Noisy Air Conditioner?

noisy air conditioner

What Causes It and What You Can Do

Noisy air conditioner systems are a common complaint we hear from homeowners. Ignoring any strange noises coming from your AC could become costly repairs. Often these noises could signal the need for maintenance, repairs, or worst-case scenario replacement of the entire unit. The sooner you can determine the cause for the noise, and you can repair your ac the better. Below we discuss what may cause a noisy air conditioner and how to fix it.


If you hear loud banging sounds coming from the condenser, it is a sure sign that there is a loose or broken part. It could be from an unbalanced indoor blower motor, a rod, piston or the compressor. The compressor is responsible for circulating the refrigerant that cools your home’s air. Parts inside the compressor can become loose and cause the loud banging sound due to normal wear and tear. In this case, most often you will need to purchase a new compressor.


Clanking is another sound that can signal a loose or unbalanced component. Like banging, this sound could also be a sign that you may need compressor replacement. It could also signal that the indoor blower or outdoor fan blades are out of balance. These types of issues could lead to costly repairs if ignored.

Clicking or Ticking

Clicking of electrical components are normal sounds at start up and shutdown of the system. However, a constant clicking or ticking sound is not a part of normal operation. There are a lot of electrical components in your unit and a clicking or ticking sound may be sign that a part within the system is not working properly. One common reason for constant clicking could be an issue with the system’s relay. If you hear the clicking or ticking at start up but your system fails to start it could be a sign of a defective or failing thermostat, or capacitor. In either case contact a professional who can diagnose and repair the issue.

Tweeting or Chirping

Tweeting or chirping sounds coming from your air conditioning system at the start of the cooling season is normal. Since the unit has been off for a long period of time, it is common sound when the machine is warming up. However, if the sounds persist and show no sign of reducing contact a professional right away.

Grinding or Humming

A humming sound is not generally serious, but it could indicate an issue inside of your air conditioner. Loose parts and refrigerant lines can cause vibration and if not inspected could lead to serious maintenance issues. Furthermore, if you are hearing humming and the compressor fails to start up, then it could bean issue with the motor or loose wiring. Humming sounds could also be a sign that your system has an unsealed motor. These types of systems need to be lubricated regularly or most importantly at the beginning of summer.

Squealing or Rattling

If you notice your air conditioner making a squealing or rattling sound, it could be a sign that there is something wrong with the outdoor fan which rattles when loose. When an air conditioner is working the system vibrates, which can cause the screws in the unit to become loose. On the other hand, it could be a sign that twigs, rocks or leaves may have fallen into the condenser causing the noisy air conditioner. The first thing you will want to do is check for loose screws or bolts, clean the outdoor condenser, and change your filter. These are all parts of routine AC maintenance as well. If you hear loud squealing or screeching coming from your indoors then it could be an issue with the indoor blower motor,its wheel or housing. Over time the bearings on the motor can become loose, or the belt can wear out. Keep in mind, that for some type of systems, the squealing sound could be normal at start-up. You should be able to identify if it is a sound your system has always made or it is a new sound.


Buzzing that is coming from the outdoor condenser could signal several issues. It could be a signal of loose parts or wiring, debris, dirty condenser coils, dirty air filter, broken capacitor or malfunctioning compressor.

Hissing or Screaming

If you hear high pitched hissing or screaming, it is best to shut the air conditioner off immediately. The most likely cause for this sound is a refrigerant leak which not only can damage your air conditioner but is a health risk as well. Over time the copper lines that carry the refrigerant can form leaks and allow the refrigerant to escape. Since the pressure inside the copper lines is high, you will notice the hissing sound as the refrigerant escapes.  Hissing could also signal a duct leak or an air filter that is not properly sized or placed. A screaming sound could also indicate high pressure inside the compressor. If your unit shuts off on its own, a sensor has shut the unit off to potentially prevent a catastrophic issue.

Contact LA Construction Heating and Air at 818-341-3406 or contact us online for ac maintenance, ac repair, or ac replacement. If you hear any strange, uncommon sounds coming from your air conditioner and believe it may signal an issue, do not ignore them. Turn your ac unit off as a precaution and contact us for an inspection. A yearly maintenance visit and inspection can prevent future issues with your system or possibly having to replace your system earlier.

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