What To Do When Portable Air Conditioner Make Loud Buzzing Noise

A portable air conditioner's occasional beeps and soft hums are familiar, but when it becomes continuous and loud buzzing noise, it may indicate problems. Often, these sounds signal something wrong that needs attention. Moreover, it can be pretty annoying and disturbing. That is why we have researched for you what to do when you encounter it. 

There are several causes why your portable AC is making loud buzzing noises, but in summary, faulty parts that need replacement could be your main culprit. It can be due to a damaged capacitor, malfunctioning connector, or a broken compressor. Observing or hiring a professional to diagnose the AC will help determine what the actual problem is and what necessary steps are needed to be done. 

A buzzing sound is one of the hardest portable air conditioner problems to solve. Since it can be due to several causes, sometimes even combinations of these. That is why you should keep reading this article as we further discuss the answer above and cover other related topics that will surely help you with this dilemma.

A white portable AC unit inside a brick walled living room, What To Do When Portable Air Conditioner Make Loud Buzzing Noise

Why Do Portable Air Conditioners Make Buzzing Noises?

Regardless if this is your first time owning a portable AC or not, the easiest way to determine the source of the buzzing sound is by thorough inspection, either by you or by a hired professional. Aside from the faulty parts, there are still other reasons why your portable air conditioner is making a buzz. 

White portable AC unit inside the living room

Imbalanced Fan Blades

Fan blades need to be in perfect condition for the unit to work correctly. Damage to any of the edges can cause it to malfunction. Open up the unit, then check if the fan is in place and for dents or dings on the blades. If damaged, replace the fan blades and clean out the surrounding area since this can help solve the problem.

Refrigerant Leak

Buzzing noise is one of the signs that there's a freon leak in the unit. It may not be that noticeable, but your unit is starting to freeze up if there's a tear in the refrigerant line. Seal off any tears or holes in the line and refill the refrigerant if it's below the standard level. 

It can be challenging to pinpoint the cause of the buzzing sound; thus, it takes a lot of patience until you single out the source. If you're not confident with your skills, better hire a technician to finish the task for you. They can also do maintenance checks, give diagnoses, and suggest enhancements for your unit.

What Are The Common Air Conditioner Noises

Woman changing the AC level

Some homeowners now prefer portable air conditioners over traditional ones due to their size and cost. It may not be as powerful as the fixture AC, but in terms of efficiency, it is comparable. Both carry on the job of cooling down the room, but the main selling point of portable AC is its mobility.

Having this kind of unit is beneficial, but it defeats its purpose if it's producing disturbing noises. These sounds are usually warning signs of something wrong with your portable air conditioner. You can quickly solve some with the ever-so-famous "turning on and off again" while others need technical expertise. 

We have listed below possible reasons behind the noises that you hear coming from your portable Air Conditioner.

  • Rattling Noise - this is often associated with loose and detached parts
  • Clunking Noise - can be a combination of broken and loose parts; worst case, the compressor is damaged
  • Whistling Noise - caused by a problem with the air vent, which causes low airflow
  • Pulsating Noise - loose compressor causing it to hit something in the system
  • Squealing Noise -unused unit that was suddenly turned on or blown out condenser fan blower motor
  • Hissing Noise - leak in the refrigerant line

Do not overlook any of the noises above, especially if it is consistent. A simple problem can turn into significant issues, causing more expenses and irreversible damage if left unattended. 

Standard Solutions To The Noise Problems

Now that you're familiar with the different kinds of noises and causes of air conditioner problems, let's move on to the solutions.

Rattling Noise

Rattling is the least of your worries out of all the portable AC noises since this is the easiest to fix. Most of the time, you only need to tighten some screws,  put it back in its proper place, or in some rare cases, replace parts. Below are the most common source of rattling noises in ACs

Debris or Dust

When the metal fan or any metal part in the system comes in contact with debris, you may hear a rattling sound. Regular cleaning will quickly fix this problem and remove any debris and dust piled up inside and outside the unit.

Unsecured Fans

Fans that are not correctly fastened will cause the panels and unit to shake. Ensure that the blower fan located in the air handler and condenser coil fan is secured.

Loose Panel Door

If not screwed in tightly, the metal-covered panel or cabinet door will hit against the unit, and as a result, it will rattle. A simple issue requires a simple solution- get your screwdriver and screw that bolt tight.

Damaged Motor

Similar to a buzzing sound, a damaged motor will need replacement. Once you have identified that this is the cause, don't use the unit until you can replace the motor. Portable AC running on a damaged motor will cause the other parts to malfunction.  Avoid using DIY methods on this issue unless you are an expert to prevent further damage.

Clunking Noise

A white portable AC unit inside the living room

Minimal clunking noise can result from loose parts that will require some inspection and adjustment. However, if the noise is loud and disruptive, this could be a sign of a failing motor, a damaged indoor fan, or worst, a broken compressor.

We highly recommend hiring an HVAC expert to inspect and replace faulty parts for you. This task requires expertise and a special set of tools to finish the job. Some professionals even find compressor-related problems difficult; we suggest avoiding meddling with the inner mechanism without ample knowledge and guidance.

Whistling Noise

The restricted air inflow is the main culprit of your unit's whistles. Dirty air filters block the airflow causing it to increase pressure. As we have previously mentioned, regular overall cleaning will eliminate most of the problems. Clean or replace the air filter and enjoy the cool breeze.

Pulsating Noise

The compressor hitting something inside the unit causes vibration, which you can frequently hear as a pulsating noise. Reduce the sound by adding a wooden platform or small rubber isolation feet. If the noise persists, check the refrigerant line and slowly try to move it away from any metal part like the casing.

Squealing Noise

Rarely used portable AC produces a squealing sound when suddenly turned on. Give it some time to warm up, and as time passes, the squealing will eventually stop. Worst case, the condenser fan blower motor is blown. Don't try to fix this on your own instead, hire a technician. You will likely cause more damage if you tinker with it.

Hissing Noise

On top of the hissing noise, an increase in the electric bill, longer cooling time, and a frozen refrigerant line are apparent signs of a freon leak. Cover any holes and tears or replace the line entirely, then refill the refrigerant to the standard level if needed.

What Are The Warning Signs For Failing Portable Ac Compressor

White portable AC in the corner of a room

  • Increasing electric bill- there's no change in power consumption and duration of use, but the bill is skyrocketing.
  • Less Airflow- as time passes, the airflow weakens until you can barely feel anything.
  • Warm Airflow- a leak in the compressor causes the refrigerant to run low
  • Strange Noises
  • Overheating

What Are The Best Portable Air Conditioner Units?

White portable AC unit inside a living room

In some instances, especially for older units, replacing the entire unit is more cost-effective than having it constantly maintained and inspected to continue operating. Keep in mind that when the cost outweighs the benefit, it's about time to change your unit. For this reason, we have listed the top picks for the year 2022.

For budget-conscious people:

Check out the Midea 8.000 BTU Portable Air Conditioner on Amazon!

For noise-sensitive people:

Check out the Frigidaire Portable Air Conditioner on Amazon!

Who Should I Call For Professional Tune-Ups?

You may have noticed that some of the issues stated require a duly licensed technician to solve the problem. You might want to reach out to Air Experts and American Home Shield if you are at a loss with who to call. Both companies offer a wide range of services from prevention to solution, ensuring peak AC performance.


A white portable AC unit inside a brick walled living room

Don't put portable air conditioner noise problems on hold; attend to it as soon as possible to avoid further damage. Moreover, regular inspection and maintenance by a professional is the most effective way to prolong your unit's helpful life.

To learn more about air conditioners, check out these articles, which can help address some of your concerns and inquiries: 


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