Return to site

Troubleshooting Common AC Noises: What's That Sound?

Have you ever been relaxing in your home on a hot summer day, enjoying the cool comfort of your air conditioner, only to be interrupted by strange and unsettling noises coming from your AC unit? If so, you're not alone. Air conditioners can make a variety of sounds, some of which are normal, while others may signal underlying issues. In this blog, we'll explore common AC noises, what they might mean, and when it's time to call in a professional for help.

1. Clicking Sounds:

Clicking sounds often occur when the AC turns on and off. This is typically a normal sound as the thermostat sends signals to the unit. However, rapid or excessively loud clicking could indicate an issue with the electrical components or relay switches.

If you notice unusual clicking, it's a good idea to have an HVAC technician inspect the electrical connections to prevent potential damage.

2. Humming or Buzzing:

A low-level humming or buzzing is usually normal and indicates the compressor is running. However, if the noise is loud or accompanied by other issues like warm air blowing, it might signal a problem with the motor or capacitor.

If the humming becomes loud or persistent, it's advisable to contact a professional for diagnostics and repairs.

3. Rattling or Clanking:

Rattling or clanking noises could indicate loose or damaged parts inside the AC unit, such as fan blades, screws, or debris trapped in the system.

Turn off the AC immediately to prevent further damage and call a technician to inspect and fix the issue.

4. Hissing or Whistling:

These noises often point to a refrigerant leak, which can be a serious issue both for your AC's performance and your health.

If you suspect a refrigerant leak, immediately turn off the AC and call a technician to locate and repair the leak. Refrigerant leaks can be harmful when inhaled.

5. Gurgling or Bubbling:

These sounds might occur due to air bubbles in the refrigerant lines or a refrigerant leak.

A technician should inspect the system to determine the cause and address it accordingly.


While some AC noises are harmless, others can be early warning signs of significant problems. Regular maintenance and prompt attention to unusual sounds can help keep your air conditioner running efficiently and extend its lifespan. If you're ever in doubt about the noises your AC is making, don't hesitate to contact a qualified HVAC professional for a thorough inspection and any necessary repairs. After all, a quiet and smoothly operating AC system is the key to staying cool and comfortable during those scorching summer days.

Call or book today!

Just Air Heating and Cooling