A pair of scissors sitting on top of an air conditioner.

Air Conditioner Making Noises? Here are Some Possible Causes


A central air conditioner is a complex system of moving parts that work together to keep your home cool and dry. Over time these parts are subject to wear and tear and may begin making sounds you’ve never heard before. Silencing air conditioner noises can be as simple as tightening a loose panel cover, or may require an inspection by a qualified technician to identify the source of the noise.

Air Conditioner Rattling Noises

Rattling noises are faily common with air conditioners. Over time the various fasteners attaching components to the unit can become loose. If you hear rattling, check the screws or bolts holding the cover plates in place. If the rattling noises persist after tightening the panels, remove the cover and check internally for the same issue. Always turn off power to the unit at the breaker before performing any maintenance.

Whistling Sounds

Whistling sounds are usually heard when air duct seals have a leak. Check for cracks and gaps in the seams of ducts near the unit and the ductwork that carries the air throughout the home. Examine the seams around these areas for loose connections and retighten any screws or bolts. If heat tape was used to also cover the seals, make sure the tape completely adheres to the duct seams.

Screeching Sounds

Like your car, the air conditioner motor has motor driven belts. Over time belts can stretch and wear out. Screeching sounds that occur when the unit turns on to blow air are likely caused by a worn-out belt that needs to be replaced. A qualified HVAC technician should check the belt and replace it if needed.

Clunking Sounds

Clunking sounds can mean something has come loose inside the air conditioner unit. A loose fan blade on a motor can make sounds as it turns. A qualified HVAC technician should inspect the unit to ensure it is operating safely.

Concerned about sounds coming from your central air conditioner? Call Air Experts. We’re here to help.