Why Your Air Ducts Are Making a Popping Sound

Do your air ducts make a popping sound? All central heating, ventilation and cooling (HVAC) systems have air ducts. After warming or cooling the air, your HVAC system will send this conditioned air into the ducts so that it can be distributed throughout your home. As your HVA turns on – or while it’s running – you may hear sounds coming from these hollow conduits, such as a popping sound.

Closed Air Vents

Closing the air vents in your home may result in a popping sound originating from the ductwork. As conditioned air travels through the air ducts, it will exit the supply vents, thereby supplying the respective rooms with conditioned air. If you close most or all of the supply vents to which a particular air duct is connected, the air duct’s pressure will increase. This additional pressure may manifest in the form of a popping sound.

Loose or Sagging Air Ducts

Loose or sagging air ducts may make a popping sound. Most residential air ducts are made of a flexible material. When your HVAC system turns on, they will expand and flex. Loose or sagging air ducts, however, may move around excessively during this process. The sudden rush of air flowing through them will cause them to shift, which can manifest in the form of a popping sound.

Leaks

Leaks in your air ducts may cause a popping sound. Air ducts are designed to be sealed. After all, any gaps or openings will allow conditioned air to escape into unused spaces of your home, such as the attic or basement. But leaks can and do occur.

Improper installation or exposure to vibrations can cause air ducts to leak. When your HVAC system turns on, you may hear a popping sound originating from the location of the weak. Since air ducts are sealed and pressure, conditioned air will take the path of least resistance: the leak. The conditioned air will rush into the air ducts, at which point it will rush through the leak while potentially creating a popping sound.

Undersized Ductwork

Undersized ductwork may result in a popping sound. If they are too small, they may not be able to handle the pressure created by your HVAC system. Undersized ductwork is more sensitive to pressure changes than properly sized ductwork. When exposed to high pressure, they may flex excessively. This flexing may cause a popping sound.