Why is my air conditioner making a loud buzzing noise?

Inside the white cabinet of air conditioners is a complex machine with many working parts. But that's not something you tend to think about - instead, you simply press the button on sweltering days and wait for the room to become pleasantly cool.

The only time you think about its working parts is when something goes wrong with it. Then, you hear a whistling sound, a humming noise, or a humming sound, indicating that your machine isn't too happy. It might still work for now, but for how long?

A pulsating noise or loud buzzing noises like this from your air conditioner is also a permanent distraction when you're trying to watch TV or entertain friends.

Read on to find out why your air conditioner makes loud noises.

The Reason Your Air Conditioning Unit Is Making A Buzzing Noise

Is your air conditioner making a loud buzzing or pulsating noise?

It could be something very minor, like a part that's come loose. Alternatively, it could signal the end of your unit's life cycle. Either way, you shouldn't ignore loud noises or strange noises. A quiet air-con is a happy air-con!

One of the most common causes of a buzzing sound in your air-con is a loose part. An air conditioner unit comprises a compressor, a condenser, a fan, a blower, a grille, and an evaporator, among other things. These parts work in unison to absorb warm air and send cool air into the room.

Buzzing can be caused by a single loose part in your air conditioner, like an isolation foot at the unit's base; equally, it can be caused by a broken compressor or malfunctioning compressor acting alone or impacting the condenser or evaporator.

Since these parts all work in unison, one loose component can affect the entire outdoor unit.

Don't repair too much when a squealing sound occurs. It could be your air-con approaching the end of its cooling cycle. Still, chances are it is no more than loose fan blades, debris in the outdoor unit, a condenser coil that needs to be cleaned, or an air filter that needs to be changed.

Try changing the filter and cleaning the unit - failing that, contact a professional ac repair company to repair your ac immediately.

Do All Air Conditioners Make A Buzzing Noise?

It's expected that all air conditioners makes some noise.

Air conditioner noises are usually humming sounds as the warm air is absorbed from the room and sent through the condenser for cooling - this is a normal operation. Chances are you're familiar with the natural sound of your air-con, so you will be able to tell when the belt connecting is a little off!

Suppose you hear a broken belt sound that wasn't there previously, or you notice a change in the natural sound of your unit. In that case, it's a strong indication your air-con has a blockage in it or a loose part.

This isn't generally a concern! Your air-con will still operate normally for some time even if the air filter is clogged or the malfunctioning compressor needs some maintenance. Unexpected buzzing can also result from an issue with a broken fan motor, loose wiring, or an electrical voltage issue.

Even though your unit will continue to operate, it will be "at-risk". This is because the fault in your air conditioner will continue to develop and might impact other HVAC system components resulting in safety issues.

It's best to take a peek inside your unit to check for dust - you might want to take this opportunity to change the air filter too. If everything seems normal, but you still hear the buzzing, you will have to contact a professional air conditioner service eventually. Sooner is better than later!

Should I Be Concerned By My Noisy Air Conditioner?

A few strange sounds coming from your air conditioner should never be ignored.

When you first hear a buzzing or a high pitched squealing noise, it means the issue will be minor. While it is easy to ignore this in the short term, it can pose a serious risk to your health if left untreated.

A buzzing sound is probably an issue with electrical components or the air filter. Fixing a few sounds should be easy enough by replacing the filter or calling an HVAC engineer with a replacement part. You need to do this as clogged up air filters can affect air quality and damage your breathing.

A bubbling sound is more serious and should be fixed right away! When you hear a gurgling sound coming from your air conditioner, it indicates an issue with the leaking refrigerant. Most likely, you have a refrigerant leak.

A refrigerant leak in the air conditioner refrigeration unit sends harmful chemicals into the air, leading to breathing difficulties, headaches, and poisoning.

The Steps You Can Take To Minimise The Noise Of Your Air Conditioning System

Some people don't want to wait around for the air-con service engineer to arrive. Instead, they want to solve the loud buzzing noise sooner, which should be possible with a few internet "how-to" videos.

If you think the issue isn't too serious and you want to have a go yourself, nothing is stopping you. Read the sections below to find out what the cause is likely to be and how to get started with your DIY project.

Don't forget; there's no shame in giving up and calling in the professionals if the task is a bit beyond you.

Fix any loose parts

The most common cause of air conditioner buzzing is loose parts. Loose parts are usually nuts, bolts, or fan blades. Loose nuts and bolts on parts like the condenser and ac compressor can produce buzzing and rattling sounds, a rattling noise, or cause refrigerant leaks.

These issues are common with a bad compressor unit, but they are also easy to fix! First, open the white cabinet of your air conditioning outside unit and investigate the sound. Next, use a duster to remove any dust build-up and debris.

Finally, check that nothing has fallen into the outdoor ac unit or that nothing has come loose.

Check all the nuts and bolts you can find. Then secure the various parts of the unit to the cabinet to prevent it from buzzing and rattling when operational. If you still have unwanted noise issues contact a professional air-con service for advice.

Remove debris from the fan

The primary moving part in an air-con unit is the fan.

There are actually two fans - one to intake air from the room and another to dispense with it in the outside air. Unfortunately, both of these fans can become jammed or clogged, causing that annoying buzz.

There's good news! Cleaning and repairing your air-con fan is super easy; you can do it yourself in a short time with some household cleaning products. First, prepare some soap and water and find a cleaning pad and paintbrush.

Open the cabinet and remove the air vanes (metal grilles used to direct the airflow). Inside you should find the heating and cooling fans along with the air-con impeller. The impeller is the fan blade connected to the air-con condenser fan's motor.

Using soap, water and a paintbrush, remove any dirt, grime, or debris from the fan blades.

Check the isolation padding

An air conditioner unit moves around a lot. The condenser fan's motor that drives the condenser causes the unit to shake, so you need some stability.

This comes in the form of isolation padding that fits onto the damaged isolation feet and copper lines of your air-con unit - these are small rubber feet. Isolation padding prevents your unit from vibrating and causing unwanted noise.

Extra vibrations can also shorten the lifespan of your air-con unit without sound dampening technology or a plastic pad!

Isolation padding comes in different forms depending on your air-con type. If your air-con is wall-mounted, you will have foam padding under the studs on the wall. This can be replaced!

If your air-con is floor-standing, you will have dimple pads underneath its isolation feet. These can also be check and replaced.

Lubricate the motor

Every air-con has a blower motor to power the fans that pull air through the condenser coils. But not every air-con has a fan motor that needs to be lubricated.

Many modern air-cons use motors that don't need lubrication, but it's probably an older unit if it's making a buzzing or rattling sound.

Lubricating the fan motor before each cooling season is a good practice. An air-con is a high capacity machine that needs regular maintenance to ensure it works as it should.

Before lubricating the motor, turn off the power at the mains. Next, open the cabinet, and you should see the motor visible on the underside secured by some loose screws. Remove the screws and find the oil ports on the motor.

Always use oil suitable for air-con motors. Never use engine oil for cars.

Time to call the experts?

If you are still having issues - it's time to call in the experts. Our Brisbane-based air conditioning repairs team are on hand to give you the assistance you need. Call us on 07 3283 5566 or fill out a quick quote to get your air con back up and running!


Can I fix my air conditioning unit myself, or do I need an AC technician?

Modern air conditioning units are complex machines with refrigerant lines; that's why air conditioner technicians require years of training to qualify.

To be on the safe side, it's always best to contact an air conditioner technician for advice or to book a service call. Technicians not only know how to fix your air-con unit properly, but they also know the appropriate safety protocol.

That said, competent people can carry out routine cleaning and minor fixes!

Does a buzzing noise from my AC unit mean I should get a service?

Is your air conditioner making a buzzing sound? This isn't something you should ignore for too long.

The banging noise might not be serious at the outset but indicates a deeper issue with the unit that you need to address, such as a leaky duct or refrigerant leaks!

The best way to identify and resolve the problem is to opt for a service from a qualified HVAC technician.

How can I stop my air conditioner making a buzzing noise in future?

AC noises and a loud buzz have many causes, and it's hard to pin down the exact problem every time.

One way to prevent indoor ac unit buzzing is to address the most common causes of weird noises when they occur and constitute professional advice if you can't find the answer. First, check you don't have a frozen ac unit or refrigerant line!

Another approach is to have your unit regularly serviced by an HVAC professional at the start of each warm season to prevent costly repairs.

Experiencing other air conditioner issues?

Check out our other guides on common problems below:

My air conditioner heat mode is not working

My air conditioner will not turn on

My air conditioner will not turn off

My air conditioner is sweating inside

My air conditioner is icing up

My air conditioner is blowing hot air

My air conditioner is leaking water

My air conditioner smells bad

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