Why Is Your Air Conditioner Whistling?

Whistle while you work! That's a good motto for a person who wants to keep their spirits up, but it's not a good motto for your air conditioner. If your air conditioner is whistling while it is running, there's a problem. It might be big, or it might be small. Here's a look at some of the most likely culprits.

Partially closed vents

Do you notice the whistling mostly in one room? The problem might just be that one of your vents is partially closed, causing the air to whistle as it rushes through the narrow space that is left. Opening the vent should stop the noise. Sometimes homeowners close vents on purpose if they do not think a certain room needs to be cooled, but this strategy can actually backfire. With one or a few vents closed, pressure can build up in the ducts, which can cause excessive wear on the air conditioner. Keeping the vents open is better overall.

Damaged ball bearings

Is the sound loudest near the actual air conditioner? Could it be described as a squealing as much as a whistling? The ball bearings within the motor that power the air conditioner's fan may be to blame. These ball bearings can get worn down on one side due to friction, and then they squeal and whistle as the motor runs. A worn bearing can cause the motor to overheat, so it is not an issue you want to ignore. An HVAC company can replace the damaged bearings within a few hours.

Debris caught in ducts

If the whistling is loudest in one room, but the vent in that room is open, then you might have something stuck in the duct leading to that vent. Sometimes birds make their way into the ducts during the off-season and build nests. Other times, a piece of duct breaks free further up the system and gets stuck further down in the ductwork. In either case, you will want to have a professional come take a look. They can send a camera down into the vent to detect the obstruction, and then they will remove it. If needed, they can also repair the piece of duct that has broken off.

If your air conditioning is whistling, this is not a problem to ignore. Check your vents to ensure they are open, and if that is not the issue, call an HVAC company to look at the ball bearings and ducts.