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Furnace Smells You Never Want to Smell

Strange smell coming from your furnace?

We can fix that.


It’s the thing that North Shore, Massachusetts, homeowners never want to have happen in the middle of winter. You find yourself bundling up in blankets in order to keep warm, so you head to the thermostat to make the house just a couple degrees warmer. The heating system is on for only a minute or two, when you begin to smell something funky coming from your vents. Is that smoke? Sewer? Burning plastic? What is that odor coming from your heating ducts, and could it be a sign that your furnace needs a repair?

As your local home heating specialist, we’re taking a moment to tell you about the most common odors we detect coming from furnaces — and what those smells might mean for your heating system.

What’s That Smell When My Furnace Turns On?


Sometimes when you turn on your heating system on for the first time in the fall, your system will put out a slight burning or dusty smell. In many cases this is normal, and the smell will go away once the dust has been blown out of your system. Changing the furnace filter may help dissipate the odor sooner.

If the smell persists, however, or if your furnace starts to smell like burning plastic, you could have a more serious issue on your hands. There could be a foreign object like a children’s toy in your ductwork, or there could be an electrical failure. Be sure to call an experienced furnace contractor who can help you diagnose the issue during a service visit.

Singed metal

Is the burning smell more like an electrical smell? If so, wires or metal parts may be getting overheated. Another potential cause could be an overheated service motor or cracked heat exchanger. Turn your system off immediately to prevent further furnace damage and schedule a service visit with your local heating system expert.

Strong chemicals

A smell of strong chemicals could indicate that there’s a crack in the heat exchanger. This is a dangerous issue that can allow carbon monoxide to leak into your home; so it’s important to turn off your heating system and schedule a furnace repair as soon as possible if you smell this unpleasant odor.

Rotten egg

Propane and natural gas are naturally odorless but have a rotten egg-like smell added to them so that leaks can be detected. If your furnace smells like gas, it could mean there is a propane or natural gas leak. Turn off your heating system immediately and get out of the house to a safe location. Then call a heating professional!

Prevent Furnace Issues with Regular Maintenance

Worried that one of these furnace smells might find its way into your home? Don’t wait until a heating breakdown happens to schedule a repair. With regular maintenance, you can prevent common furnace problems — and get other added benefits like increased furnace efficiency, greater energy savings, and lower annual heating costs.

Our team of professionals has extensive experience with both oil and natural gas furnaces and is ready to help you keep your home on the North Shore warm and comfortable all winter.

Time for a furnace repair? Call 978-388-0845or contact us to schedule an appointment!