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does you air conditioner make grating, high-pitched sounds from the vents? This can be irritating. If your air conditioner is making an irritant noise it probably has a poor return airflow due to problem with the fan. A correctly working air conditioner will let in air through the filter and over the cold evaporator coils and then recycle the cold air in the room.  The ac has another fan on the motor shaft that refrigerates the condenser coils. Any bent, damage or buildup of dirt on either of the fans will cause imbalance which might result in unusual noise. Here are other reasons for low return airflow

  • blocked return vents
  • closed dampers
  • dirty or cloaked air filters

We will in a short while look at ow low airflow causes the air conditioner to make unpleasant whistling noise and what you can do fix the problem. But first let’s look at how low airflow causes   air conditioner whistling sound

Why the whistling sound?

 Your ac constantly circulates cold air in your home but if enough air is not coming due to some blockage or restriction in the airflow, it becomes starved of air. This causes an increase in pressure and velocity which causes a louder sound. This is akin to whistling when someone has to create a narrow passageway for air to pass through causing a high pitched whistling sound. The whistling sound alerts the owner that there is a problem in your ac. This causes an increase in your energy bills to go through the roof.

How to remove the whistling noise caused by low airflow

Dirty filters

Filters help to remove unwanted material from your home’s air.   But a dirty filter can prevent smooth airflow leading to unpleasant noise, overheating and ultimately high power bills.  The solution is to regularly change filters in your ac, once in three months at a minimum.

Blocked vents

Return vents are usually in passageways such as staircase, hallways and other open areas. Any blockage of this vents by debris or heavy dust will result in restriction of airflow.  The solution is to clean the return vent to remove any blockages such as furniture and debris blocking smooth airflow


Closed doors

If too many doors in home are constantly closed, then the air has to find way under small gaps under the door to the return vent. This makes your blower to work harder to pull in fresh air causing a high-pitched whistling sound. The solution is to keep most of your doors open to allow smooth air flow

Closed dampers

These are metal valves that can be shut in your ductwork to regulate passage of air into various parts of the house. The solution is to make sure that the dampers are arranged in line with your ductwork for proper airflow.


These hacks we have shared can help any homeowner to solve sound problems in their ac but sometimes a whistling sound can be a sign of even bigger problems that might need the attention of a professional