There’s A Squealing Noise When Your Air Conditioner Is Turned On?

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Updated September 16, 2022

Nobody likes it when their valuable appliances talk back to them. However, sometimes, even the best air conditioners start making noises. Such noises usually indicate that something is amiss. So, if you’ve been nervously asking yourself, “Why is my air conditioner squealing?” keep reading.


  • AC units often make squealing noises because of worn-out fan motor parts, like belts or bearings.
  • Most older units power fans via a belt, while newer models use bearings.
  • Squealing can also result from restricted airflow caused by dirty filters or evaporator coils.

And if it’s a knocking noise that has you concerned, check out our article explaining why air conditioners make a knocking noise.

Insider Tip

Perform a routine maintenance check of your AC unit before you need it for the summer to catch problems early and save money on repair costs.

Reasons Your Air Conditioner Is Squealing

Every air conditioning unit needs proper care. And sometimes, when the air conditioner has issues, it can make a high-pitched squealing noise. Fortunately, there are a few common areas to check when you hear this strange sound but having an HVAC professional check your unit as soon as possible is essential. Doing this can help prevent further, more expensive repairs.

If you’re in the market for a new machine because you think your unit is beyond repair, read our comparison of Bryant vs Comfortmaker air conditioners.

Worn Out Fan Belt

Many fans in older units are powered by a belt attached to the blower motor. As humidity levels change, the belt expands and contracts. Eventually, the belt wears out, which can cause a loud squealing noise. Typically, replacing a worn or broken belt costs around $100-$200.

It’s important to note that AC units make noise regardless of mechanical problems. So if loud noise is a concern, you should buy the proper unit to minimize it. To that end, read our article comparing high-cool vs low-cool air conditioners.

Condensor Fan Bearings

Newer AC models use bearings instead of belts to power the fan. When they become worn out, they make a loud squealing or screaming noise. Unfortunately, when the bearings are bad, this usually indicates that the entire fan motor needs replacement, costing up to $700.


Some sources say that a squealing noise might signify nothing at all; however, it’s crucial to investigate the cause to avoid damage to your AC unit.

Low Airflow

Air conditioner noises, such as squealing, may also occur when the unit’s airflow is impeded. Impediments to the airflow can be anything from a dirty air filter to duct blockage to dirty evaporator coils. When the airflow is restricted, it can sometimes result in strange noises. Air filter replacements and coil cleanings are tasks that can be accomplished without professional help and are necessary to the overall health of any AC unit.

STAT: Keeping a clean air filter can reduce a homeowner’s monthly energy bill by up to 15%. (source)

Why Is My Air Conditioner Squealing FAQs

Can you replace the AC drive belt yourself?

This procedure can be done without professional help with proper knowledge and the right parts. However, AC owners always risk causing further damages if they operate without consulting a professional.

How can I stop the squealing noise?

Sometimes, spraying a lubricant will make the noise go away. However, this is only a temporary fix for a unit that requires part replacement.

When should I be worried about the squealing noise?

If your AC squeals during the first few minutes of being powered on, this is usually not a cause to worry. However, if the loud noise persists, odds are there is a broken, worn, or loose part.
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