10 Simple fixes to quiet a noisy window air conditioner

Written by Jason Hutchinson
6 Min read

Why is my AC so loud?

Window air conditioners can be manna from heaven, especially if you live in a warm climate or have to deal with hot summers.

But that cool air dream can turn into a nightmare pretty quickly if your AC starts rattling or just generally making an annoying noise.

So, how do you dampen the din from a loud window air conditioner?

In this blog, we’ll take a look at some of the most common ways to stifle the racket from your appliance. From the conventional fixes to some more off-the-wall ones.  

Before we get into the solutions for your noisy air con, we thought we’d go through some common reasons why it’s disturbing the peace in the first place.

Unfortunately, if you don’t know the first thing about a window air conditioner, then there can be a number of reasons why yours is being so unruly.

However, the normal reasons are age, installation, cleanliness, and set-up. If your machine is too old, in the wrong place, or generally unkempt, then noise is a common side effect. So, how can you turn down the volume on your window air conditioner?

1. Insulate the sides

A common quirk of window air conditioner units is that they never fit your space perfectly. Most frequently, that noise you’re hearing will be coming as a result of the rattle between the unit and the window frame.

To battle this complaint, manufacturers now supply units with sliders to help negate the issue. However, they rarely do the job.

Instead, you could use foam insulation or buy air con weatherstripping online for a more robust solution.

Window air conditioner unit

2. Level the unit

Another common reason that your window air conditioner is rattling could be that it either wasn’t installed level or has been knocked off its level by something.

Small lumps and bumps in your window frame may cause your machine to operate off the level. When this happens the inner workings of your HVAC may start to vibrate or knock against another surface, as they’re designed to operate flat.

Grab a spirit level and just ensure your unit is nice and level before you discount it altogether.

How To Insulate A Window Air Conditioner

3. Reposition it

Following on from that talk of leveling off, you may need to reposition your unit. If you can see that parts of your window air conditioner are knocking, banging, or vibrating against something else, then you’ll want to adjust it. After all, that misplacement could be bad for your air con and whatever it’s hitting against.

4. Hang up a blanket

A slightly unconventional method of silencing your window air conditioner is hanging a blanket roughly 6 feet away. This solution is probably only useful if your unit is trying to cool a larger space, so if you live in an apartment or flat, then this won’t be pertinent to you.

Hang the blanket and sit across the other side of the room or building from it. The blanket should dampen the noise and it will also help the air circulate better around the room. Sometimes the simplest fixes are the best!

5. Fill the gaps

Continuing on that theme of simple solutions. If you get up close to your machine, can you see a gap where the issue may be emanating from? Sometimes there may be a space between the cage and window that is causing the rattle.

If so, an easy fix is to cut up a piece of insulation and jam it into the hole. This will provide a cushion between the two hard surfaces and prevent the knocking as the internal fan whirs. It’s the same principle as when you place a piece of folded paper or card under a rocking table or chair.

6. Tighten the cover

That noise you’re hearing may not be a structural or internal issue with your window air conditioner. In fact, it may just be something as simple as a loose cover or front panel.

But there’s only one way to find out. Grab your screwdriver and set it to work tightening the screws around the panel.

7. Check the fan blades

Getting slightly more technical now, if all of the above solutions haven’t gotten to the bottom of your noisy air con problem, then it’s time to look inside the unit. However, make sure the power is off before you head inside.

Once the power is off you can remove the cover and take a look at the fan blades. If this is where the noisy issues lie then it may be because you have a broken or crooked blade. On the other hand, if all seems to be in working order you may have some dirt or dust on the rotors.

Give the fan blades a clean with a dry cloth to knock off any lint or foreign objects which may be catching on the other internal parts. Return the power and see if that got the job done.

TROUBLESHOOTING Wall & WIndow A/C Units(Step By Step)

8. Inspect the motor

If your fan blades are clean but you still have the rattle then you may want to turn your attention to the motor.

If you have a particularly old window air conditioner or you’ve had to reinstall it from being in storage, then you may find that the bearings in the motor have come loose. You can easily replace the bearings with new components.

On the other hand, especially if your machine has been off for a while or in storage, you may find that the motor lubricant needs replacing. You can do this by removing the caps and adding a few drops into there and on the motor shaft.

9. Try the coils and coil fins

Just like when your refrigerator won’t cool, the condenser coils in your machine may need a good clean. These components are what allow your window air conditioner to complete those all-important temperature changes.

However, if they haven’t been cleaned for a while or have become covered in dust particles then their performance can be hindered. In your window air conditioner, the coils expel warm air out of the room allowing it to be replaced by cooler conditioned air.

Window AC Coil Cleaning and Charge

10. Get an upgrade

Now, at Appliances Made Simple, we always try to fix a problem before thinking about just throwing a machine away and getting a new one.

However, if you’ve had your machine a long time, before you start interfering with the internal workings of your air-con, you may think is it worth just cutting my losses?

A window air conditioner has a lifespan of around 10 years. So, if you have an old machine you may be better served just getting a new one.

But, when you get that new appliance, it pays to stay up to date with the maintenance to ensure you don’t find yourself back here again.

Preventing your window air conditioner from making a noise

As we said at the start, when your window air conditioner starts making a noise it can be one of the most annoying things to have to live with.

However, if you want to avoid this nagging problem then the solution is simple. You need to look after your machine. Whether you’ve taken our advice above and bought a new unit or you’re sticking by old faithful, up-keep is key.

But it’s not difficult. All you need to do is give your unit a spring clean a couple of times a year to ensure nothing untoward happens.

Clean your machine

Inside your unit, you’ll see some of the key components we’ve outlined above. If these areas are allowed to get thick with dust, then they won’t work properly.

The filter, coils, fins, fan, and motor can all get choked by debris. So, when you’re bringing it out to help soothe the summer heat or packing it up for the winter, why not remove the cover and give these components a good once-over?

Unclog your filter and dust off the fan blades and coil. Plus, you might also want to straighten any misplaced fins. You can do this by gently running a comb along them.

DEEP CLEANING a window air conditioner unit (step-by-step details)

Store with care

While we’re on the subject of packing it away for the winter, you should probably take some care about how you store your window AC.

Rather than just dumping it in a cold storage room or facility. Put it in a decent box and store it over those cooler months in a dry spot.

It will thank you when summer comes around again and it hums back into life without any issues.

Generally speaking, a noisy window AC unit is an unhappy unit. But there are a number of solutions you can try to help quell the cacophonous crackle.

From insulation stuffing through to motor and fan surgery, there are answers to your problem. However, the simplest and most common solution to this issue is machine maintenance.

If you look after your window air conditioner, it will look after you.

Appliances made simple. 

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