AC Smells Like Burning

Does your AC system smell like burning? When you crank on the heat, the last thing you want to experience is a burning smell coming from your system.

A burning smell is typically an indication of a part overheating or catching on fire, so it’s important you do not ignore this sign and turn off your AC system immediately. Once your AC is off, you’ll want to try to trace the source of the smell and, most importantly, make sure there isn’t a fire in your home.

If you see smoke or fire, evacuate your home immediately and call the fire department.

7 Reasons Your AC Smells Like Burning

If your AC system is blowing a burning smell, here are some of the most common reasons.

1. Burning Dust

The most common cause of a burning odor coming from your HVAC system is dust being burned off. When not in use for long periods of time, such as in the summer, the heating elements and other parts in your HVAC system will sit idle, collecting dust and other small debris.

Solution: If this is the first time you turned on your heater in a while, the smell should go away after a few minutes. However, if the problem persists or you see smoke, turn off your AC system immediately.

2. Clogged Air Filters

If you haven’t changed the air filter in your HVAC system in a while, it can become clogged and cause a burning smell when your heater kicks on. This can also make your AC system work and run harder than usual, creating a burning odor and a potential fire hazard.

Solution: If this is the cause, change your air filters immediately.

3. Electrical Issues

Burning odors can occur if the blower is about to burn out. Blowers have two purposes: to pump cool air in the home out during the heating process and to keep the temperature of the furnace in check. Blowers are designed to last for at least a decade or more, but running the blower too much can shorten its lifespan and cause it to burn out. If this is the case, it can produce a burning odor and can also be a fire hazard.

Solution: Turn off your system AC immediately and call a local HVAC company.

Outside AC Unit Smells Like Burning

4. Bad AC Capacitor

Every AC system has a capacitor that powers the motor and helps it run. If the capacitor starts to fail or goes bad, the motor can overheat and give off a burning smell.

AC capacitors can go bad or start to fail for many reasons, including overheated circuitry, normal wear and tear, or due to power surges.

Solution: When an AC capacitor goes bad you will need to replace it. Turn off your AC system to prevent any damage to its other components and call a local AC company for a repair.

5. Overheating Fan Motor

If your AC system’s fan motor is working too hard and overheating it will give off a burning smell.

If the capacitor is working fine then the problem may be with the bearings. As a result of normal wear and tear, your fan’s bearings can wear out, causing the motor to overheat.

Solution: Turn off your AC system and try lubricating the bearings. If this doesn’t solve your problem, you’ll need to replace the fan motor.

AC Smells Like Burning Rubber

6. Overheating Belt-Drive Motor

Some AC systems have a belt-drive blower instead of a direct-drive blower. In these systems, there’s a rubber belt that can wear down over time, causing a burning rubber smell.

Solution: If you notice a burning smell that also smells rubbery, it’s probably time to replace the rubber belt.

AC Smells Like Burning Plastic

7. Burning Electrical Components

If the burning smell smells more like burning plastic, this could indicate a dangerous electrical failure. Plastic components surround the wiring within your AC system and when the wiring starts to burn, you will notice a foul odor. This can happen as a result of worn electrical connections, loose screws, or short circuits.

Solution: Turn off your system AC immediately and call a local HVAC company.