What’s that burning smell?

Why Does my Heater Smell Like Burning When I Turn it On?

With temperatures dropping here in Central Indiana, you might have finally turned your heater on after who knows how long. And when you fired it up for the first time in a long time, did it have a burning smell? It probably did.

A burning smell coming from a long dormant heating system is normal if it hasn’t been used for a while. While that initial burning smell is considered normal, it doesn’t mean you should ignore it. Here are some things you should know about burning smells when the heat is on:

The burning smell is usually from dirt and dust that accumulates in air vents, registers, and the furnace itself. Over the spring and summer, parts of your HVAC system gather dust and dirt from disuse. This dirt and dust burns off when you turn the heating system back on.

Clogged Air Filter

The dust and dirt on a clogged air filter might cause a burning smell from the heat passing through it. We constantly remind you to change your air filters regularly, and this is especially important when using your heater. Replacing your old air filter with a clean, new filter could get rid of that nasty burning smell. 


Anything near your heating unit or vents can cause a burning smell when the heat is on. If you haven’t used your heater in a while, it’s possible you may have placed flammable objects where they don’t belong. Whether it’s fabrics, plastics or any other flammable material, check to make sure they’re not in close proximity to your heating unit or register vents. In other words, make sure there is plenty of distance between objects that can burn and the heating elements that can burn them.

Types of Smells

As we already mentioned, the initial burning smell from turning on a heater that’s been inactive for a long time is normal and should dissipate quickly. However, there are several causes that could bring about a burning smell and ways to identify them. The following are several types of burning smells that could emanate from your heater and what the causes could be: 

  • Burning Dust Smell

Accumulated dust burning is the very common odor you smell when turning your heater on for the first time in a long time. This means dust has settled on the heat exchanger, burners and other heating components over the period of inactivity. So once the heat comes on, the dust burns off and the odor passes through your air vents. The smell of burning dust should go away after a while, so there’s no cause for alarm. However, if the initial burning dust smell has passed and your heater still smells like it’s burning, it could be something worse.

  • Electrical Burning Smell

If your heating system is on and it smells like electrical wires are burning, then you have a more serious problem on your hands. This could be a sign of an overheated blower motor. Normally as a safety measure, your system will shut itself off if it overheats. However, if something is malfunctioning or damaged, your heater might continue to operate and become dangerously hot. The smell of electrical burning could also be exactly that: frayed or damaged electrical wiring. If your heater emits an electrical burning smell, it could be a cracked heat exchanger, which is a very serious and potentially dangerous problem. So if your heater is emanating an electrical burning smell, turn it off immediately and call us at 765-568-9459 for help!

  • Burning Plastic or Rubber Smell

Another smell coming from your heater could be that of burning plastic or rubber. Usually this means a foreign object such as a toy has found its way into your heating system. A plastic or rubber object burning will give off fumes and can be hazardous to breathe in. If you smell burning plastic or rubber, immediately shut off your furnace or heater and find the object that is burning. And if you can’t find the culprit in your heating system, vents or ductwork after a thorough inspection, call us immediately so we can locate the source and eliminate the problem. The smell of burning plastic or rubber is  more serious than a misplaced object. It can mean electrical failure, so don’t run your heater if you can’t find what’s causing it to smell.


  • Musty Smell

A musty odor is a sign of mold and mildew in your heating system or ductwork. Changing a dirty air filter could solve the musty smell problem. But if it doesn’t, you might need something more powerful like a home duct cleaning to sanitize the air. Duct cleaning uses specialized equipment for removing any and all bacterial growth from your ductwork. We should point out that while duct cleaning is highly effective at removing mold and mildew from your duct work, you should still schedule an inspection to find out if mold is growing in other parts of your home. A mold problem beyond your HVAC system requires a reliable mold removal company to rid your entire home of it.

Other types of smells you might encounter are smoky or oily smells, as well as an odor very similar to gunpowder. These are all signs of very serious problems that should only be addressed by a professional.

Furnace Safety Tips

  • Never store combustible materials near your home’s furnace.

  • Keep the area around the heating and air condition unit clear. This means no bikes leaning against it or cardboard boxes stacked up.

  • Change your air filter regularly

  • Test your smoke and carbon monoxide alarms before you turn the heater on in the fall

  • If your home’s smoke detector or carbon monoxide alarm goes off after turning on the heater, get out immediately and call the fire department for help.

  • Likewise, call your utility provider if you smell natural gas.


Burning smells from your heater are usually not a big cause for concern. But if troubleshooting the problem yourself doesn’t resolve anything, call us at 765-568-9459 and we’ll take care of it for you!

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