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 Dracut?

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.

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I am proud of the skills and knowledge I have gained during my 15 years working Plumbing and HVAC. I started as an apprentice, assigned to do basic tasks like carrying tools and materials, drilling holes and digging trenches. I was hungry to learn and expand my career opportunities, so I enrolled in an after-school training program for both my HVAC training and Journeyman license. I loved learning about both trades and felt like I was finally on the right track. When I passed my Journeyman Plumbing exam, I started to do side jobs which allowed me to experience the business owner side of things. This completely changed my perspective on my career and drove me to continue to pursue owning my own Plumbing & HVAC business. I continued my training and earned my Master’s license. With the support of my amazing wife, I started my own business SDP Plumbing, Heating and Cooling in 2016. Three years later, we rebranded the company as New Era Plumbing & HVAC. I could not be more proud of my career path and my company. Our core values are: Faith, Family, Empathy, Giving, Service and Quality. I train our team on adhering to these every day. We love taking care of our customers and are proud to serve our community.

Danny Pen


1 New Boston Rd Unit D,
Contact us at (978) 344-6833 to get started!

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