Air Conditioner

6 Common Types of Air Conditioner Noises and Their Causes

Hearing unusual sounds coming from your air conditioner should never be taken lightly. Be it rattling or buzzing noises, any sound from it should prompt you to contact an HVAC specialist immediately.


Loud rattling noises often indicate loose screws, springs, or bolts within your compressor. They could also suggest that fan blades are interfering with its operation and must be cleared away for optimal air conditioner operation.


Is your AC making a screeching noise? If so, you can check this article out to find the solution.

1. Rattling

Rattling sounds can indicate many issues; sometimes, the problem lies with screws that were dislodged but were never appropriately tightened.


Misaligning fans could also be to blame, with misaligning fan blades of an indoor blower fan or outdoor condenser unit creating a rattling noise and creating the potential source of the issue.


Rattling air conditioning units indicates that parts are beginning to break apart and can damage the compressor, prompting air conditioning repair services to contact you immediately and make necessary repairs more cost-effective. Ignoring such signs could prove more expensive, so it is best to call an HVAC technician directly for repairs.

2. Bangs and Clacks

Humming sounds from your air conditioner as it runs are normal; anything else could signal problems with its system. A rattling sound typically indicates loose parts which could cause irreparable harm to other components in your unit.


If your air conditioning unit emits a slapping sound, it could be because something has become lodged between its fan blades – potentially due to poor maintenance or debris, such as branches entering through an open doorway into its condenser unit.


Loud clicking noises could indicate an issue with your AC’s contactor, which regulates electricity to your AC and controls the current flow. If this is true, this may result in damaged motor and additional issues requiring professional care to resolve.

3. Squealing

Squealing noises indicate that something is amiss with your air conditioner, often signaled by rattles or bangs in conjunction with loose parts in the unit or an inefficient compressor. If these noises accompany metallic grinding sounds, this is often an indicator that a belt in your blower motor needs immediate repairs.


Humming noises don’t usually indicate serious problems in an AC system, but they do signal something is amiss that needs professional assistance. Loose pipes or an obstruction such as tree branches obstructing fans could be culprits here.

4. Booming

An air conditioner’s normal whooshing noise shouldn’t cause alarm; however, if it gets louder as you move through your home, it could indicate an issue that requires attention.


Pulsating noise indicates that either your compressor or refrigerant wires are vibrating, which could result in extensive damage if left uncorrected immediately.


Your booming noise may result from a malfunctioning or worn-out contactor that prevents the unit from starting up and emits an audible buzzing noise – this should be addressed quickly by an expert technician.

5. Buzzing

An audible buzz is a sure sign it’s time to call in professional HVAC help and shut off your air conditioner immediately. Much like when your car starts producing metallic grinding noises, an AC buzzing is indicative of serious problems which need immediate resolution.


Sometimes a buzzing sound from your outdoor unit simply indicates something is lodged inside it – not necessarily a major problem on its own, but it could lead to other severe complications if not quickly addressed. 


A licensed HVAC expert should assess and address this problem by lubricating the motor and belts if necessary to stop buzzing noises.

6. Whistling

If you hear a whistling sound coming from your air conditioning unit, switch it off immediately and contact an AC professional asap. 


Such noise could indicate that either the compressor and fan motors aren’t properly lubricated or that a blower belt has slipped, both of which could potentially increase refrigerant pressure within your system and pose serious safety concerns.


Whistling noises could also be caused by dirty air filters or blocked vents. Many homeowners close vents in rooms they are no longer using, restricting normal airflow and forcing your cooling system to work harder to cool your home. 


A quick solution could be moving furniture or clearing away vents in order to restore normal airflow and restore normal temperatures in your home.


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Christophe Rude

Christophe Rude

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