Why is My Air Conditioner Making Noises?

Central Air Conditioner in Alpharetta, Georgia

Some people hear noises and immediately try to find their source. Other people hear noises and just try to ignore them, hoping they will eventually go away. When it comes to your air conditioner, more than likely, those unusual noises aren’t just going to go away. They are far more likely to get worse and worse until something costly happens.

Learning to identify the sound will help you not only figure out what is going on but reduce your stress. After all, if you understand the problem, you can begin to figure out the solution and keep your system running well.

To help you out, here are some of the most common noises you may hear coming from your air conditioning unit. If you hear any of these, call for a repair technician to help you keep your system cooling properly.


While you may expect some screaming to come from a horror movie or a toddler, it should alarm you if it’s coming from your AC. Whether the screaming sound is coming from inside or outside your home, it likely means a refrigerant leak. Some people report hearing more of a hissing sound, depending on the severity and location of the leak.

If you continue trying to run your system with a leak, you are likely to damage the compressor. A damaged compressor is expensive to repair and is preventable in many cases. Turn your system off right away and call for a repair technician.

If the leak is inside your home, this can be hazardous to all occupants. Consider opening a window or two to allow the refrigerant to escape your home.


A rattling is a common sign that something is caught in your system and is being tossed around. It could be some simple debris that made its way into your system. It could also signify something has come loose or broken inside your system. Regardless, if it is not taken care of quickly, it can cause extensive damage to your system.

Rattling can also be a sign that your system is aging, and some components are coming loose. A repair technician will check the common items that come loose during a maintenance visit and tighten them back down.


Your system may normally make a few clicking sounds as it cycles on and off. However, they should hear the click, and then the system will move on. If any part of your system continues to click or make a chattering sound, you may have a problem.

If the chattering sound comes from your condensing unit outside, you may have a problem with your contractor. This is the switch responsible for turning your compressor on and off at the appropriate time. If this malfunctions, it can cause your compressor to cycle rapidly and burn it out.


If you hear something banging around, it likely means something has broken. From outside your house, the likely culprit is the air conditioning compressor. From inside your house, it could be as simple as your blower motor being off balance.

If the banging seems to be coming from inside your house, it could be your ductwork. As it cools with air passing through it, it may cause a banging sound.


Humming usually means there is an electrical component working. A faint humming may actually be normal, depending on your particular system. However, if the humming is loud, you probably have a major problem.

This is especially true if the humming is coming from your outdoor condensing unit, and you can hear it inside. This usually means your capacitor is malfunctioning, preventing the compressor from starting properly. A capacitor is a relatively easy fix but should be done by a professional to avoid severe electric shock.


Buzzing can mean any number of things, from debris caught in the system to a failing component. Sometimes, a piece of paper or some other debris will get caught in a fan, causing a buzzing sound.

However, it could also mean an out-of-balance fan, loose parts, or even a motor that is about to fail. If you hear a buzzing sound, call in a repair technician to find it and fix it before it becomes a major headache.


You have likely heard the squeal of a loose fan belt in your car. Your air conditioner can make a similar sound, and you should pay heed when it does.

Most modern air conditioners do not rely on belts to run the system. So when it sounds like a belt going bad, you know it is something else entirely.

Likely, this sound is coming from either the blower motor or condensing fan motor going bad. Both of these motors are relatively easy and inexpensive to replace. However, letting them completely fail will reduce your system’s efficiency and possibly damage your compressor.


Does your system sometimes sound like a helicopter getting ready to take off? This sound is potentially caused by several problems. There may be some debris caught in one of the fan blades, which is a simple fix once you turn off your system. However, it could also indicate failing parts.

When the fan blades in the condensing unit start coming loose, they may make a whirring sound. It could also indicate a bearing wearing out in the blower fan motor or a faulty fan motor either inside or out.


If your air conditioner makes a constant whistling or whining sound, you have a problem. This may actually be caused by an airflow restriction.

Start by replacing your air filters, something you should plan to do every three to six months anyway. If that does not fix it, consider having your ducts cleaned or schedule a maintenance visit to clean your evaporator coil.


As your system runs, it will cause the moisture in the air to condense on the evaporator coils. As that warms up during the off-cycle, it will melt and get caught in the drip pan.

The drip pan has a condensate drain on it, which allows all of this water to drain away from your unit. As it does, it may cause a bubbling sound. Sometimes these condensate drains get clogged, so be sure you keep an eye on it.

This gurgling sound may also be caused by a refrigerant leak. If you hear this kind of sound, try to identify the source. If it does not appear to be coming from the condensate line, shut down your system and call a repair technician to pick it up from here.

When your air conditioning system makes an unusual noise, it is giving you a sign it needs some attention. If you catch the problem early, some problems can be resolved with simple system maintenance. If you let the problems persist, you almost certainly increase your repair bills, sometimes catastrophically.

People around Alpharetta have trusted [company_name] for air conditioning repair for over 45 years. Our expert technicians provide AC and heating installation, repair, and service, along with hot water heater and indoor air quality services. Call to schedule your air conditioning repair today. We look forward to serving all of your home climate comfort needs.