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Common Sounds Ac Unit Makes

6 Common Sounds That an AC Unit Makes and Their Causes

6 Common Sounds That an AC Unit Makes and Their Causes

How can you tell if there is an issue with your air conditioning unit? When your AC makes certain sounds, it is a common indication that there is a problem. Now, different sounds may mean different things. Here are some sounds that an AC unit may make and their possible causes.

1. Buzzing

AC units create vacuum pressure by cycling gas through a condenser coil, which absorbs heat and cools the active ingredients inside the unit. These units are typically very quiet, but they can begin to buzz when they are working.

A buzzing AC unit results in various symptoms, depending on what part of the system is malfunctioning. Most commonly, a buzzing AC unit means that there is something wrong with the internal workings of the unit. More seriously, it could mean that the refrigerant has leaked out or the fan blades aren’t balanced correctly, both of which need immediate attention.

2. Banging

A banging sound from inside your air conditioning unit is most likely caused by a broken or disconnected part. It can be a moving part, such as a crankshaft, piston pin, connecting rod, or rotating fan blade inside the compressor unit. If one of these is broken or disconnected, then you must replace the compressor.

3. Clanking

If you hear loud noises from your AC, the coils in the unit have likely become unbalanced. This can happen if an internal component of the compressor breaks, usually requiring repairs and replacement.

If parts like the internal fan hit other internal components, the problem will only worsen and cause more damage. Not only will loose parts be damaged, but they’ll also knock other parts out.

4. Squealing

Indoor blower motors and outdoor fan motors begin to squeal when they’re failing. You should evaluate the sound’s tone, frequency, and duration to distinguish it from regular squealing.

5. Clicking

When the unit is turned off and then on again, it is normal to hear a clicking sound, but if the unit is turned on and the clicking starts or stops, it can be a sign of a thermostat problem. If the unit is on and the clicking is frequent or perpetual, it could be a sign of a control problem.

However, if you checked and confirmed that it isn’t a thermostat or control problem, it could be an electrical issue. Electrical issues can lead to more costly and even dangerous problems, so if you notice any frequent clicking sounds after turning your unit on, you should address the issue quickly.

6. Humming

Humming noises in air conditioning systems are often the result of loose refrigerant piping or some other parts. This can develop into a bigger problem if it goes ignored. Humming noises in air conditioning systems might also indicate electrical troubles. If there’s loose wiring or a malfunctioning compressor, humming is also likely to occur, and it needs to be investigated.


It is not wise to ignore unusual noises from your air conditioner because they may be signs that your unit has a problem. Ignoring the sound will increase the need for repairs in the future. To properly address the issue, you can have it inspected by a professional.

Looking for reliable AC repair in Castle Rock? CG Heating & Cooling is a licensed and insured HVAC company with over 20 years of experience. We provide heat pump repairs and new unit installations. Contact us now to request a quote.