What Are Those Strange Noises My Central Air Conditioner Is Making?

Central air conditioners have many moving parts that must work together to keep your home cool. Over time these parts are subject to wear and tear as belts stretch and fasteners. AC noises can be a simple fix, like a loose panel cover, or a sign of a more serious problem.

Air Conditioner Rattling Noises

Rattling noises are a pretty common with air conditioners. Over time the various fasteners attaching components to the unit can come 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. After listening for rattles, always turn the power to the unit off at the breaker.

AC Whistling Sounds

Whistling sounds are usually heard when seals are leaking. 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 re-tighten 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 uses belts. If there is periodic screeching that only occurs when the unit turns on to blow air or cool the air down, it is likely a worn-out belt that needs to be replaced. Over time belts can stretch and wear out. 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. Or it could be  a plastic component or cover plate coming into contact with the. A qualified HVAC technician should inspect the unit to ensure it is operating safely.