Don’t Fret Over These 5 A/C Noises — Learn What They Mean

air conditioner

air conditioner

Your home’s air conditioner makes certain noises when it’s operating, but when you hear odd new sounds, it’s hard not to worry whether there’s a serious problem. Learning what some common A/C noises mean can help you decide if it’s necessary to call for professional help.


A buzzing sound is usually a warning of an electrical issue that may pose a fire hazard. An experienced professional can check the A/C’s electrical components, including the thermostat, contacts, compressor relays and circuit breakers, to locate the source and get it fixed promptly.


If there’s not enough lubrication on the indoor or outdoor fan motor, you’ll start to hear squeaking noises. An imbalance of the fan blades due to a severe dust accumulation is another possible culprit. Your HVAC technician can isolate the cause and clean the fan or oil the motor.

Clanking and Thumping

Sounds like these coming from the indoor unit can be caused by a loose or misaligned blower assembly. If you’re hearing these noises at the outdoor unit, hardware like a fan blade or motor mount has likely worked loose. Before the loose part comes off and harms nearby components, have your HVAC pro locate the offender and reattach it properly.

Hissing or Bubbling

These types of noises originating from the evaporator coil, coolant lines or compressor unit typically indicate a refrigerant leak that can cause a loss of cooling capabilities or serious component damage. To prevent these problems, an HVAC technician needs to locate the leak source, fix it and then recharge the refrigerant.

Loud Screeching

If you hear this sound coming from the outdoor unit, shut off its breaker in the main electrical panel and call for help right away. A screeching sound points to a potentially dangerous rise of the compressor’s internal pressure and this needs immediate attention.

Learn more about McAllister’s solutions for diagnosing and quieting A/C noises, or give us a call if you need immediate help. Call us today at 877-216-3505.