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Why is My AC So Loud?

Why is My AC So Loud?

It may be Fall, but for Floridians, the summer heat is just now letting up. You’ve spent the entire summer listening to the steady hum of your AC unit – the light click when it powers on, the steady whisp of air, and the cool breeze that protects your home from the humidity and heat of the outdoors. At this point, you don’t even notice your system anymore… Until one day, when your AC unit is suddenly making significantly more noise. Whether it got louder over time and you’re just now noticing, or the switch was night and day, how do you quiet a noisy AC unit? And, why is your AC so loud in the first place?

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Causes of a Loud AC Unit

While the reason your AC unit is suddenly so loud can vary, the underlying cause remains the same – something is wrong. Your AC unit shouldn’t make significant noise, but if it does, the reason could be:

  • Obstructed air ducts or vents
  • Loose bolts, screws, or fasteners
  • The compressor is going out
  • Your fan motors are wearing
  • Your thermostat is broken
  • Faulty ductwork
  • A refrigerant is leaking
  • Electrical issues
  • The unit needs to be replaced

How to Quiet a Noisy AC Unit

Not all causes can be treated at home, and the best solution for your AC unit is always to call an HVAC technician, but some solutions can be troubleshot and fixed on your own. These solutions are based on the kind of noise your AC is making. Before proceeding, first, stop and listen to your unit. Is the loud noise a banging, humming, clicking, buzzing, or squealing noise?

5 Types of AC Noises

Here are five types of AC noises, what they mean, and how to fix them.

1. Loud Banging

If your AC unit is banging around, it’s likely due to something being loose.


  • Identify where your unit is making the noise/where it’s loudest
  • Turn off the power to your unit
  • Reinforce the component using a screwdriver if the problem is easily accessible – otherwise, contact an HVAC technician to identify and fix the problem

2. Loud Humming

It’s normal for your unit to produce a quiet hum when turning off and on, but if that hum is incredibly loud, it could be an issue with a loose part or a failing motor.


  • Turn off the power to your unit
  • Reinforce loose components if you can easily identify the problem – otherwise, contact an HVAC technician
  • Identify if the hum is coming from a motor – if so, your motor is wearing down and needs to be replaced

3. Loud Clicking

Your AC unit will usually click when it turns off and on, but if your clicking problem is consistent, it could be caused by a broken thermostat, a defective control board, or a worn-down compressor.


  • Test that your thermostat is working properly – if a wire has come loose, you’ll need to shut off power and attempt to fix it yourself or call an HVAC professional
  • Call an HVAC technician to replace the worn or defective part

4. Loud Buzzing

Buzzing can be caused by something as simple as loose debris in the vents, to as complex as an electrical issue.


  • Turn off the power to your unit
  • Inspect your vents and use a vacuum to remove any visible debris – if you don’t see any debris, you should call an HVAC technician to identify the cause

5. Loud Squealing

If your unit is squealing or making hissing sounds, the cause could range from a blower wheel or fan breaking down to a refrigerant leak.


  • Turn off the power to your unit
  • Check your coils to see if they’ve frozen over
  • Check your unit to see if anything else has frozen – if you see frost forming on the condenser unit, it could be a refrigerant leak that needs to be addressed by an HVAC technician ASAP. Do not put this on the back-burner, since breathing in a refrigerant leak could lead to poisoning.
  • If nothing is frozen, parts of your AC may be breaking down – call an HVAC expert to get the parts replaced

Professional AC Maintenance and Repair by Sansone

You rely on your air conditioning system to keep you cool and comfortable for the better part of the year. That’s why it’s important to have a reliable air conditioning company you can call when you need fast service. At Sansone, we offer an extensive list of products and services designed to keep your home cool and comfortable for less.

Contact us today if your AC is making a lot of noise or if you need any other air conditioning, electrical, or plumbing services.

Broward: (954) 800-2858
Palm Beach: (561) 701-8274
St. Lucie: (772) 879-5656