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What Do Those AC Noises Mean?

Is your air conditioner making unusual sounds? If so, something may be wrong inside of the unit. Different sounds can point to different problems and it is important for you to be able to discern when a problem may be serious.

You can keep reading to learn more about five unusual AC noises and what each one might mean. Then give our team a call to schedule your air conditioning repair in Satellite Beach, FL. It’s important to stay ahead of problems so that they don’t lead to a complete AC breakdown.


A grinding noise inside of your air conditioner usually indicates that two metal parts lack the lubrication that usually allows them to work together smoothly. When you hear grinding, there may even be grime buildup in between the parts that is making it even harder for them to operate the way they should for cooling. 

The solution to this problem is cleaning the components and re-lubricating them. Keep in mind that you want to call sooner rather than later for service, because putting it off can lead to permanent damage.

Hissing or Bubbling

When you hear a hissing or bubbling sound, there is usually a leak in the refrigerant line. Refrigerant can be in both a gas form and a liquid form, depending on where it is in the refrigerant lines. A hissing sound means that refrigerant is leaking out as the gas. 

Bubbling means that refrigerant is leaking out as a liquid. Both are equally dangerous for your home and family. Plus, they had a lot of strain on your air conditioner because it reduces cooling ability. Our team can identify the source of the leak, repair it, and recharge the refrigerant so levels are adequate for cooling again.

Knocking or Tapping

Tapping sounds are usually a little bit gentler and quieter. Knocking may be louder and more obvious. No matter what type of tapping or knocking sound you hear, a component is probably loose somewhere inside your unit. A quieter sound can indicate a smaller component is loose. 

A louder sound can indicate that a larger component is loose. When you hear either of the sounds or suspect that something inside of your air conditioner has broken free from its usual position, turn off your unit to protect it from additional damage and then call for service.


A rattling sound usually indicates loose ductwork. While this is not your air conditioner itself, it is still very important. Rattling ductwork can mean that individual pieces are loose, which may result in a lack of airflow to your home. 

It is important to know that rattling is normal to hear for a few seconds when your AC first starts up because of temperature changes. But if rattling goes on for too long, it’s definitely a problem. Your ductwork may need to be resealed or resecured.

Making families happy on the Space Coast since 1975. Schedule an appointment with Complete Air & Heat, Inc.

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