How To Install a Window Air Conditioner In Sliding Window? (2022)

Horizontal sliding windows (also known as slider windows) are more often used in regions where space is at a premium and may not be as popular in areas that experience colder weather. A horizontal slider window design can make it a challenge to install an air conditioner, but it can be done safely with proper measures.

This article covers everything from the preparation requirements to installing a window air conditioner in a sliding window.

Installing an air conditioner in the sliding window might not be as simple as installing one in a standard frame, but it’s possible. Before starting the project, measure your air conditioner’s width and height. Also, include any vents that might stick out on the sides and the size of the window’s opening.

Table of Contents

Can You Put a Window Air Conditioner In a Sliding Window?

Yes, you can put a window air conditioner in a sliding window.

If you’re longing to install an air conditioner in a sliding window, you’ll need to ensure that the unit is adequately secured, so it doesn’t fall out when you slide the window open or closed. To do this, we recommend using retaining rods or some other type of securing mechanism.

Window air conditioners are created to fit within a common window space with minimal clearance requirements. The Consumer Product Safety Commission (CPSC) expresses that air conditioners should fit securely within the window opening. There is not more than two inches of space on either side or four inches above or below.

(Video) Install an Air Conditioner in a Sliding Window

There are two classes of window air conditioners:

Casement/slider units are designed to fit horizontally sliding windows. They come in several sizes, and most have slide-out chassis for easy installation and removal. In addition, many have accordion panels on the sides to help you seal the gap between the air conditioner and the window frame—be sure your window is wide enough for the unit you choose so you don’t block the view.

Standard/double-hung units can be installed in vertically opening (aka double-hung) windows. These also come in various sizes, but they don’t have slide-out chassis. So you’ll need to remove them from the window frame when they’re not in use.

How Difficult is This to Do?

If a window air conditioner is your only option, you can still find a way to make it work in a sliding window.

Whether it’s a small apartment or rental home, there are numerous reasons why a central air conditioning unit is not an option. Fortunately, window units are an easy and simple fix for any homeowner.

Before beginning the process, pick up an installation kit, so your unit fits securely into place and doesn’t move around while in operation.

How Long Does it Take?

You can station a window air conditioner in a sliding window in about an hour and a half.

How Much Do Materials Cost?

The total cost of installing a window air conditioner in a sliding window depends on the materials you need to purchase and their prices in your area. This project will set you back $250-$700.

Material costs will depend on the type of unit you choose, how much insulation you need, and whether or not the installation is straightforward or complex.

(Video) Installing an air conditioner in a sliding window

Items You Will Need To Install a Window AC In Sliding Window

How To Install a Window Air Conditioner In Sliding Window? (1)

Window air conditioners are a tangible way to stay cool during the year’s warmer months. They are also simple to install, and they can be installed in many different types of windows, including sliding windows.

You will need to guarantee you have some essential tools and supplies before getting started. Here’s what you’ll need.

  • Deck screws
  • Saw
  • Screwdriver
  • Plywood Scrap
  • Electric drill
  • AC unit
  • Measuring tape
  • Scissors
  • Wrench
  • Ladder (optional)
  • Window sill
  • Weatherstripping

How To Install a Window AC Unit In a Horizontal Sliding Window

Installing a window AC unit in a horizontal sliding window requires some DIY know-how, but it’s not too complicated.

Choose a Window

Choose a window that is at least 6 inches larger than the width of your new AC unit. If you want to find the exact size of your unit, look at the label on the side that says “BTU” (British Thermal Unit).

You will notice two numbers, one on top of the other – the maximum number should be ten times larger than the bottom one. The top number is how many inches wide your unit is.

Be sure to choose a window that can fully support the weight of the air conditioner. Horizontal sliding windows are recommended, as they provide the most space for the unit and allow you to install and remove it quickly.


You’ll need to install weather stripping around the sides of your AC unit to prevent warm air from plunging through any gaps between the unit and the window frame. The type of weatherstripping you choose will depend on the materials used in your window frame.

Apply weatherstripping around the sides of your window frame to ensure no gaps between the frame and the casing. It will keep your unit secure and help stop air leaks that could affect its performance. Just measure your window frame carefully before buying it, so you know how much you’ll need.

(Video) How to install window A/C on a sliding window DIY

Support Brackets

These brackets will hold your AC securely in place while allowing you to open and close the window without removing it from the frame.

A support bracket is essential for keeping your air conditioner in place while you slide it into place on the track of your sliding window. Install the frame at least one foot down from the top of the unit to prevent it from sliding out of place when you open or close the window.

Slide out the side panels of your air conditioner unit, then slide them back in until they click into place. Using one hand to hold it up, use your other hand to mark where you’ll need to drill holes for support brackets with a pencil. Be sure that there is enough room for your window to open over them when fully installed!

Assemble the AC Unit

Before you can plug in your air conditioner, you’ll need to assemble it. It is a simple process: attach the side panels to the central unit. Then, secure them with the two screws included in your kit.

The manufacturer will provide you with a kit and instructions for assembly, so follow them carefully. Once the unit is fully assembled, you must attach the accordion panels to either side of the air conditioner. These panels are usually foam rubber material, filling gaps between the AC and the window frame.

Closing the Gap

If your sliding window has a gap where it fits in the frame, you must use insulation strips or weatherproofing foam to close it before installing your AC unit. Closing this gap helps keep outdoor air from entering your home and keeps internal air leaking outside.

You must also install a window seal or weather stripping around the window frame to close any other gaps to prevent heat exchange through those spaces. Again, this helps maximize the efficiency of your air conditioner, which saves you money on energy bills over time.

It will also ensure that it’s secure when you put it into the window. It also helps direct the airflow into your room instead of letting it out of your window! To close up those gaps, use weatherstripping tape and silicone caulk.

Place Your Air Conditioner

After you’ve closed off any gaps, place your air conditioner in the window and set it down on a pillow if necessary to eliminate any possible vibrations. Then, slide open both windows about an inch. It will let your air conditioner rest against the frame of your window without sliding back inside your home.

(Video) How To Install A Window Air Conditioner Unit In A Horizontal Sliding Window 🛠 | HVAC Training 101

If you have a screen installed in your window, remove it from its tracks, then place it back on once you’ve got everything in place. Make sure that it is balanced on both sides. You want to make sure that it fits inside correctly and that you cannot see any gaps while in place.

Securing the Unit

The last step is to secure the unit. First, you’ll want to screw the stabilizer bracket into the sash. Next, measure and cut the window seal foam. (The foam will be placed around the entire perimeter of the air conditioner.) Finally, press the window seal foam against the frame of your window, and then put your air conditioner back in its spot.

Slide it against a piece of wood that is cut to fit snugly against your windowsill. Next, use a drill to attach some brackets to the top of the unit. It will keep it from moving around while you’re operating it.

Attach a couple of screws to the bottom of the unit. It will prevent it from falling out when you’re tilting it back and forth to clean off your window sill.

Tips and Safety Considerations When Installing a Window AC Unit In a Horizontal Sliding Window

How To Install a Window Air Conditioner In Sliding Window? (2)

When installing a window AC unit in a horizontal sliding window, you will want to use screws to secure it in place. In addition, you will want to keep the unit tilted slightly upward. It is to prevent condensation from forming. You can do this by placing the frame on a few small wooden blocks.

  • After you have installed your unit, you will want to check its level. You can do this with a leveler. If the AC is not level, it will not function properly and may even cause damage to your home.
  • You’ll want to make sure that the AC unit is powerful enough to cool your space. To do this, check out the energy efficiency rating (EER) for the air conditioner. A higher EER is better! You’re looking for an EER of 10 or higher.
  • Ensure to take precautions while installing it to prevent it from falling out of the window and injuring someone. Have a friend hold it in place while you secure it with screws. It will help keep you safe and allow you to focus on lining up your screws correctly.

People Also Ask

How Do I Secure an AC in a Horizontal Sliding Window?

You’ll be happy to know that securing your AC unit in a horizontal sliding window is easier than you might think. The key is to install the support brackets, which will help ensure the unit is to both the window frame and the house’s side.

  1. First, make sure they are the right size for your AC unit to install the support brackets.
  2. Next, clean the area where they will be installed (the window frame and house’s side). Again, you’ll want to use some cleaner to remove any dirt and debris before proceeding.
  3. Then, ensure that you have wooden screws if your frames are made of wood or vinyl or siding or sheet metal screws if you have metal frames.
  4. Once everything is ready, it’s time to install! Using one bracket on each side, attach them securely to the window frame and house’s side.
  5. Add L brackets in front of each frame. It will prevent the window from being opened inadvertently, decreasing the unit’s risk of dropping out the window.

Is it Safe to Have a Window Unit in a Horizontal Sliding Window?

The answer is yes, it’s safe to have a window unit in horizontally sliding windows—as long as you take a few precautions.

Many homeowners are concerned about placing their new AC unit inside a sliding window for fear of scratching or damaging the glass. In most cases, this won’t happen unless you’re not using an in-window support bracket as part of your setup process.

(Video) AC window installation - in a slider window - the easiest way

The bracket prevents the weight from sitting directly on top of the glass pane, which keeps it safe from being scratched or damaged by the weight of your new AC unit.


The bottom line is that you can put a window unit in a sliding window, but you must be very careful. The most hands-on way to deal with this is to put the AC on a track—that way, it won’t hang down as far and will be less likely to get caught by people or furniture.

Overall, installing a window air conditioning unit in a sliding window can be easy with a few tools and your instruction manual. With careful measurement and installation, you will have your own relaxed and comfortable space in no time at all.


Can you put an air conditioner in a slider window? ›

Fit the frame or if you had screwed the air conditioner in the frame, fit them both on the space left by the sliding window. You can screw the air conditioner's structure against the window's frame using large screws to tighten it. Once you are done, you can plug in the A/C and turn it on.

Do window air conditioners work with sliding windows? ›

There are a number of window air conditioners on the market that can retrofit into sliding windows. These units are typically much smaller than traditional window air... conditioners, and they're designed to fit into a sliding window frame.

How do I fill the gap in my sliding window air conditioner? ›

How to Seal an Air Conditioner Window Gap - YouTube

How do you install a portable air conditioner in a horizontal sliding window? ›

Learn How to Install a Haier Portable Air Conditioner into a Sliding Window

How do you install a LG portable air conditioner in a horizontal sliding window? ›

How To Install Portable Air Conditioner In Horizontal Sliding ...

What is the smallest width window air conditioner? ›

The Smallest Air Conditioner

Not only is the 5,200 BTU model by Friedrich the smallest window air conditioning unit (it fits windows starting at 22 inches wide and openings 12 inches tall), it's also quieter than the top pick on this list.

How do you make a window air conditioner support? ›

How to Support a Window Air Conditioner - YouTube

How do you seal a gap in a sliding window? ›

‍ How to Seal Sliding Windows | elLiven | HowTo - YouTube

What do you put around a window air conditioner? ›

To get the perfect seal on the outside of the unit, use exterior caulk all around the perimeter. An alternative to weather stripping is spray foam insulation. The kind you get in a tube from Lowe's or Home Depot. If you never plan to remove your window air conditioner, it's fine to apply directly.

Can you put an air conditioner in the top part of a window? ›

Most of them have hired help, but you can totally do it yourself if you are handy and have help with the lifting, etc. The main thing is that the unit has to be attached to your window frames (screws), which is a little trickier with metal frames, but definitely doable.

How do you install a long long portable air conditioner in a sliding window? ›

How to set up your De'Longhi portable air conditioner - YouTube

How do you vent a portable air conditioner in a sliding glass door? ›

How to Install a Portable Air Conditioner Through a Sliding Door

How do you install a Toshiba portable air conditioner in a sliding window? ›

Toshiba Inverter Portable AC Overview - YouTube

How do you install an air conditioner in a swing out window? ›

Install an Air Conditioner in an Old-Fashioned Casement Window

How do you install an air conditioner in a aluminum window? ›

How to Install and Reinforce Window AC Unit - YouTube

How do you make a window air conditioner frame? ›

DIY - Window AC Unit Installation - YouTube

Most window air conditioning units are designed to sit in vertically opening windows. Those specially designed to fit into sliding windows cost more than the regular window air conditioners so created a guide for you to learn how to install a window air conditioner in a sliding window. Since wind

Most window air conditioning units are designed to sit in vertically opening windows.. Those specially designed to fit into sliding windows cost more than the regular window air conditioners so created a guide for you to learn how to install a window air conditioner in a sliding window.. This article provides a step-by-step process for installing a sliding window air conditioner in a horizontal sliding window.. Source: Shutterstock A window air conditioner Plexiglass or plywood Weatherstripping Power drill Measuring tape Scissors Screws Flathead and Philips screwdriver Table saw. Subtract the height of the air conditioner from the height of the window sill to get the right height dimensions for the frame.. From the bottom side of the long lumber pieces, mark the height of the window air conditioner.. If you don’t have the time, patience, or skills to construct your own frame for your window air conditioner unit, you can find a window kit and installation kit online that you can use instead for installing a room air conditioner in your sliding windows.. It should fit such that when you close the sliding window, the outer sill of the window fits on the outer edge of the frame.. Then install the window air conditioner.. Slide the air conditioner forward until the bottom of the lower frame is in touch with the bottom of the top rail.. That way, the frame prevents the window air conditioner from leaning forward further.. Install weatherstripping all around the air conditioner unit once it is secured in place.. Make sure you use weatherstripping in the space between the top rail and the bottom of the frame, on the sides, and between the windowpane and the bottom of the air conditioners.. Once you place the bottom of the air conditioner on the windowsill, ensure the unit’s weight is evenly distributed.. Learning how to install a window air conditioner in a sliding window does not have to be a complicated process.

With the differences in temperature that tend to be more and more dramatic, every house needs an AC unit. Useful in both cold and warm weather, these devices are ideal if you want to quickly make the temperature in your house comfortable while keeping the bacteria and unwanted allergens away.

Pros: 👍 When used in Dry mode, it eliminates 2.3 pints of moisture per hour from the air – you won’t need to run the dehumidifier in the room where you install the AC anymore. 👍 When the Energy Saver mode is activated, the unit draws considerably less power when it runs so that you won’t overspend when the energy bills are due. 👍 Airflow direction control – you decide where exactly in the room the air goes for added comfort. 👍 When the filter needs to be cleaned, the Check filter indicator lets you know – no more guesswork regarding upkeep routines. 👍 Use the included remote control to adjust the settings as you like from anywhere in the room. 👍 Easy to install and operate – perfect for first-time AC owners. Pros: 👍 You can set the 24-hour timer in 30-minute increments to customize the unit’s operation and reduce running costs. 👍 Automatically restarts with the pre-selected settings when the power comes back after an outage. 👍 Sleep mode gradually increases the temperature a few degrees as the hours pass, maintaining a comfortable living space and saving energy in the process. 👍 The washable filter saves you money since it doesn’t need replacement but rather only routine cleaning, and it traps dust to keep it from affecting the AC’s efficiency. 👍 Energy efficiency ratio of only 10.4 – doesn’t cost much to keep the AC running as long as you need it to each day. Pros: 👍 The 24-hour timer lets you program when the unit should turn on or off beforehand. 👍 The 4-way air directional louvers let you pick the airflow direction. 👍 Rated at 10,000 BTUs cooling – perfect for areas of up to 450 square feet. 👍 When used in Dry mode, it can eliminate up to 55.7 pints of moisture per day. 👍 Full function remote control with Follow Me technology included in the package. Like any top-of-the-line AC, it integrates multiple operating modes, so you can use it for more than simply cooling the room – it works as a dehumidifier ( it can withdraw up to 55.7 pints of moisture every 24 hours ), and a fan ( there are 3 speed settings to pick from, and it circulates the air in the room just as effectively as a specialized fan would ).. Pros: 👍 Very efficient as a dehumidifier – eliminates 2.3 pints of moisture from the air. 👍 Automatic restart function ensures the unit picks up its operation from where it left off. 👍 Thermostat function remote control included for added convenience when operating the AC. 👍 Backed by a 1-year warranty on parts and labor, and 5 years for the sealed system. Pros: 👍 Removes up to 50.6 pints of moisture per day when used in Dry mode – enough to replace a standalone dehumidifier. 👍 Lets you set the temperature from 61 to 86 degrees Fahrenheit. 👍 The included remote has a 16-foot range – change the settings without getting off of the couch. 👍 Among the quietest entries available – produces only 49 dB when it runs. 👍 Backed against defects by the manufacturer for 2 years. Do window AC units include filters?. Can I run my window AC all day?

The best window air conditioner unit will keep your home cool while conserving energy, even during the hottest months of the year. We gathered the best window AC units for rooms of all sizes, a variety of window measurements, and various cooling needs.

The window air conditioner's display is also extremely easy to use, and you'll be able to connect to a device, change the fan speed, turn on night mode, and more in just the press of a button.. When it comes to energy efficiency, the Midea window air conditioner is one of the best available: It was named one of Energy Star's most efficient air conditioners of 2022 , using almost 38% less energy than competing models.. While several other window air conditioners on our list have stellar energy efficiency ratings, the GE Inverter model boasts a Combined Energy Efficiency Ratio of 15.7 and ties for first place in Energy Star's top air conditioners of 2022 .. Why You Should Get It: Powerful enough to cool rooms up to 550 square feet, this unit has multiple fan speeds, cooling settings, and a convenient remote control so you can change settings from across the room.. Plus, it offers two fan speeds to keep small rooms in your home cool.. One downside to the GE window air conditioner is its noise levels, which range between 52 and 59 decibels, depending on the fan speed you set it to.. Why You Should Get It: This vertical window air conditioner is designed to work in sliding windows, but it still offers all the same features and quiet noise levels you can find in the best horizontal window AC units.. Window air conditioner units are easy to install yourself, they're less expensive than purchasing a central air conditioner, and they're highly energy efficient, allowing you to save money on your energy bill every month.. Our top pick for the best window air conditioner is the Midea Inverter U Window Air Conditioner due to its innovative design that minimizes noise and its high energy efficiency rating, which can save you as much as 38% on your energy bill compared to other models.. Room Size: Since different window AC units have varying cooling capabilities, you'll want to keep your room's square footage in mind.. However, most rooms in your home won't need such a high-powered unit; rooms that are between 150 to 500 square feet will need somewhere between 5,000 to 12,000 BTUs of power to keep them cool.. However, some window air conditioner units may need professional installation.

Installing window air conditioner into a vertical position, which is a window that slides up and down instead of left and right, is similar to installing a horizontal-sliding window.

Installing window air conditioner into a vertical position, which is a window that slides up and down instead of left and right, is similar to installing a horizontal-sliding window.. The portable air conditioner is the quickest growing in popularity of all the home air conditioner units.. Simple to install with just one person Fit in all different kinds of windows instead of just standard sizes Portable AC with heat spec can be used year-round Can be used as an accessory with a central AC system and located in a bedroom or living room to keep extra chill without turning down the thermostat to the full home.. The number 1 reason that portable AC units are returned to stores is that consumers do not realize that the system must be vented.. Pull out any extension pieces so that there is a perfectly tight seal between your room and the outside globe.. Once the window kit is in location the end steps to install a portable AC are nothing more than applying a safety bracket to the window so it can be unlocked from the outer area, hooking up a vent from the AC to the window panel, and plugging the system is a grounded outlet.. Vertical air conditioners are not just an affordable cooling choice, but they are also very efficient in the amount of power they use.. To help you figure out what kind of AC unit will be the top solution for you, we have compiled a list of advantages you should expect from vertical window AC.. The first big benefit that vertical window air conditioners have is their affordable and low cost.. Not only are they quite affordable to buy, but they are also extremely affordable to run on a monthly basis.. Many window AC does more than just offer chill air.. There are lots of window units accessible that can offer both cooling and heating for your home.. There are many different techniques for a chilling room with no windows.. You cannot run a window air conditioner without a window, you can run a portable AC sans window as long as you have a new way of accessing the outside.

What size air conditioner do I need? There are several metrics you should consider before buying an air conditioner. You have different EER and SEER ratings, power, amperage, voltage, and so on. The most important metric is the cooling capacity (measured in BTU/hr). It denotes the size of your air conditioner. BTU meaning: British Thermal ... Read more

What size air conditioner do I need?. What is BTU is an AC unit?. ft. area with 8 feet ceilings, average sun exposure, average climate, and not including kitchen (you can find this BTU calculator below and use it for your situation; with 4,000-24,000 BTU room size table) :. Based on room size, ceiling height, and other conditions, you can calculate how many BTU air conditioner you need:. Example: When you use the BTU calculator below and get, let’s say, 10,000 BTU for a 500 sq ft area, start looking for a 12,000 BTU air conditioner.. Question: What is the 12,000 BTU air conditioner room size ?. If the room or area you’re looking to cool down is generally facing the sun, you will need a bigger air conditioner.. Example: If you have a 500 sq ft sun cabin near Texas with many glass windows, you should be looking at 10,000 BTU air conditioners (as recommended).. It would be best if you were looking at 14,000 BTU portable air conditioners, for example.. That means that a 500 sq ft room needs a 10,000 BTU air conditioner.. Of course, do make sure to buy an AC unit that is a bit stronger if you have high ceilings, live in a hot climate, and have an above-average sun in those rooms.. Window AC units .


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