We recommend the ONLY sliding window air conditioners worth knowing about. Get the perfect fit for your window space today with our comprehensive guide.
There are lots of sliding window AC units on the market so we've narrowed down the choice to five of the most reliable, functional, and energy efficient models that we recommend over the rest.
If you’ve never bought a vertical window air conditioner before (or a horizontal AC for that matter), you could probably do with some advice to point you in the right direction.
In our buyer’s guide, you’ll find all the information you need to choose the right sliding window AC for your home. Check this out especially if you're unsure about getting the right cooling capacity for your room.
Some of the links below are affiliate links, meaning, at no additional cost to you, we may make a commission if you click through and make a purchase.
Our Recommended Sliding Window AC Units
See how the top vertical window air conditioner compare in the table below.
There's a key that explains all the table contents below.
We review all five recommendations in the following section.
HomeLabs 6,000 BTU WiFi
Our #1 Recommendation
Midea 12,000 BTU EasyCool
Most Energy Efficient
LG 8,000 BTU
Energy Efficiency: the Energy Efficiency Ratio (EER) is the ratio of energy used to cooling power. The higher this number the more energy efficient the AC unit is.
AC for Sliding Window Reviews
Now, we take a closer look at each of our recommended window mount AC units. Find out all the details and what we think and why.
Our Top Pick
Midea 12,000 BTU EasyCool
An energy efficient window mounted AC for spaces up to 500 sq. ft.
This is the AC for vertically sliding windows that we recommend over the rest.
Well suited to rooms of up to 500 square feet, it manages to cool energy efficiently and quietly too.
But most importantly, will it fit your window?
Provided you have a vertically sliding window between 23 and 26 inches wide, which can slide up to provide an opening of 15.5" then yes it will!
It comes with mounting accessories and instructions and provided you don't have some obscure window set-up, installation should only take 30 minutes.
With 3 modes of operation, it's a versatile little window AC. Besides air conditioning it also works in 'fan only' and 'dehumidify' modes. The dehumidify mode is pretty powerful too. It will happily remove up to 2.5 pints of water from the air every hour.
It's air conditioning that it does best though (thankfully!). There are 3 special modes that make it stand out. They are EcoSave, SleepWell and EasyTimer.
The EasyTimer allows you to program temperatures for up to 24 hours, while EcoSave is an accurate thermostat that allows the most energy efficient operation possible.
On the point of energy efficiency, this AC has an EER of 12 and comes with that coveted Energy Star Certificate that only the most economical appliances have. An EER of 12 is really good considering it's a more powerful AC unit at 12,000 BTU.
It comes with a fully functional LED remote control that while in your possession can be set so that the fans follow you as you move around the room.
The Midea EasyCool is compact, reliable, and capable of cooling efficiently and effectively.
HomeLabs 6,000 BTU WiFi AC
An energy efficient window mounted AC for spaces up to 500 sq. ft.
This 6,000 BTU window-mounted air conditioner from HomeLabs is one of the smaller models on the market and is ideal for cooling room of up to 250 square feet in size.
It's a great choice for compact homes, bedrooms, apartments, tiny houses and dormitory rooms. It's actually available in larger sizes that will cool spaces up to 550-700 square feet too.
Measuring just 18.5 x 15.5 x 13.4 inches, it's a really compact unit that's perfect for window spaces between 23-36 inches wide (it needs 14" of vertical space). It comes with a special window installation kit for windows of this size.
There's actually an even smaller 5,000 BTU version but it doesn't have a thermostat so it didn't make our shortlist.
At well under $250 it's a really affordable option that has value for money firmly at its core. But, that doesn't mean it's not without all the essential features (for us anyway).
Regular AC cooling is combined with fan only, and dehumidify modes to offer 3 distinct functions.
A timer, thermostat, and eco mode are also available for efficient and effective cooling. Heat settings range from 62 °F to 89 °F.
A nice addition to this newest iteration to the HomeLabs range is the WiFi integration via the smartphone app. While paired with your phone you can control the AC down to the smallest detail.
You can even have the fan direction follow you as you move around the room (the fans point in 4 directions)! Voice control is also available through Alexa and Google Assistant.
It also stands out when it comes to energy efficiency. With an Energy Efficiency Ratio (EER) of 12.1 (the higher the better) it rates as one of the more energy efficient sliding window ACs. It actually comes with an Energy Star Certificate which is a real selling point.
Air conditioners can be loud so it's important we highlight the noise levels. This model ranges from 52 to 56 dB which is about average these days. The lower level is with the fan setting on low.
There is an inclusive antibacterial filter which can be washed using dish soap and warm water or even cleaned with a vacuum cleaner. It can then be reused to improve the cooling power of your unit.
If you experience respiratory problems or allergic reactions, or are worried about air pollution then an air filter like this could help.
This model comes complete with everything you need to install it. You’ll get support brackets, window sealing foam, a drip-free installation guide and leaf guards as well as the unit itself. The power cord is reasonably long at six feet but not the longest you'll find.
The HomeLabs 6,000 BTU WiFi is a really efficient piece of kit that's incredibly compact and full of intelligent features.
Most Energy Efficient
LG 8,000 BTU
Ideal for spaces up to 350 square feet, this AC for windows has energy efficiency firmly at its core.
Specifically for vertical sliding windows of 22 - 36 inches wide, this 8,000 BTU air conditioner cools spaces of up to 350 square feet with efficient ease.
With 3 modes of operation including air conditioning, dehumidifying, and a multi-directional 3-speed fan, it's versatile and suited to cooling in a variety of climates.
The dehumidifier itself can remove 2.2 pints of moisture from the air every hour, while the fan can produce airflow of up to 250 cubic feet per minute (CFM). This is ideal for saving energy during slightly cooler weather when you just don't need the extra cooling power of air conditioning.
With an impressive Energy Efficiency Rating of 12 and an Energy Star Certificate, you know this window AC for side sliding windows has your back when it comes to saving energy and money.
Key features such as a programmable timer and an accurate thermostat are key to its energy saving credentials. Simply set your preferred temperature or times of operation and let it get to work in the most economical of ways. There are precise temperature intervals between 60 and 86 degrees Fahrenheit available.
It's not loud either. At 54 dB it makes around as much noise as a refrigerator. That's pretty good for an air conditioner for a side sliding window and it compares favorably with the competition.
If energy saving is a priority of yours, this 8,000 BTU model from LG is well worth closer inspection.
EdgeStar Koldfront 12,000 BTU
If you’re struggling to keep your home cool during the summer heat, the EdgeStar Koldfront 12,000 BTU air conditioner is a great choice.
It can supply a space of a maximum of 500 square feet with plenty of cooling power, so whether you want to cool down your living room, home office or bedroom, you’ll have no difficulties.
This narrow window air conditioner is compact yet really powerful. It’s surprisingly simple to install, and since it can fit any window between 23 and 36 inches in width and with a height of 15.5 inches or higher, it can accommodate most needs.
You won’t need to exert yourself to actually manually adjust the settings thanks to the included remote control which allows you to alter the operational settings from as far as 16 feet away.
It has been Energy-Star certified so you can save on your bills while still staying comfortable during the hotter days of the year. The Energy Efficiency Ratio (EER) of 12 is really impressive and makes this the most energy efficient window AC unit around.
Further energy-saving features include a thermostat-controlled operation, a sleep mode and a check filter indicator so you can maximize your savings. The sleep mode is especially beneficial. It periodically adjusts the temperature by 2 degrees Fahrenheit before going back to the chosen temperature after 6 hours.
There are three different fan speeds to choose from so you can get your optimal level of cooling and, as an added advantage, there’s also a dehumidifying function which will cleanse the room from any excess moisture. This will help your environment to stay healthy and mold-free.
How does it compare to the rest?
Very favorably! This sliding window AC unit is one of the best in the business. For starters, it's Energy-Star certified for being one of the most efficient models of its kind. The EER rating of 12 beats most of the competition hands down.
It'd also impressively priced. Despite being the most powerful and most efficient model on this list, it's not actually the most expensive. It's in the mid-price range which makes it a great value purchase.
Bottom Line: It's hard to beat this gem from EdgeStar. Price-wise it offers great value for money, and performance-wise it's powerful and efficient. This is the window AC that we recommend over all others.
Frigidaire FFRS0822S1 8,000 BTU
If you’re looking for an ideal cooling solution for your room measuring a maximum of 350 square feet, this air conditioner for a horizontal sliding window ticks all your boxes.
Designed specifically to fit in a casement-style window, this 8000 BTU 115V conditioning unit couldn’t be easier to use. Its electronic controls enable the user to select options easily with a single touch of the button.
If you prefer to control your unit from a distance – and who doesn’t when the weather’s too hot to move – you’ll lovely the fully functioning remote control. It allows you to control the fan speed and temperature from anywhere in the room without ever having to get up from your sofa.
The multi-speed fan has three speeds to choose from to give you the ultimate in cooling flexibility, while the four-way air direction controls enable you to choose exactly where you want to direct the cool air.
You can rest assured that your home will stay comfortable and healthy thanks to the integral mesh filter. It can be slid out and washed to reduce room odors, airborne particles and bacteria in your space.
Whether you suffer from allergies, asthma, or whether you’re just concerned about your indoor air quality, this horizontal window air conditioner will help you maximize your well-being. Since it also runs really quietly, you won’t need to worry about your sleep being disturbed.
Bottom Line: Overall, we think this is a really great choice of casement window air conditioner if you’re looking for simplicity, convenience and function. Your room will stay cool and you won’t be disturbed by loud running.
Recommended Reading: Don't miss our guide to the top performing quiet & portable AC models!
Frigidaire FFRS1022R1 10,000 BTU
Frigidaire’s casement window air conditioners are known for their high quality and excellent performance. This one won’t disappoint.
Having been specially designed for installation in sliding and casement windows, this model comes complete with an installation kit so you can get straight on with fitting it in your window.
This 10,000 BTU unit is capable of cooling a space measuring up to a maximum of 450 square feet. It also has a dehumidifying function which is capable of removing as much as 3.4 pints of excess moisture every hour. This is excellent news if you need to guard against mildew and mold build-up in your home.
This slider window air conditioner comes equipped with electronic multi-speed controls while the 24 hour on and off timer makes it easy to ensure your room is the perfect temperature when you get up in the morning or when you come in from work in the evening. There is also a fully functioning remote control so you won’t need to physically adjust the controls.
There are several modes to choose from – the auto-cool function, a sleep mode and an energy saving mode – so you can reduce your bills while still benefiting from maximum cooling. There is also four-way air direction so you can get the cool air to every part of your room in the most effective way.
You won’t need to worry about bacteria in the air – there is an integral mesh filter which can be removed and washed at regular intervals. You’ll have a healthier living environment and allergic reactions and respiratory problems will be reduced. There is also an alert letting you know when it’s time to check the filter so you can keep your unit running as efficiently as possible.
This Frigidaire unit can be used in windows of between 21.5” and 40” in height and with a minimum width of 15.5”. Whether you’re using it in a living room or bedroom, you won’t need to worry about being disturbed, since the quiet operation of this cooling unit makes it very unobtrusive.
Bottom Line: Convenience and multi-functionality come as standard with this air cooling unit. You can benefit from a healthier home environment thanks to reduced bacteria and mold build-up while also reducing your energy bills and keeping your home comfortable. If you’re looking for a reputable brand, this could be the perfect model for you.
Recommended Article: In need of a tiny mini-split AC unit? We've got the perfect guide for you here.
We’ve recommended five different models in our guide, all of which are suitable for use in different sizes of spaces.
Whether you’re searching for a suitable unit for your compact dorm room or whether you need a model which is capable of cooling down a much larger space, we’ve suggested a window air conditioner that’s ideal for you.
Although all the models that we’ve recommended are excellent choices. In our opinion, these are the three that are top of the class.
HomeLabs 6,000 BTU WiFi
Our #1 Recommendation
Midea 12,000 BTU EasyCool
Most Energy Efficient
LG 8,000 BTU
Recommended: Learn how to clean window AC units in this guide.
If you’re choosing your first slider window air conditioner, you may not know how to begin making a final purchasing decision.
If so, read on and discover our helpful buyer’s guide. We’ll give you all the information you require to make the right choice for your home.
From the top things to consider before making your final choice to the best way to install your unit, we’ll tell you everything you need to know.
Things to Consider Before Buying
If this is the first time you've shopped for an air conditioner for sliding windows then this section is well worth a read.
These are the things to pay special attention to so that you get the right AC unit for your room.
1. Getting the Right Cooling Capacity
Probably the most important decision you need to make is about the cooling power you require.
The cooling power is expressed in BTUs (British Thermal Units). A unit with a higher BTU rating will be able to cool a bigger space.
However, it's important that you don't just go for a larger size because it's more powerful. This doesn't make it better and in fact this could be costly in the long term.
It's crucial that you match the cooling power of a window air conditioner (or any other type of AC) to the size of the room or space that needs cooling.
By getting the right sized AC unit you'll ensure that it cools as efficiently as possible and doesn't waste energy. You'll also ensure that it doesn't overwork and that it lasts 10 or 15 years instead of 2 or 3.
Here's what you need to know:
Area Needs Cooled (in sq. ft.)
Cooling Power Required (BTUs)
The table above is a great guide but you might need to make some slight adjustments in the following situations:
2. Plan for Installation
Getting the right cooling capacity is crucial but ensuring your new sliding AC unit actually fits in your window frame is quite important too!
Firstly, you'll need to pay attention to the type of window you have.
Does your sliding window open vertically or horizontally? Is it a casement window (one with hinges)?
You'll also want to take measurements of the available width and height within your window frame.
All ACs for sliding windows come with installation kits that require little more than a screwdriver to install. Installation is always advisable for 2 people as these units can be heavy and someone should hold it in place while the other does the fitting.
Remember you'll need to plug it into an electrical source nearby too! A cord won't be more than 10 feet long (but please check) and a powerful electrical appliance like this should NEVER use an extension.
3. Energy Efficiency
Not only will you find each unit has a BTU rating, you’ll also find they have an EER rating too.
The Energy Efficiency Ratio (EER) is a number representing the energy output compared to cooling power.
It's basically a way to measure how well engineered an AC unit is. How much energy does it require to cool you room?
If the EER number is higher, you’ll reduce your energy bills when compared to a model with a lower EER number.
You’ll also reduce your carbon footprint – something which is very appealing in this day and age.
If a model is particularly energy efficient then it may have an Energy Star certificate.
Typically, you should be looking for a sliding window air con unit that has an EER of above 10 but some expensive models offer closer to 15 these days.
The balancing act here is that you pay a lot more for an energy efficient appliance but it will save you money on energy bills over the course of its life.
It's usually more economical in the long-term by paying more initially and recouping the money with cheaper energy bills. This is especially true in 2023 with rising electricity bills.
4. Noise Levels
Window mounted air conditioners can be a bit noisier than your regular wall mount/external compressor ACs.
Since they're all-in-one units, you can't isolate the noisy compressor outside.
However, some clever design ensures they're not as noisy as they might be.
Typical noise levels range from 45dB on the quiet end up to around 50-55 dB on average.
The smaller, less powerful models are quieter than the bigger ones. Also, those with weaker fans tend to be quieter.
The feature that you shouldn't be without is a thermostat. This allows you to run your air conditioner at its most energy efficient.
Simply, set the desired room temperature and it will automate the cooling process by turning itself on and off when required. This saves energy as your AC is only running when it needs to.
A 24-hour timer is also a useful feature that can save energy. You can also use it to have your room cooled and ready for your arrival home.
You'll see 'Sleep Mode' advertised quite often and this varies from manufacturer to manufacturer but it generally works by increasing the temperature automatically (in small increments) through the night. Like an increasing thermostat setting.
Remote controls pretty much come as standard these days but the functionality they offer varies wildly. Some offer the full spectrum of controls that you'll find on the main unit itself while others only offer the most basic of functions.
Some window air conditioners feature excellent filters, others don’t.
You should look for a model which filters out allergens, bacteria and dust.
Whenever possible, choose a unit with a longer-lasting, reusable and rewashable filter as this will maximize its lifespan and improve the efficiency of your unit.
7. Fan Settings
You'll want to have at least a couple of airflow speeds to choose from.
In fact, you might want to have as many options as possible to choose from to give you all the flexibility you need in different weather conditions.
This is particularly important during the night as the lower air speeds are quieter for when you are sleeping.
You can run in 'fan only' mode too which is a lot cheaper than engaging the compressor and using the AC fully.
While sliding window air conditioners aren’t expensive compared to the other types, you should still look for a good warranty.
Warranties tend to range from 1-3 years. But 1-year is definitely what you'll find in most cases.
The compressor warranties are usually much longer with around 5-years being the average.
Why Choose a Window Air Conditioner?
Although sliding window air conditioners can be ideal for many people, for some people they aren’t the right choice.
Here, we look at the pros and cons of choosing an air conditioner for sliding windows.
- Lower priced than a central air conditioning system
- Not permanently fixed into your window so you can remove it if necessary
- Wide selection of options available so you can find one to suit your needs
- Versatile – you can adjust the settings and controls to suit your needs and the current temperatures
- Efficient – when you choose an Energy Star certified model you can be confident that you’ll save on energy and reduce your bills
- Quiet running – the best sliding window air conditioning units are designed to operate quietly so they won’t disturb your sleep or leisure time
- Drainage without added plumbing – these types of window air conditioning unit are designed to drain away water without needing to hire a contractor to fit new plumbing systems
- Ideal for use in locations where summers are short
- Aesthetically unappealing
- May reduce the security of your home
- Can be bulky and heavy to install, especially if you’re installing the unit alone
- Hard to insulate and seal well
- Sometimes, you’ll need to add exterior support
How to Install Your Sliding Window Air Conditioner
The good news is, if you’re already familiar with your window opening size before you buy, you’ll find installation a breeze.
It’s always wise, however, to have another person to help you, especially if you’ve chosen a higher BTU model since these units can be heavy and bulky to handle.
You can install your air conditioner by following these rough steps. But always consult your specific manual.
- Open the window as wide as possible.
- Put the air conditioner on the bottom of your window.
- Slide down the window until it has made contact with the unit.
- Using the shims, level the air conditioning unit. You’ll need to ensure that it is angled slightly towards the outside of your property to ensure proper drainage.
- Add installation hardware to support the unit then seal around your window. Sometimes, you’ll need to improvise when it comes to sealing in order to get an effective seal and eradicate air gaps.
- Add some additional support brackets outside to offer more support if you have a very heavy unit.
- Plug your new unit into a power outlet.
- Your cooling unit will now be ready to cool down your room.
Visit this page for more detailed instructions.
There are lots of questions you may want answered when choosing a sliding window air conditioning unit.
We've done our best to answer a few of the most common questions we receive below.
Can I use an extension cord to power a window AC unit?
This is a fire hazard!
These are powerful devices that you shouldn't take that kind of a chance with.
You should choose a window for your air conditioner which is close enough to a power outlet so that you won’t need an extension cord.
Alternatively, hire an electrician who can install a new power outlet close enough to the unit.
Can I get a slightly lower BTU unit to save money?
No, this isn't a good idea and it won't save you money like you think it will.
A less powerful unit will just need to work harder to maintain the same temperature.
This will impact its lifespan and you'll just need to replace it sooner than with a model that's the right size for your room.
If you're unsure about sizing, we've got a great resource here.
Is a casement (or sliding) window air conditioner right for me?
If you live in an area with warm weather all year round and are looking for a long-term ongoing solution to cooling, you might want to consider a central air conditioning system instead.
This will probably be a more practical solution in the long run.
Alternatively, if you want an air conditioner which you can easily move between rooms, a portable model might be a better choice.
A window air conditioner is a great semi-permanent solution for cooling in a lot of cases though.
With so many different sliding window air conditioning units to choose from, it can be difficult to make the right decision.
However, if you follow our buying guide and our product recommendations, you can be sure that you’ll have all the information you require to find the best sliding window air conditioner to suit your individual needs.
Whether you’re looking for a model for a larger or smaller room, we have the perfect cooling solution for your home when a central air cooling system isn’t possible.
We hope you've found our guide useful. If you have any questions then be sure to leave a comment down below!