Why Is My AC Making a Loud Noise?

There are a lot of different noises your air conditioner may be making. For each type of sound, there are different possible reasons. To determine what makes your AC so noisy, you need to listen to it carefully. Check out the list below to determine why your AC is making a loud noise.

Banging Sound

It is very rare for an AC to make a loud banging sound. But if it does, it is most likely from the compressor inside the outdoor unit. If your AC is old, it might simply be caused by wear and tear. The parts probably got loose and damaged. If this is the case, then you likely need to buy a new AC unit.

Clicking Sound

If your thermostat is running on “Fan Mode” while your outdoor unit is making a constant clicking sound, it is probably your fan. There might be an object stuck inside, or the blade might be loose. Take a look at your outdoor unit and see what your fan blade is hitting. If you can’t solve the problem, call a professional repairman.

Hissing Sound

A hissing sound usually means something is leaking. It can either be your refrigerant or a leak in your air duct. Aside from the hissing noise, you may also feel that your AC is not cooling the room. This is because the cold air is failing to make its way to your room.

Leaking generally occurs if you neglect the regular maintenance of your HVAC system. If there is a leak in your HVAC system, it is important to fix the problem as soon as possible.

Screeching Sound

Screeching sounds commonly come from friction between two worn-out metal parts. Most of the time, just a bit of lubrication will solve this problem. Unfortunately, a screeching sound can also mean that the motor has been damaged. If that is the case, lubrication will not help at all. You would need a total replacement.

Whistling Sound

A sound similar to water boiling in a kettle usually means that there is an airflow problem in your HVAC system. You need to check the compatibility of your air ducts with the machine. If the duct is undersized, the airflow pressure may create a hissing sound when coming out of your vents. A leaking duct and clogged filters can also cause a whistling noise.

Rattling Sound

A rattling sound coming from an old appliance usually happens because there are some loose parts. It can be as simple as a loose metal screw, but it can also mean that your motor is starting to wear off. Ask for a licensed HVAC technician for a proper inspection.


Ideally, your AC should not make much noise at all. Its job is to make us feel more comfortable inside the room. Loud noises contradict that goal. By noticing and identifying the type of noise,  you can determine the real culprit and solve the problem. In the future, remember to never skip your regular HVAC maintenance. You have no idea how much money you can save by taking good care of your appliances.

ECM Air Conditioning, with its headquarters located in Boynton Beach, FL, provides air conditioning services within Palm Beach County, Broward County, Martin County and St. Lucie County. If you’re having issues with your HVAC system, we’re on-call and ready to assist you with your air conditioning needs. So if you’re in need of AC service, don’t hesitate to contact us today to schedule an air conditioning service call diagnostic! Our AC service experts will diagnose any issues that may be occurring with your HVAC system and help to repair your AC issue on the spot.

Best of all, because ECM is the largest AC company in South Florida, our 69,000-square foot local warehouse facility houses over $1 million in inventory and fully stocks our 127 vehicles on the road, making us one of the very few AC service companies capable of repairing most issues right on the spot. That means no waiting and no downtime without air conditioning for you and your family in the blistering Florida heat! 

Call us at 561-295-1763 or contact our AC service team online by clicking here.

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