Best Window Air Conditioner: Top 5 Window Air Conditioners of 2021

Best Window Air Conditioner: Top 5 Window Air Conditioners of 2021

If you don’t have central air conditioning, a window air conditioner is the best option to stay comfortable and cool. Window air conditioners are energy-efficient, inexpensive, and still provide excellent cooling performance. The best part is that you do not need a contractor to install a window AC. Installation is designed to be an easy DIY effort.

Choosing an air conditioner for a room is a simple calculation based on the size of the room and the window opening. The cooling capacity of a window air conditioner is measured in BTU’s (British Thermal Unit). We may intuitively think that an AC with a higher BTU rating is going to do a better job in cooling a room but that is not necessarily the case. Also, many people mix up air purifiers with air conditioners. Please keep in mind air purifiers simply remove pollutants from the air instead of keeping the room cold.

In this article, we’ll review the essential factors in selecting a window air conditioner. We’ll also look at features to consider like how running an air conditioner can improve indoor air quality by filtering out pollen and dust. There are many nifty features like wifi connectivity and customizable settings designed for convenience and temperature control — all geared to maximize energy savings. And, finally, our popular picks will help you keep your cool.

Best Window Air Conditioners in 2021

Window Air Conditioners: Factors to Consider Before Buying

Cooling Capacity & Room Size

As we mentioned, the cooling capacity of the window air conditioner is measured in BTU’s (British Thermal Unit). Selecting an air conditioner purely on BTUs is a common miscalculation which does not take into account the room size and the window opening. What’s nice is that a proper sized air conditioner will help manage both the temperature as well humidity in your room. In short, if the air conditioner is too small for the room it will run constantly, which could be a nuisance and money drain. On the other hand, an oversize air conditioner will make your room unpleasant.

Measuring the window size and estimating the square footage of the room allows you to choose a window air conditioner designed for your room. Here is a chart so you can calculate the correct BTU’s based on your room size:

Room Size sq.ft. BTU’s
Small Room .
100 – 150 5,000
150 – 250 6,200
250 – 300 7,000
Medium Room .
300 – 350 8,000
350 – 400 9,000
400 – 450 10,000
450 – 550 12,000
550 – 700 14,000
Large Room .
700 – 1,000 18,100
1,000 – 1,200 21,000
1,200 – 1,400 23,000
1,400 – 1,500 24,000
1,500 – 2,000 30,000
2,000 – 2,500 34,000

Keep in mind that this table is prepared for a generic living area. There are a few additional factors that you may want to consider when sizing your window air conditioner. As an example, if your room faces direct sunlight it is a good idea to go up by 10% on BTU’s. Also, if your ceiling height is more than 8-ft consider the next size up on BTU’s. Finally, this chart assumes occupancy by 2 people. For each additional person allow 600 BTU cooling power.


Energy Efficiency: What is EER vs CEER?

When considering which particular window air conditioner is right for your room, one of the critical determining factors is the Energy Efficiency Ratio (EER). You can find the EER of the window air conditioner on the specifications document. The higher the EER, the more efficient is your air conditioner. For the technical minds, Energy Efficiency Ratio is simply BTU’s over watts (i.e. the electric energy used).

The Department of Energy (DOE) expanded on the definition on EER in 2014 with the introduction on CEER rating which stands for “Combined Energy Efficiency Ratio”. While EER measures efficiency while the air conditioner is in use, the CEER also takes into account the power usage during stand-by, therefore, you will notice CEER rating to be slightly lower than that of the EER rating. Think of your phone charger. Even if you leave a phone charger on an outlet it keeps on working even when your phone is not attached to it.

All in all, an EER rating of 11.2 to 12 is considered really good for a window air conditioner. Also, a high EER rating is a relevant barometer when it comes to quality of an air conditioner. Most window AC’s on the market have EER ratings of 9 to 12.4. Mini split, ductless air conditioners clock an EER rating of up to 20 but they are harder and more expensive to install.

Most of modern window air conditioners have the revered ENERGY STAR certification. If you are trying to compare 2 models simply check out their Energy Star labels and compare the EER values. Imagine having to spend 10% less on energy bills and still get the best window air conditioning performance.

What is the Best Refrigerant for an Air Conditioner?

The best refrigerant for modern air conditioners is R-410A. The R-410A replaced the old standard R22 (a.k.a. HCFC-22) in 2006. In short, if you purchased your AC before 2006 and if you are trying the decide to fix it or replace it we strongly suggest that you consider replacing your air conditioner with a more energy efficient and environmentally friendly model that uses the R-410A refrigerant.

Are Window Air Conditioners Quiet?

You should consider how noisy a particular room air conditioning unit is before you make up your mind. Most prefer an air conditioner that will emit little or no noise and still function well. A noisy air conditioner may disturb your sleep if you prefer sleeping with the unit running.

While good air conditioners may have a whirring sound as the only source of its noise, a modern-day room air conditioning unit has systems that are designed to create white noise. Consider an air conditioner that meets your cooling needs and does not make much noise while at it.


Directing Air flow

Most window air conditioners are built to blow air in one direction (except for some that have extra revolving fans). Your new window air conditioner will serve you better if the air from it is directed towards the center of the room. Before making a purchase is might be a good idea to learn if your AC has louvers that you can adjust.

Filter Location

To ensure proper cleaning and better air circulation, take the filter location into consideration. Make sure the filter is accessible, can be removed easily for cleaning, and can also be adequately re-inserted. To ensure cleaner air circulation, select a window air conditioner with easily accessible filters.

Proper Installation

This is where knowing the right fit for your window and room really comes into play. Most window air conditioners are built for double-hung windows. For casement windows, you should consider a through-the-wall room air conditioner.


While installing the unit, make sure the unit is installed at an appropriate level for easy and adequate draining. Place the unit on the lip of the windowsill and if the unit has pull open screens, close up gaps as snugly as possible.

It is also important not to have the window air conditioner dangling from a window sill. We highly recommend that you use a supporting hardware to secure your AC.

Window Air Conditioner Mounting Kit

What is a chassis? What is the difference between fixed vs slide out chassis?

Originally a French word, the chassis means a load bearing frame. A rugged chassis helps secure your window air conditioner better. It is a requirement to have a chassis on an air conditioner in dense urban neigborhoods.

A fixed chassis is just a sturdy frame that does not move. A slide-out chassis on the other hand moves when you need to maintain your air conditioner. As air conditioners usually weigh more than 50 lbs and are awkward to handle, you will appreciate a slide-out chassis when the time comes to change the filter or when you would like to winterize your AC.


When faced with a hard choice of having to pick one of two similar products, the warranty offer is usually a determining factor. Products with an extended warranty are more likely to be preferred over others. Before you purchase any unit, check for the manufacturer’s warranty offering. Considering that your air conditioner is going to serve you for 7 to 10 years, it might make sense to get an extended warranty plan to reduce the risk of an unforeseen expense.

Best Window Air Conditioners

Now, let’s look at our choice for the best window air conditioners of 2020.

1) Best Overall: LG LW8016ER


Dimensions (W x D x H): 19 9/16-in x 19 3/8-in x 12 3/8-in | Weight: 58 lbs. | Noise Level: 54 dB | BTU’s: 8,000 | Cooling Area: 340 sq. ft. | CEER/EER: 12.0/12.1 | Chassis: Fixed | Voltage: 110V

Why We Like It:

  • Great performance for the price point
  • Compact size yet packs 8,000 BTU cooling power ideal for small to medium rooms
  • 3 cooling speeds with auto speed bring convenience
  • 4-way air direction by adjusting the deflection (up, down, left, right)
  • Remote control
  • Filter change reminder light (comes with a washable filter)
  • Fresh air vents lets outside air to come in when you want it


  • Meets the industry average on quietness
  • We recommend that you purchase a heavy duty safety bracket
  • No wifi. Consider getting the sibling product LW8017ERSM for wifi.

The LW8016ER can cover more than 340 square feet of space. This excellent performance is thanks to its 8,000 BTUs cooling power. But besides its coverage and the cooling power, the LW8016ER has a three-fan cooling speed and a 4-way direction which further boosts its performance.

The LG window air conditioner comes with a washable filter which helps to maintain fresh air within the room always. The unit has a filter change reminder light which makes the washable filter even more fascinating. At 54dB, the unit just beats the industry noise level requirements, which makes it great for any room in the average household.

The LW8016ER more than meets all the requirements for an excellent window air conditioner, and it offers all these at a great price point. That, and its awesome energy saver option, makes the unit a great choice for most families.

2) Best Budget: Frigidaire FFRA051ZA1

Frigidaire FFRA051ZA1

Dimensions (W x D x H): 16″ x 15.25″ x 12″ | Weight: 41 lbs. | Noise Level: 51 – 56 dB | BTU’s: 5,000 | Cooling Area: 150 sq. ft. | CEER/EER: 12.0/12.1 | Chassis: Fixed | Voltage: 110V

Why We Like It:

  • Excellent energy rating
  • Budget price point for a quick cooling solution.
  • Restores settings and restarts after a power outage
  • SpaceWise adjustable optional side panels are sold separately for custom fit for your windows


  • Does not have a fresh air vent
  • No wifi
  • Accommodates only a very small room

The popular FFRA0511R1 was phased out to give way to its new and energy-efficient sibling, the FFRA051ZA1. Besides its excellent performance, the Frigidaire FFRA051ZA1 stands out because it is very easy to install. All you need is a screwdriver and the accompanying mounting kit, and you have your window AC unit serving you as it should.

Just like the LG LW8016ER, the FFRA051ZA1 has a washable filter which helps to maintain fresh air in the room. Its effortless temperature control feature helps to maintain the preset room temperature, keeping you cool at all times. With adjustable side panels, the unit is designed to fit your window perfectly.

It has intuitive controls which makes it pretty easy to operate, and it is also lightweight. Thanks to its 5000 BTU cooling power, the FFRA0511R1 can comfortably serve a 150 square feet room. The unit is not noisy and is an excellent fit for studio apartments and small rooms, especially if you have a tight budget.

3) Most Quiet: GE PHC08LY


Dimensions (W x D x H): 19″ x 18 1/8″ x 14 3/8″ | Weight: 58 lbs. | Noise Level: 43 dB | BTU’s: 8,000 | Cooling Area: 200-350 sq. ft. | CEER: 11.4 | Chassis: Fixed | Voltage: 115V

Why We Like It:

  • Ultra quiet at 43 dB. 50% quieter than that of similarly sized air conditioners
  • Wifi Connectivity including Apple, Alexa, Google Assistant
  • Easy installation kit included
  • 8,000 BTU’s is ideal or a 250-350 sq. ft. room
  • Filter reset light reminds you to clean (reuseable filter)
  • Comes with side curtains and EZ mounting bracket
  • Remote control


  • GE obfuscated the model number on this product which confuses customers. This model is also known as AEC08LY in big box home improvement stores.

If quietness is your number one desired feature in a window air conditioner, then the GE PHC08LY is the perfect product for your home. At 43 dB, this air conditioner will be quieter than your dishwasher (and 50% quieter than that of its competition). But besides the ultra-quiet performance, the PHC08LY has excellent connectivity features, making it one of the best window air AC units on the market.

Unlike most window air conditioning units, the PHC08LY is designed to work with Apple Home Kit, Alexa, and Google Assistant for effective voice control. You could also control it remotely with your smartphone.

The PHC08LY can comfortably cover a 250 square feet room, thanks to its 8,000 BTU cooling power. The unit is an excellent choice if you desire extra convenience and an ultra-quiet reading/working environment.

4) Best for Large Rooms: Frigidaire FFRE123ZA1

Frigidaire FFRE123ZA1

Dimensions (W x D x H): 24″ x 21 1/2″ x 18 1/6″ | Weight: 79 lbs. | Noise Level: 57-59 dB | BTU’s: 12,000 | Cooling Area: 550 sq. ft. | EER/CEER: 12.1/12.0 | Chassis: Fixed | Voltage: 115V

Why We Like It:

  • Powerful for a medium size room at 550 sq. ft.
  • Able to let fresh air in
  • SpaceWise adjustable optional side panels are sold separately for custom fit for your windows
  • Anti-Bacterial, washable filter
  • Clean air ionizer removes pollens
  • 5 Year refrigerant warranty


  • Meets industry average on quietness
  • Must purchase a heavy duty window bracket

The Frigidaire FFRE123ZA1, with a powerful 12,000 BTU cooling power, is an excellent fit for rooms with up to 550 square feet of space. Besides the extra space covered, the unit has wifi connectivity features, allowing you to control it remotely using your smartphone or voice (Alexa and Google Assistant).

The FFRE123ZA1 has a Clean Air Ionizer feature which purifies the air, removing pollen and unwanted impurities, for a much cleaner air supply. The unit also has a mesh antibacterial filter and an easy install window kit to add to its good points. If you are looking for an excellent window AC which can cover your large and provide an extra touch of convenience, then the Frigidaire FFRE123ZA1 is perfect for you.

5) Most Reliable: Friedrich CCW06B10A

Friedrich CCW06B10A

Dimensions (W x D x H): 19 3/4″ x 23 3/4″ x 14 5/8″ | Weight: 44 lbs. | BTU’s: 6,000 | Cooling Area: 250 sq. ft. | EER/CEER: 12.2/12.1 | Chassis: Slide-out | Voltage: 115V

Why We Like It:

  • Slide-out chassis makes it easy to maintain
  • Washable antimicrobial air filters come with a visual alert
  • 8-Way airflow control to deliver cool to all corners in your room
  • Expandable side curtains for excellent fit
  • Excellent energy saver ratings
  • Quiet operation


  • We wished that Friedrich published their noise levels

The Friedrich CCW06B10A is a remarkable window AC unit with ultra-quiet performance, excellent CEER levels, and one of the best window AC cooling performance in the industry. Top of its features include; the Quiet Master Technology for low noise levels, wifi connectivity with Amazon and Google Home integration, and the expandable curtains that ensures a snug fit during installation.

The most interesting feature of the CCW06B10A is the ease of maintenance. The unit has a slide-out chassis which gives you better access to the interior for easy maintenance. It uses the eco-friendly R-410A refrigerant and has the ENERGY STAR certification.

Besides these, the unit also has a money-saver feature which allows only the fan to keep working when your room is cool, further reducing your energy spending. These make the CCW06B10A the easiest mad least expensive AC unit to maintain.

Which AC Size/Model is Best for Me?

To determine the window air conditioning model that is perfect for your room you’ll need to weigh options like room size, energy efficiency, personal taste, and of course, your budget.

A 5,000 BTU unit is perfect for a room of 150 square feet, while a 10,000 BTU will serve a room of more than 450 square feet. The units we reviewed have several price points to meet your budget, and they all meet the latest energy standards in the industry.

Consider Modern Features

Fortuately, cooling technology has gotten more energy efficient over the years and manufacturers have designed features to make operating these units more intuitive and convenient. We’ve listed some modern features worth considering.

Digital controls
Digital controls allow you to set a precise temperature and makes the readout for the timer, sleep mode and other features clear and easy to use.


Timer and programmable start
Equipped with a timer and programmable start, you can plan on when to turn your air conditioner on and off as well as set a time for how long you’d like it to run.

There’s extra cost savings and peace of mind when you can program your cooling cycles based on your daily schedule. For example, if you and your family are home by 6pm, you can program the air conditioner to turn on at 5:30pm.

Wifi Connectivity
Wi-fi technology allows you to control your air conditioner remotely with an app. This cost-savings and energy-savings option helps if you’ve forgotten to turn the unit off before leaving home or would like to start cooling before arriving home. It’s also helpful if you’d like to start cooling the bedrooms from a different room in your home.


Sleep mode, economy mode, energy saver mode
These modes are designed for energy-savings and temperature control over a period of hourly use. For example, you may want a cool temperature at bedtime with a slow increase of 10 degrees until the morning hours.


Take advantage of an inverter air conditioner over a standard compressor
When an AC comes with an inverter it continuously measures the temperature in the room and speeds up or slows down the compressor. This allows your air conditioner to rapidly cool the room. However, the benefits don’t end here. Inverter air conditioners are at a minimum 25% quieter than that of standar compressors. They also save you meaningful amount of money on your energy bill which helps with the modest upfront cost difference.

Standard compressors cool on one or two speeds (high and low). ACs that have a traditional standard compressor are a tested and true choice, however, they are not energy efficient and also tend to be louder.

Most recently LG release dual inverter window air conditioners with 9,500 / 14,0000 / 18,000 and 22,000 BTU selection.

Air quality features

Fans speeds and fan-only mode
Window units have between 2 to 4 fan speed settings. Some have fan-only mode.Fan speeds allow for versatile climate control within a room. Fan-only mode will continue to dehumidify and filter the air even when the compressor isn’t running. However, please keep in mind that an air conditioner is not a replacement for a dehumidifier. During summer months it is a good idea to run a dehumidifier especially in your basement. The opposite is true for the winter months when a humidifier conditions the air with proper amount of moisture.

Fresh air option
If you’d like fresh air to circulate, choose an air conditioner that can pull in fresh air from the outside to cool and dehumidify. This feature does use more energy since the air outside needs to be cooled and dehumidified before its circulated inside.

Clean filter alert
A light or digital notification lets you know the filter is ready to be cleaned. By removing pollen, dust, and dirt, a clean AC filter allows for cleaner air to circulate.

When an AC has an ionizer, pollutants are captured with an electronic charge. This produces cleaner air and can alleviate allergies and hayfever.


Auto restart after power outage
This is an important feature for areas that have frequent power outages. With this feature, when power is restored, the AC will turn back on and return to the setting it was on prior to the outage.

Remote control
A remote control makes it easy to adjust the AC temperature or other settings from across the room or from another room.


Window AC vs Portable AC

Window air conditioning units serve better if installed well. They are energy-efficient, quieter, less expensive, and will not take up floor space, unlike portable AC units. Portable AC units are meant for homes which have window designs that prevent the installation of window AC units.


Window or room air conditioners are designed to provide cooling comfort and relief in homes that do not have a central air conditioning system. They are energy-efficient, inexpensive, and easy to install. The best window air conditioning units offer more value for money, with some having extra features like wi-fi connectivity functions. Check out our window air conditioner catalogue to pick out one or two of your choice.

Avoid Costly Mistakes: Additional Installation Tips

Verify that your allowed to install a window air conditioner
Check with your homeowners’ association or your condo board to make sure that you are permitted to install a window air conditioner. You may have seen other neighbors with an AC, that does not mean the condo association had certain specifications and installation guidelines. Remember safety comes first when installing an AC.

Invest in mounting rails and side accordion panels
Accordion-style side panels help with a proper fit and insulation. Mounting rails have the proper grooves to accommocate the side panels for a snug fit.

Slightly tilt down the window air conditioner
You want to make sure that the drain water never enters your home. Therefore, it is a good idea to slightly tilt the window air conditioner to allow the drain plate to direct water towards outside.


How long does a window air conditioner last?

On average, a good window air conditioner is meant to serve you for 10-15 years if maintained properly. The quality of the particular product, overall usage and how it is winterized are all influencing factors that affect the lifespan and durability.

Can you leave a window air conditioner on 24/7?

It is NOT advisable to leave a window air conditioner running for hours on end because it could quickly wear the machine out (thereby reducing its lifespan). This would also increase your overall energy costs. Remember to turn off the air conditioning unit if the room is cold and comfortable enough.

How often should one clean a window air conditioner?

For proper maintenance and longer-lasting value, clean your air conditioner at least once every six months. This will also help you detect when the refrigerant is low or exhausted.

Is it okay to spray water on your window air conditioner?

It is okay to use a little warm water and detergent mixture to clean out dirt on the air conditioner parts. You could also make use of a hose with preferably medium or low pressure to spray only specific parts like the aluminum fins, coils and fan. Avoid pouring water on the unit, as this may cause some electrical damages.

Why does my window air conditioner drip water?

While cooling the air inside your room, the window air conditioner also removes humidity from the air and condensates water. Eventually, the AC discharges this water through its outside drain. In some situations, the dripping water can get annoying for neigbors or might damage the wood on your patio. It is a good idea to funnel the water properly via a hose or a small gutter.

It is also important to note that a window air conditioner should never drip water inside your room. This would indicate a faulty installation or one of the following scenarios:

  • Time to change air filters: Over time the air filter on an AC might get dirty and might cause the evaporators coils to freeze which would lead to an unwanted leak.
  • Cracked condensate pan: Your window air conditioner has an internal pan that captures water and channels it to the outside drain. A crack on the condensate pan might lead water funneling to the wrong direction.
  • Cracked drain: Less likely scenario but a crack in your drain pipe might cause water leaks.
  • Low refrigerant: Over the years the refrigerant level in your AC might get low. This causes the evaporator coils to ice and might overwhelm the drain pan.

What do I do with my window air conditioner in the winter?

It is a good idea to uninstall the window air conditioner in the winter months. If this is not possible you should consider winterizing the exposed coils on the outside with protective material. Low temperatures may cause the myriad of small pipes in your AC to freeze and thaw which would eventually cause them to crack.

What is SEER rating?

SEER stands for “Seasonal Energy Efficiency Ratio”. SEER is not widely used but it is a derivative of EER or CEER which we explained earlier. SEER takes into account changes in weather. As an example, an air conditioner is usually more efficient in 75-85 F weather than in the middle of a heat-wave of 95-105 F.

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SIDENOTE. This post was last modified on April 20, 2021. However, we regularly update our content as we test more products and new models are released. We also listen to the feedback of our customers and make changes to our product recommendations based on their experiences. So don’t be surprised if you see some old comments below! Since reader comments contribute to the topic, we have decided not to delete them.

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