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Burning Smell from Your AC? Here are 5 Common Causes and How to Fix Them

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A burning smell from your air conditioner can be concerning. This is frustrating, especially when it’s warm, and you need a comfortable environment. However, every issue has a solution, and this odour is a sign that your air conditioner needs attention.

When you turn the heating on, you may smell something weird when the settled dust gets heated. You don’t need to worry about a fire starting but should act quickly if you smell something burning when you switch your AC on.

We’ll look into five common causes of this burning odour in your ac unit and how they can be resolved.

Is your AC giving off a burning smell? Learn what’s causing it and how to fix different issues in your air conditioner.

1. Accumulated Dust and Debris

Most times, dust and debris get deposited on the air conditioner’s components. This happens when the unit remains unused for a few months.

When you turn it on after a long period of inactivity, it will likely put out a burning smell. However, this smell doesn’t last long and is cleared within a few minutes.

If it doesn’t, then you need to get it checked by an electrician. You can easily find an electrician, no matter which part of the country you live in. Whether you are looking for an electrician in Nashville or Portland, you are bound to find one!

How to Fix it:

  • Turn off the AC and unplug it, or turn off the breaker.
  • Remove the access panel to check for dust buildup.
  • With a soft brush or vacuum cleaner, clean the coil and surrounding area.
  • Clean air filters since clogged air filters also cause dust buildup.

2. Clogged Drain

Drain lines are in the air conditioner to remove excess moisture and condensation. Due to frequent usage and certain weather conditions, it is possible that the drain line becomes clogged with algae, mold, or even debris.

Clogged drains are a common issue, like many other hidden problems within our homes. This can lead to the water flow being restricted, causing a burning smell to develop.

How to Fix it:

  • Power off the AC and disconnect it for safety.
  • Find the drain line and carefully remove any obstructions in it.
  • Mix water and vinegar to prepare a cleaning solution for the drain line.
  • Install a drain pan treatment tablet or regularly maintain and clean the drain line.

3. Clogged Air Filter

Another very common reason for your air conditioner to smell like it’s burning is a clogged air filter. If you don’t clean or change the air filters often, dust accumulates in them.

The dust stops the air from flowing smoothly, which leads to the system components overheating. The overheating results in a burning smell. To avoid this situation, clean your air filters once every month.

How to Fix it:

  • Power off the AC and disconnect it.
  • Open the AC return panel and take out the air filters.
  • Clean air filters thoroughly or change them if you use disposable filters.
  • Clear dust and debris thoroughly using a vacuum cleaner.
  • Change air filters 12 times a year to avoid this from happening.

4. Overheated Motor

Many times, an overheated motor or other faulty parts in the air conditioner result in a bad odor. When the bearings are worn out completely, they can emit a burning smell when the AC is turned on.

This burning odor is a sign that there are issues in your air conditioner that require instant attention. The motor is responsible for driving the fan and the compressor. It overheats when there is excessive strain on it or if there is a lack of lubrication.

How to Fix it:

  • Turn off and unplug the AC.
  • Check the motor for signs of overheating, such as an odor or weird noises.
  • Go over the motor’s instruction guide and lubricate it thoroughly.
  • If the motor is highly damaged, don’t turn the AC on and consult a professional for help.

5. Faulty Capacitor

While the motor runs the fan and compressor, the capacitor runs the motor. The capacitor is the component that jump-starts the AC unit and helps the motor kick into gear. If the capacitor is faulty, it may result in a burning smell.

A capacitor may break due to a power surge or electrical fluctuation. It can also become faulty over time due to extended use. Capacitors will need to be replaced if they’re broken or faulty.

How to Fix it:

  • Turn off the AC and disconnect it.
  • Call a professional electrician or technician to determine the capacitor’s condition and determine whether it needs replacing.
  • Regularly check the capacitor for any faults that may result in a breakdown.


A burning smell from your AC should never be ignored since it indicates an underlying issue that requires immediate attention. While some of these issues can be resolved easily at home, others will need the assistance of a professional heating and air technician.

To avoid a burning smell from your air conditioner, you should maintain and clean it regularly. Failing to keep your system clean makes can create a potential hazard when turning on your AC. In case you detect something serious with your air conditioner, turn it off and call an electrician to check it out for you. 


Can an AC compressor cause a burning smell?

If there’s an issue with your AC compressor, then you may smell something like burnt rubber when the air conditioner turns on. This causes the belt to drag and produces an odor.

Is bad AC smell harmful?

If your air conditioner smells like something is burning, it means that there is something wrong with it. Continued use might lead to further damage to the system and also cause a drop in air quality due to the smell.

Can I clean AC coils myself?

Yes. Even though there are plenty of coil cleaning solutions available in the market, you can make your own using some detergent and water. Apply the mix to the coils using a hose.

Do dirty AC coils smell?

Dirty AC coils may emit a bad odor that is similar to the scent of dirty socks or sweaty clothes. This smell is a sign of dust accumulation on the coils.

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