It’s normal for air vents to make some noise when your HVAC system is on, but an unusually noisy vent can indicate a problem. If you have noisy vents in your home, use the following information to figure out what’s causing them and what to do about it.

High-Pitched Noise

One of the most common reasons for noisy vents is a lack of adequate return airflow. This can cause your return vent to make a high-pitched noise as your HVAC system works harder to compensate for low airflow. Airflow problems can occur for a number of reasons, including the following:

• Dirty air filter: A clogged air filter can block airflow. If this is causing your return airflow problem, replace the filter with a new one.

• Closed dampers or vents: When you close dampers or vents in your home, it increases the pressure in your home and forces your HVAC system to work harder to distribute air. Open any closed dampers or vents to stop your return vent from making noise.

• Objects blocking vents: Furniture and other items placed in front of the return vent can cause high-pitched noises. Keep the return vent clear to prevent this from happening.

• Ductwork design problems: Ductwork with a poor design or ducts that are too small can cause inadequate return airflow. Making your return vent larger or installing another vent can solve this problem.

Rattling Noise

Air vents can also make rattling noises when small items are inside them, such as nails or toys. This type of noise can also occur when you have a supply register that has come loose. In this case, tightening the register can stop this rattling sound. If you have items inside your vents, having professional duct cleaning done can solve this problem.