How to Quiet a Noisy Window Air Conditioner

How to Quiet a Noisy Window Air Conditioner

Window air conditioners are pretty noisy by nature.

After all, they sit halfway in and out of a window with a motorized compressor sitting right behind the vents where the cool air comes out.

  But like any machinery, window air conditioners can become noisy after time.

  New vibrations, parts clanging, new outdoor sounds can make a window AC unit much louder than it was intended to be.

But for every problem, there is a solution. Usually.

In this article we are going to attempt to help you identify the noise, and give you a solution to get rid of the sound or at least dampen it.

Let’s get rolling.

How to Quiet a Noisy Window Air Conditioner

1.  Gurgling

The gurgling sound coming from a window air conditioner is one of the most noticeable noises that a window AC unit can make.

And to be honest, it’s not one that you’re going to always be able to get rid of.

The problem arises when condensation builds up to the point that there is water standing inside of the air conditioner.

Not only will you start hearing a gurgling noise, you will also start to feel mist coming out of the vents.

  This is a drainage issue.

It is either caused by a drain hole being stopped up to the point that water does not drain,

Or an air conditioner that is unlevel so that the water does not flow towards the drainage hole.

If the drainage hole is stopped up, the easiest thing to do is to take a water hose and spray the inside of the air conditioner out and take a pencil or something similar and dig the gunk out of the drain hole.

If the stoppage is more extreme, then there is the possibility of having to take the outside of the air conditioner off and doing a thorough cleaning inside.

In the case of an uneven window air conditioner, leveling it can be done using a level and some shims.

Most window ACS call for the rear of the AC to be slightly tilted backwards so that the water runs towards the outside of the house and not the inside.

But like I said before there’s not always an answer for this problem.

  The reason is that some window air conditioners do not have drainage holes and are meant to rely on evaporation to get rid of the condensation.

But if the humidity outside is too high, sometimes it can overcome the ability of the air conditioner to evaporate the condensation.

This can result in water inside of your air conditioner making a gurgling sound.

2. Walls vibrating

This is a problem that can create an annoying buzzing sound in the walls.

  There are a couple of things to look for when you have vibration sounds around the air conditioner.

   The vibration in the walls is a direct result of the vibration of the air conditioner.

If the air conditioner is sitting directly on the window sill without a buffer between the unit and the wood, then the walls will vibrate with the vibration that is happening naturally with the air conditioner.

Putting a piece of foam window seal weather stripping between the air conditioner and the window seal, as well as the window should cut down the amount of vibration coming from the air conditioner quite significantly.

If the vibration is extra loud, it is a result of an abnormally heavy vibration coming from the window unit itself.

  In this case, it’s more than likely that something has come loose inside of the air conditioner and is shaking.

A screw has worked itself loose and you have something shaking that should be tightened down.

The solution is to take the air conditioner out of the window, remove the outer casing and look for, then tighten down the part that has vibrated loose.

Once everything is fastened down and foam insulation has been installed between the windowsill, the AC, and the window, you should notice a big difference.

3.  Outside noise

Rarely does a window air conditioner take up the whole space of a window.
That is why they provide you with the plastic, adjustable fillers to place on both sides of the air conditioner.

  Those fillers tend to work fine for a little while as far as keeping the outdoor air on the outside. But even for that they tend to weather fast and break.

   But they were never meant to keep the outdoor noise out. The plastic on those things is much too thin to be considered a noise dampener.

Replacing the window fillers that come with the air conditioner with something much thicker will keep the outside noise outside much better.

  Even some 3/4 inch plywood can block the outdoor noise way more efficiently.

   And even more sound absorbing material is an insulation product called mineral wool. Not all of your hardware stores are going to carry it, but it is the same stuff that they make sound absorbers for music studios.

It is not strong enough to work as a standalone product when you’re talking about using it as a window filler, so it will have to be glued to another product. Like the three quarter inch plywood.

The whole process is to cut the plywood to the exact measurements that you need to fill in the spaces on the side of the AC.

Cut the mineral wool to the exact same sizes as of the wood and glue it on to the wood with some spray adhesive.

  You can cover the pieces with some fabric or wallpaper so that the mineral will insulation is not exposed.

Put your new pieces into the window and fill in the gaps around them with some spray insulation.

4. Other outdoor noises

Some outdoor noises come directly through the grill of the air conditioner.

Usually the sound of the compressor inside of the air conditioner is loud enough to cover up any outdoor noises coming through the unit itself.

But there are times when this is not the case.

How do you dampen an air conditioner noise?

One solution is to build an enclosure around the air conditioner. This can be a fully( open bottom) insulated box that sits on the outside of the air conditioner.

Important: But there is one stipulation. It must sit at least a foot around the air conditioner.

  The reason a window air conditioner needs to be in the window is because of the heat that exhausts out of the rear and the side grills that let air into the air conditioner to keep the components cool.

So any encasement around an air conditioner has to allow for these two things to occur.

Putting anything directly against the outside of the air conditioner will cause the unit to not only not cool the air like it’s supposed to, it will overheat and trip the overload button.

This is why, even though there are people selling them for this reason, putting a weighted blanket on the outside of the air conditioner to reduce the outdoor noise is not a good idea.

How to stop rain noise on window AC?

Another outdoor noise that can be a little loud inside of the house when you have a window air conditioner is the sound of rain hitting the unit.

Very similar to the sound of rain hitting a metal roof.

This can be solved by putting a dampener directly on the outdoor portion of the roof of the AC.

  One ideal is to use rubber welcome mats.
You can purchase them with foam inside of them also, which would make a great sound dampener.

And they are also easy to cut with a pair of scissors.

Very simply measure the size you need and cut it out of the welcome mat.

You can send it directly on the AC. If it is too windy in the area that you have the AC, double-sided tape can be used to keep it from blowing off.

Leaves and branches

Another outdoor noise is simply the sound of please brushing up against your air conditioner.

In this case a little bit of outdoor maintenance in the form of clearing out some brush is going to be necessary.

6. Window air conditioner compressor noise

Compressor noise comes with an AC window unit.

Unlike other types of air conditioners like mini splits and HVAC which are split into two halves with the compressor completely outside, window ACS are an all in one box type solution.

In other words, there’s no getting away from the sound of the compressor running on a window AC completely.

But not all compressor noises or meant to be there. Compressors are machines that vibrate. Vibration can lead to parts breaking and parts coming undone inside of the air conditioner over time.

Why does my window AC sound like a helicopter?

If the compressor is abnormally loud, and though this is not normally true of brand new units, something in the compressor might have come loose.
Which is making an extra sound inside of the air conditioner, providing extra noise then usual.

This is a disassembling job. You’ll have to take the air conditioner out of the window, unscrew the casing and take it off and then search for what is making the noise.

If you turn it on without the outside casing , and the noise is not there anymore, then your problem lies with the casing.

Maybe something has come loose and is tapping the casing or the casing has gotten bent and is pushed up against a component inside of the air conditioner.


How to quiet a noisy window air conditioner?

Window air conditioners can create a lot of noise and they can also allow a lot of noise to get through them.

  Some of the different kinds of noises include gurgling water sounds, mechanical banging sounds, loud outside noise getting through the air conditioner, and standard compressor noises.

In the above article, we talked about making sure that the air conditioner is level and the drain hole is completely open.

We also talked about vibrations and how to handle the result of what a vibrating window air conditioner can give.

We also talked about how window air conditioners are inherently noisy because they are an all-in-one solution that has the running compressor directly inside of it, and vents little love the noise to come directly into the room that you were using the air conditioner in.

Hopefully one of these tips is what you were looking for and you are able to quieten down your window AC.

Published by

Dennis Reed

Dennis Reed Owner and Author @