A window AC is a good option when you want to cool a single room rather than the whole house. It is small, compact, and easy to install; and it costs a lot less than a full home-unit. The units are equipped to function in different modes and you can cool the air in varying degrees depending on the model. Some models have a heating option that comes in handy during the colder months – but in general most popular units are made with the cooling feature as the main function.

Choosing a Window Air Conditioner

A good window AC is designed to work efficiently while still keeping power consumption low. In order to pick the right model you need to look at some of the main functions and see how they compare with your cooling needs. Check how the unit handles humidity, ventilation, and temperature; and to determine the right size for you, start by calculating the length and width of the room.

Air conditioners are measured using the British Thermal Unit (BTU) rating; which indicates the approximate amount of heat the unit can remove from a room. The higher the number, the more powerful the unit.

Use these figures to compare your room size with the unit’s BTU:

  • 1,050 to 1,600 sq ft: the ideal unit has between 18,500 and 25,000 BTU
  • 550 – 1,050 sq ft: the ideal unit has between 12,000 and 18,500 BTU
  • 350 – 550 sq ft: the ideal unit has between 8,000 and 12,000 BTU
  • 150 – 350 sq ft: the ideal unit has between 5,000 and 8,000 BTU

Top 3 Best Smallest Window Air Conditioner Units to Consider

#1 Pick #2 Pick #3 Pick
Frigidaire FFRA0511R1 - 5,000 BTU hOmeLabs Window AC - 5000 BTU Frigidaire FFRE0833Q1 - 8000 BTU
Frigidaire FFRA0511R1 5,000 BTU hOmeLabs Window Air Conditioner - 5000 BTU Frigidaire FFRE0833Q1 - 8000 BTU
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Important Considerations for Window Air Conditioners

The majority of window ACs are designed to fit the type of double-hung windows that have a sash for raising and lowering. The dimensions of the window must be carefully measured to make sure the unit fits perfectly. For the best results, don’t rely on estimates.

Here are a few issues to consider:

a) You may need help to install the unit. Air conditioners in general tend to be heavy, and while some people have an easy time setting them up, consumers who are not handy with electrical appliances may need to hire a specialist.

b) Fix the AC in a shaded window to improve functionality. If the window faces North it gets a lot of shade. This isn’t absolutely necessary but it serves to improve the unit’s performance.

c) There needs to be a power outlet in the room to plug the device into. You might need to use an extension cord if the power outlet is located further away from the window.

d) Air conditioners consume a higher power load, so the circuit should be able to handle the extra power usage. Check with an electrician if you’re not sure about this.

e) Check whether the unit’s power configurations are compatible with your outlet. If it isn’t, contact the manufacturer or get a licensed electrician to connect the appliance safely.

Common Features on Window Air Conditioners

– Practically all models come with a timer that shows when the unit is turned on and lets you program when the it will turn on and off. This is important because it lets you manage the running time so that your power bill doesn’t run too high during the hot seasons. With a programmable timer you only power the unit when you absolutely need to, and the device turns itself on and off at selected times.

– There are a number of mechanical controls that let you adjust things like cooling level, fans speed, and other features. The controls give the user flexibility over how to use the unit.

– Most models have a sleep setting that raises temperatures incrementally over a selected time-period before going back to the original setting. It means that the AC maintains comfortable temperatures in the room at night without making it too cold. This feature also makes the unit run quietly to reduce the usual humming.

– An electronic ionizer keeps the AC from picking up dirt and pollen from the air so the air in the room stays clean.

– There are different venting options in the features to accommodate different air conditions. Try them out to see which feature you need.

– Each unit comes with a remote control device to make it easier to adjust settings and turn the device on and off. You can also get a remote that acts as a temperature sensor, activating the device when the air gets too warm or cold.

– A dehumidification feature is enabled in most window ACs.

– An alert goes off to let you know the air filter needs cleaning.

Best Smallest Air Conditioner Units – Reviews

#1 Frigidaire FFRA0511R1 – 5,000 BTU

Frigidaire FFRA0511R1 5,000 BTU

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Our first choice, the FFRA0511R1 Frigadaire comes with 5,000 BTU and is perfect for smaller rooms. It works quietly so it won’t keep you up at night, and the unit has full-width control to guide air direction. It also has a variety of mechanical controls to regulate the unit.

If you room is small and you have a tight budget to work with, this is a good option for residential and office spaces. It gets high scores on Consumer Reports, particularly due to efficiency, smooth running, and the fact that its very affordable compared to other brands in the market today.

A mesh filter that is fitted inside the unit can be detached from the side to clear room odor and dirt particles in the air. This improves the quality of air in the room to make sure your family stays healthy while sleeping. Power consumption is minimal with this model because of a low-power start capability and overall low consumption.

Other important features include a two-speed cooling feature and two fan speeds. It works quickly and its two-way air direction produces cool temperatures even in the hottest weather.

The unit measures 12X15X16-inches; which makes it one of the smaller window ACs on sale today. Side panels are included to fit it into larger windows. Installation is easy thanks to a compact design and easy-to-follow instructions for setting up the unit. For the best results, install in an insulated room and shield it from direct sunlight. The FFRA0511R1 is one of the smallest window air conditioner on the market.

#2 hOmeLabs Window AC – 5,000 BTU

hOmeLabs Window Air Conditioner - 5000 BTU

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This is our second-favorite window AC and it has the same capacity as the Frigidaire FFRA0511R1, which makes it ideal for rooms measuring about 150 square feet. This product ships with an air conditioner kit that includes a filter, leaf covers to use on the side panels, window seal foam, a support bracket, and a user guide. For the best results, it should be installed in a small apartment, a small or medium-sized bedroom, or an RV.

The main features include a seven-speed mode, two cool fans, and leaf guards. It is also washable so at the end of every season you should do a thorough cleaning. If you have a small office that heats up from running too many electronics, this is a great AC to keep temperatures regulated and it takes just 15 minutes for it to work.

This small unit runs quietly with 2-way air flow and adjustable fan settings. The design is fairly simple and the unit doesn’t have digital controls, but it’s still a good purchase and it gets the job done. It measures 12X16X15.4-inches and can be fitted onto windows that measure between 23 and 36 inches wide.

#3 Frigidaire FFRE0833Q1 – 8,000 BTU

Frigidaire FFRE0833Q1 - 8000 BTU

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If you’re looking for a unit that’s made for medium-sized rooms, this is a good bet. It has 8,000 BTU and can regulate temperatures in a room of about 350-square feet. It is relatively small and it runs quietly even on the hottest days. It also has high ratings on Consumer Reports especially due to the low power usage and comfortable cooling modes. It comes with a clear display to show temperature and running time, and a remote control allows easy usage when you’re in bed or multitasking.

A clean-air ionizer keeps the air in your room free of allergens and pollutants. When installed, this unit doesn’t protrude too far out from the window, and it only weighs 50 pounds so installation isn’t too much of a hassle. A removable filter means you can clean it as many times as needed in order to keep air clean and to improve functionality. It takes just 10 minutes to unpack the unit and installation is simple – though you may need assistance.

#4 GE AHM05LW – 11,600 BTU

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This is one of the most energy-efficient window ACs today, and it has a high energy saving capacity. It works on 115-volts and can be fitted onto windows that measure between 24 and 36 inches wide. The main features include a programmable timer, a magnetic remote, and 5,500 BTU for small and medium-sized rooms. It can be used in a small apartment or as a backup AC.

Use caulk when installing the unit on metal housing, and make sure to seal properly to prevent heat and bugs from getting in. This model uses water to cool down the coils and it has a plug that you can pull to refill the water when its used up.

#5 Haier HWE12XCR

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For larger rooms, we recommend the Haier HWE12XCR. It has 12,000 BTU and is designed to cool down spaces measuring up to 550 square feet. It has a magnetic remote control, several cooling modes including auto cool; three fan speeds, different cooling speeds, and functions such as “energy save” that reduce performance to minimize power consumption.

This unit has a digital display, easy-to-use controls, an electronic panel, and it can be installed on large and smaller windows. It cools down the room relatively fast and the filter doesn’t need to be cleaned too often compared to other units. For a unit of this size, the Haier HWE12XCR is fairly-prized: however on the downside, it’s not as quite as the other units.

What to Know Before Buying a Window AC

There are a number of things that can help guide your decision when shopping for a new AC. The following guide is useful for anybody planning to install a window AC for the first time.

Prevent energy loss

Units that are made with quality insulating materials will ensure you properly seal the area around the machine to prevent leaks.

Check noise levels

You can always check Consumer Reports to see how a unit measures on their noise test. Ideally, the only sound you should hear is the fan running.

Air conditioners that are loud cannot be used in or near a bedroom because of the effects of sleep disruption.

Consider window location

Window ACs normally perform better when they’re made to blow air in one direction. This only becomes a problem when the window is not centered on the wall.

In order to cool a room uniformly, make sure the air is directed to the center, and check whether the unit needs to blow air in a specific direction.

You can get units that have fan arms that extend outward, allowing you to swivel the fan to blow air in different directions.

Proper installation

To make sure you’re getting the most from your unit, installation must be done according to the manufacturer’s instructions. Remember, most of these units are made for double-hung windows.

Rooms that have a casement window are better off with a through-the-wall AC. Also try to keep the unit level so that it drains properly, and keep any heat-generating devices like computers and TV away from the AC.

Filter location

Always make sure the filter is accessible and clean it when needed to keep the unit functioning optimally.

Intelligent cooling

This is a feature in some units that make it smarter, allowing the user to turn the unit on and off from their smartphone, as well as adjust settings.

Check the warranty

The warranty may be long or short depending on the manufacturer but you can check on their website for more information about the warranty for the model you want to buy.

Tips for Carrying Out Annual Maintenance

To keep the unit functioning at its best, its important that you perform annual maintenance. Some manufacturers recommend a thorough checkup after every season to ensure optimal performance.

The good thing about doing maintenance is that it reduces chances of the unit failing or using too much power.

We have included some tips on performing maintenance.

Start by cleaning the vents

It takes just a few minutes to dust off the vents and if you do this regularly it improves performance.

Change the filter

After the first year of use, you may need to change the filter because they get worn out over time. The filter is an important part of the air-cleaning process and should be replaced regularly.

Check the cooling agent

Most ACs use a Freon as the cooling agfent and in most cases you won’t have to change it or fill it up; however when doing annual maintenance its worth checking whether the cooling agent is intact. You can have a technician take a look to make sure there aren’t any leaks.

Cover any blockages

The part of the unit that sucks in air can sometimes get blocked by dirt, which is why it should be cleaned at least once a year.

Check whether coil fins are bent

The coil fins can get bent over time and that interferes with performance. You don’t need to get replacement for the coil fins if they are bent: there is a special fin comb that it used to straighten them up.

Preparation and storage

Check the unit before the start of the season to make sure its functional. Once you’re done using it, inspect it again before putting it into storage. Make it a habit to inspect it when taking it out of storage and before you put it back.

You can help keep the air in the room cool by closing fireplace dampers and wall registers. Only open them when using the fireplace.

Temporary vs. Permanent use

Decide whether you plan to remove the AC or leave it in the window year-round. Keep in mind that both options have trade-offs. A permanent setup means you won’t have to install the unit again the next year, and it can also mean a longer life for the machine because its not constantly being moved.

With that said, even when a permanent AC is well insulated, there’s still a chance it won’t be draft-free as a window that is completely shut. This can be a problem if you live in a place with extremely low temperatures in winter. People who live with mild winter should do just fine.

Think about condensation

One problem with window ACs is the condensation they cause as they run. They work a lot like dehumidifiers, pulling moisture from the air. When this water is collected inside the unit, it usually pools in a small drip tray inside. Some manufacturers advice you to drill a small hole on the bottom to allow drainage – the other option is to hook a drain hose in there to channel the water wherever you want it to go.

Power Usage

Most ACs today run at 120V; though this wasn’t the case some years back. Older models needed 240V to operate, but thanks to Energy Star certification, manufacturers now focus on energy efficiency. But even with reduced power usage, ACs still need a dedicated power source and if your unit is installed in a room with another power-hungry device, you may need to call an electrician to add another power circuit for the AC.

Don’t ignore the small stuff

Features like size and cooling power might seem minor but they play big role in how the AC performs over time. Some units make a racket when running, so confirm the noise level before purchase, and make sure you can seep comfortably when the unit is powered on. A variety of smart features have come out and brands such as Frigidaire and GE now have air conditioners that can be synced with your phone through an app, as a way to give you more control over how the machine operates.

Some of the smaller units cost less than $200 and they are super convenient especially for fitting into a small room. And if you want to cool a bigger room, you won’t run out of options when searching for a window AC. Before you check the prize of the unit, determine first the size you want, the space you want to cool, and also where the unit will be place.

If your unit is installed permanently, consider using a protective cover in winter so it doesn’t get damaged. Pick a covering that secures the machine in place without obstructing air flow.

During maintenance, if you hire a HVAC expert to perform inspections, have them look at the thermostat, coils, and electrical controls. These are the most sensitive parts of the unit and require a trained technician to inspect and/or repair.

Window sizes don’t really follow a standardized measuring system, so you need to measure your windows by yourself to know what you’re dealing with. Once you have that information, you can then start comparing it against the products available. This way you won’t have any nasty surprises.


When the weather heats up, it can get pretty uncomfortable indoors, and a window AC is a cheap, effective solution for cooling down smaller spaces. If you’re thinking of a way to beat the heat, you’re not alone.

Millions of room air conditioners are sold in the US every year, and on average every household spends 13% of their energy bills on cooling. That’s why its important to pick the right unit. If its too big it might cool down the temperatures too fast without removing moisture, and that causes the air in the room to be cold and clammy.

Now you have all the information you need to find the right window AC for your room. We’ve also showed you how to keep it functioning optimally for the longest time, and how to prevent unnecessary power load when the unit is turned on.

Unless you have other more specific needs for cooling your room, this should be enough to get you started on buying your preferred brand of window air conditioner.