10 Reasons Your Air Conditioner is Making Strange Noises

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Why Is My Air Conditioner Making that Noise?

The ideal sound for your air conditioner to make is no sound at all. Unfortunately, what starts as a low hum can sometimes develop into clicks, clanking, screeching, and squealing. 

Not only is it loud and annoying, in some cases, noise from your air conditioner can signal a problem that requires a repair (or possibly even a replacement). However, many times, a thorough cleaning of your air conditioner or air ducts (or a few minutes of maintenance) can solve the problem quickly. 

A few common issues that could be diagnosed by sound alone include: 

  • Loose parts or screws
  • A lack of lubrication
  • Debris and dust buildup in the unit
  • Debris and dust buildup in your air ducts and vents

It’s hard to know whether you should be worried or not when a new noise starts coming from your vents or AC unit. Here are some of the top reasons your air conditioner is making a strange noise and what steps to take next: 


It’s never good to hear screaming from anywhere, but it can be particularly alarming when it’s coming from your air conditioning unit. A screaming sound from your unit typically indicates there’s an issue with the air compressor. It’s an indication of high pressure, which could be dangerous. Be sure to call your HVAC professional to have it repaired before turning it back on. 

Clanging or Knocking 

Clanging from your AC unit typically means something is loose or there’s an obstruction that’s getting in the way of the fan. Like above, be sure to contact an air conditioning expert to have your unit inspected and fixed. 


A sharp screeching sound could indicate that you have to replace your fan motor. The bearings may be shot, so get in touch with an HVAC professional (or call us to ask for a recommendation of specialists we work alongside). 

Noises in the Ductwork 

Although some noises will come directly from your air conditioner, others can be heard in the ductwork throughout your house. Most people become accustomed to these noises because they start appearing slowly, but they shouldn’t be ignored. In most cases, small clinks and clanks (especially regular ones) are telling you that there’s buildup in your ducts. A thorough duct cleaning will help keep your airflow quiet. 

Humming, Buzzing, or Clicking 

Clicking can happen when you turn your unit on and off, but excessive or ongoing clicking could be a sign of electrical issues in your system. The same goes for humming or buzzing, which aren’t necessarily indicative of an issue, but could signal a problem if they’re ongoing or increasing in volume.

Hissing and Bubbling 

Any type of hissing or bubbling tends to be the result of a leak in your refrigerant line. It’s not a critical repair, but it is important to get this fixed as soon as you can so you don’t end up with a larger issue down the road. 

Still Not Sure What That Noise Means? 

Diagnosing issues in your air conditioner, furnace, or ducts can be difficult to do on your own, but it’s critical to do it quickly, or it could lead to future problems that could be expensive or inconvenient. 

 A trained professional can help sort out what’s going on. Clean Air Solutions has over 30 years of experience helping homeowners determine what’s going on in their ducts and beyond. If you aren’t sure what type of professional help you need, reach out and tell us what you’re hearing.