Window Air Conditioner with Highest BTU for Large Rooms

If you are looking to buy a window air conditioning unit for large spaces, then you probably need the most cooling power you can find. The cooling output of air conditioners is measured in BTU and the higher it is, the larger the area of coverage. Window-type units from 18,000 BTU capacity and above are considered “large” air conditioners, but for spaces 1,000 square feet and wider, you need at least 20,000 BTU cooling capacity. 

Another important factor to consider when choosing a large window AC is the energy efficiency ratio or EER/CEER rating. You want to make sure the unit is efficiently using the power it consumes. To make the task of choosing a large window air conditioner easier for you, we have curated this list of the five best units with at least 22,000 BTU cooling capacity. Note that these large window ACs only plug into 230V outlets, like any unit larger than 15,000 BTU. 

You can take your pick from this list, or use our buying guide to help you choose the best air conditioner with the highest BTU for your room.

Window Air Conditioners with the Highest BTU (22,000+)

  • Dimensions: 26.5 x 26.5 x 18.63 inches
  • Coverage Area: 1900 sq ft
  • BTU: 28,000
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  • Dimensions: 26.5 x 26.5 x 18.63 inches
  • Coverage Area: 1500 sq ft
  • BTU: 25,000
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  • Dimensions: 26.22 x 25.89 x 17.72 inches
  • Coverage Area: 1300 sq ft
  • BTU: 22,000
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  • Dimensions: 26 x 28.13 x 17.7 inches
  • Coverage Area: 1560 sq ft
  • BTU: 24,500
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  • Dimensions: 26.5 x 26.5 x 18.6 inches
  • Coverage Area: 1500 sq ft
  • BTU: 25,000
View On Amazon →Read Our Review

Reviews of the Best Window Air Conditioner for Large Rooms

Highest BTU: Frigidaire FHWC282WB2

Frigidaire FHWC282WB2

Frigidaire is a well-known and trusted name in the home appliance market. This brand offers a wide selection of window air conditioners ranging from the small 5,000 BTU units to this 28,000 BTU, the largest window-type AC we’ve found. This quiet yet efficient unit can effectively cool down spaces up to 1,900 square feet. 

Despite its enormous cooling capacity, Frigidaire 28,000 BTU unit produces a minimum of 59 dB noise levels at the lowest setting, and 67 dB at the highest setting with a maximum of 461 CFM airflow. This is incredibly quiet for its size. Just like most Frigidaire products, this window AC unit is Energy Star certified with a 9.4 CEER rating. It also removes 9.5 pints of moisture from the air per hour. 

Furthermore, it is designed to make operation very easy using electronic controls. It features all the standard function modes, including Cool, Dry, Fan, and Auto modes. It has three fan speeds with six-way directional airflow to keep the whole room cool. You can also find the energy-saving Eco mode, Sleep mode for quieter operation, a 24-hour On/Off timer, and a Check Filter indicator. Also included is a remote control for hassle-free adjustment of settings from anywhere in the room and a convenient feature of remote sensing of temperature.

Although large in size, it is easy to install in a single or double hung window with its slide-out chassis. Priced below $1000 to $900, this 28,000 BTU window AC is a great investment for extra large spaces or even multiple adjacent rooms. You can rely on Frigidaire appliances built with high quality, durable materials so that your unit can last up to 10 years, well beyond the standard one-year manufacturer warranty. There are currently no reviews for this model on Amazon, but you can check Sylvane and Frigidaire.

• Highest cooling output of 28,000 BTU
• Largest coverage area up to 1,900 sq ft
• Good energy efficiency for size with 9.4 EER rating
• Quiet for a high capacity unit
• Comes from a reliable brand
• Very few reviews

Biggest Window AC with Heater: Koldfront WAC25001W

Koldfront WAC25001W

Our top pick for 25,000 BTU window units is the Koldfront WAC25001W. Koldfront is another reliable brand when it comes to air conditioners. Next to the 28,000 BTU Frigidaire, this Koldfront unit is the most powerful window AC on our list if we look at the maximum wattage. To generate 25,000 BTU, Koldfront WAC25001W requires 2660 Watts, which means that it is less energy efficient than similar units. However, there is a reason for this. The Koldfront 25,000 BTU unit is the largest window air conditioner with a heating function. It can generate 16,000 BTU of heating output, at 4800 Watts electricity input. 

Additionally, it’s the best air conditioning unit for large rooms with high humidity issues. It can remove up to 137 pints of moisture per day, which is equivalent to more than two portable dehumidifiers combined. This Koldfront large window AC has a recommended coverage area of up to 1,500 square feet for cooling and 700 square feet for supplemental heating.

Koldfront features easy-to-use electronic controls with a digital thermostat and display as well as an LCD remote control. It maintains the temperature from 62°F (17°C) to 86°F (30°C) with four modes and three fan speeds. You have the standard Cool mode, where you can set the temperature and fan speed manually; Energy Saver mode, where the fan cycles on for ten minutes and will turn the compressor back on if the room temperature exceeds the setting; Dry mode, where the unit runs on low speed to dehumidify the room; as well as Fan Only and Auto modes. You also have Sleep mode for a quieter operation and less energy consumption at night. The air louvers on the top can be adjusted four ways to direct the airflow.

The Koldfront WAC25001W fits windows between 31 and 42 inches wide and at least 19.5 inches high. For its size, it’s the best and only window AC that can provide efficient cooling as well as the option for supplemental heating in cold months.

• Second highest cooling capacity for window ACs
• Has the highest moisture removal rate of 137 pints per day
• Large coverage area up to 1,500 sq ft
• Can also provide supplemental heat up to 16,000 BTU
• Koldfront is a reliable HVAC brand
• Requires more power due to heater inclusion
• Has below 10 EER rating

Best Energy Efficiency: LG LW2217IVSM


LG is a leader in manufacturing inverter compressors for various home appliances and electronics, including air conditioners and refrigerators. In terms of energy efficiency, nothing tops the LG LW2217IVSM 22,000 BTU Dual Inverter Window Air Conditioner. This large unit cools spaces up to 1,300 square feet. It is not only efficient but also quiet, with a minimum 44 dB noise level. At a powerful 500 CFM Turbo fan speed, the noise can reach 62 decibels, whereas other similar non-inverter window ACs can be louder than 70 decibels. 

Using an inverter compressor, this unit surpasses the Energy Star minimum requirements with an impressive 14.5 CEER rating that can save you up to 15% more energy. This is because inverter compressors automatically adjust the unit’s speed to maintain the set temperature without periodically cycling on and off.

This LG 22,000 BTU unit has all the features you can find in most window-type ACs, including digital controls with multiple function modes and fan speeds, such as Turbo mode and Energy Saver function. In Dry mode, it can remove up to 5.6 pints of moisture per hour. It also includes a 24-hour on/off timer, Sleep mode, and a Clean Filter reminder.

Additionally, this unit is Wi-Fi enabled so you can easily change the settings and monitor the operation from the LG ThinQ app on your mobile, or use voice commands with Alexa or Google Assistant. The Dual Inverter technology is also available in 9,500 BTU, 14,000 BTU, and 18,000 BTU variations with similar features. While this is an extremely useful feature for the tech-savvy, a number of users have encountered issues with the Wi-Fi and voice controls. However, that’s not the best selling point of this smart air conditioner. 

It fits windows 29 to 41 inches wide and at least 19 inches high. It’s a really big, bulky unit, but is quite easy to install. LG provides a one-year warranty on parts and labor for this unit.

• High energy efficiency
• Good value for its price
• Wi-Fi compatibility
• Comes from a reliable brand
• Potential problems with Wi-Fi and voice controls

Largest LG Window AC: LG LW2516ER


LG is a trusted brand of air conditioners and their biggest offering yet is the LW2516ER 24,500 BTU model. With a 1,560 sq ft coverage area, this large unit provides the highest airflow for any window AC. In fact, it doesn’t generate only the required minimum airflow of 300 CFM, but it can deliver up to 530 CFM airflow when operating at the highest fan speed. And it does so with minimal noise output at only 61 to 65 dB at the lowest setting. This unit has similar variations available in the smaller 5,000 BTU, 6,000 BTU, 8,000 BTU, 10,000 BTU, 12,000 BTU, and 18,000 BTU cooling output. 

Like most LG products, the LW2516ER window air conditioning unit has high energy efficiency with a 10.3 EER rating and Energy Star certification. It features the standard settings for Cool mode, Fan Only, and Dry mode, as well as multiple fan speeds. It also includes an Energy Saver function, Sleep mode, and a 24-hour Timer function. You can adjust and monitor operation with the electronic controls on the front panel or with the included remote control. 

The stylish, modern design blends well in most rooms with a single hung or double hung window 29 to 41 inches wide with 19 inches minimum height. It comes with a standard one-year manufacturer warranty. LG is a trusted brand with budget-friendly products like this large window air conditioner. Although, there are a few complaints about the customer service. But if you have prior experience with LG, then you can also rely on this air conditioner.

• Large capacity and coverage area
• Good energy efficiency with 10.3 EER rating
• Exceptional airflow rate of 530 CFM
• Budget-friendly price
• Comes from a reliable brand
• Mixed reviews

Best for Budget: Keystone KSTAW25C

Keystone KSTAW25C

By far the cheapest 25,000 BTU window air conditioner in the market today, the Keystone KSTAW25C can save you at least $30 upon purchase compared to the rest of our picks. While Keystone is a smaller brand, it’s known for low-cost yet energy efficient appliances. This 25,000 BTU Keystone window AC can handle huge spaces up to 1,500 square feet with a 523 CFM maximum airflow. It has a CEER rating of 10.3 which earns it the Energy Star certification for large air conditioning units.

Like most Keystone air conditioners, this unit is designed for easy operation using electronic controls. It maintains the room temperature from 62°F (17°C) to 86°F (30°C) and removes up to 5.7 pints of moisture from the air every hour. You can select from the three cooling functions and fan speeds, including Cool, Dry, Fan, and Auto settings, as well as the Energy Saver and Sleep mode, and set an on/off timer for up to 24 hours. Also included is a remote control for hassle-free operation, designed with the “Follow Me” temperature sensor that allows the AC to track the temperature according to the remote control’s location, so it can cool the room evenly. 

Although not as popular, Keystone provides all the basic needs in a window AC at a competitive price. It’s not the best looking of the bunch but it still does the job well.  We don’t love the design of the LCD display and control buttons, but this doesn’t affect the cooling performance of the unit. With a slide-out chassis, this unit can be easily installed in a window 31 to 42 inches wide or into a wall.

• Energy efficient
• High airflow rate at 523 CFM
• Budget-friendly
• Less popular brand

BTU Capacity and Coverage

The most vital factor to take note of when choosing an air conditioner for a large room is its cooling capacity. An air conditioner’s capacity to cool (or heat) a given square footage of space is typically measured in BTU or British Thermal Units By formal definition, BTU is a measurement of energy, particularly the amount of heat required to raise the temperature of one pound of water by 1°F. When talking about air conditioners, BTU/hr (or simply BTU) is the amount of heat it can remove from the room in one hour. 

A rule of thumb is that an air conditioner needs at least 20 BTU to cool one square foot. So, a 20,000 BTU unit can cover around 800 to 1,000 square feet, a 25,000 BTU unit can cover around 1,300 square feet, and so on. A “large” window AC unit range from 18,000 up to 28,000 BTU capacity. Portable air conditioners typically have a lower capacity. The largest portable units are around 14,000 BTU.

Before purchasing a large room air conditioner, you want to make sure you get the right BTU capacity. If you get an undersized unit, it will not cool the room effectively. You’ll need to run it at the highest fan speed or set it at the coldest temperature to try to keep up with the task. This results in warm and uneven temperatures on different parts of the room, and it’s also wasteful of energy. 

Meanwhile, you may be tempted to use the biggest window unit you can find. After all, it can cool the room a lot faster at a lower setting. For instance, you get the 28,000 BTU unit for a 1,000 square feet space. While it’s true that it can achieve your desired temperature more quickly, it will also create a less than ideal environment in the process. This is because a larger unit will cycle on and off fast without removing enough moisture in the air, producing a cool and clammy room. 

So when choosing a window AC, you must always consider the total room size. Manufacturers usually indicate the square footage of space recommended for each model depending on the BTU capacity of the unit. 

Energy Efficiency (EER Rating)

Air conditioners pull a lot of electricity to reach desired temperatures. Because of this, homeowners are concerned with the energy efficiency of the product. Energy efficiency is the ability of the appliance to use less energy to accomplish its task, and higher efficiency helps cut down your electricity bills and reduce pollution. 

To measure this, the Energy Efficiency Ratio or EER compares the unit’s cooling capacity (in BTU/h) to the required energy to power the air conditioner (in Watts). For example, a 24,000 BTU unit that uses 2400W has an EER rating of 24,000 / 2400 = 10. A higher EER means higher energy efficiency. 

For large window ACs (24,000+ BTU), an EER of around 10 or more is considered energy efficient. Although, note that the actual energy costs of your unit may vary depending on the climate in your region. Additionally, for a more accurate measure of energy efficiency, the Department of Energy defined a new metric called the Combined Energy Efficiency Ratio or CEER. This is the combined ratio of the air conditioner’s cooling output to its power consumption when actively cooling and when the unit is on standby. 

To quickly determine the air conditioner’s efficiency before you purchase, look for the Energy Star logo. Energy Star grants this certification to units that meet the EPA’s minimum requirements for energy efficiency. Energy efficient ACs can save energy by at least 10% more than the average non-Energy Star unit of the same size.

Airflow and Noise Level

For large rooms, another essential feature of air conditioners is the airflow rate, measured in CFM. This refers to the volume of air the unit can process per minute. A faster fan speed gives more airflow and usually higher noise levels. A higher cooling capacity requires more airflow to distribute the cool air evenly to the entire room. Thus, large air conditioners (20,000 BTU and above) often generate louder noises. 

Quiet window air conditioners have noise levels below 60 decibels, but the quietest can go even lower than 45 to 50 decibels. Large air conditioners are usually at least 65 to 70 decibels loud. For reference, a whisper is around 30 decibels, rainfall is around 40 decibels, while a normal conversation goes from 50 to 60 decibels. In most cases, window ACs become noisy during the compressor’s startup. With an inverter compressor, it will not cycle on and off, but rather constantly operate at the lowest possible setting to maintain the ideal temperature. This reduces the noise generated as well as the energy consumed. 

Installation Requirements

Large window air conditioners require a large space for installation on your window sill. Make sure you have the right dimensions for the width and height of the window where you can install the unit. If you have the working knowledge, you can do this yourself with a helper. Some models make the process easier with a slide-out chassis, while some can also fit into a wall provided an appropriate wall sleeve for the unit.

Another important consideration before you install any air conditioning unit is the electricity requirements. All of the units we recommended above plug into 230V outlets on 20 to 30 amps. They will not work on the standard 110V power outlets. All air conditioners larger than 15,000 BTU capacity run on 230 to 240 voltage and you may need to provide your AC its own outlet when installing.

Build Quality and Warranty

It’s also important to look at the quality and design of your air conditioner. Make sure it’s easy to use the digital controls where you can input the exact temperature for the thermostat. Also look at the additional features the unit offers, including multiple function modes and fan speeds, as well as a programmable timer. This gives you greater control over the unit’s performance and energy use.

Finally, you must also look for the warranty included with your window AC. Most manufacturers offer a minimum one-year warranty on parts and labor, that you may be able to extend when you register the product. Some may also provide an additional longer warranty for the AC compressor. This is important because a longer coverage gives you confidence in the quality of the product and assurance that you can return the unit or request free replacement parts in case any issue occurs. However, a one-year coverage from big brands like Frigidaire and LG is still better than a similar warranty policy from less popular brands with poor service.


Is higher BTU better for AC?

A higher BTU air conditioner is not always the better option. An oversized unit may cool the room fast but it will also leave the room humid. Meanwhile, a unit with a smaller BTU than needed cannot cool the room down even as the unit works at the highest settings. 

Is higher BTU more expensive?

Generally, an air conditioning unit with a higher cooling capacity is also bigger and heavier physically. In consequence, it will be more expensive compared to smaller units from the same brand. 

How much space will a 25,000 BTU air conditioner cool?

The room coverage of an air conditioner is proportionate to its cooling capacity. Typically, a 25,000 BTU unit can cool rooms around 1,300 to 1,500 square feet, depending on the climate in your region and the location of the room.


Getting the right BTU size is most vital when choosing a window air conditioner. The larger the room, the higher the BTU cooling capacity you need. Air conditioners with 20,000+ BTU capacity are a huge investment for your home and you can benefit from them for a long time if you know what to look for. Remember that you need not sacrifice your electricity bills for a powerful and effective unit. Look for an Energy Star label and a CEER rating of about 10 or higher, or better yet, choose an inverter model for the highest efficiency and energy saving. Whatever you choose, the actual performance of the unit will rely on how you use and maintain the unit. While it’s tempting to get the largest unit you can find, always consider the size of your room first.

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