Why Is There a Burning Smell Coming From My AC Vents? A Tech Expert Explains

February 23, 2021

Burning smell coming from ac vent

Worried about that burning smell coming from your vents?

Before you panic, ask yourself: Is this the first time you’ve turned on your heat in a while?

If so, this burning smell is totally normal. You see, during months of inactivity, it’s normal for dust to settle on the heating coils/strips of your heating system. When the heater warms up, it naturally burns off the dust—which explains the burning odor you smell.

The good news is that this burning smell is temporary. After 15 to 30 minutes, the smell should go away.

That said, if the smell persists, it could mean you have one of the following issues:

  1. An overheating component
  2. An electrical problem

We’ll explain what causes both of these more serious issues below.

Burning smell lasting longer than it should? Call (888) 853-5143 or contact us online to have a trusted Florida technician fix the problem for you.

Issue #1: An overheating component

The burning smell could be the result of a component that’s overheating in your HVAC system.

The component most likely to overheat is the blower motor. This motor powers the blower (fan) that pulls indoor air into the HVAC system to be cooled or heated, then pushes the conditioned air back into your home.

Several problems could cause the motor to overheat, including:

  • A dirty air filter: A dirty air filter makes the motor work extra hard to bring in sufficient air to be cooled or heated. This extra stress often causes the motor to overheat, which could explain the burning smell.
  • Dirt buildup in the motor: Dirt buildup in or around the motor prevents heat from escaping, which causes the motor to overheat. This could explain why the motor is producing a burning smell.
  • Old age: The bearings in aging motors can wear out, causing the motor to overheat and give off a burning smell.

Besides the burning smell, you may notice the following signs if your blower motor is overheating:

  • Loud or strange noises coming from your HVAC system
  • The heating system shuts off randomly
  • The heating system will not turn on

Solution: To troubleshoot this problem, start by checking your air filter to see if it is dirty or not. If the filter is dirty, replace it with a new one.

If your air filter looks like the one pictured on the right, it’s dirty and should be replaced.

Still notice the burning smell after you change your filter? If so, it’s time to contact a professional for assistance. An HVAC technician can quickly determine if a component is overheating and fix the issue.

Note: Air filters aren’t usually top-of-mind for most homeowners, and it can be hard to remember to purchase and replace your air filter regularly. Instead, order your air filters from our online store, that way they are delivered directly to your home whenever you need them!

Issue #2: An electrical problem

The burning smell could also be caused by an electrical problem in your HVAC system. An electrical burning odor often has a fish-like scent or the strong smell of melting plastic.

Examples of common electrical problems include:

  • Worn electrical connections or wiring
  • A short circuit(when electrical current escapes the intended path)
  • Bad capacitor(a component that helps the motor start)

Solution: If the burning smell seems like it could be caused by an electrical issue, turn off your HVAC system and contact a professional ASAP. Running your AC or heater while there’s an electrical issue could damage your HVAC system, so we recommend turning it off until a technician can diagnose and repair the problem.

Need help from a trusted HVAC pro?

Our trustworthy and highly-trained technicians can quickly find what’s causing the burning smell and fix the issue. When you hire Air Experts, you can count on 5-star customer service and thorough repair work (backed by a 100% customer satisfaction guarantee).

For more information about what to expect when you hire us, visit our AC repair service page.

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