Looking for an AC unit that will fit a casement window?
We’ve got you covered! In this proHVACinfo review, you’ll learn:
- What is a casement window air conditioner (are they any different?)
- Are there different types of casement window air conditioners (surprising answer)
- What to look for in the best casement window air conditioner (3 crucial considerations)
- The top casement window air conditioners (best in 2021)

Our Overall #1 Rated Pick
January 2, 2022

Koldfront 10,000 BTU Casement Window Air Conditioner
Check on AmazonFor this guide, we put four solid air conditioners designed specifically for casement windows to the test.--break--At the end of the day, this 10,000 BTU model from Koldfront came out on top!--break--There’s a lot to like about this air conditioner.--break--First, it’s on the higher end in terms of BTUs (10,000 instead of 8,000) so it’s sure to keep you cool even on those hot assumer days.--break--Next, it’s energy efficient (an Energy Efficiency rating above 10 – more on that below), so you know it’s going to be easy the environment (and on your wallet!)--break--Finally, it has some additional features that really set it apart, including multiple fan speeds and a sleep mode!
In a hurry? Here’s an easy list of our top window ACs for sliding windows!
Image | Product | |||
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Our Top Pick ![]() | Our Top Pick | Koldfront 10,000 BTU Casement Window Air Conditioner
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| View on Amazon |
High-End Pick ![]() | High-End Pick | Keystone 10,000 BTU Casement Window AC
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| View on Amazon |
Best Budget Pick ![]() | Best Budget Pick | Frigidaire 10,000 BTU Casement Window AC
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| View on Amazon |
![]() | PerfectAire 10,000 BTU Slider Window AC
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| View on Amazon |
What Is a Casement Window Air Conditioner (Are They Any Different)?
First, let’s make sure we’re on the same page about casement windows.
When we say “casement window” in this article, we mean the following:
Either your window has hinges on the upright side (i.e. the vertical side) of the window and opens by cranking outward (almost like a door), or your window slides horizontally from side to side.
Either way, these windows are much taller than they are wide, and for that reason casement air conditioners are structured differently than typical window AC units.

The casement window AC has a vertical orientation and is usually at least 20 inches taller than traditional window air conditioners. They require a specific setup to secure the AC in place.
Casement window ACs sit on the window pane, and a panel is cut to fill the empty space above (and, when needed, to the left and right of) the air conditioner.
Now that we’ve clarified the terminology, let’s get into the details.
Are there different types of Casement Window Air Conditioners?
Casement window air conditioners are surprisingly difficult to come by (especially considering how common casement windows are). Because they’re so rare, there’s less variability among casement ACs than traditional ACs.
The most important variations among casement window ACs are the size and the BTU ratings
Size is especially important if your casement window cranks out. Unlike with a sliding window, there is no flexibility in the width of the window.
Be sure to measure your window width carefully because, put simply, a 14-inch AC unit cannot fit in a window that is 13-inches wide!
This is less of a concern if your window slides horizontally.
The other variation among casement window ACs are the British Thermal Unit (“BTU”) rating. Casement ACs only come in two: 8,000 and 10,000. More on that below!
What to Look for in the Best Casement Window Air Conditioners
The things to keep an eye out for when it comes to casement ACs are largely the same as traditional window ACs. Because casement ACs are less common, though, you should really hone in on two factors:
- Cooling capacity
- Energy efficiency ratings (EER)
Cooling Capacity
This is an important consideration for any window air conditioner, and casement ACs units are no exception!
All AC units are rated according to their British Thermal Units (“BTU”). The higher the BTU, the more powerful the AC, and the more quickly it can cool down your room.
Check out this table, which tells you how many BTUs your AC unit should have based on room size!

As we said above, casement ACs only come in two sizes: 8,000 BTUs and 10,000 BTUs. So they work well for rooms that are between ~300 and ~450 square feet.
The table is a good benchmark, but you might want to size up from an 8,000 BTU unit to a 10,000 BTU unit for rooms that get a lot of sunlight or have fixtures that produce heat (the kitchen or garage, for example).
Energy Efficiency Rating (EER)
Energy Efficiency Rating (EER) is another big factor when shopping around for a new casement window AC. The EER tells you how efficient your AC is. You see – different AC models require different amounts of energy to produce the same BTUs.
More efficient units reduce waste and are easier on your electric bill.
You’ll find this number on the yellow BTU sticker. The higher the EER, the more efficient your AC.
Also read: How Much Does it Cost to Run a Window Air Conditioner?
The Top 4 Casement Window Air Conditioners (Reviewed)
Koldfront 10,000 BTU Casement Window Air Conditioner (Our Top Pick)
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Our top pick is the Koldfront 10,000 Casement Air Conditioner!--break--Dimensions: 23.5 x 14.5 x 20.87 inches--break--Coverage: ~450 Square Feet--break--CFM: 324 (highest setting)--break--We liked it for its combination of features, performance, and overall good value. Its powerful performance will keep you covered up to areas of 450 square feet.--break--It has an easy-to-use interface and a straightforward remote control for added convenience.--break--Our favorite feature when it comes to this model is that it doubles as a dehumidifier, so you’re essentially getting two devices for the price of one for added comfort!
Pros
- Overall good value--break--Powerful performance--break--Doubles as a dehumidifier--break--Remote control for added convenience
Cons
- Directional vents are limited in maneuverability--break--Some users had a problem with noise
Keystone 10,000 BTU Casement Window Air Conditioner (High End Pick)
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Our high end pick is the Keystone 10000 BTU Slider/Casement Window Air Conditioner.--break--While it doesn’t have a specified EER, this unit has a dedicated energy saver mode that helps both the environment and your electric bill!--break--Dimensions: 26.5 x 23.3 x 13.3--break--Coverage: ~450 Square Feet--break--The Keystone casement window AC also has a 3-speed fan that allows you to control the temperature in your room.--break--If you’re looking for a casement AC for a bedroom, this is your best bet!
Pros
- Energy saver mode--break--Sleep mode
Cons
- Price--break--Remote does not have full functionality--break--Larger size
Frigidaire 10,000 BTU Window Air Conditioner (Best Budget Pick)
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The Frigidaire FFRS1022R1 10000 BTU Window Air Conditioner is our best budget pick! It has many of the same features as other models on this list, but at a lower price point.--break--Dimensions: 23.5 x 14.5 x 20.25--break--Coverage: ~450 square feet--break--Energy Efficiency Rating: 10.4--break--This casement window air conditioner comes with several programmable modes, including sleep mode, energy saver, and auto cool.--break--It also has a 24-hour on/off timer.
Pros
- Price--break--Front grille is easy to clean--break--Remote control--break--Straightforward temperature control--break--Multi-speed fan
Cons
- Some users reported issues with damaged packaging upon arrival--break--Can be noisy
PerfectAire 10,000 BTU Casement Window Air Conditioner
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The PerfectAire 10000 BTU Slider Window Air Conditioner is another high-end unit with several helpful features, including auto, sleep, dry and energy-saver modes.--break--Dimensions: 23.5 x 14.75 x 21--break--Coverage: ~450 square feet--break--Unlike other models we came across, this unit takes some of the hassle out of installing a casement window AC, because it comes with a mounting kit.--break--So, if ease of installation is something you’re looking for, we recommend this model!--break--It also has Follow Me portable thermostat technology for total room coverage.
Pros
- Installation kit included--break--Easy-to-clean filter--break--3-speed cool and fan modes--break--Remote control
Cons
- Noise level--break--Price
Final Thoughts on the Best Casement Window Air Conditioners
Casement windows are a unique architectural design that can add a lot of character to your home (or office).
Even though ACs for this window design are harder to come by, we’ve found several great options that have many of the bells and whistles of high-end traditional window AC units.
We hope this guide is helpful in picking out your next casement window air conditioner!