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Window Too Wide for Air Conditioner? (With Solutions)

When installing the air conditioner on our window, it becomes too wide or short. In most cases, the windows are too large to hold the AC properly.

We need to fill up some gaps to get the best and most secure fittings. It might be an issue to install the AC on the window.

Today, I will share my experience with you and show you how you can sort out the problem using some materials. There are some different gap fillers available for the window. You need to use them to get a secure fit with some tips.

What to do if the window is too wide for an air conditioner?

If the window is too wide for the air conditioner, you need to fill the gap by using some fillers. Some tips will help you properly install the AC on the window. If possible, you can redesign the window and give it a friendly design to hold the air conditioner perfectly.

You can follow some tips to install the air conditioner on your wide window. If the window is too wide, it will be challenging to install the air conditioner without filling the gaps and blocking the window with some wood or other materials.

Let’s see how to do that.

Gap Fillers:

When installing the window air conditioner at the wide window, it might leave some gap around the fittings.

As a result, the fittings won’t be that secure. You can use some gap fillers to solve this problem and fit the AC properly with your too wide window.

Since hundreds of gap fillers are in the market, you need to choose the right one according to your gaps and material.

If you have a wood made window and the width is too big, try to purchase some wood gap fillers. It will give you the best result.

Using Wood:

The second best way is to use wood or timber. If your window is too wide to install the air conditioner, you can reduce the width using wood. You can purchase some wood and close the extra width of your window.

Then the window will get the desired space to hold your air conditioner securely. It will be better if you cut the wood in the perfect shape. It will help fill the gap and install AC on the window.


Although it’s tiresome to resize or reinstall the window by cutting it and doing extra work, it’s worth it.

If your window is too wide to hold the AC, you can resize the window. It will cost some extra bucks, but the effort will ensure the best fittings.

If you’re building a new window, you have to give it the best size to fit the AC. You can measure the air conditioner size and then design the window accordingly. This tip is only applicable if you don’t install the window yet.

Enclose with Hardwood:

If your window is too wide and unsure what will secure the AC, you can enclose the air conditioner using hardwood.

You can use the hardwood and cover the entire air conditioner. It will give extra support and help to fit the window properly.

You can also buy the ready-made enclosure from the hardware shop. It might be expensive, but the finishing and fittings will be amazing. You can purchase the enclosure and install it within a while.

Do window air conditioners fit all windows?

Window air conditioners don’t fit all windows. They have different sizes, and the window has different widths.

Therefore, you cannot expect to fit the window air conditioner if you don’t resize the window or buy the perfect size window AC. In most cases, the windows are too big to fit the AC.

At that moment, users use different methods to seal the gap and fit their ACs. Some use wood, whereas others use gap sealers. Both are fine and give you the best result to fit your window AC. To get the best fittings, you should redesign or reinstall the window.

It will then work out and fit the window AC. You are building a new house and plan to design your windows. At that time, if you plan to install the window AC soon, you must measure the window accordingly. Don’t use too wide a window for no reason.

Because the window AC won’t fit your average or regular size window. It must be compact in size, and the average length should also be limited with the window AC length.

Window air conditioners have different sizes that are not compatible with all the windows.

What are some air conditioner gap fillers for wide windows?

We find the top 5 air conditioner gap fillers for wide windows. They are:

HQRP Foam Strip Seal:

If you want to fill the gap with foam-made sealers, then HQRP strip seal would be your good choice. It’s one of the best air conditioner gap fillers for wide windows.

It has a smooth and soft texture that will reduce the rust and corrosion between the windows and air conditioners.

Filler Kit:

You will find some filler kits that are very popular with AC users. It’s almost a regular and ready-made sealer that you can install along with the window air conditioner.

It will take up the extra space around the AC and give it the best fitting.

Foam Insulation Panel:

Another best way to cover the extra width of the window and install the window AC is a foam insulation panel.

It’s an excellent gap filler for the different wide windows. You can purchase it from Amazon and install it within a while.

Side Panels:

Sometimes air conditioner’s side panels also fill the gap between the AC and wide windows.

Although it’s not that reliable and may not fill the entire gap, it will surely give you the best support. If you have a small gap, you can use side panels.

How do I make my air conditioner fit in a wide window? How to enclose a window air conditioner?

You can make your air conditioner fit in a wide window differently. Let’s find them and get the job done.

Measure the Gap:

Your first job to fit your air conditioner in a wide window is measuring the gap.

Get the width of the window, and then measure the air conditioner. Now, you have two results. Subtract the air conditioner size from the window wide; you get the gap size.

Use Spray Foam Sealant/Other Sealers:

After getting the gap, you should decide what you want to use to cover or seal the gap.

You can either go for the spray foam sealant or choose wood or other sealers according to your budget & requirements.

If you want an instant and quick solution, spray foam sealant might be suitable. You need to spray around the gap and seal it accordingly. It will dry and give you a solid fill.

Install the Window:

After sealing or closing the gap, you can install the window AC.

In contrast, you can install the window first, then seal the gap using spray foam or other sealers. Both will be suitable to get the window air condition fittings.

After getting the fits, you must enclose the window to protect it from different weather.

Both the summer and rainy seasons can damage your air conditioner motor. Therefore, enclosing the AC is a must-do job. Let’s see how you can enclose it.

Buy/Make the Frame:

You will find different frames or ready-made enclosures from the market.

If budget is not an issue, you can place the order from an online marketplace. On the other hand, you can also make the frame using wood and plastic.

Making an enclosure might be a tiresome task. You have to collect wood, plastics, and screws. Then, make a box that can cover the outer part of your window AC.

Install the window and the Enclosure:

You can install the window when you have the box or the enclosure. After that, you can install the enclosure. When installing the enclosure, check the fittings and tighten all the screws properly.

Clean the Surroundings:

After installing the new enclosure around the window AC, you need to clean the ac and its surrounding.

When you install the AC or the enclosure, you use a drill machine that might leave some concrete particles around the AC.

You must clean the surface using hard cleaning material and vacuum it properly. Otherwise, the debris will damage the AC motor and your enclosure too.

Final Thoughts

If your window is too wide for the window air conditioner, you can use different sealers, enclosures, and wood to fill the gap. You will find other sealers to help you seal the gap between the window and the AC. It depends on your requirements and the AC size.