Air Conditioner Noises To Be Aware Of

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

There is no such thing as a completely quiet air conditioner. Even brand new units produce some level of noise which is considered normal. In most cases, the noises that the air conditioning unit generates are due to normal operation and should largely be ignored. However, some noises may already be a sign that your A/C unit is not working as it should and needs a professional HVAC checkup right away. With an air conditioner making noise, it is usually due to a malfunctioning component or components. This is why you might notice that your air conditioner is not working as it used to.

Explore Our Air Conditioner Repair Services Call To Schedule A Free, In-Home Estimate

Air Conditioner Noises to Watch Out For

Newer air conditioners are designed to run on very low noise levels compared to older A/Cs. Due to advancements in HVAC technology, some models even have noise-dampening features along with variable speed compressors that allow A/C units to produce noise at a maximum of 55 dB. That is how much noise a regular dishwasher makes. If there is a problem with the unit, you can expect it to produce certain sounds, such as:

Buzzing Air Conditioner

An A/C unit that produces a buzzing noise likely has a problem with loose fan blades located in the outdoor condenser or has an electrical issue. A buzzing noise may be caused by other issues as well, including dirty condenser coils, a damaged fan motor, or loose components. A refrigerant leak problem can also cause the A/C unit to produce a buzzing noise.

Air Conditioner Makes Humming Noise

image of an air conditioner fan and condenser

A humming noise from the air conditioner is usually caused by a defective contactor relay switch. A damaged switch will prevent the A/C unit from turning on. To start up the condenser or outdoor unit, the contactor relay switch has to receive a signal from the thermostat. If the relay switch is malfunctioning, it will fail to start up the unit. This is typically an electrical issue and should only be fixed by a professional HVAC technician. Sometimes, a humming noise can be traced to a fan motor issue.

Call Today: (732) 741-6300

Clicking Noise When Air Conditioner Turns On

A clicking noise is not always a sign of trouble because the air conditioner also produces a clicking sound at the beginning and end of the cooling cycle. However, continuous or frequent clicking noises could be a sign that the thermostat is malfunctioning. In this case, an air conditioner replacement is the only solution that will work. Call up your licensed HVAC technician to handle this problem.

Screeching Air Conditioner Noise

image of an air conditioner condenser

A defective A/C unit will produce a distinct screeching sound. If and when this happens, the most likely cause is a problem with the fan motor in the condenser unit. The fan works to remove heat from the refrigerant or coolant. A damaged fan or fan motor will result in the failure of the air conditioner to cool a room.

A screeching noise can also be caused by a damaged blower fan motor. A blower fan helps in cooling ambient air by removing heat and humidity within an enclosed space. It does so by blowing the air towards the return ducts so it can be cooled by the air conditioner. The blower fan later pushes the cooled air through the air vents.

Screeching noises from the air conditioner may also point to a damaged fan belt or fan motor bearings. Once your A/C unit starts to screech or squeal, get in touch with your HVAC technician immediately.

Learn More About Our AC Repair Services Call To Schedule A Free Estimate

Clanking Air Conditioner

A clanking noise sounds like a metal component is loose and is banging against another component, usually metal. If this is the sound your AC system is making, a component likely needs a replacement. Loose or unbalanced parts are usually the reason why you hear a clanking noise. Fan blades on the indoor blower or outdoor fan, for example, could come loose and start hitting other components inside the air conditioning unit. This causes the clanking sound. Do not try to open your A/C unit and fix the problem yourself. A mechanical problem should be handled only by a trained HVAC technician. Once you hear a clanking sound, turn off the A/C unit immediately to prevent further damage.

Whistling Air Conditioner

image of air conditioner refrigerant

A whistling noise or one that is similar to a high-pitched scream is usually caused by high pressure in the compressor or a refrigerant leak. Both issues are serious and should only be handled by an HVAC technician. If you hear this sound, turn off the A/C immediately.

Air Conditioner Makes Banging Noise

A banging sound can usually be traced to a defective compressor. If you have an older A/C system, this should not be surprising because older systems often produce this noise. Over time, even well-maintained A/C systems will begin to break down and give in to wear-and-tear. Components might come loose or unfastened or some may become broken. In many cases, the affected components are the connecting rod, the piston pin, or the crankshaft, all of which are in the compressor. An out-of-balance indoor blower may also produce a banging noise. Once the A/C unit produces this sound, you likely will have to replace the compressor.

Call To Schedule A Free Consultation

Whirring Air Conditioning Unit

Some noises from your air conditioner are quite normal and are actually a sign that it is working normally. However, abnormal sounds similar to a drone or even a helicopter could mean a mechanical problem, including a malfunctioning blower fan motor, a faulty fan, or a damaged fan belt. Loose fan blades will produce a whirring noise. In a few cases, the sound might be due to debris trapped in the indoor blower fan or outdoor fan unit. This will sound like a strip of paper hitting a turning fan. If you hear this sound, call your HVAC contractor right away.

Air Conditioner Sounds Like It’s Rattling

A rattling noise is usually caused by loose debris or component within the condenser unit. Debris such as dirt, twigs, and leaves have found their way inside the unit. To fix this problem, simply unscrew the outdoor unit open and clean it. Removing the debris will help eliminate the noise they make when the A/C unit is turned on. However, if the unit is clean and there is no debris inside the condenser unit, there may be a problem with its electrical contractor. Have your HVAC technician look at the unit right away to avoid further damage.

Call To Make An Appointment Explore Our Case Studies



All air conditioners that make their way to the retailers and into your home underwent a quality test by the manufacturer to ensure that they are working properly. With proper installation and regular maintenance, a brand new A/C unit should give you reliable service for at least 15 years. With time and regular use, however, the air conditioner may lose its efficiency which will affect its performance. If it starts to show problems, do not take on the responsibility of trying to fix it. Some A/C noises signal a more serious problem, so it’s best to ask a trusted HVAC contractor to inspect the unit and resolve the issue/s that may be present.

Call Lawes Company For Superior Heating & Cooling Solutions

Lawes Company Logo

Lawes Company is one of the leading heating and cooling service providers in Monmouth and Ocean County, New Jersey. All our services are performed by certified HVAC technicians who can perform a range of heating and cooling services, from installations and tune-ups to repairs and replacements to ensure that your HVAC system is in good shape. We offer the most competitive services in the county and you can be assured that every job we perform is guaranteed to meet your expectations and budget. If your A/C unit is not performing as it should, give Lawes Company a call today. We offer in-home estimates at no cost to you.

Call Now: (732) 741-6300 Read Our Reviews

Contact us now at (732) 741-6300 to find out more!