How to Stop Your AC Unit From Making All That Damn Noise

Not only are window air conditioning units crucial for keeping cool during the hot summer months (at least for those who don’t have central AC), but they can also provide the soothing white noise some people like to have in the background while working or sleeping.

Unfortunately, they aren’t always quiet. In fact, they can make quite a racket—to the point where you find yourself having to choose between dealing with the noise, or turning it off and sweating it out. The good news is that sometimes the sounds are easy to identify and fix. Here are a few examples of why that can happen, and how to get your AC unit to pipe down.

Why is my AC unit making so much noise?

Loud air conditioning window units aren’t just annoying—they’re typically caused by something that needs attention anyway. Here are some of the possibilities, and how to fix them—just be sure to unplug the AC unit before attempting any of these:

It’s dirty

Given their location in your window, it’s not surprising that AC units get dirty, dusty, and full of debris over time. Sometimes enough accumulates inside of it that it can get caught in the fan or other parts of the machine and make noise.

The solution: We’re advocates of trying the easiest solution first, so before checking other parts of your AC unit, give it a thorough cleaning. This post will walk you through the process.

It needs a new filter

Similarly, if your window AC unit’s filter is the type that’s designed to be replaced, not doing so can clog the evaporator coil and make noise.

The solution: Change your air filter, following the instructions in this previous Lifehacker post. And while you’re in there, clean out the coil fins.

It needs some lube

Like most machinery, some AC units require some lubrication to keep them running smoothly, and without it, could start getting loud.

The solution: Check the unit’s fan motor housing to see if it has oil ports. If so, remove the caps from one and insert a few drops of light (SAE-10) non-detergent oil into each port, making sure that none of the oil comes in contact with the motor’s electrical components. More information and instructions are available here.

It has a screw loose (or maybe several)

As you use your AC unit, screws and other parts may become loose over time, causing a rattling noise.

The solution: Take a close look at the unit (including taking off the cover and looking inside) and tighten any screws or other fasteners that are loose.