Window AC Unit Making Noise? How to Get It to Cool Down

An air conditioner can be a lifesaver. It can also be a rattling, clicking, buzzing, headache-inducing nuisance. If you crave the cold but not the noise, read on to see how you can reduce the sounds coming from your window air conditioner unit.

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My Window Unit Is Buzzing, Rattling, Clicking or Crackling. Is That Bad?

Not all noises indicate a problem. Soft hums, thumps and clicks are normal sounds for a functioning window unit to make. It’s when these noises get louder, or a new one appears that you need to investigate the source.

Reasons Why Your Window AC Unit Is Making So Much Noise

Before we can restore your home to silence, we need to figure out why your window unit is rattling in the first place. Let’s look at some typical causes of window unit clicking and see if we can solve them. Often, these fixes won’t even require professional maintenance.

Find the Rattle

Rattling noises are sometimes the most common and easiest to fix. First, check to make sure the front panel or cover isn’t loose. Tighten any loose screws around the panel. Also, look at the space between the window unit and the window itself. Are there gaps? The noise could be because of these gaps and often, getting some foam insulation and filling the gaps can solve the problem. This will also help your window unit run more efficiently, as less cold air will escape.

Check also to make sure the unit is secure in the window frame. Use mounting brackets or other apparatuses to keep the unit upright if it seems tilted or wobbly. Use a level to make sure it’s aligned.

If your window unit is still rattling and you feel comfortable doing it, check and clean the condenser coils and change your indoor air filter. Check that the unit is turned off and there’s no power running to it before this step. You should regularly change or clean the air filter based on the manufacturer’s recommendations.

Check the Fan

Temporary clicking noises are normal, especially when you turn on or off your AC window unit. It’s time for some concern when the clicking noise continues for most of the time the unit is running.

The first thing to do is check the fans. There could be some sort of obstruction. Be sure the unit is off. Remove the front grill and take a damp cloth and wipe the fans clean. There may be a larger issue if this doesn’t stop the clicks. Things that could cause your AC unit to click include broken blades, a damaged thermostat, faulty electrics, or a loose fan. These should all be taken care of by an HVAC professional.

Electrical Issue

It's typical for many window AC units to make a low, soft humming noise. If your humming noise has risen above your comfort level, it could be a sign of an electrical problem. If your compressor hums or refuses to start, this problem is probably electrical, perhaps loose wires or a defective motor and once again, should be examined by an electrician or HVAC pro.

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Maybe it’s Mechanical

It could be mechanical if it’s a hissing or whirring noise coming from the window unit. A problem with the fan, blower fan motor, or even a bad belt will create this whizzy sound. An HVAC technician can help you troubleshoot.

Compressor Problem

If the noise coming from your window unit is a loud bang or clang, there may be a loose piece or broken part in the compressor. Out-of-balance fan blades can also cause clanging noises when they hit other parts of your unit. Both of these reasons necessitate a call to a professional. Sometimes the compressor can be fixed with a replacement part; sometimes, the entire compressor will need to be replaced.

Refrigerant Leak

If you have a refrigerant leak, your window unit may make a loud screaming or whistling sound. A refrigerant leak can be dangerous, so if you hear this noise, turn off the machine and call a professional.

Alternatively, if your window unit is running but not producing cold air, this may also indicate a refrigerant leak. Another potential cause of a whistling noise is internal pressure in the compressor. This is another serious issue that requires professional assistance.

Window AC Unit Making Weird Noises? It Might Be Time For a New One

A considerable, loud, unusual noise that won’t go away could mean your AC unit is on its way out. If it is an older machine, these noises could indicate it’s starting to break down and parts of it may be deteriorating.

The sooner you identify and fix the cause of your window air conditioning unit noise, the better. Letting the noises continue may mean a minor issue becomes something requiring a significant fix. Regular, professional window unit maintenance will also ensure your home is not only peacefully quiet, but also kept at the desired temperature.