If you’re in a hurry, check out our favorite casement window pick: Frigidaire FFRS0822S1 8,000 BTU Heavy-Duty Slider Casement Window AC.
If you have windows that slide horizontally, rather than the typical vertical or up and down windows, then you’ll need a casement or vertical AC to cool your room. These ACs are also known as sliding/slider window ACs and gliding window ACs. These vertical ACs are usually taller and less wide than regular window ACs; this is so that they can fit sliding windows better.
In this article, we’ve reviewed our five favorite casement window ACs. If you’re in a hurry, take a look at our list, with our favorite on top:
How to Choose a Casement Window AC
When choosing a casement window AC, your options are already narrowed down since there are only a few pickings on the market. However, in order to get the best unit, you want to focus on your room size, cooling capacity requirements, room activity, and energy efficiency.
Room Size and Cooling Capacity
Cooling capacity for ACs is measured in British Thermal Units, or BTUs. Every casement window AC you look at will specify its BTUs. To figure out how many BTUs you need, first measure your room’s area. Measure (in feet) the length and width of your room and multiply the two numbers. Then look at the table below to see how many BTUs you should be aiming for.
| Area of Room in Square Feet | Capacity Needed (BTUs/Hour) |
| 100 – 150 ft | 5,000 |
| 150 – 250 ft | 6,000 |
| 250 – 300 ft | 7,000 |
| 300 – 350 ft | 8,000 |
| 350 – 400 ft | 9,000 |
| 400 – 450 ft | 10,000 |
| 450 – 550 ft | 12,000 |
You can be rest assured that these numbers are energy efficient because they’re sourced from Energy Star.
Although the table above is clear-cut about what capacity you’ll need for your casement window AC, you’ll need to make some Energy Star-suggested adjustments before you buy:
- If the room is regularly sunny, then increase capacity by 10%.
- If the room is dark, then reduce capacity by 10%.
- If there are regularly more than 2 people in the room, then for each additional person, add 600 BTUs.
- If the AC is being used in the kitchen, add 4,000 BTUs.
Once you’ve adjusted your BTU value for the items above, look at the table and round down to the nearest thousand. For example, if you have a requirement of 9,338 BTUs, then round down to 9,000 BTUs. Keep in mind that most casement window ACs on the market today have a cooling capacity of 8,000 BTUs – 12,000 BTUs.
Why Should I Estimate Lower for BTUs?
More BTUs in a unit does not automatically translate to more efficiency. You actually want to round down when estimating BTU needs because an oversized AC will not remove humidity efficiently, leading to a too-humid room.
Example BTU Calculation
Suppose you have a living room which is 16 feet x 22 feet. That’s 352 square feet. According to the table above, you would need 9,000 BTU. But remember the adjustments we must make? Since the room is facing east, it’s quite sunny which means you can add 10% to the BTU calculation. There are regularly three people in the room, so you want to add 600 BTU for that extra person. Overall, your total BTU capacity requirement is 10,500. We’ll round down to and our final number is 10,000 BTUs.
Energy Efficiency
When looking at different casement window AC units, you’ll see a number come up often—the EER number. Keep this in mind because EER stands for energy efficiency rating. It’s a number that divides the BTU measurement by the power consumption. You want to choose an AC with a higher EER rating because this will increase the unit’s efficiency.
Reviews of the Best Casement Window Air Conditioners
We’ve reviewed 5 casement window ACs below. We’ve listed them below for easy reference, with our favorite on top:
- Frigidaire FFRS0822S1 8,000 BTU Heavy-Duty Slider Casement Window AC
- Frigidaire FFRS1022R1 10,000 BTU Slider/Casement Room AC
- Koldfront CAC8000W 8000 BTU 115V Casement AC
- Koldfront CAC10000W 10,000 BTU Casement AC
- PerfectAire 10,000 BTU Slider Air Conditioner Window AC
Frigidaire FFRS0822S1 8,000 BTU Heavy-Duty Slider Casement Window AC
This Frigidaire FFRS0822S1 casement window AC is heavy duty and has a cooling capacity of 8,000 BTU. It’s meant to cool rooms of up to 350 square feet. It’s EER is 10.9 and estimated yearly energy cost is very low at $66. It also uses the standard 115-volt outlet so it’s very convenient to install. Here are some of its key features:
Pros:
- Heavy-duty
- Three-speed fans
- Four-way air direction
- Remote control and digital display
- Dehumidifiers up to 3 pints/hour
- Quiet cooling: low setting is 48.4 decibel (dB) and high setting is 55.1 dB
Cons:
- Not Energy Star certified
- Instruction manual is not very clear, may it be difficult to install without prior experience or a technician’s help
Frigidaire FFRS1022R1 10,000 BTU Slider/Casement Room AC
The Frigidaire FFRS1022R1 casement AC is one of our favorites for a few reasons. Its cooling capacity is 10,000 BTU and can cool an area of up to 450 square feet. It comes with a casement-window installation kit that helps you install the unit easily. In terms of energy efficiency, it has an EER of 10.4 and the estimated yearly energy cost is $87. It uses the standard 115-volt outlet, so you don’t have to create a special setup. Here are some pros and cons:
Pros:
- Dehumidifies 3.4 pints/hour
- Three-speed fans
- Four-way air direction
- 24-hr timer
- Remote control and digital display
- Energy saving sleep mode
- Quiet operation
Cons:
- Heavy at 72 pounds and a little difficult to install due to the weight, you will need more than one person for installation
Koldfront CAC8000W 8000 BTU 115V Casement AC
The Koldfront CAC8000W casement AC is another favorite of ours. Its cooling capacity is 8,000 BTU and can cool an area of between 300-350 square feet. In terms of energy efficiency, it has an EER of 11.0, which is higher and thus better than the ones we’ve discussed before. It’s also Energy Star certified. The estimated yearly energy cost is only $71. It uses the standard 115-volt outlet, so the setup is simple. Here are some of its pros and cons:
Pros:
- Built-in dehumidifier
- Has a sleep mode and energy saver mode
- Three fan speeds
- Remote control and digital display
- Check-filter alert
Cons:
- Instruction manual is not very clear, it may be difficult to install without prior experience or a technician’s help
- Heavy at 75 pounds and a little difficult to install due to the weight, you will need more than one person for installation
Koldfront CAC10000W 10,000 BTU Casement AC
The Koldfront CAC10000W casement AC is another great unit. Its cooling capacity is 10,000 BTU and it can cool an area between 400-450 square feet. It has an EER of 10.4, and an energy saver mode. It uses the standard 115-volt outlet, so you don’t have to create a special setup. Here are some of its qualities:
Pros:
- Built-in dehumidifier
- Sleep mode
- Three fan speeds
- Remote control and digital display
- Check filter alert
- Easy to install
Cons:
- Heavy at 77 pounds and a little difficult to install due to the weight, you will need more than one person for installation
PerfectAire 10,000 BTU Slider Air Conditioner Window AC
Last but not least, we reviewed the PerfectAire casement window AC. It has a cooling capacity of 10,000 BTU and is meant for rooms of 400-450 square feet. Its EER is 10.4, which is fair. It’s easy to set up due to it requiring a 115-volt outlet. It’s also easy to install due to the mounting kit that comes with it.
Pros:
- Three cool speeds
- Three fan speeds
- Noise level is between 58-61 dB
- Has an energy saver mode
- Remote control with thermostat and digital display
Cons:
- Not Energy Star certified
- Lowest temperature is 62 degrees Fahrenheit, which may not be cold enough for some people
Our Favorite Casement/Vertical Window AC
We’ve reviewed five really great vertical window ACs and we hope that you found something that suits your needs. These have a high EER score and are designed for low-cost, efficient cooling. Our favorite from this list is the Frigidaire FFRS0822S1 8,000 BTU Heavy-Duty Slider Casement Window AC. The initial investment with any vertical window AC is considerable, but the yearly energy cost for this unit is estimated at a low $66. It’s also very quiet and works to effectively cool your room.
For further reading, check out our other cooling articles: