If your air conditioner is making pulsating noise, usually, it isn’t something to worry about. However, air conditioners are not quiet appliances, and they typically make some pulsing noises when the A/C unit is operating.

Air Conditioner Making Pulsating Noise

But if the pulsating noise of your outdoor AC is too loud and you can hear from inside the apartment.

This may indicate a part of the unit is loose and needs to be replaced as soon as possible. If you ignore it, it could eventually lead to extensive and expensive maintenance.

This article will help you determine why your air conditioner is making a pulsating noise and what you can do to make it quiet.

Most Common Causes for the Pulsating Noise

Multiple problems can cause a pulsating noise in the heat pump or AC compressor. Some of the likely culprits are mentioned below:

Air Conditioner Noise

If your AC is on a plastic pad, it may inhibit the insulation of sound waves coming from the compressor’s movement. When these compressors’ waves strike the plastic, they make a pulsating or humming noise.

Sometimes refrigerant lines contacting the wall may also cause pulsating noise as waves pass through. The line could be rubbing against the wall if sound-dampening insulation is not installed in the unit.

Fan coil or fan blades are loose and require tightening or replacing. In some cases, a simple tune-up of these parts might fix the problem right away.

A faulty capacitor and fan motor can also make pulsating sounds.

How To Fix the Pulsating Noise?

Open the outdoor AC unit with a mini-split and access the AC compressor and try to fix the problem in place. The AC compressor looks like a car battery. Locate it, and stop the compressor vibrations.

If the AC compressor is on the plastic pad, replace it with a wooden pad to eliminate the pulsating noise and dampen the vibrations.

Fix the Pulsating Noise

Tiny rubber isolation feet can also be used for additional support to stop the AC compressor from shaking. Rubber isolation feet can also help to suppress the pulsating noise and dampen the vibrations.

If refrigerant lines are causing the noise, try to wiggle refrigerant lines away from any hard things like the wall. 

If your window AC unit is making pulsating noise, remove the back panel to access the AC compressor. Usually, the compressor’s rubber isolation feet are missing or damaged and need to be replaced.

You can also use additional support to stop it from shaking and making noises- consider underpinning it with a piece of wood. Also, tighten the screws that are used to grasp the compressor in place. Mainly compressor’s screws get loose after 10+ years of use.

Different Types of Air Conditioner Noise And How to Fix Them?

Modern air conditioners are quieter than ever. But if something is wrong with your air conditioning system, it can make multiple types of sounds. And ignoring the irritating noises can turn minor issues into significant maintenance.

We want to make sure if you hear any unusual noise from your HVAC system, you can determine and fix the problem effortlessly. Here are some of the most common sounds your air conditioner can make:

1. Banging Noise

A loose or broken part like a piston pin, connecting rod, or crankshaft inside your air conditioning compressor could make a banging noise. Sometimes an unbalanced indoor blower can also produce banging sounds.

It’s best to turn off your air conditioner after hearing a banging noise and contact a professional to inspect the unit. Maybe the problem is a simple fix. Continuing to use your AC can further damage your system.

2. Weird Noise

If the belt which is fastening the motor to the blower has slipped, it produces a weird high-pitched noise. Sometimes the bearings on your condenser fan’s motor can also slip and make strange sounds. In both cases, replace the belt and motor.

Sometimes debris inside the unit may also cause weird sounds. Make sure to remove any debris around the fan blades. However, insulation of other things may fall into the system and produce strange sounds when blades move.

3. Clicking Noise

Usually, Electrical parts at start-up and shut-down make clicking sounds, but constant clicking should be inspected. For example, continuous clicking noise from your system may indicate a failing thermostat or defective control. Ensure to check potential electrical issues and fix them ASAP before you have more significant problems on your hand.

Repetitive clicking also indicates that a fan blade has gotten bent, damaged, or blocked. In some cases, a minor repair or blade replacement can quiet the noise.

A clicking sound can also be fixed by simply removing leaves and debris from your system and tightening bolts.

4. Chattering/Rattling Noise

In outdoor AC, the fan works to propel air across the condenser coil. Fan blades are usually designed with thin steel or aluminum. When a loose or misaligned blade hits components of the casing can cause a chattering or rattling noise.

A chattering/rattling noise may indicate that your AC is loosening some of its parts and it is starting to deteriorate.

Your first line of defense is to clean condenser coils, tighten the loose fasteners and bolts in the AC’s casing, and replace your indoor air filter. If your air conditioner is still causing this noise, contact a professional.

5. Humming Noise

A humming sound is generally not something to worry about, but it still indicates that something inside your AC is off. Refrigerant piping, electrical problems, and loose parts usually make a humming or buzzing noise and, if left unchecked, can lead to expensive maintenance.

In some cases, the condenser fan motor on the AC cannot rotate but still has electricity reaching it, producing friction that makes a noticeable, often loud, humming noise.

Furthermore, when the contractor relay used to start the outside unit of your AC fails, it makes a humming noise. If your air conditioner is still making noise, contact the professional to inspect your unit and identify the problem.

6. Whirring Noise

The whirling noise in your air conditioner signifies a broken fan or defective bearings of the blower’s fan motor in either the indoor blower unit or the outdoor unit. Also, when the fan begins to fall apart or fan blades start loosening, you will notice a helicopter-ish sound.

air conditioner troubleshooting

A faulty or damaged belt in the system can also cause a whirring noise. However, other than a defective part, debris or a piece of paper can get trapped in the blower fan, making a loud and helicopter-blade-like whirring noise.

To resolve these issues, consider tightening the loose parts, removing debris from the unit, and replacing the damaged components of your system.

7. Screaming Noise

In the case of high-pitched whistling or screaming sounds, immediately shut the AC off and call an expert right away. The most likely culprit is a refrigerant leak, which can threaten your family’s health and damage your system.

The high internal pressure of your home AC compressor can also cause screaming sounds, which is very dangerous. If your air conditioner automatically switches off, consider it a good sign. An in-built sensor works to protect you from a potentially hazardous situation.

Is a Noisy Air Conditioner Dangerous?

Air conditioners are not quieter appliances. They usually make some sounds. But if you hear constant unusual noise from your system, you should never ignore it.

High-pitched irritating sounds can indicate that a part of your air conditioner is loose, damaged, or not functioning correctly. These issues can’t only damage your AC. It can cause serious health issues for your family as well.

Why Does My AC Sound like a Helicopter?

Mechanical issues with either the indoor blower or the outdoor blower can cause a whirling or helicopter-like noise.

Typically, a faulty bearing, motor, or fan in the blower units can cause this problem. Also, when fan blades start loosening or the fan begins to fall apart, a helicopter-ish sound can occur.

However, other than a defective part, debris or a piece of paper can get trapped in the blower fan, making a loud and helicopter-blade-like noise. To resolve these issues, consider tightening the loose parts, removing debris from the unit, and replacing the damaged components of your system.

Can an Air Conditioner Explode?

ACs are not designed to explode, but they can overheat and catch fire, leading to an explosion. When mechanical, electrical, grim, and dust-like problems build up on the condenser coil, and the system can’t emit enough heat from the unit, then the air conditioner is constantly forced to run to cool the space.

This increased temperature and pressure can make the home AC compressor overheat and rarely leads to an explosion.


Pulsating noise in your air conditioner often requires a simple fix, such as tightening up a loose part, removing debris and leaves, and placing some sound-reducing material like a plastic pad between the unit and the heat pump. And you can quiet your air conditioner’s noise within minutes.

However, if you find something serious with your air conditioner, call a professional to fix the problem.

Robert Castelao
Robert Castelao

Robert is an electronic engineer with more than five years of experience with a solid affinity for helping people reduce noise. He writes about these silent home appliances and easy soundproofing measures to help everyone avoid the negative effect of extended exposure to high noise levels.

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