4 Tricks for an Air Conditioner Not Fitting in a Window

A person checking the internal components of an Air Conditioner

Are you having a hard time fitting your Air Conditioner on your favorite window?

Welcome to the club! DIY installations are fun and can save you a lot of money, but sadly, they’re not without shortcomings.

One of the most problems that can arise during this process is measuring the space you need to install an appliance incorrectly. Something like this can leave you with a fridge that won’t fit into the space you designated for it, or an AC unit that’s too bulky for your window frame.

I know that having this happen is no fun, especially during sweltering days. But don’t worry, you need answers, and that’s exactly what you’ll get. Below, you’ll find a list including 4 alternatives you can try to bypass this issue for good.

When your Air Conditioner is not fitting in your window, you can try using a support bracket or building a custom frame for the unit. If that doesn’t sound too appealing, you can also put the appliance through the wall or opt for a ductless alternative.

Read on to enjoy the breeze!

#1 Use a Support Bracket

Let’s start off by addressing the obvious. If your Air Conditioner is not fitting your window, nothing short of breaking the window frame or damaging the appliance will work, so we’ll have to look for alternatives.

The first thing I’d suggest is to return the appliance if you still can and get another that does fit into your window. There are many ways to determine which product will work for you.

Now, I know this isn’t always possible, so my next recommendation would be to keep the AC you already have and place it on a support bracket outside the window frame. Granted, this will require you to install the bracket and place additional insulation around the window frame to ensure proper contact between it and the Air Conditioner.

But if you’re in this situation, this is worth trying.

A window AC's support brackets
Brackets can be the difference between enjoying your window AC and letting it go to waste

By placing a support bracket, you can keep your window AC and have it work just as well as it would have if it had fit the window. Moreover, installing an alternative like this is usually not too expensive.

Solution: Installing a window support bracket for your Air Conditioner is very simple. In fact, there are already several manufacturers out there that sell preassembled brackets or simple designs that can be built in minutes.

Just make sure you know your unit’s weight and size before going online, as this will help you find the right product.

#2 Build a Custom Frame

Assuming you don’t want to use a support bracket and prefer to make your own solution, then I’d recommend building a custom frame. This will take more time and effort, but it will also ensure that you don’t go wrong when choosing the right size for your appliance’s support.

Now, I know this isn’t for everyone. If you don’t have the right tools or expertise to build your own custom frame, you’ll have to turn to a professional, which can sometimes be expensive.

A wooden board being drilled
Unless you’ve got some serious carpentry or metalworking skills, you might have to call someone to build your frame

In scenarios like that, it’s a good idea to weigh the cost of a premade support bracket bought at a hardware store against the cost of hiring someone to build you a custom solution. Sometimes, even if you don’t love the alternative, going for a bracket can save you a lot of money, which you can then reinvest in something else.

Solution: If you do decide to build your own frame, I’ll go ahead and assume that you’re well-versed in DIYs, so there’s not much information you need from me in this regard. Just remember, measure twice, cut once. And don’t forget to ensure there’s enough breathing space for the Air Conditioner to work efficiently!

#3 Put the AC Through the Wall

Another trick that I like when an Air Conditioner is not fitting on a window frame, is ignoring the window altogether.

I know that sounds strange, so let me elaborate.

Depending on how hell-bent you are on keeping your window unit and placing it in the room you’re having trouble with, you might be more or less inclined to try an extreme alternative. If trying a different area to place your appliance is out of the question, then putting the AC through the wall might be a viable solution.

This will, of course, mean that you’ll have to make a big hole in the wall to fit the appliance, which might be a good option if you’re a homeowner, but not so much if you’re renting.

A technician checking the exterior side of a through-the-wall Air Conditioner
If you’re in a position to be able to put a big hole in your wall, try making some space for your window Air Conditioner

This solution is by far the most extreme one I’ll recommend on this piece, so don’t worry. I promise the next step won’t involve getting a wrecking ball!

Solution: Should you choose to go this way, you’ll need to take into account the thickness of your wall, as well as the materials it’s made out of. If your wall is too thick, there will not be any breathing room for the AC, which can not only cause it to work harder than it should and trip your breakers, but also drive up your utility bills.

Ideally, you want about 60-70% of the appliance to be “hanging” outside your wall.

Assuming that the conditions are right, please follow these easy steps to turn your window AC into a through-the-wall unit:

  1. Measure the appliance carefully to determine the size of the hole you’ll need to make in the wall.
  2. Find the spot where you want the AC to go, and make sure there aren’t any pipes, wires, or metal studs behind the wall. If there are, you’ll have to find a different location.
  3. Once you’ve made sure the coast is clear, mark the silhouette of the Air Conditioner on the wall and chip away. If you don’t have the right tools or feel unsafe attempting this part on your own, hiring a professional might be a good idea.
  4. Place the Air Conditioner in the hole in the wall and connect any cables needed for proper functioning.
  5. Once everything’s set up, you’ll need to install a cage support on the exterior end of the appliance that protects it, holds it in place, and allows for adequate breathing.
  6. Make sure to insulate the edges of the hole in the wall both inside and outside your home, as this will increase the efficiency of the AC unit.

#4 Go Ductless

Lastly, let’s consider a different option.

As I mentioned earlier, if your Air Conditioner is not fitting on your window, and you’re still in a position to return it, I’d go ahead and do that. After all, there’s no need to struggle if you have an alternative, right?

Assuming you can replace your appliance and don’t mind paying extra for labor and installation costs, you might want to look into a ductless AC unit. These, of course, are a lot more complex to install but could solve the problem you’re currently having trouble with.


That about covers it.

When your Air Conditioner is not fitting into one of your windows, you can start feeling frustrated and worried that you might have wasted your money on the wrong appliance.

Luckily, I hope this piece has helped you see that, in most cases, there are many workarounds to solve the problem and get cool or heated rooms successfully. More often than not, simple actions, like installing an external support bracket, or placing the AC unit through the wall, should do the trick.

Thank you very much for sticking with me all the way to the end. If this article piqued your interest and answered your questions, you’ll be happy to know that there’s much more content to keep learning from below.

On the site, you’ll find all sorts of solutions for daily appliance issues, such as a swamp cooler that’s smelling bad, or a patio heater with no gas flow.

Have a great week!

— Craig.

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more