to grow in the system or ductwork and create an unpleasant musty and burning smell. It could also create health issues for people with respiratory problems. Regular filter changes and annual HVAC maintenance will help prevent many of these smells.

Faulty Electrical Wiring


One of the more serious problems resulting in a burning smell is an electrical issue. General wear and tear can cause issues with electrical wiring in your system over time. If the wiring is damaged, it could lead to issues such as a cracked heat exchanger, an overheating blower motor, or a variety of other problems. In some cases, these issues could create dangerous situations with carbon monoxide leaks, causing serious health problems. If you suspect an electrical problem, you should contact a service technician immediately and stop using your heating system.

Other types of smells like smoky or oily smells and rotten egg or gunpowder odors could be signs of serious issues. If you are concerned about any smell coming from your heating system, you should contact a qualified HVAC technician.