Window Air Conditioner Making Clicking Noise? (We Have a Few Fixes)

Ryan Womeldorf
by Ryan Womeldorf
Window air conditioner units are common and can make the difference between a comfortable or miserable summer. It can be off-putting when a window AC unit starts making a clicking noise, but it’s generally due to problems with your thermostat. Whether it be a defective thermostat or controller, let’s take a look at what you should do when your window AC unit makes a clicking noise.

Your air conditioner, whether it is the central or window variety, is a comprehensive piece of machinery. During the hottest months of the years, it is imperative that it work properly. After all, there is nothing quite like having to sweat it out when the temperatures are at their hottest.

From time to time, you may notice that your air conditioner is making a clicking noise. Usually, a clicking noise is the sign of a malfunctioning thermostat or a defective control. There are a number of sounds that you may hear that could be indicative of different problems.

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What is That Clicking Noise?

Whenever you start or stop your window air conditioner, hearing an occasional clicking noise is perfectly fine. It is when that clicking noise is constant that there is a potential problem that needs to be assessed and addressed.

The most likely culprits when you hear constant clicking are a malfunctioning thermostat or a defective control. Because the air conditioner has quite a few electrical parts that are vital to operation, it is important to ensure that they are all in proper working condition.

If you only hear that clicking noise during the startup and showdown of your window air conditioning unit, there’s nothing that needs to be done.

Compressor Hardware Issues

The compressor is one of the main components within your air conditioner. Even if the problem isn’t coming directly from the compressor, it could cause further issues. You can troubleshoot the issue yourself, even replacing the compressor, but it might be best to call in a professional to do the job.

Clicking and creaking that comes from the outside could be indicative of a potential cooling system collapse. Should you fear this problem, it is imperative that you address the issue immediately or the results could be catastrophic.

External Clicking Noises

Even external clicking noises can result in compressor issues. Most of the time, the clicking is as simple as a loose bolt or screw, but it bears checking out the problem immediately. Remember, small issues start that way but can typically grow into much larger issues in short order.

Fan Blockage

Another common potential issue when it comes to clicking in your window air conditioner is that the fan has become blocked. Thankfully, the inside air filter fan unit is one of the most easily accessible portions of your window air conditioner.

When you hear a clicking noise that starts slowly and builds up over time, it could be due to a blockage in the fan. Whenever debris hits the fan, it will create the clinking noise and will continue until you either remove the obstruction or it somehow clears out on its own.

Faulty Thermostat

Finally, if you’re hearing a clicking noise but feel confident that there are no loose components and no debris within, you could check to see if the thermostat is working properly. Depending on the age of your window air conditioning unit, the thermostat can wear down. The thing is that your air conditioner can continue to work even if the thermostat has started malfunctioning.

Troubleshooting the issue can be fairly easy though somewhat time-consuming. What you are looking for is not the clicking noise at startup, but the frequency and development of that noise. It may take a bit of time to really pinpoint the issues with consistency, but you can over time develop a sense of what the problem may be.

What About Those Other Noises?

Unfortunately, clicking isn’t the only possible noise that your window air conditioner might make. There are several other possibilities that could lead to potential issues with your window air conditioner. Being able to identify those sounds is the first step towards potentially correcting the issue and getting your air conditioner working properly once again.

Banging Noises

The banging noise isn’t quite as precise as some of the others in that it can actually mean one of several different things. For the most part, a banging sound isn’t something drastic though it does need to be addressed in short order.

When you hear a banging noise, it could be the result of a loose crankshaft, a broken connecting rod, a loose piston pin, or even an unbalanced indoor blower. The very worst-case scenario is that the compressor will need to be replaced, but that is in more unlikely scenarios.

1. Turn the AC off. When you hear a banging noise, start by turning the air conditioner unit off.

2. Check the compressor. Next, give the compressor system a once over. More often than not, the banging is a loose component that can be remedied right on the spot or simply replaced.

Clanking Noises

Much like the banging noise, this is more than likely indicative of a potentially unbalanced or loose component within the window air conditioner. Some portions of the closed unit are the likely cause, meaning that the compressor has come loose. When the compressor is loose or damaged, you will likely have to replace it altogether.

If it isn’t the compressor, the other culprit could be the fans of the indoor blower being out of whack. When the fans are out of place, they can potentially collide with other components. That is the clanking noise that you are hearing. Don’t ignore clanking noises; they can potentially lead to bigger issues and should be addressed in short order.

Buzzing Noises

Whereas the clinking, banging, and clicking noises are coming from the interior of the window air conditioner unit, most buzzing noises are coming from the outside of the unit. For the most part, those buzzing noises are indicative of one of any number of issues.

It could be loose components like the aforementioned banging or clicking and can even be unbalanced or loose fan blades. It could, however, also be a potentially bad condenser coil, a defective blower, or an air filter that needs to be replaced.

Copper Wires

Additionally, the reason for the buzzing noise could come down to copper wires that have become intertwined, the presence of some kind of debris (whether indoor, outdoor, or perhaps both)., or even a leakage in the refrigerant. The latter is especially bad as it can potentially cause freezing in your window air conditioning unit.

Humming Noises

For the most part, humming is totally fine and normal. Just listen closely to it, however, because humming can also be an indication that there is something wrong with your window air conditioner. If the humming noise is abnormal, there are two likely causes.

1. Refrigerant piping. The first is refrigerant piping and the second is a potentially loose component. Both of these can cause vibration, which is what produces the humming noise. Leave the problem to persist and it can potentially lead to further complications.

2. Loose wiring. In some less likely cases, that humming can be the result of loose wiring. Should you notice loose wiring, it could be either electrical or motor-related. The simplest solution is to look for any loose internal components that can be popped into place or replaced entirely.

Squealing Noises

During the start-up of your air conditioning unit, a squealing noise is perfectly fine. But if you hear it any other time, typically emanating from the fan or blower, it could be a potentially serious problem. Other parts such as the blower housing and wheel could potentially squeal when they malfunction.

1. Look for the cause. The first step towards solving the problem is to identify the origin. If the noise is only present during the start-up, don’t worry about it.

2. Change the indoor blower or outdoor fan. If it is a newer development, you might want to consider changing out the indoor blower motor or the outdoor fan motor to alleviate the issue.

Rattling Noises

This is one of the noises that you definitely don’t want to hear because there is no positive spin to it. When you start to hear rattling noises, it is a sure indication that your window air conditioner is on the decline.

1. Loose parts or debris. The first possibility is that, not only are there loose parts, but they can begin to wear and tear down rather quickly. Another possibility is that twigs or leaves have started to gather somewhere in the system, causing an obstruction.

2. Compressor issues. If you don’t identify the rattling problem in short order, it can lead to very serious repercussions for your air conditioner, primarily with the compressor. Another potential source of rattling in your window air conditioner is a loose fan.

Should you hear consistent rattling, the first thing that you should do is to look at the air-con for any loose bolts or screws. When you’ve verified that this is not the reason, replace the indoor air filter and clean up the unit’s condenser coils. If the noise sticks around, call in a professional because the problem could be quite serious.

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Grinding or Screaming Noises

If you hear this noise, shut your air conditioner off right away. These sounds are indicative of a major problem, most notably a potential refrigerant leak. Refrigerant leaks are a serious deal since they can damage not only the air conditioner, but they can be potentially harmful to humans as well.

In the event of a grinding or screaming noise, call in a professional immediately before the situation can get worse.

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Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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