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Why Is a Burning Smell Coming From My Furnace? A Phoenix Tech Answers

February 26, 2021

A burning smell coming from your furnace can be concerning, but is normal if you’re turning your furnace on for the first time this year—it’s just your furnace burning off dust.

But if you smell something burning after you’ve been using your furnace regularly this season, something could be wrong with it.

In this article, we’ll go over:

  • When a burning smell coming from your furnace is normal
  • When it’s not normal and you need to call a technician for help

Need a tech ASAP? Our furnace techs are standing by and ready to help. We’ll come diagnose the issue, repair your furnace, and get it running properly.

A burning smell is normal when first using the furnace

In the summer months, when you’re not using your furnace, dust accumulates inside it. When the burners kick on the first time you turn on the heat, they burn off that layer of dust, which explains the burning smell.

The dust should burn off relatively quickly, meaning you shouldn’t smell burning for long—a few hours at most.

When a burning smell from your furnace is not normal

A burning smell coming from your furnace isn’t normal when:

  1. The smell won’t go away
  2. Smoke is coming from your vents
  3. You smell burning plastic or rubber

If you encounter any of the issues above, turn off your furnace immediately and call a technician to diagnose the issue.

We’ll cover each situation in more detail.

The smell won’t go away

If you still smell the burning for longer than a day or so, there’s likely an electrical or mechanical problem with your system that needs to be repaired.

For details on furnace repair costs, visit our blog “How Much Does a Furnace Repair Cost in Phoenix?

Smoke is coming from your vents

If smoke is coming from your vents, that’s definitely not normal.

Smoke coming from your vents could mean:

  • A component is overheating
  • Your heat exchanger isn’t burning gas properly, creating soot

You smell burning plastic or rubber

The smell of burning plastic or rubber could indicate several issues:

  • A clogged air filter. A clogged filter means your furnace isn’t getting proper airflow and could be forced to work overtime. This would cause the furnace to overheat and give off a burning or burnt rubber smell.
  • Electrical problems. If any wiring inside your furnace is frayed, damaged or just old, the plastic covering the wires could overheat, causing a burning plastic smell.
  • A foreign object got too close to the furnace. The smell of burning plastic could also mean that something, like a toy or other object, has been placed next to or made its way inside your furnace and melted from being so close to the burners.

Prevent issues with regular maintenance

To help prevent burning smells from your furnace:

  • Replace air filters regularly. Some filters should be replaced every month, while others (like HEPA or other high-efficiency air filters) can be changed every 3–6 months.
  • Get an annual tune-up. An annual tune-up does for your furnace what an annual physical does for your health—it helps catch any minor issues before they turn into major problems. During an annual tune-up, the technician will clean, test, and inspect your entire furnace system to make sure it’s running properly.

At Patrick Riley, we offer a 100-point heating tune-up, which includes cleaning the air filter, to ensure your furnace is ready to tackle the winter.

Need help from a Phoenix tech?

We’ll diagnose the burning smell and quickly fix the issue. At Patrick Riley, you can count on our exceptional customer service and that we’ll repair your furnace correctly the first time around.

Learn more about what to expect when you hire us by visiting our furnace repair page.

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By Ty Lindsay

Ty Lindsay is the Director of Field Operations at Patrick Riley | Isley’s and a 15-year veteran of the plumbing and HVAC trades. In 2010, Ty earned his Journeyman’s plumbing license. He became a Master Plumber five years later and earned his Journeyman HVAC technician’s license that same year. Ty’s breadth of knowledge in plumbing and HVAC includes both residential and commercial work. He’s been a loyal member of the Patrick Riley | Isley’s team since 2016.