Most of us are aware that air conditioning systems are rarely silent, with any type of forced air HVAC system, there will always be some sounds associated with the air flow moving through the duct work. This is one of the reasons why some people may choose quieter radiant heat methods in winter. Some systems emit a whirling noise that can blend in to background noise after you get used to it, while other types of equipment may sound like a jumbo jet is taking off in your living room.

Although the airflow noises are necessary with forced air conditioners, there are other types of sounds that can indicate some fault or malfunction in the system. One such noise is a persistent clicking sound. Although this may not seem as sinister as loud banging or fire crackling noises, it is still something that needs to be investigated.

Where the Clicking May Originate?

An air conditioner can create a cacophony of noises and sounds that may indicate an underlying issue. You may notice hissing sounds from a duct leak, bubbling from leaking refrigerant, loud bangs from a pump or buzzing noises from electrical components such as relay switches. Fortunately, clicking sounds tend to be fairly easy to diagnose, as in most cases, they originate from inside the air handler or the outside condenser or compressor. The clicking sounds may be slow when you start up your system or a rapid staccato after the system has been shut down. It is important to take note of the frequency of the clicking noises, as this can help your HVAC technician to troubleshoot the underlying issue.

The Causes of Air Conditioner Clicking Noises

There a number of primary causes of clicking noises coming from air conditioning systems. These include:

  • A Fan Obstruction: The simplest area to check and the first place to start is the fan unit. This is located on the indoor air handler, and you may notice the clicking starts slow and progresses as the unit starts to warm up. This is often the result of a bent fan blade or a fan obstruction. Just like cards in your bike wheel spokes when you were a child, there will be a click every time one of the blades hits the obstruction. This will continue until the blade breaks, or the obstruction is cleared.
  • Issues With a Capacitor or Control Board: You may not be aware, but your air conditioner is likely to make an audible click each time it starts up. This is a single click as the thermostat sends a communication signal to the capacitors that will fire up the system.

If there is a constant click sound, but the system won’t turn on, it is likely to be an electrical problem. Your thermostat has sent a signal, but it isn’t being actioned as the wires may be shorted together or your relay (control board switch) or capacitors have gone bad. In either of these scenarios, you will need to call a service technician to trace the underlying issue and provide an effective solution.

  • Compressor Hardware Issues: If you can trace the clicking sound to outside of your home, it could be due to a compressor issue. This is not an issue that may instantly cause alarm, as the issue may be nothing more than a loose bolt or a piece of shipping hardware, such as a bolt that wasn’t removed initially. If your refrigerant tubing is loose it may also cause a soft click noise, as the vibrations of the unit operating may cause the tubing to hit the frame of your air conditioner unit. If the clicking noise is accompanied by a shuddering or rattling, it may indicate a more serious issue with the compressor. The compressor is a major part of your air conditioner system, so a malfunction may compromise the overall operation of your system.
  • Wear and Tear: Your air conditioner works very hard, so over time components can loosen. This can cause clicking sounds as the fan or belts loosen. This is often a very quick fix, as components can be tightened, or where necessary replaced. These issues can also be avoided completely with regular maintenance, as your technician will check for any worn components during the service visit.
  • Malfunctioning Thermostat: If your air conditioner is running with an intermittent clicking noise, it may be due to a malfunctioning thermostat. Over time wires can become loose and thermostats can wear out, creating undue strain on your air conditioner. The thermostat acts as the brain of your air conditioning system, so when the signals are not consistent, your equipment can struggle to keep up. An HVAC technician can easily repair or replace a thermostat, but it can also be an opportunity to upgrade to a smart thermostat to not only eliminate the clicking, but increase your energy savings.

Is It Cause for Alarm?

It is important to remember that while clicking noises may range from a minor nuisance to an aggravating intrusion, you need to consider the underlying cause. It is essential to have a professional HVAC technician inspect your system to investigate any potential issues to determine the source of the clicking. DIY work on air conditioning units carry the risk of electrical damage, but there is also a risk of damage to the components, so it is best to leave it in the hands of a licensed air conditioning expert.

An experienced HVAC specialist has the skills, expertise, and knowledge to troubleshoot your system to trace the underlying issue causing the clicking. Whether this is a minor issue requiring a quick repair or a more complicated issue, your technician will be able to provide you with an effective solution.

If you can hear a clicking noise when you run your air conditioning system, you can rely on an experienced HVAC specialist to provide an effective solution. Your HVAC technician will assess your system to check for underlying issues and ensure that your air conditioner is operating at peak efficiency to guarantee your home comfort.