Updated 4/24/24

Is Your AC Making Noise?: Here’s What It Could Mean

With the summer heat coming in strong, you decide to turn on your AC unit. After a few minutes, it starts making strange buzzing noises. You let it go for a while, but the sound keeps getting louder.

There are many reasons why your AC unit could be making noise. It could be a malfunctioning compressor, damaged isolation feet, or you may have a few loose parts rattling around in there. Either way, you’re going to want to get it fixed.

To help you identify the source of your problem, here are is a quick guide on the different noises AC units make when they are in distress.

1. Buzzing

Buzzing is going to be one of the most common noises you’ll hear your AC make when there is something wrong. When you hear this loud sound, chances are one of the following things is wrong.

Malfunctioning Compressor

Your compressor works to pressurize and cool the refrigerant found in your unit. If your unit is making a buzzing noise then this means that it’s not doing it properly and you need to have it looked at.

It could also mean that the electric voltage that’s running through your outdoor unit isn’t at the right amperage.

Heating and air conditioning unit
Damaged Isolation Feet

Your compressor is mounted to your unit and sits on rubber feet. These rubber feet are called isolation feet. After a while, they tend to break down and disintegrate. When this happens, the compressor will become unbalanced and cause a loud buzzing sound.

Frozen AC Unit

You may think this is a weird one since you run your AC during the summer. Sadly, even the extreme temperatures can’t save your unit from freezing over.

If something causes your refrigerant to leak then things will get a bit frosty and make your unit buzz.

Loose Parts

Like with many machines, if one thing in your AC breaks then chances are other parts will follow it. If one part stops working or comes loose then it will cause other parts to work harder.

The harder these other parts have to work the faster they will wear out. This premature wear may cause your unit to buzz in protest.

2. Squealing

It is normal for your blowers and fans to make squeaking noises. What isn’t normal is if they make a loud squealing sound. This is a huge indicator that they are going bad. It could also mean that the belt that connects your motor to your blower slipped.

Sometimes this sound can be a natural occurrence when you first turn your unit on and it’s staring up. For the most part, the sound will go away after a bit though. If it doesn’t then this means that it needs to get looked over.

3. Clanking and Banging

Clanking and banging usually means that you have a loose part sort of swimming around in your unit hitting against other things. The worst-case scenario is that your compressor is what came loose which means you’ll need a replacement.

This sound could mean that your fan is off balance to the point where it can knock against other parts in the unit. If any of these problems are left alone then it can lead to bigger issues down the line.

4. Clicking

A little bit of clicking when you turn the unit on and turn it off is normal. It’s the sound of your electrical components starting up or shutting down. If the clicking doesn’t stop after a few minutes then there may be something wrong with your thermostat.

Whatever the source of the clicking sound is, you’ll want to stay on top of it. Electrical problems are nothing to play around with.

5. Rattling

Rattling is usually a sign that your AC unit is starting to break down. When this happens parts will come loose and cause the noise.

The electrical contractor could be causing the sound. If this is the case and it’s left unchecked it can damage other parts in the unit such as your compressor.

Sometimes the culprit is a loose fan. The problem could also be something as simple as twigs and leaves stuck in your outdoor unit.

AC Repair Installation Maintenance

Whatever it may be, the first thing you need to do is look around the casing for loose bolts. Make sure to also change your air filter and clean the condenser coils.

6. Humming

Most of the time humming is caused by loose parts as well. Loose refrigerant piping tends to vibrate and creates this humming sound. Loose wiring will do it as well.

If the problem doesn’t stem from a loose part then it could point toward an electric issue. You may have a problem with your motor if the compressor makes a humming noise and then refuses to start up.

7. Screaming

If you turn on your unit and it screams then you need to switch it off right away. It means you have a refrigerant leak which can break your AC unit and be hazardous for your family.

Call a professional to come out and look at the problem and don’t touch your unit again until they arrive.

What It Means When Your AC Is Making Noise

With the summer heat coming in strong, the last thing you want is for your AC unit to break down on you. If it does, knowing the common sounds that it makes when it’s starting to fall apart could help you get it fixed faster.

What if the noise stops on its own?

Even if the noise stops temporarily, it’s still advisable to have the AC inspected by a professional to identify and address any underlying issues before they worsen.

How can I prevent my AC from making noise in the future?

Regular maintenance by a professional HVAC technician can help prevent many issues that lead to noisy operation, such as loose parts, worn-out components, or dirt buildup.

What if the noise only occurs when the AC first starts up or shuts down?

This could indicate issues with the compressor, motor, or fan blades. It’s best to have a professional inspect the system to determine the cause and recommend appropriate repairs

What can happen if I skip AC maintenance?

Skipping AC maintenance can result in decreased cooling efficiency, higher energy bills, increased wear and tear on components, more frequent breakdowns, and reduced indoor air quality.

We hope you were able to use this guide to find out why your AC is making noise so you don’t have to go without cool air.

Do you need to call someone out to fix your unit? Contact us to tell us about your situation.