Noisy Air Vents

When it comes to your A/C and heating vents, some noise is to be expected. Popping noisy vents are completely natural and happen during a shift of cold or hot air throughout your home. For example, when you’re warming your house, your ductwork will expand from the hot air. The opposite happens with cold air. That popping you hear happens when your ducts begin to shift to accommodate your temperature needs.

What types of noises can you hear in the HVAC system?

You’re probably already asking yourself how to identify problem sounds. As we mentioned, cold or warm air passes through the ducts when the system is running, it’s normal to hear a low sound of air moving. It should not bother you. However, let’s see when it’s time to check:

Disturbing noises coming from the air ducts

• Rattling
• Clicking
• Knocking
• Hissing
• Creaking or squeaking
• Humming

Should you notice any of these unusual noises in your HVAC system’s ductwork, it’s best to have a technician perform the necessary inspection.

Most common causes of Noisy Air Vents.

Closed or Blocked Registers

Check if the supply and return registers are being obstructed by furniture, rugs or long curtains or drapes. Make sure that they’re open to allow air to circulate properly through the system.

Narrow Air Ducts 

Vents can make loud whooshing noises if the supply air ducts are too narrow. Debris can also block the ducts or cause one or more vents to close. You can use a flashlight to see if the vents look too dirty. However, you’ll need to reach out to an HVAC contractor if the noise persists.

Dirty Air Filters

Dirty or clogged filters can cause high-pitched whistling sounds, as well as loud thumping noises. Another indication of clogged filters is rapid on-and-off cycling. Clogged filters should be replaced immediately, which is why we recommend checking your air filter regularly and cleaning or replacing it every three months to combat this problem.

Loose or Separated Duct Joints

Metal duct sections will rattle, clank and flap if duct joints get loose or separated. You can wrap loose sections with metal tape.

Debris in the Ductwork

Nails, screws, and other small items can fall through the slats in the registers. You may need professional assistance if you can’t reach the debris.