When your air conditioning system turns on, do you hear a high-pitched whistling noise coming from your vents?

The reason your air conditioning system is making that noise is because it has low return airflow. That means not enough air is moving through its return vents. This problem is usually caused by one of four things:

  • Dirty air filters
  • Blocked vents
  • Closed dampers
  • Too many closed doorsWhy Is My Air Conditioner Whistling?

When the air conditioner is running, the blower constantly circulates air throughout your home. If the blower isn’t receiving the air it needs to complete this process, it doesn’t have the right amount of air for completion. This adds pressure inside your home, which means you’ll hear a loud, high sound – a whistle.

It’s similar to the process you use when you whistle, compared with normal breathing. With your mouth open, a full supply of air moves in and out of your body. When you close your lips down to whistle, only a tiny stream of air moves, which causes a high-pitched sound.

And while it may be annoying, it can also be a good thing. This whistle is telling you your air conditioning system has a problem. It’s giving you a chance to fix it before it escalates into something bigger.

Change your air filter

The easiest step to take is to replace your current air filter. Air filters pick up unwanted contaminants in your home’s air, but when they are dirty, they restrict the airflow process.

Unblock vents

You have two kinds of vents in your home: return and supply. Both need to be clean from dust and dirt, and should never be blocked by furniture or drapery. Clean the vent grills and remove anything that may be blocking its path.

Open dampers

Dampers are the metal levers in your ductwork that you can shut down to prevent delivery of airflow to certain rooms in your home. They can be knocked closed by a simple movement, including vacuuming or moving furniture around. Locate the dampers and ensure they are aligned with the grills for proper airflow.

Open doors

If too many doors are closed in your home, the air has to sneak through the gap underneath the door. This makes your air conditioning system work harder to accomplish the same task, and can cause a whistling noise. Whenever possible, keep your door open for proper airflow.

Still have an issue with your air conditioning system? One of our trusted technicians will be happy to visit your home and diagnose the problem.