Air Conditioner Noises To Be Aware Of

image of a homeowner covering ears due to AC unit making noise.

There isn’t an air conditioner in the world that’s completely quiet. Even a new air conditioning unit is going to produce a certain amount of sound which is perfectly normal for everyday operation. More often than not, these noises are merely part of everyday use and they aren’t cause for concern. However, in some instances, if your air conditioner making noise, this might be a sign of a larger issue and should likely be inspected by an HVAC professional right away. Some noises mean that one or more components aren’t functioning properly. As such, the air conditioner itself isn’t functioning properly either.

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What Air Conditioner Noises Should I Listen For?

Modern air conditioners tend to operate with far less noise than many older models do. Advances in HVAC technology have led to many models that have noise-dampening abilities and variable-speed compressors that keep AC noise at 55 decibels or lower. This is about the amount of noise produced by the average dishwasher. If there’s a problem with the air conditioner, it will probably emit the following noises:

Buzzing AC Unit

Buzzing noises from your air conditioner can indicate electrical problems or loose or imbalanced fan blades at the outside condenser. Other loose components can also be responsible for buzzing noises, as can dirty condenser coils or a fan motor that’s damaged or broken. If your air conditioner has an AC refrigerant leak, this can also lead to buzzing sounds.

Air Conditioner Is Humming

image of an air conditioner fan and condenser

You may have a defective contactor relay switch if your air conditioner is humming. When this component is broken the air conditioner might not turn on at all. A signal is sent from the thermostat to the contactor relay switch to start the outside condenser. This is an electrical issue and should only be addressed by a licensed HVAC company. In some instances, humming sounds could be the result of fan motor issues.

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Clicking Noises Coming From Air Conditioning System

Clicking noises can be difficult to associate with problems because they often sound a lot like the sound that the air conditioner makes at the start or end of the cooling cycle. However, if your air conditioner is making continuous clicking sounds or clicking frequently, there could be troubles at the thermostat. When this is the case, it may be time to have a new thermostat installed. This is a job that a licensed HVAC technician should handle.

Screeching Air Conditioning Unit

image of an air conditioner condenser

Screeching sounds are among the most distinctive noises that air conditioners can make when they’re malfunctioning. The fan motor in the condenser is the most likely cause. This fan is designed to draw heat from the refrigerant. When it malfunctions, the air conditioner will not be able to reduce the temperature indoors.

Screeching noises can also be the result of a damaged blower fan motor. Blower fans remove indoor humidity and heat, forcing the air back into the ducts where it is cooled by the air conditioner. Cooled air is then distributed by the blower fan back into the home via the ducts and vents.

A bad fan belt or damaged bearings in the motor fan are a common cause of screeching noises. If your AC equipment is squealing or screeching, get in touch with a trusted AC professional right away.

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Air Conditioner Is Clanking

If your air conditioner is making a noise that sounds as if a metal component has come loose and is banging against something else, it’s probably time to have a part replaced. Loose or unbalance parts cause clanking sounds. This can happen when indoor blower blades or outdoor fan blades get loose or are improperly balanced and begin hitting other parts as a result. This is what causes the clanking sound. Don’t hesitate to contact an HVAC company if this is the issue you’re dealing with. The problem can spiral out of control. Remember that metal on metal noises can only cause progressive damage and lead to more expensive air condition repairs.

A/C Unit Is Whistling

image of air conditioner refrigerant

High-pitched whistling noises coming from your air conditioner are another red flag. This often indicates excess pressure within the compressor or a refrigerant leak. Both of these issues are quite serious and should be handled by an HVAC professional as soon as possible. When your AC starts whistling, turn it off and contact a trusted HVAC company.

Cooling System Is Banging

A defective or damaged compressor is the most likely cause of banging noises. A lot of older air conditioners make banging sounds. As time goes on and progressive war is sustained, various internal components can become loose or unfastened. It may even be that an AC part is broken. Among some of the most common components to experience these issues are the crankshaft, the piston pin, and the connecting rod, all of which exist within the AC compressor. When the indoor blower isn’t properly balanced, this can also lead to banging noises. If this is a problem you’re dealing with, the compressor will need to be replaced.

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Whirring Air Conditioner

If your AC sounds like it’s got a drone trapped inside of it or even a helicopter, it likely has a faulty fan, a damaged, blower motor, a belt malfunction, or another mechanical problem. Whirring sounds occur when the fan blade is loose. At best, the problem could simply be the result of debris that’s gotten trapped in the indoor blower fan or the outside fan unit. If you think of how a sheet of paper sounds when held in front of a fan, this is an air condition sound that should serve as a red flag.

Rattling Air Conditioning System Sounds

When the outdoor condenser unit is filled with loose debris, this can result in a persistent rattling sound. Debris can include leaves, twigs, dirt, and any other elements that have fallen into the condenser. The fix for this issue is an easy one – just open the condenser and take the debris out. If it is otherwise clean, there may be issues with the electrical contractor. This should be repaired as soon as possible to ensure that more serious problems don’t occur.



An air conditioner that has passed its manufacturer’s quality test and was correctly installed can last for 15 years or longer with reasonable use and routine AC maintenance. However, time and ongoing wear and tear will catch up with this equipment eventually, and it may stop performing the way in which it once did. If you don’t know how to resolve the problem, don’t automatically assume that it’s a simple one. Call a trusted HVAC company to properly diagnose and repair the issue.

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Call Hart Home Comfort For Superior Heating & Cooling Solutions

hart-logoNassau County, Suffolk County, and Queens, New York locals can always turn to Hart Home Comfort with their HVAC questions, concerns, and repair needs. We are staffed by a highly trained team of HVAC technicians who are ready to handle all of your installations, repairs, and tune-ups. They are knowledgeable and have ample experience with all of the top HVAC products for servicing your cooling or heating system properly.

When you want the most competitive rates on heating and cooling services in the region, contact Hart Home Comfort. You will enjoy higher levels of energy efficiency and home comfort, as well as lower energy bills when you work with us. Should you need to replace your existing HVAC equipment with a new model, let our team help you find the perfect model for your budget and your home heating and cooling goals. All of our work comes backed by our solid satisfaction guarantee. To set up an appointment for HVAC service, call Hart Home Comfort right now. Our in-home estimates are available at absolutely no charge.

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