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How To Insulate Around a Window Air Conditioner

Old Styled Air Conditioner On The Wall

We are guilty of applying scotch tape and small clothes to the cracks around the window AC.

These tiny cracks let the cold chilly air penetrate even the warmest blankets. It’s a mutual issue for people with window ACs in their homes.

Cliche methods like using plastic and paper around the area are undesirable as they interfere with the room’s overall aesthetics and are not a permanent solution to the problem.


Insulating the window AC units can be the most energy-efficient yet most difficult thing you can do after their installation.

Here are some quick fixes to insulate your AC unit for the best performance and elegant aesthetics:

  • Try Using Caulk
  • Fill the Cracks With Spray Foams
  • Foam Insulation Panels won’t Disappoint
  • Custom Designed Fabric Cover

In this blog, I have covered the best methods I have come across regarding insulation in terms of ease, better room aesthetics, and longevity of results.

4 Ways To Insulate Around a Window AC

You might think that surviving without insulation can be an option, but this option works only until you don’t have a window AC.

No one can know the value of insulation around such AC than the person who sleeps next to the window. The chilly air blows will seep into your blanket and won’t let you sleep peacefully.

Moreover, leakage of conditioned air through these cracks also greatly affects your energy bills.

Therefore, you can adopt the following methods to enjoy a peaceful sleep and affordable energy bills:

1. Try Using Caulk

White Silicone Sealant Cartridge And Yellow-Black Sealant Gun

One of the most affordable methods of insulating the areas around your window air conditioner has to be the caulking method. Not only does this work wonders, but it also lasts for a long period.

You will not have to apply caulk every other day or every week. Once applied correctly, it can stay there for as long as you want it to last. You can have months to years of peaceful nights of sleep.

You will need to buy or rent a caulk gun to perform get this technique correctly:

  • Fill the gun with caulk
  • Mark the surface you will caulk around
  • Stay focused, and with firm movements of hands and arms, start applying the caulk to the target area

When talking of affordable insulation methods, nothing can beat caulking. Still, you will need to be good at handling the gun and carefully applying the solution on the marked surfaces.

2. Fill the Cracks With Spray Foams

Foam-Filled Joint Between Aerated Concrete Blocks

Second, on the list, we have spray foams. The insulating spray foams work like magic as they expand after they have been applied to a surface. They are best to fit into spaces that are irregular and where no other insulation tactic works.

Do not judge their efficacy by their ease of application. They might seem a nice quick fix, but they can last for an unexpectedly long time. They are perfect for covering the holes and small cracks when running out of time.

Not only do they set up quickly, but they also offer a variety of application tips. You can choose a size that best fits your needs. For instance, buy a spray with an additional narrow pipe attached to it to fill in small, difficult-to-access holes and cracks.

3. Foam Insulation Panels Won’t Disappoint

Glued Solid Pine Slices Wafer Structure For Warm Building

You will never be disappointed with insulation panels in terms of price and performance. The only struggle with the insulation panels is the sizing part. You will have to be extra careful and accurate regarding the sizing.

It is better to buy them from a hardware store than anywhere online because you can easily measure the size when physically buying. Online ordering for a particular size can be complicated.

There are some budget-friendly regular-size options, but you will need to cut those sheets and panels into your desired size before using them.

4. Custom Designed Fabric Covers

Composition Of Interior Fabric Laminated Samples In Various Texture And Color

Lastly, we have custom-designed covers on our list. You can buy or order thick insulating fabric covers for your AC by their size. The insulating covers will keep them safe and insulate the small cracks and areas around them.

They are one of the most effortless and time-saving options available when it comes to fast insulation. However, you can not rely on this method as a permanent solution because this can only work best as a temporary solution for the time being.


Insulation around the AC can not be done better than using the caulking method, customized fabric covers, and spray foams. You can also go for insulation sheets for this purpose, but that might come with an extra effort for accurate sizing.

For best results, you can mix and match any two or three options by the area you need to cover in insulation and the size of your window AC. The peaceful sleep you will experience after this will be worth all your efforts, as it can make a huge impact.

Frequently Asked Questions

What Is a Window Seal Kit?

It is a kit with pre-cut insulating panels and sealers that a specific model makes of a window AC. You can use this kit for insulation around your window AC.

How Much Can Window Insulation Foam Panels Cost?

They can cost anywhere between $10 for small window surfaces to $100 for large window-size foams. The price can further go high if you are buying them in sets.

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