If your air conditioner is making a loud noise, it may be its way of telling you something is wrong. Air conditioners can make a variety of different noises. While some of these noises are harmless and are part of normal operation, others can be quite concerning and signify a bigger issue.

If you’ve noticed loud noises coming from the indoor or outdoor unit of your air conditioner, it may be time for you to contact a professional for a tune-up or repair. The HVAC technicians at Ravinia Plumbing, Sewer, Heating & Electric are expertly trained to identify all types of AC issues and make the appropriate repair. Keep reading to learn why your central air conditioner is making a loud noise.

Common Causes of AC Noises

Here are some of the most common air conditioner noises that might occur without proper annual maintenance or repair service.


If the outdoor air conditioning unit, known as the compressor, makes a buzzing sound during normal operation, it could mean many different things. Most commonly, the loud buzzing noise is coming from a loose part vibrating against the unit, debris caught inside the unit, a loose or faulty outdoor fan motor, unbalanced or loose fan blades, vibrating or rubbing copper lines, or even a dirty condenser coil. A buzzing sound can also occur if the compressor is having difficulty starting.  During a tune-up, a technician will check all these issues and put a stop to the buzzing sound.

Rattling or Chattering

A chattering or rattling noise usually indicates a loose part that is rattling about or vibrating against another part. Oftentimes, these sounds come from an older air conditioning unit that has started to deteriorate over time, resulting in loose parts. Though you can check for loose screws on your air conditioner unit’s casing yourself, you should call a technician to perform a regular tune-up or make a repair right away. They will check every part and connection for a tight fit while looking for issues that may cause you bigger problems later.


Hearing a clanking or banging noise coming from your air conditioner could mean that a part is either loose or out of balance, but in this case, the louder sound points toward parts inside the sealed part of the unit. It could be that your compressor has come loose, that your blower fan blades are out of balance, or other problems. Clanking or banging noises may occur suddenly, or they may worsen over time due to missed maintenance and service calls. A tune-up may resolve the issue, but if the sound is severe, it may require an air conditioner repair.


Clicking sounds can occur for a few different reasons, and some are normal. For example, even a loud click is normal as the air conditioner first starts up, and if a leaf or twig falls into the outdoor compressor, the fan bouncing off the debris can make a clicking sound, as well. Though a tune-up certainly cannot prevent debris from falling into the compressor, it can help a technician catch other potential issues that could lead to bigger problems such as electrical issues, or a part stuck in the blower fan blades. It’s a smart idea to maintain your outdoor unit in between service appointments by keeping your unit clear and removing any fallen debris from the outside of the unit.

The Importance of Air Conditioner Maintenance

An air conditioner tune-up involves a thorough inspection of each part of your unit, and when it is performed properly by a trained and licensed HVAC technician, you can rest assured that they did everything possible to prevent future problems and noises. Often, these tune-ups are the best possible way to prevent noises like the ones above and extend the operating life of your air conditioner.

You should have a tune-up performed on your air conditioner once a year, preferably in the spring before you turn the unit on for the first time. When you enroll in Ravinia Plumbing’s Home Care Club, you’ll see several benefits, including priority service, discounts on repairs, and reminders for when service is due for your HVAC system.

Contact Ravinia Plumbing for AC Maintenance and Repair Service

At Ravinia Plumbing, we want to make sure your home is cool and comfortable during the hot summers in Chicago’s Northwest suburbs and Chicago’s North Shore – and we don’t want a noisy air conditioner keeping you up at night. If you hear loud noises coming from your AC unit contact us to schedule an appointment.