Why Is Air Conditioner Making a Loud Humming Noise?

Air conditioners are integral to many homes, providing much-needed relief from hot and humid weather. However, a loud humming noise from your air conditioner can be frustrating and annoying. It can also be a sign of a potential problem with your unit.

An air conditioner can make a loud humming noise for various reasons. It could be due to an issue with the condenser fan motor, loose components, or a failing compressor. A loose belt can also cause inadequate tension or misalignment of the motor, resulting in a loud humming noise. 

In this article, I’ll discuss some of the most common reasons your air conditioner might be making a loud humming noise and explain exactly how to fix each of these issues. Let’s get started!

1. A Malfunctioning Fan Motor

One possible reason for a loud humming noise in an air conditioner is a malfunctioning fan motor. The fan motor powers the air circulation, and if it is not functioning correctly, it can cause a loud humming noise in your air conditioner.

The noise can usually result from the following reasons:

  • The motor may struggle to turn the fan blade, which can cause a humming noise. 
  • The motor may malfunction, causing it to vibrate and create a humming noise.
  • The motor may be overheating, which can cause noises from the fan and motor. 

How To Fix?

There are a few steps you can take to diagnose and repair a malfunctioning fan motor:

  1. Turn off the power to the air conditioner: Before you begin any repairs, it is essential to turn off the power to the air conditioner to prevent any accidents or injuries.
  2. Clean the fan blades and motor: If the fan blades are dirty or covered in debris, they may not be turning smoothly, which can cause a humming noise. Similarly, if the motor is dirty, it may not be functioning correctly, which can also cause a humming noise. To clean the fan blades and motor, turn off the power to the air conditioner and carefully remove the fan blade. Once the blade is removed, use a soft cloth to gently clean it and the motor.
  3. Replace the fan motor: If cleaning the fan blades and motor does not fix the problem, you may need to replace the fan motor. This is a more complex repair that should be performed by a professional. The technician will need to remove the old fan motor and install a new one.
  4. Check for any other issues: If the humming noise persists after cleaning the fan blades and motor or replacing the fan motor, there may be other issues with the air conditioner. This is a more complex repair that should be performed by a professional. The technician will need to remove the old fan motor and install a new one.

Read: How Does An Air Conditioner Work?

2. Loose or Broken Components Inside the Air Conditioner

Another potential cause of a humming noise in an air conditioner is loose or broken components inside the unit. These components could include screws, bolts, or other metal parts that have become loose over time. 

When components inside an air conditioner become loose or broken, they can cause a humming noise for several reasons:

  • The loose component may rub against other parts of the air conditioner, causing a humming noise. 
  • The broken component may be causing the air conditioner to work harder, which can also result in a humming noise.

How To Fix?

To fix loose or broken components in an air conditioner, you can follow these steps:

  1. Turn off the power to the air conditioner: Before you begin any repairs, it is important to turn off the power to the air conditioner to prevent any accidents or injuries.
  2. Disassemble the air conditioner: To locate the loose or broken component, carefully disassemble the air conditioner. You may need to refer to the owner’s manual or seek the assistance of a professional repair technician to do this.
  3. Locate the loose or broken component: Once you have disassembled the air conditioner, you can search for the loose or broken component. This may involve looking for screws or bolts that are loose or identifying broken or damaged parts.
  4. Secure the component or replace it: If the component is loose, you will need to tighten screws or bolts or use a repair adhesive to secure it in place. If the component is broken, you will need to replace it.
  5. Reassemble the air conditioner: Once you have secured or replaced the component, you can reassemble the air conditioner. Follow the instructions in the owner’s manual or seek the assistance of a professional repair technician if needed.

Read: How To Troubleshoot A 2-Stage Air Conditioner?

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3. A Failing Compressor

The compressor is an essential part of the air conditioner, responsible for compressing and circulating refrigerant. If the compressor is failing or not functioning correctly, it can cause a loud humming noise that can be heard from within and outside the home. 

When the compressor in an air conditioner fails, it can cause a humming noise for several reasons. 

  1. The compressor may struggle to compress the refrigerant, causing it to vibrate and create a humming noise. 
  2. The compressor may be malfunctioning, resulting in a humming noise.

How To Fix?

A failing compressor is a complex issue that a professional should assess and repair. The technician will have the knowledge and experience to diagnose the problem and determine the best action.

The compressor will be examined to identify any issues causing it to fail. This may involve checking for damaged or worn parts or testing the refrigerant levels. Based on the assessment, the technician may recommend repairing the compressor by replacing damaged or worn parts or refilling the refrigerant. If the compressor is beyond repair, the technician may recommend replacing it.

Read: Top 5 Common Problems With Two-Stage Air Conditioners You Need To Know

4. Loose or Worn Belts

The belt in an air conditioner is responsible for transferring power from the motor to the other components of the system, such as the compressor and the fan. When the belt is loose or worn, it may not be able to transmit power effectively, causing it to slip or make noise.

If you notice a loud humming noise coming from your air conditioner, it is important to diagnose the problem immediately. A loose or worn belt can cause severe damage to the system if left unrepaired.

To check if a loose or worn belt is the cause of the noise, locate the belt and inspect it for signs of wear. A belt that is too loose will sag and may have visible cracks or frays. A belt that is too tight may be stretched or distorted.

How To Fix?

If the belt is loose or worn, it will need to be replaced. This is a task that should be completed by a professional. The technician will have the proper tools and safety equipment to perform this repair safely. However, suppose you have experience with basic repairs and feel comfortable replacing the belt yourself. 

In that case, you can follow the steps below:

  1. Turn off the power to the air conditioner and shut off the gas if it is a gas furnace.
  2. Locate the belt and use a wrench to loosen the bolts that hold it in place.
  3. Carefully remove the old belt and replace it with a new one. Ensure the new belt is the correct size and type for your air conditioner.
  4. Tighten the bolts to secure the new belt in place.
  5. Turn the power and gas back on and test the air conditioner.

If the noise persists after replacing the belt, there may be another issue with the air conditioner that needs to be addressed. In this case, it is best to consult a professional HVAC technician for further diagnosis and repair.

Summary

When an air conditioner makes a loud humming noise, it can be caused by several issues, including loose or worn fan blades, a failing compressor, or a loose or worn belt. Understanding the source of the noise can help you determine the best course of action. 

To ensure a safe and efficient repair, it is recommended that you consult a professional HVAC technician who has the knowledge and experience to diagnose the issue correctly and determine the best solution. 

With the proper repairs, you can restore your air conditioner to working order and enjoy a comfortable environment indoors.