With large systems like air conditioners, noise is a typical thing when they keep you comfortable day-to-day. But enough humming, buzzing, and rattling would make anyone start wondering what is causing their AC to make these loud noises.
The expert HVAC experts from Charles Stone have broken down the concerning noises to look out for, the reason behind them, and what you can do to make them stop.
Common Air Conditioner Sounds You Shouldn’t Ignore (and How to Fix Them)
The following are the most common sounds an air conditioner makes when something is wrong—along with what you can do to address them:
Banging Noise
A loud banging sound isn’t normal. If you hear this noise, it is most likely the compressor of your outdoor AC unit. With enough use over time, these components loosen, resulting in detached parts hitting the compressor’s exterior frame and causing a loud banging noise.
Solution
Unfortunately, compressors are not meant to be disassembled, meaning you may need to invest in an AC replacement altogether. We recommend getting a professional inspection performed to gain a comprehensive understanding of the problem.
Screeching Noise
When your outdoor AC unit is running normally but begins to create a loud screeching noise, your compressor motor is likely malfunctioning. Additionally, the screeches can come from the blower fan motor inside your home, which collects the house’s hot air.
Solution
When the screeching won’t go away, it’s time to call for a professional air conditioning repair, as waiting long enough can result in the compressor or fan motor completely giving out. Without these key components, your unit won’t be able to operate at all.
Buzzing Noise
If you hear buzzing from your AC, it’s a clear sign that an electrical issue is occurring. This sound is often the result of your electrical wires becoming frayed or loosened over time, or it may indicate that components, such as capacitors, are damaged.
Solution
Electricity is never something you should try handling by yourself. Call a professional HVAC technician to provide a comprehensive inspection to diagnose the issue and provide the proper repair.
Humming Noise
Loud hums from your AC indicate that the contactor relay switch is malfunctioning. This is the key piece that kickstarts your outdoor condenser unit when signaled by your indoor thermostat.
Solution
As soon as you hear this noise, turn off your system, as these issues can begin wreaking havoc on your unit if left unchecked. Leave the system off until it has been thoroughly reviewed and repaired by a professional HVC technician.
Hissing Noise
If your system is making hissing noises, it likely has a refrigerant leak somewhere. Refrigerant is the chemical that absorbs the heat of your home and releases it outside through your outdoor unit.
Solution
Refrigerant is toxic and odorless, so it’s always best to get the assistance of a trained professional when dealing with a leak. An HVAC technician will help locate the leak, provide the necessary repair, and also refill the refrigerant.
Clicking Noise
It’s normal to hear a few clicks during the beginning and end of the AC cooling cycle, but when the sound persists, it’s bad news. The constant clicking indicates that your thermostat is malfunctioning.
Solution
As simple as thermostats look, removing or replacing them with a brand-new one is best handled by a certified professional to accurately address and resolve the problem.
Rattling Noise
A rattling AC can be linked to a few things. The first, simple debris, such as sticks and leaves, has gotten caught in the outdoor unit. The other is that the system’s electrical contractors have been severely damaged.
Solution
Dealing with debris is simple enough, as you can simply disassemble the condenser unit to remove the objects. But for a damaged contractor, you will want to have a professional inspect the system and provide the needed repair before it’s any more damaged.
Bubbling Noise
When you think of bubbles, your mind probably goes to water. And that right there is the problem, as this bubbling sound is coming from a system containing too much moisture. This excess moisture can derive from a crack or clog in the drainage line.
Solution
With the right tools and knowledge, you can disassemble your AC unit to inspect the drainage line. However, if you don’t, it’s best to call a certified HVAC technician, as they have the expertise to disassemble the unit and correctly identify the issue.
Grinding Noise
When you hear a distinct grinding sound, it’s your red flag that something is wrong with the compressor or a motor, often caused by worn-down pistons when the system is turned on.
Solution
If it’s just the motor giving you problems, try oiling the unit regularly and see if the grinding stops. If your compressor is the problem, a replacement is the ideal solution rather than attempting to repair the individual components.
Prevent a Noisy HVAC System with Regular Maintenance
Most of these issues can be avoided altogether by simply performing routine air conditioning maintenance. Typically, you want to have your system checked by a professional at least once a year. This allows them to identify underlying issues, such as loose components.
With routine checks, these minor issues are found quickly and resolved before they can snowball into costly repairs or a potential breakdown when you need your AC the most.
Join Our $179 HVAC Maintenance Membership Program
Keeping your AC running at peak performance is simple when you become a member of Charles Stone’s HVAC Maintenance Membership Program.
For just $179 a month, HVAC owners are provided with two yearly maintenance checks, one in the spring for your AC and one in the winter for your heater. As a cherry on top, members receive a 10% discount on all parts and labor and a 50% discount on any emergency repair fees.
If you are a commercial HVAC owner, don’t worry, as we have benefits just for you. Our commercial members receive a completely customizable HVAC schedule, ensuring you receive maintenance checks exactly when needed, as well as various discounts on parts, labor, and emergency fees.
Professional Air Conditioning Repair, Replacement, & Maintenance
Keep your HVAC systems running smoothly and your summer season comfortable with the reliable air conditioning experts from Charles Stone.
Our HVAC technicians offer a comprehensive range of services, including timely repairs, routine maintenance, replacements, and air filter replacements. Regardless of the condition of your system, our team offers timely and cost-effective solutions to keep you and your home cool this summer.
If your air conditioner is making strange, loud noises, there is no time to wait. Call Charles Stone today or schedule your inspection online.
FAQs
What does a blown AC compressor sound like?
A blown AC compressor will produce a rattling, banging, or humming sound when components have loosened or broken. It is also worth checking for clogged air filters, as they can lead to rattling as well.
Additionally, a hissing sound is also produced when the unit’s internal pressure is too high, or a buzzing noise when there is a loose or weak electrical connection.
Should I turn off my AC if it’s making noise?
If you have heard any of the previous sounds, we advise shutting off your system right away. Often, these loud noises are indicative of an internal malfunction, and continuing to run your system can result in far more severe damage.
