Your air conditioning system makes some quieter noises even when it’s running well, but sometimes there are sounds that indicate an immediate need for repairs or maintenance work. You’ll want to know about these because they indicate problems that can cost you big money if not dealt with quickly.


The typical unit does some buzzing when first turned on or off, but loud or consistent buzzing in the outside unit could mean a number of things:

  • Debris in the unit
  • Loose parts or motor
  • Dirty or clogged air filters
  • A bad blower
  • Leaking refrigerant


Banging can mean that you have a loose or broken part. It can also mean something is out of balance or that you need a compressor replacement. Broken parts can cause additional damage, so you should probably call a professional.


It’s normal to hear some clicking when you turn your unit on or off, but if the clicking continues after startup, then it’s a sign that something is wrong. It could be just a malfunctioning thermostat, or it could be electrical issues that need to be addressed.


Rattling noises can indicate that parts are loose or that the system is clogged with debris.


This is the most potentially dangerous sound your HVAC system can make. Turn off the unit immediately for your own safety.

This sound can be caused by a refrigerant leak, which can damage the unit as well as being detrimental to your health.
Worse still, it could mean the internal pressure of your compressor is dangerously high. You’ll need to shut down your system right away if this happens.

Most of these problems can be avoided with regular maintenance. If you live in or around San Antonio, consider calling Quality Star Services. We perform a variety of services, including AC repair, maintenance, and much more. Contact us today!