Why Does My Heater Smell Like Something Is Burning?

If you haven’t already turned on your furnace, you will be sooner than later. And while most people love the comforts of fall—pumpkin spice everything, fuzzy blankets, warm coffee on a chilly morning— turning on your furnace for the first time of the new season might put a damper on your fall fun.

After months of disuse, new season furnace smells are pretty common, but that doesn’t mean you should shrug your shoulders and assume all is well. Although furnace odors are rarely dangerous, they can be—which means they’re always worth investigating. Downside? Your furnace doesn’t smell so great, and now you have to figure out what’s causing it. Upside? You get to play detective.

Here’s what those common furnace smells mean and what you can do about them:

  • Furnace Smells Like Burning Dust: This is the most common and (thankfully) least worrisome smell. While you’re not using your furnace in the summer months, dust settles everywhere. After that first ignition and first few cycles, the dust will burn off and create that familiar odor. No reason to panic! If it doesn’t stop after a few cycles, try changing or cleaning your filter.
  • Furnace Smells Like Burning Plastic: If it smells like a horse it’s probably a horse, right? First check all your vents and ducts for wayward plastic toys, plastic wrapping, or other debris—especially if you have little ones. You know better than anyone that your kids’ favorite toys end up in the most unlikely places! Checking for the obvious can save you lots of time and worry.
    However, a burning plastic smell can also mean overheating. Capacitors, plastic-coated wires, and fan belts are the usual culprits of that plastic smell. Make sure to turn off the furnace and take care of this one quickly, since burning plastic is toxic.
  • Furnace Smells Oily or Smoky: You’ll experience this if you have an oil furnace. This usually means the oil filter needs cleaning or replacing. It could also be a blocked chimney. Regardless, turn off your unit immediately and inspect the issue further.
  • Furnace Smells Metallic, Electrical, or Chemical: Usually, if your furnace is overheating, it will automatically shut off. But if there’s something wrong with the blower motor or heat exchanger, this safety feature won’t kick in. These overheated parts create a metallic, electrical, or chemical smell. Some people say this issue causes a smell like formaldehyde. (Oh, such fond memories of dissecting frogs in biology class.) Turn off the furnace and inspect it for damage.
  • Furnace Smells Like Burning Gunpowder: If you’re getting a distinct odor of gunpowder, you probably have a fried circuit board or fan motor. Turn off the furnace and call us for a safety inspection.
  • Furnace Smells Like Rotten Eggs: Natural gas is odorless, but your gas company adds sulfur to make gas leaks easier to find and correct. So, a rotten egg smell means you’re having an issue with your gas supply. Immediately get everyone out of your home (including you!) and then call your gas company or fire department.
  • Furnace Smells Musty or Mildewy: If you turn on your furnace and it smells like a damp basement or moist dirt, there are a couple potential causes. The first thing to check is your air filter and to replace or clean it as needed. Next, check your humidifier filter (if you have one) for mold. Clean with water and vinegar for an easy fix.

Need more help with your furnace in Austin?

If your furnace smell continues, gets worse, or you can’t find the cause, call your local fire department for a safety inspection. When it comes to furnace and fire safety, you’re always better safe than sorry. Then give us a call! We take pride in keeping you and your neighbors safe and comfortable in their homes.

Matthew Burnside
2022-11-07
Excellent company. Does everything the right way and honest. Use them yearly.
James McNulty
2022-11-02
Jaime at Grande Air was a pro. The AC check-up was both less costly and way more thorough than the competitions I called. Save yourself some time and book these guys today.
Veronica Bonilla
2022-10-25
Jaime had the thorough knowledge to explain step by step the issue so we can understand what the problem was. His professionalism and great customer service made us not think twice that we were in good hands. After several quotes and run around with other companies, we are now customers of Grande. Grande has our business and look forward to the next maintenance. Thank you Jaime and Grande!
Raquel Gomez
2022-10-21
Jaime was here and was very professional and provides me with great service. He was very informative and very knowledgeable.
Iris Alejo
2022-10-20
They ar awesome always their when I need them.
Jeannie Winters
2022-10-15
My husband was very impressed with the service we were given and said the Tech was very knowledgeable and came straight to us first thing in the morning when we called after business hours the night before. Our AC was not blowing cold air and he fixed it easily and told us that our system was still under warranty so all we had to pay for was labor. Now were cool and happy in Texas hot October nights lol
Araceli Xochitla
2022-10-11
Excelente servicio
Amilcar AKA Tegou
2022-09-26
Carlos was super professional and savvy. Highly recommended.

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