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Your Comfort is Our Priority!

Emergency Service



5 Sounds You Don’t Want Your AC Making

Monday, May 23rd, 2022 at 11:00 am

woman-holding-hand-to-ear-to-listenThe sound of your AC kicking on is one of the sweetest sounds in the world… unless you hear one of the noises we’re about to mention below.

There are many reasons why your AC might start making strange noises, but all of them point to the need for a technician. Having a professional take a look at your AC can get to the root of the problem quickly, without costing you more time, money, or comfort than it needs to.  

At Climate Masters, we always encourage homeowners to schedule a springtime tune-up to make sure their AC is in top shape for summer. If you have already started to run your air conditioner and notice any of these sounds, don’t hesitate to give us a call.

Let’s take a closer look at sounds you never want to hear from your AC and what they might mean.

Knocking or Banging

While the sound of your AC “kicking on” is normal, it should cease quickly. Ongoing banging usually means that your fan has a loose blade or that something has come undone inside your system. If something gets caught on your fan’s blades, it can hit other parts of the unit, creating the persistent bangs and clangs that have you scratching your head.

Any type of knocking sound usually stems from the outside unit, the condenser. Loose screws, bolts, or support springs can all cause this sound to occur. Most of them are easy fixes that a technician can quickly resolve. 

Believe it or not, a dirty air filter can also cause a knocking sound too. Built-up dirt stains your blower motor, so routine cleaning/replacements are key. 


A hissing AC may stem from a refrigerant leak. When there’s a hole in your refrigerant line, it escapes as a gas, which causes a strong hissing or blowing noise. If you have a refrigerant leak, you may even hear hissing when your air conditioner is turned off. 

Screeching or Shrieking

A loud, metallic screeching or shrieking from your AC usually means motor trouble. This can occur as your AC gets older or its motor begins to wind down. Getting it professionally assessed and repaired ASAP is critical to your total system’s health. 

Replacing old bearings on an AC motor is a common repair we perform, and it can save your air conditioner’s life! 


Grinding gears typically happen when mechanisms are loose. It can also occur when there’s too much dust or dirt built up in your system. Routine AC maintenance is important to preserving your system and preventing any build-up.

Whenever you hear a grinding noise, it’s best to shut off the air conditioner and call a professional. Running your system with persistent grinding sounds can lead to additional strain and damage. 


One of the strangest sounds you might hear come from your air conditioner is bubbling. Another sign of a refrigerant leak, bubbling sounds from an air conditioner indicate a leak at any point along the refrigerant line.

AC systems make a bubbling sound when air gets trapped in the line. Leaking refrigerant can pose health and environmental risks as well as drain your AC’s supply. This can lead to total shutdowns later, or a unit that blows nothing but hot air.

For the quickest solutions and least amount of stress, calling a professional HVAC technician is your best bet. 

Contact Climate Masters today for quality AC services in St. Augustine, FL and beyond.

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