AC makes noise - 7 Causes & How To Fix it 2025

AC makes noise – 7 Causes & How To Fix it 2025

If you hear loud buzzing noises coming from your air conditioner, it’s very likely that it is malfunctioning. Typically, the issue is either loose parts, missing or broken isolation feet, refrigerant leaks, or a malfunctioning compressor.

I have a portable window mount ac set up. Sometimes it runs okay and at other times it makes a lot of noise. I’ve tried to fix the noise coming from my ac but it always comes back. I believe it’s caused by excessive vibrating. Do you have any suggestions?

Squealing – If your air conditioner is making a squealing sound, the belt connecting the motor to the blower may have slipped, or the bearings on your condenser fan’s motor may be worn down. Clanking, or Banging – If you’re hearing these sounds from your unit, the issue is usually the blower assembly or the motor.

If your AC is making noise, potential causes include: loose parts within the unit, a faulty fan motor, dirty condenser coils, clogged drain lines, a failing capacitor, refrigerant leaks, or issues with the ductwork, which can manifest as rattling, buzzing, whistling, gurgling, or banging sounds; depending on the noise, you can try cleaning the unit, tightening loose parts, checking for leaks, or contacting a professional HVAC technician for repairs.

Common AC noises and their potential causes:

Rattling/Banging: Loose parts in the indoor blower fan or compressor, unbalanced fan blades, or worn bearings.
Buzzing: Faulty condenser fan motor, electrical issues with the compressor, or frozen evaporator coils.
Whistling: Leaky ductwork, loose seals around air ducts, or obstructions in the airflow.
Gurgling/Bubbling: Clogged drain line causing water to back up.
Screeching/Grinding: Worn fan belt, failing compressor, or damaged motor bearings.
Hissing: Refrigerant leak.
Clicking: Issues with the electrical relay switch or capacitors.

What you can try:

Basic maintenance: Clean or replace air filters, clear debris around the outdoor unit, check for loose screws and tighten them.
Inspect the fan: Check for loose or bent fan blades, and tighten the fan hub if necessary.
Check the drain line: Clear any clogs in the drain line using a wet/dry vacuum.
Check for leaks: Look for visible leaks in the ductwork and seal them with duct tape or mastic sealant.
Professional repair: If the noise is severe, persistent, or accompanied by other issues like poor cooling, contact an HVAC technician to diagnose and repair the problem.

AC Loud Buzzing or Popping Noise: The issue could be tied the circuit breaker, the fan motor, or loose wiring. If it’s the circuit breaker, a common cause is dirty air filter or debris around the AC unit. For the other issues dealing with the fan motor or loose wiring, call your technician for help.

Solution: AC makes noise

There are many reasons why an AC makes noise. Sometimes loose hardware is the culprit. Air conditioner noise could be caused by the refrigerant tubing that has a bend in it that produces rattling because it’s too close to other parts of the air conditioner.

You can correct this by carefully bending it back into its original place. Take a look at the unit and see if there are any loose parts that could be banging around causing the noise. It may be the fan blades have gotten bent over time. To remedy this simply bend them back to their original position.

Are you portable ac mounted properly in the window? While the ac unit makes noise and rattling carefully apply pressure to the window sash and listen for any changes in the sound.

This can be remedied by inserting shims between the air conditioner frame and the sash. Another good idea is to check the screws on the front panel of your air conditioner. If loose they’ll need to be tightened.

There may be more serious problems that would require a service technician such as compressor issues. Refrigerant flood back occurs when the liquid enters into the compressor crankcase.

This ac noise would usually occur when the compressor starts up. Another issue could be oil leaks causing a low oil level in the compressor but it would probably be pretty rare.

It’s most likely the way your ac is mounted that is causing it to makes noise. Experiment with the shims and I’ll bet it goes away. Remember to unplug it from your electrical outlet before attempting to do any internal work on it.

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AC makes noise – 7 Causes & How To Fix it

1 Banging

Banging is usually a sure sign that there’s a loose or broken part — a connecting rod, piston pin, or crankshaft — inside the air conditioning compressor.

Or perhaps, your indoor blower is unbalanced. A banging noise may also indicate that your system needs a compressor replacement.

2 Clanking

Clanking is another sign of a loose or out-of-balance part. The parts inside the sealed unit have likely failed, and the compressor itself may have become loose, possibly necessitating a replacement.

This sound can also mean that the indoor blower or outdoor fan and its blades are out of balance and hitting other parts. These types of issues will only get worse and create bigger problems if ignored.

3. Clicking

The clicking of electrical components at start-up and shutdown is a normal part of the system’s operation, but constant or ongoing clicking is not typical.

It could be a sign of a defective control or a failing thermostat. There are a lot of electrical parts in your unit, so it’s critical to pay attention to potential electrical issues as soon as possible before you have bigger issues on your hand.

Buzzing

A buzzing noise from your outside unit could mean:

Loose parts
Debris in either the indoor or outdoor unit
The outdoor fan motor is loose or about to fail
Fan blades are loose or out of balance
The copper lines from outside to inside are rubbing against something
Air condenser coil needs to be cleaned
The air filter needs to be changed
The blower is going bad or out of balance
Refrigerant leaks, resulting in your air conditioning freezing up. If it’s conditioning not cooling, this could be why.

Squealing

Blower and fan noises such as squeaks, squeals, and rattles may be transmitted through the duct system. Outdoor fan motors and indoor blower motors squeal loudly when they’re going bad.

The blower wheel and housing will also squeal when they malfunction. For some units, this sound is normal upon start-up.

You should be able to identify whether it’s a sound that the unit always makes or if it’s something new. Looking to purchase a home warranty plan, view:

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6 Humming

A humming sound generally isn’t serious, but it still signals that something inside your air conditioner is off.

Loose parts and refrigerant piping can cause vibration and, if left unchecked, can lead to a more serious maintenance issue.

Sometimes humming or buzzing noises point to electrical problems. If the compressor hums and refuses to start, there may be an issue with the motor, though loose wiring could trigger this noise, too.

Chattering/Rattling

A rattling noise can mean that your ac is starting to deteriorate, and some of its parts are loosening. Another cause could be twigs or leaves that have clogged your system.

The electrical contractor in the equipment can also make a chattering sound, which can damage other components including the compressor if allowed to continue.

Another culprit could be the fan, which rattles when loose. Your first line of defense is to check for loose screws or bolts in the unit’s casing, clean condenser coils, and change your indoor air filter.

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How to Stop a Noisy Window Air Conditioner in 2025

The most popular type of air conditioning, other than central air, is a window air conditioner. If your home is not equipped with central air conditioning throughout the house, you can use a window air conditioner to cool the house.

Most people like using window air units over floor models because they do not need to be moved from room to room and they don’t take up space in the room.

One thing about window air conditioners is that they are noisy. The noise level depends on the type and size of the unit. Noise levels are usually given in decibel ratings.

The higher the decibel the louder the unit will be. For every 10 decibels increase the sound pressure increases by a factor of 10.

For example, 50 decibels is 10 times louder than 40 decibels and is 100 times louder than 30 decibels.

There are many things that cause noise in ac units. Some cannot be helped. There are a compressor and fan in each unit which causes the most noise.

Other causes could be maintenance issues such as worn bearings, dirty or rusty fan blades, and basic wear and tear.

Besides basic wear and tear, your unit could be noisy because it is vibrating because it is not installed correctly.

A unit should not be unbearably noisy. If yours is, you should have it looked at by an authorized service professional.

There are some things that you can check on for yourself. To stop some vibrating, try tightening the screws holding the front panel onto the unit.

You might have bent fan blades which would be causing your unit to make noise. It shouldn’t be too difficult to bend the blades back into place.

Other places where you may be getting some vibration noise is between the ac frame and the sash or the glass and the frame. Check these out before you call in a service professional.

Conclusion:

The present air condition systems are calmer than at any other time. What’s more, we need to ensure yours remains as such. High-productivity AC units consolidate sound-hosing innovation and two-stage (variable speed) blowers to keep commotion levels under 55 decibels.

So on the off chance that you hear surprising sounds originating from your forced air system during ordinary activity, don’t disregard them, as this could be an indication that the unit needs a fix or redesign.

Your AC compressor is the part that’s responsible for circulating refrigerant (the liquid/gas that cools your home’s air). Due to normal wear and tear, parts inside the compressor can become loose and create a loud banging sound as they rattle around inside the compressor’s outer casing.

Overlooking the baffling commotions from your AC can transform minor issues into significant costs, as these clamors could flag anything from requiring a straightforward check-up to expensive fixes, as well — thinking pessimistically — replacement of the whole unit.

The sooner you can decide the reason for the commotion and resolve your AC noise issues, the better. At the point when your ac makes a boisterous commotion, particularly shaking clamors, it implies there is something incorrectly.

The most evident explanation behind this is a weak engine, which when it turns sour makes a shrieking commotion.

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REASONS FOR A NOISY AC UNIT

An AC Making Noise Often Signals Loose Parts. Loud humming or buzzing AC sounds are often caused by loose parts, such as nuts, bolts, etc. The unit is icing up. In many cases, cracking and popping noises involve ice forming inside the unit. This can happen if the temperature is set too low or if it’s not set.

Slipped or Old Belt
Loose Parts
Capacitor or Fan Motor Failure
Duct Leaks
Electrical Malfunctions
Trapped Twigs and Debris
Falling Compressor

Be that as it may, there are different reasons too. At Quality Degree, Inc., we need you to keep away from such a situation which is the reason we’ve assembled the best seven reasons why your AC may be making a clamor.

On the off chance that you do hear noise originating from your AC, make certain to call our gifted AC specialists. We work rapidly and proficiently to guarantee you’re agreeably lasting through the year.

Why is my air conditioner making so much noise?

Air Conditioning Repair in Houston, Tx

Every electrical appliance will make noise. It is valid for the refrigerator, microwave, and air conditioner. However, most late model central ACs run quietly. If the noise from your air conditioner is becoming irritating, you may have a problem.

It would help if you didn’t have to live with a noisy air conditioner that interrupts your relaxation time or keeps you awake at night. Call a certified HVAC technician to resolve the problem.

airflow problem

When an HVAC technician checks a noisy air conditioner, one of the first things they will consider is the type of noise. A kind of hissing or whining noise could indicate an airflow problem. Airflow problems are common on older systems that have been built piece by piece over the years. For example, you may have connected a new air conditioner to older ductwork. Sometimes these different components don’t work well together. If the duct system is too small, a hissing noise can result from the high volume of air the air conditioner pushes through it. It is also possible that the vents are too small.

Another possible cause of hissing is damaged ductwork. Occasionally, the ducts can develop cracks and leaks. When air escapes through those cracks, it creates a hissing sound. The technician can repair your ductwork to eliminate the sound.

Also, clogged or dirty air filters can sometimes cause noise. It indicates that the filter requires cleaning or replacement.

Noisy Central A/C: Compressor Problems

Sometimes a defective compressor causes annoying noises in the air conditioner. Compressors can produce all kinds of noises. For example, if you hear a clicking sound when you turn on the air conditioner and the air conditioner doesn’t start, the compressor may have an electrical problem. Also, compressors can produce a loud screeching sound. If you hear this noise coming from the outdoor unit, the compressor motor may need to be replaced.

In other cases, the outdoor unit may be making a knocking noise instead of grinding noise. It could also be a faulty compressor. Due to damage caused by normal wear and tear, the internal parts of the compressor can loosen and vibrate around the casing.

However, it is unnecessary to damage a compressor to cause loud noises. Sometimes all it takes is lowering the amperage to quiet the compressor.

Engine Problems

Another possible cause of the knocking noise coming from the outdoor unit is a faulty fan motor. When a fan motor becomes unbalanced, it can fit inside the outdoor unit and cause irritating noises. Fan motors can experience a similar problem. When a fan motor gets very dirty, it can lose its balance. It can cause it to move and create noise.

Also, it is possible to have engine problems affecting the indoor air conditioning unit. If the noise from your air conditioner sounds like a screeching noise inside the house, the fan motor may be to blame. This fan is responsible for drawing hot air from inside the house into the unit to cool it down. The cold air is then blown into the house. However, the blower fan motor can become damaged over time due to normal wear. Also, the fan belt may be worn. It usually results in screeching rather than a screeching sound.

Unusual AC Noises – Electrical Problems

In many cases, worn components are blamed for the noisy air conditioner. However, sometimes an unusual sound could indicate an electrical problem. If you hear a buzzing sound in your house, it probably doesn’t mean a bee has entered. It could mean that your air conditioner’s electrical system needs attention. Note that a clicking sound may indicate a problem with the system relays. An electrical problem is not something you want to try to fix yourself. Instead, call a certified HVAC technician.

Coolant Problems

Do you hear an unusual hissing sound coming from your air conditioner? A hissing sound could indicate a coolant leak. Refrigerant leaks can also cause your system to turn on more often but not cool your home adequately. You will need an HVAC technician to find the source of the leak, repair it, and recharge your system.

If your air conditioning unit is making noise, it can indicate various issues. Here are seven common causes and potential fixes:

1. Loose Parts

Cause: Vibration can cause screws, bolts, or components to become loose.
Fix: Turn off the unit and check all screws and bolts. Tighten any that are loose.

2. Dirty Fan Blades

Cause: Dirt and debris can accumulate on the fan blades, causing imbalance and noise.
Fix: Clean the fan blades with a damp cloth. Ensure the unit is off and safe to access.

3. Debris in the Unit

Cause: Leaves, twigs, or other debris can obstruct airflow or get caught in the fan.
Fix: Inspect and clear any debris from around the outdoor unit and inside the air handler.

4. Worn Out Bearings

Cause: Bearings in the motor can wear down over time, leading to grinding noises.
Fix: If you’re comfortable, lubricate the bearings. If the noise persists, consider calling a technician to replace them.

5. Refrigerant Issues

Cause: Low refrigerant levels can cause the compressor to struggle, leading to unusual noises.
Fix: Check for refrigerant leaks and consider having a professional recharge the system.

6. Faulty Compressor

Cause: A failing compressor can produce loud clicking or grinding noises.
Fix: If the compressor is the issue, it may need repair or replacement by a professional.

7. Electrical Issues

Cause: Electrical problems can cause buzzing or humming noises, often indicating loose wiring.
Fix: Turn off the unit and check the electrical connections. If you’re not experienced, contact a technician for safety.

General Tips:

Regular Maintenance: Schedule annual maintenance to keep your AC unit running smoothly.
Listen Closely: Pay attention to the type of noise (hissing, buzzing, grinding) to help identify the issue.
Consult a Professional: If you’re unsure or the noise persists, it’s best to consult an HVAC technician for a thorough diagnosis and repair.

AC makes noise – 7 Causes & How To Fix it 2025