Is Your AC Running Loudly? Better Catch It And Reduce The Noise With These Simple Fixes

Owning a home can be rather overwhelming. From the initial purchase to repairs and maintenance, it is easy to see the challenges of ownership. Of course, with proper upkeep, protecting your investment is simple. Unfortunately, most homeowners do not place much effort on maintaining their heating and cooling systems. Improperly maintaining your system can lead to inefficient function and even loud noises. Although uprising to hear, a loud outdoor unit is a common complaint from neighbors. Use this list of common noises for repair and maintenance.


If you hear a loud rattling inside your outdoor unit, you are most likely dealing with a broken or loose fan in the condenser. Fortunately, this is an easy fix for most homeowners.

To get started, shut off the power to your unit. Then, locate the fan. If there is any noticeable debris, carefully remove it. Inspect each of the fan blades to determine if one or more are loose. Use a screwdriver to tighten the screws on any loose blades.

Lastly, be sure each blade is straight and not broken. If you notice warping or cracks on a blade, a replacement is necessary. One small imperfection on the fan is capable of creating a great deal of noise.

Loose parts may also be a cause of rattling inside your units. While not overly loud, loose screws, nuts, or bolts can affect the overall function of your unit. In turn, this can lead to issues affecting your motor or condenser.


When your unit is running, a soft humming noise is common. However, you may experience a loud humming when your unit is running. This louder noise may be due to one of the following issues:

  • Debris – Any amount of debris inside your unit can cause this loud humming sound. Remove any leaves, grass clippings, mulch, pine straw, trash, and dirt from inside your unit. When planting trees, shrubs, and flowerbeds, be sure to distance them to reduce the risk of debris accumulating inside your units. For the best protection, ensure there is at least 24-inches of space between your unit and any landscaping. 
  • Motor – For many homeowners, the humming stems from improper lubrication. Add a few drops of all-purpose oil to the ports on top of the motor. Lubricating the motor once a year is smart.
  • Bearings – Located inside the motor, bearings enable the fan to spin. If these bearings are dirty or blocked, your unit will require additional power to work. This excessive power creates a louder humming noise. To determine if your bearings require maintenance, manually spin the fan. If it moves freely, there are no issues. If it struggles to spin, clean and lubricate the bearings.


If you hear a periodic buzzing inside your outdoor unit, you may have an electrical problem. Although common in outdated air conditioning systems, this buzzing is a serious matter that requires a professional diagnosis and repair. Here are a few common electrical issues that may affect your heating and cooling system:

  • Connections – Your HVAC technicians will need to inspect each element of your system to determine if there are faulty electrical connections.
  • Circuit Breakers – Powering on your system may be causing your breaker to trip. This usually results in a quick buzzing noise.
  • Fan Motor – In many cases, a buzzing sound may occur each time your fan motor turns on and off.
  • Relay Switch – Controlled by your interior thermostat, this relay switch is necessary for powering on your unit. While it produces a very low-voltage, it is imperative for operation. In most cases, the noticeable buzzing sound is due to a faulty relay switch. Thankfully, replacing this switch is inexpensive.

With proper maintenance, your home's heating and cooling system will be functional and quiet. However, hearing these sounds periodically are normal. With this guide, you will know what to do to stop your outdoor system from making so much noise. Contact a maintenance company, like Christian Brothers Plumbing Repipe/Broken Water Pipe Service, for help of more information.