Air Conditioner Noises To Be Aware Of

image of homeowner covering ears due to air conditioner noises

Air conditioning units are never 100% quiet. Even new units will generate sounds as part of their normal operations. Most of the time, there is nothing to worry about. However, when your air conditioner makes noises that are out of the ordinary, it indicates a bigger problem. If so, an HVAC professional should inspect it immediately. Odd noises usually show that a component isn’t working as expected, meaning the air conditioner isn’t functioning as it should. This article explores what to do for an air conditioner making noise.

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Air Conditioner Noises To Watch Out For

Modern air conditioners offer quieter operations than older ones. HVAC technology has developed many models with noise-dampening technology and variable-speed compressors, ensuring that air conditioners emit 55 dB or less. This is the noise rate that average dishwashers produce. A problem with your air conditioner will likely produce any of these sounds:

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AC Unit Is Buzzing

image of an air conditioner condenser

Buzzing air conditioner sounds may mean that fan blades in the outdoor condenser have become loose or unbalanced. It can also indicate an electrical issue. Dirty condenser coils, a damaged fan motor, and other loose parts may also result in buzzing noises. Also, you will hear a distinct buzzing sound from your air conditioner if it has a refrigerant leak.

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Air Conditioning Screeching Sound

A screeching sound is a distinct noise a defective air conditioner generates. The most likely cause is a malfunctioning fan motor in the condenser unit. The fan is responsible for getting rid of the heat from the refrigerant. A damaged fan means that the air conditioner cannot lower the temperatures inside your home.

A defective blower fan may also cause screeching noises. This component helps eliminate heat and humidity inside your home, forcing the air to go to the return ducts where the air conditioner cools it. The blower fan then circulates the cold air indoors through the air vents. 

Faulty fan motor bearings and a bad fan belt are other possible causes for an air conditioner that is producing screeching noises. Call your trusted HVAC technician immediately if your air conditioner lets out a loud screech or squeal.

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Humming Coming From A/C System

image of an air conditoner fan in the outdoor unit

A defective contactor relay switch may result in a humming air conditioner. The unit may not switch on if this component isn’t working. The thermostat signals the contactor relay switch to start the outdoor unit. A licensed HVAC contractor should handle this electrical issue. Another cause of humming noise is fan motor problems.

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Air Conditioner Clicking

Adjusting and setting thermostat

Clicking sounds can be confusing since they sound like the noise your air conditioner makes during the start or end of a cooling cycle. However, hearing frequent or constant clicking sounds can mean a problem with the thermostat. The thermostat requires replacing if this is the case. Be sure that a licensed HVAC technician conducts this task.

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Air Conditioner Is Clanking

If your air conditioner sounds like a loose metal part is hitting another metal part, you likely need to replace the component. Loose or unstable parts can cause clanking noises. If there are loose or unstable outdoor fan blades or indoor blowers, they will come in direct contact with other components. This, in turn, produces the clanking sound. Call a licensed HVAC technician immediately if this is the issue with your cooling unit. Do not wait for the problem to worsen. Remember that metal hitting metal can only lead to further damage and costly air conditioner repairs.

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A/C Unit Whistling

image of an hvac contractor checking ac refrigerant levels

Another sign to watch out for is a high-pitched noise or whistling that sounds like the air conditioner is screaming. High pressure in the compressor or a refrigerant leak can be the root cause of this noise. Both problems are severe and should be resolved by a professional immediately. Turn off your air conditioner if this sound is heard from the unit, and call your trusted HVAC technician immediately. 

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Cooling System Is Banging

A defective compressor can result in banging noises coming from your cooling system. Older units commonly produce this sound. Age and regular wear and tear can cause the air conditioner components to unfasten or become loose. Another possible reason is that there’s a broken component in the air conditioner. These parts may be the crankshaft, connecting rod, or piston pin, all of which are inside the compressor. Banging is also produced when the indoor blower is out of balance. There is a good chance you need to replace the AC compressor if this problem is present.

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Whirring Air Conditioner 

A mechanical issue, like a defective blower fan motor, a broken fan belt, or a faulty fan, may cause your air conditioner to emit a sound like there’s a helicopter or drone inside it. Another reason your AC is producing a whirring sound is a loose fan blade. The best scenario is that the problem is due to trapped debris in the outdoor or indoor blower fan. If you know how a piece of paper sounds when it hits a fan, consider it a warning if you hear it coming from your cooling system.

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Air Conditioner Is Rattling

Loose debris in the outdoor condenser can cause your air conditioner to emit a rattling noise. Branches, leaves, or dirt may have fallen into the unit. This requires an easy fix because you only need to open the outdoor unit and remove the debris. There may be an AC electrical contractor issue if the unit is clean. Avoid the problem from escalating further by getting it fixed right away.

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Air conditioners that pass the manufacturer’s quality test and are installed properly should last 15 years or over as long as they receive regular maintenance and are used reasonably. However, air conditioners will age and may not function like they used to. If you aren’t sure what action to take, don’t assume it only has a simple problem. Call a certified HVAC technician to diagnose the issue correctly and apply the right solutions.

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