Updated at: 30-09-2022 - By: Sienna Lewis

Does the sound of your air conditioner upset you, and do you wonder why it makes such a loud noise when it first turns on? You’ll find six different noises and explanations below to pique your interest.

I’m curious to know what those noises represent. The varied noises your air conditioner makes will soon become grating.

This is your unit’s method of letting you know there’s a problem. But don’t worry, because this article is here to help. Don’t stray from the path!

Different Sounds Your Air Conditioner Makes When Starting

In the event of even the smallest alterations in your unit, you should take immediate action because it could escalate to more serious issues. Cooling your space and improving air quality are the AC’s primary duties.

It’s up to you, however, to ensure that you get the most out of your investment. Sound waves originate from a wide range of sources. You’ll be able to remedy the problem once you understand why it happened in the first place. So, here are some of the sounds you may hear from your device and the likely causes for them.

Sound #1. Banging

The sound could be linked to a wide range of AC components. It has a wide spectrum of tones, from gentle thudding to harsh and downright horrifying. The following are some potential causes of the noise:

Cause #1. Stuck debris

You should expect to find sticks and leaves inside your window air conditioner if the outside of the unit is exposed to trees or plants.

It is possible for small stones and other hard objects to slam against your AC components. The seriousness of this circumstance necessitates that you take action immediately.

Cause #2. Loose fan

When AC blowers or fans become dislodged, they may come into touch with their surrounding materials, such as the cages they’re enclosed in. As quickly as possible, we need to address this issue.

Metals hammering loudly and continuously can act as an indication of this. It’s best if you turn off your unit when you try to investigate. Because failing to do so could result in serious harm to both you and the environment.

Sound #2. Screeching

There is nothing worse than the sound of metals shrieking. Most likely, the metal blades of your fan or the motor bearing are to blame if the noise is coming from your air conditioner. Additionally, it’s possible that the fan is set at an incorrect angle.

It’ll cause a screaming sound when the blades come into contact with the cage during rotation. In the meanwhile, your AC compressor’s high pressure or damaged metal bearings can cause this noise. In addition, following issues should be resolved.

Sound #3. Clicking

Our air conditioner always makes a clicking sound. When the speed increases and does not slow down, it could pose a serious threat. As a result, you should only utilize it after you know what’s going on. This sound has at least two plausible explanations, both of which are interconnected.

A faulty thermostat would be the most likely culprit. When you turn on your air conditioner, you’ll hear a distinct click. But if you switch it on and it doesn’t work, you’ll hear a constant clicking sound.

Probably, your air conditioner is trying to turn itself on, but it can’t. A faulty capacitor has led to this predicament. For your AC components, the capacitor is the source of power. This means that the device will continue to run even if there is no power.

Sound #4. Hissing

This is a particularly frantic tone. Also, turn off your air conditioning system and dial a repairman right away. The hissing sound is most likely caused by a leaking pipe. The refrigerant may be leaking because of a tear in the wires or ducts, for example.

Also, check to see if your compressor has a leaky valve or a valve that isn’t properly sealed. If our air conditioner can’t handle high pressure in particular areas, the hissing noise will be heard.

Sound #5. Whistling

The preceding noise would be a good analogy for this one. However, the pitch isn’t as shrill. Clogged filters, leaks, and a host of other issues could be to blame. Your air filter will not function properly if it is covered in dust. As a result, your blower motor could also suffer.

Your motor will require more air, but it will forcefully perform that function because of limited airflow, and this would result in high pressure in your blower motor, which produces the whistling sound.

Sound #6. Cracking

Your blower motor will generate a whistling sound since it will have to work harder because of a lack of airflow, which means it will need more air.

If they’re too heavy or too solid, they’ll break. This sound will be made as a result of the breaking. As a result, your air conditioner may generate an audible start-up noise.

Loud AC Noises and What They Mean

Identifying the specific sound your air conditioner is making will allow you to fix problems quickly and extend the life of your machine.

Clanging and Banging

If your unit makes a lot of noise when you turn it on, debris may be lodged inside. There’s a good chance that the problem isn’t debris, but rather a loose fan. If you hear this, turn your device off right away. You run the risk of further damage to your device if you continue to use it.

Debris in the unit is the main culprit in this case.

Remove the impediment or re-tighten the fan to its original position.


There is a possibility that your fan motor bearings have failed, if you hear a screaming sounds like metal grinding against metal. However, if you can’t get an HVAC professional to your home, you may want to turn off your unit for the time being until they arrive. If you continue to use the appliance, you may wind up with more issues.

Why did it happen: The fan motor bearings were destroyed and will not be repaired

Fix: a new fan motor must be installed.


If your unit makes clicking noises when you try to start it, but it doesn’t switch on, you may have an electrical problem. You must not attempt to resolve this issue on your own.

In this situation, the thermostat, compressor, or capacitator may be malfunctioning due to electrical issues.

Make an appointment with a heating and air conditioning technician. If you have an electrical problem, don’t try to fix it yourself.

Common Fixes for Loud A/C Units

If your air conditioner is making loud noises, there are a few simple adjustments you may implement on a regular basis.

Clean and Straighten Coil Fins

Improved efficiency can be achieved by ensuring that the coil fins on your unit are in good condition. You can use a fin comb to straighten the coil fins and a vacuum attachment with a brush to remove any remaining debris.

Tighten Loose Screws

Running can cause screws in your equipment to loosen due to vibration. This can generate a rattling sound while the device is running, but it can also lead to loose parts over time. When performing normal maintenance or attempting to resolve a noise issue, be sure that all loose screws are tightened.

Remove Debris Caught in Blades

To check for debris, find the fan after opening the A/C cabinet. Make sure to remove any debris surrounding the fan blades to reduce the noises you hear when your machine is turned on. A few minutes of your time should be all it takes to perform this simple task.

Straighten Bent Blades

Regardless of whether or not you detect any debris, you should inspect the blades. Be careful when bending the blades back into place. By being negligent, you run the risk of inflicting even more damage on your unit.

Verify that the screws holding the blades in place are tight after they have been straightened. As with any screw on the device, make sure to tighten these down. Because of vibration, your device may make more noise when it first begins to run.

Lubricate Motor

An unlubricated motor may make a screeching or grinding noise when turned on. Use SAE 10 oil to lubricate the engine. You’ll find the oil ports on the fan motor’s underside, near a couple of little holes near the screws.

3 Preventative Measures to Stop Future Problems From Starting

The last thing you want to do after dealing with the noise is deal with it again. Maintaining your HVAC system is the best way to avoid costly repairs in the future.

1. Install Noise-Reducing Barrier

The average decibel level of today’s units is below 55, but if yours is exceptionally loud, you may want to consider building a noise-reducing barrier. It is possible to reduce the noise of air conditioners by using a noise-blocking fence, quiet fence or sound blanket.

2. Schedule Regular Inspections

Preventative measures can be taken by conducting regular inspections. It is the job of an HVAC specialist to identify any system flaws and recommend remedies.

To keep your heating and cooling system in good working order, you should plan to get a maintenance inspection once or twice a year.

3. Call in an Expert

If you have any reason to believe that your HVAC system is about to have issues, you should contact a local HVAC professional right away. There is a good chance they can help you get your appliance serviced before it becomes a full-blown disaster.” Long-term savings in terms of both time and money

Why Is My Air Conditioner Making a Banging Noise?

An AC system’s compressor is the most common source of a start-up bang. A malfunctioning fan motor in your air conditioner could possibly be to blame.

The compressor degrades in performance with time. It may become unbearably loud as it nears the end of its useful life. Compressors and the parts they include can usually not be repaired. As a result, you’ll need to completely overhaul the entire system.

In some cases, a broken motor can be replaced. In some cases, the motor is covered for a lengthy period of time and can be replaced if necessary. Replacing the motor after the warranty has expired might be expensive, so it’s best to get a new air conditioner altogether.

Why Is My Air Conditioner Making a Rattling Noise?

When an air conditioner’s internal components break or are damaged, you may hear a rattling noise. Small pieces of the motor or screws, for example, may be missing or broken.

Dirt and debris in the air conditioner unit can also generate a rattling sound. Leaves and sticks may have found their way inside if your unit is outside or near trees and plants.

Without dismantling the AC unit, it can be impossible to determine the specific problem. A professional HVAC technician should inspect and dismantle the system if you can do so safely while the unit is turned off.

Why Is My Air Conditioner Making a Squealing or Screeching Noise?

Most often, problems with an air conditioner’s engine are to blame for loud screeching or squealing noises. Damaged fan motor, worn-out bearings or a broken belt could be the cause. When the screaming noise becomes unbearable, the system must be shut down.

In addition, running the HVAC unit can be dangerous. Call an HVAC professional immediately to shut it down from the main power source. In some cases, you may need to replace the air conditioner’s motor or all of it.

Why Is My Air Conditioner Making a Humming Noise?

A faulty contactor relay switch frequently results in humming noises coming from an air conditioner. When the thermostat tells it to, the switch activates the outdoor condenser unit. For safety reasons, you should not turn on the machine until the issue has been rectified.

Low lubricant levels or bent fin coils can also generate humming noises. If you continue to run the machine with low lubricant levels, the humming sound will transform into a grunting noise. Fin coils that are bent are easy to spot and can be straightened with a metal comb.

Why Is My Air Conditioner Making a Buzzing Noise?

There is a buzzing sound if there are loose parts that haven’t fully separated. The buzzing sound you hear is caused by the vibrating elements of the device when it is turned on.. Dirty condenser coils, faulty wiring, or an unbalanced fan motor might also cause this problem. Whatever the case may be, you should have it inspected by an expert who can provide recommendations for necessary repairs.

Why Is My Air Conditioner Making a Clicking Noise?

When a cooling cycle begins or ends, an air conditioning unit will make a clicking sound. In this case, it is possible that the thermostat is malfunctioning. The thermostat will need to be replaced as a result of this.

Changing a thermostat can be a hard task that necessitates the help of a certified contractor, depending on the thermostat model you select.

An AC fan obstruction, incorrect electrical signals, or the discharge of capacitors could potentially generate a clicking sound. The compressor will be unable to run if the problem is caused by a discharge in the capacitor. As a result, the entire system will not function. Instead, it will make a clicking sound whenever you turn it on.

You’ll hear a clicking sound if your outdoor AC unit’s fans are obstructed, but the unit will still run. To keep the fan running smoothly, the air conditioner requires regular maintenance. After shutting down the device and removing its outer shell, it’s easy to perform the task yourself. Then, you can clean the fan blades.

Why Is My Air Conditioner Making a Hissing Noise?

A hissing sound can be caused by a number of different causes, including a refrigerant leak, an AC compressor valve leak, or an excessive amount of compressor pressurization. An annoying screeching noise can be heard if the problem is caused by excessive compressor pressure.

Damage to the refrigerant line is the most common cause of a refrigerant leak. The unit can be severely damaged by any of these possible sources. In order to fix the problem, you need shut down the entire system and call an expert.

Why Is My Air Conditioner Making a Grinding Noise?

When you turn on your air conditioner, you may hear a grinding noise. The pistons that compress the refrigerant gas often make a grinding noise. You may hear a grinding noise if your AC compressor is worn out, which may necessitate an AC compressor replacement or a whole AC unit repair.

Bottom Line

Why does your air conditioner create such an audible noise when it’s turned on for the first time?

As soon as you hear anything strange, turn off the system and call an HVAC professional for help diagnosing the problem and determining the best course of action.

Your air conditioner may start making a loud sound because of a minor problem, but it might also be an early symptom of a far more serious problem that could lead to serious damage to the unit. Finding the source of the noise can be a challenge. Let the specialists handle your diagnostic and repair.

Professionals are the only ones who can keep your air conditioner running at its peak efficiency. Also, have it inspected by an HVAC professional on a yearly basis.