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AC Noises Explained

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As Pennsylvania heats up this summer, the last thing you want to deal with is a broken air conditioner. Most AC systems today are designed to run without a sound. Some even incorporate sound-dampening technology. But when your AC needs servicing, the system can produce a symphony of less than harmonious noises. 

Don’t delay when your AC starts bringing out the band. Ignoring these abnormal noises can make minor issues become major ones. Recognizing abnormal sounds for what they are can help you better communicate your repair needs with one of our NATE-certified technicians. Consider the following nine sounds an HVAC system will make when it needs attention. 


One of the most common sounds that you may hear from a struggling AC is a buzzing sound. This sound can mean there are loose or unbalanced fan blades in your outside condenser unit. Other reasons for this sound include dirty condenser coils, a broken fan motor, a refrigerant leak, or other loose components. 


Humming noises often indicate an issue with the contactor relay switch. This component is tasked with initiating an air conditioning cycle when it receives a signal from your thermostat. This type of electrical issue can cause extensive damage to your central air conditioning unit if it isn’t corrected promptly and lead to AC replacement.

Request a service call from a licensed AC technician for AC repair in Pennsylvania as soon as possible.


An oversupply of moisture in your system can produce bubbling sounds when it is operating. Moisture buildup occurs when there is a hole, crack, or blockage in your drainpipe. Your AC technician will need to disassemble the unit to evaluate the drainage line to diagnose the issue. An issue with your refrigerant can also produce a bubbling sound. Refrigerant problems require special training to correct and should always be addressed by a professional. 


A loose or unbalanced component in your AC system’s outdoor condenser will produce a noticeable clanking sound. Causes for this sound include compressor issues or unbalanced fan blades in the indoor blower or outdoor fan. It is also possible that the noise is generated by something that fell inside the unit colliding with the fan blades.


Electrical issues are often the root cause of clicking sounds coming from your AC unit. Faulty thermostats, capacitors, or compressors will make these sounds when they are malfunctioning. If anything is obstructing the fan in the outdoor unit, you may also hear a clicking noise.


Compressors reaching the middle or end of their life span can be the source of the banging sounds you hear from your AC. Loose parts inside the compressor will collide against the compressor’s exterior framing leading to the banging sounds you hear. Compressors are not fabricated for easy disassembly.

Contact a skilled HVAC technician in Pennsylvania to render efficient AC repair


Squealing sounds indicate that there is an issue with your AC unit’s fan belt. Regular AC operation can cause your fan belt to become misaligned or worn down, requiring belt or bearing replacement. When you hear this sound, cease operating your AC system and contact a technician to prevent the belt from breaking. 


This cacophonous sound will grab your attention quickly. Your system will produce this sound if there is too much pressure in the compressor, if the fan motor needs to be replaced, or if there is a refrigerant leak. All these reasons require a professional to inspect the unit and perform AC repair.


Dirt, debris, leaves, or other loose particles inside your outdoor condenser unit can produce rattling noises when it is in operation. To resolve the issue, the condenser unit will need to be disassembled and cleaned. If the sound isn’t caused by loose debris, the rattling could be coming from a damaged electrical contractor in your systems. This problem can damage the compressor if it isn’t repaired quickly.

Annual AC Maintenance Prevents Noisy Operation

Noisy air conditioners can be a distracting nuisance in your home living environment. As your unit reaches the end of its life span, it may be time to replace it with a quiet, more energy-efficient model. Practicing dedicated air conditioning maintenance can help you avoid AC noises from occurring and keep your system running strong all summer long. 

When you need AC service, our NATE-certified technicians are just a phone call away. Our precise and professional services have been benefiting the Chester County area for 75 years. Experience five-star customer service and unparalleled operational excellence with the Mattioni Team at your side.

Contact Mattioni Plumbing, Heating & Cooling today to learn more about our upfront pricing and highly reviewed services.

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