The Ultimate Guide to Installing an AC in Your Casement Window: A Step-by-Step Approach

When summer comes around, staying cool and comfortable is a top priority for many homeowners. One of the most efficient and cost-effective ways to achieve this is by installing an air conditioner (AC) in a casement window. In this comprehensive guide, we will walk you through the entire process of putting an AC in a casement window, so you can enjoy a cool and comfortable living space during the hottest months of the year.

What is a Casement Window?

Before we dive into the installation process, it's essential to understand what a casement window is. Casement windows are hinged at the side and open outward, either to the left or right. They are usually operated by a crank handle and provide excellent ventilation and unobstructed views. Casement windows are a popular choice for many homes due to their versatility, style, and energy efficiency.

Choosing the Right AC for Your Casement Window

Before you can install an AC in your casement window, you need to choose the right unit for your needs. There are two main types of air conditioners that can be installed in casement windows: vertical window AC units and portable AC units.

Vertical Window AC Units

These units are specifically designed for casement windows and are taller and narrower than traditional window AC units. They can be installed directly into the window opening and are secured with brackets and support systems. Vertical window AC units are an excellent option for those who want a more permanent solution and don't mind sacrificing some window functionality.

Portable AC Units

Portable AC units are freestanding units that can be moved from room to room. They require a venting hose that can be attached to a casement window using a window installation kit. Portable AC units are a versatile option for those who want the flexibility to move the unit around their home and don't want to obstruct their window view.

Measuring Your Casement Window

Before purchasing an AC unit, it's crucial to measure your casement window to ensure the unit will fit. Measure the height and width of the window opening and compare it to the dimensions of the AC unit you're considering. Make sure to leave some space for brackets and support systems when measuring the window.

Preparing the Window for Installation

Before installing your AC unit, you'll need to prepare the window by removing the screen and any hardware, such as the crank handle. You may also need to remove the window sash if it interferes with the installation of the AC unit. Be sure to follow the manufacturer's instructions for your specific AC unit when preparing the window.

Installing the AC Unit

Now that your window is prepared, it's time to install the AC unit. The installation process will vary slightly depending on the type of AC unit you've chosen.

Installing a Vertical Window AC Unit

1. Attach the support brackets to the bottom of the AC unit according to the manufacturer's instructions. These brackets will help support the weight of the unit and prevent it from falling out of the window.

2. Carefully lift the AC unit and place it in the window opening. Ensure the support brackets are resting on the window sill and that the unit is level.

3. Extend the side panels of the AC unit to fill any gaps between the unit and the window frame. Secure the panels to the window frame using screws or other provided hardware.

4. Attach any additional support systems, such as an L-shaped bracket or support bar, to the exterior of the window. These supports will help prevent the AC unit from falling out of the window and provide additional stability.

5. Seal any gaps between the AC unit and the window frame using weatherstripping or foam insulation. This will help prevent drafts and improve the energy efficiency of your AC unit.

Installing a Portable AC Unit

1. Attach the window installation kit to your casement window according to the manufacturer's instructions. This kit typically includes a venting hose adapter and a window panel that can be adjusted to fit the width of your window.

2. Connect the venting hose to the AC unit and the window adapter. Ensure the hose is not kinked or twisted, as this can reduce the efficiency of the unit.

3. Place the AC unit in a location where it can be easily connected to a power outlet and has enough clearance for proper airflow.

4. Turn on the AC unit and enjoy your cool and comfortable living space!

Maintaining Your AC Unit

To ensure your AC unit continues to function efficiently and effectively, it's essential to perform regular maintenance. This includes cleaning or replacing the air filter, checking for any debris or obstructions in the vents, and cleaning the condenser coils. Regular maintenance will help prolong the life of your AC unit and keep your home comfortable all summer long.

In this guide, we've covered everything you need to know about installing an AC unit in a casement window. With the right AC unit and proper installation, you can enjoy a cool and comfortable living space during the hottest months of the year. So, don't let the heat get you down – follow these steps and stay cool all summer long!

Casement Window


Casement windows are the most common style of window. They feature hinged panels that swing open and closed. Casement windows are available in single panels or multiple panels. The direction a door swings, either to the right or the left, is called the handing. In addition to handing, window are identified as either inswing or outswing depending on whether they open into the house or towards the outside.


Our team of experts will work with you to develop a bespoke plan that fits your needs. We take a holistic approach to the planning process, combining our technical expertise with our knowledge of customer requirements and project constraints.


Freedom to dream "truly custom-made"

Doorwin provides one-stop solution for professional windows doors manufacturer and installation. We have been serving customers with our high quality and branded products in United States, Asia and worldwide.


This newly built private house is in Sydney, Australia. The area occupied by the fenestration system in our scheduled design drawings was up to more than 110 square meters. A wide range of design details made the perfect mix of modern aesthetics and traditional sophistication, the simulated vertical hung windows with tilt & turn opening systems in this home are absolutely breathtaking. SDLS (Simulated Divided Lites with Spacer Bar) brings some historical vintage feeling to the whole building without losing any energy saving performance. Long narrow fixed windows creating larger-than-life expenses, coupled with German high-end systems made this project stand out from the rest.

Simulated Hung Window with Tilt & Turn Openings

The client's idea was to maintain a certain vintage feel, and our aim was to meet the energy efficiency needs and standards of modern houses as much as possible while maintaining a retro design. Doorwin’s 61S simulated hung windows with tilt & turn openings is a respectful modernization of a classic architectural masterwork.

Why choose the tilt and turn opening method?

Because it generally has better air seals than sliding, single hung, or double hung window frames. Tilt and turn windows form a complete seal when fully closed, this means they are less prone to water leakage, and cold draughts and you’ll keep more of your heating indoors where it belongs. They can be opened in the upper tilt way to ventilate at a minimum opening status and are easy to clean outside of the glass; when there’s a good day, they can be opened as normal inward casement windows.

Large Energy Efficient Fixed Windows

Our well-crafted bespoke systems enhance the functionality and panoramic view of this modern house.

Huge, fixed glass walls up to seven meters long and two meters high bring great lighting and open views, making it really refreshing to the mind. Five meters high long narrow windows give the whole building a contemporary aesthetic.

Every window’s placement and shape not only add to the uniqueness of this home but also provide a more energy-saving ability for the owners.

Doorwin energy-efficient integrated glazing units feature double-pane glass, warm-edge spacers, argon gas fill, Low-E coatings, and fully tempered glass, they can not only create a comfortable and natural indoor environment but also save electricity bills and heating bills of more than 100 USD for the owner, it’s a real bargain compared to choosing a regular glazing set.

Custom Designed Thermal Break Aluminum Entry Door

Aluminum Door offered an air of uniqueness and elegance to a home. With their luxurious patterns and beautiful finishes, it provides this house with a bounty of aesthetics and security. Aluminum entry doors allow you to resist any weather extremes, corrosion, and pests. So aluminum is one of the most resilient and durable materials you can select for front doors considering the price/performance ratio.

With pieces of double panes, and Low-E tempered glass. The door provides a good insulation performance.

Custom Designed Grilles and Transom

Divided lite windows and doors offer unique architectural solutions for buildings without compromising energy efficiency or aesthetics. Doorwin provides multiple muntin and glass options to customize your divided lite windows and doors. Further customization is available with a variety of colors and materials, creating an infinite number of design combinations to best suit your style.

In this project, we use SDLS (simulated divided lites with spacer bars), these bars permanently adhere to both sides of the glass, and spacer bars are installed between the glass, this is the most energy-efficient way to create the look of classical décor grilles. The windows in the bathroom bedroom and study have an Arch Transom Design, making these rooms, which are often used by the owner, have some traditional aesthetics.

BTW, Doorwin offers free design assistance, so if you need a custom design like this one, contact us right away and we will provide you with the most aesthetically and functionally pleasing design solution.

German Imported Hardware System

For windows and doors, hardware is as important as the engine is to the car. The continuous technological innovation of the European hardware industry has strongly promoted the performance improvement and functional innovation of windows and doors. In this project, Doorwin uses Hoppe™ multi-point locks, hinges, and handles from Germany.

Multi-point lock systems provide not only the burglar-resistance but also a tighter compression seam, making the window keeps good energy-efficient performance. Together with Technoform Bautec’s insulation edge bond and sealant strips, these make up our products' top insulation and energy-saving performance.

Save Your Money On Installation Costs

We have several international patents to reduce clients’ labor costs, such as our unique flanges and assembly type tubular design, which is different from the other products on the market. What sets us apart among Chinese counterpart is that all our products are equipped with nail fin structures for quick and easy installation. Labor costs during installation may exceed of the window and door price, therefore, our exclusive patent allows users to not only get a significant increase in installation efficiency, but also greatly reduce the labor cost of window and door installation. A cost that may bring you unexpected savings that far exceed the price difference you may care about now.

Free Design Assistance

With our own expertise, we provided the no-cost design development and contract documentation with CAD & BIM drawings, including elevation, details about the project, and installation help.

Before production, we will provide accurate sample drawings, which will clearly show the cross-sectional pattern, size, opening method and direction, pattern of the warm spacer, and the installation nodes. We will not go into production until you have signed off on the drawing to ensure that you receive a final product that meets the exact requirements of your project.

About Doorwin

Doorwin's professional packing system guarantees all products are delivered safely and without any damage. We apply a four-point packing system. Firstly, adhesive plastic film is applied on interior wood frames and exterior aluminum frames to avoid scratches on the surface. Then, a paper board is applied after we apply air bubble film surrounding the whole windows/ doors to avoid any destruction or clash. Lastly, we place them into a durable non-fumigation plywood crate to avoid any possible damage during transportation.

With years of experience shipping our products worldwide, we could guarantee to ship our products to their final destinations intact and without any damage.

About Doorwin Factories

Doorwin is one of the most professional window & door manufacturers are known for its great customized products. In Doorwin, a variety of colors, styles, and sizes of products are available to meet the client’s unique requirements. We own three ISO9000-certified modern factories in China. With a factory area of 20,000 m2 and a production capacity of 100,000 m2 per year. Doorwin Group has the scale to ensure timely delivery and the flexibility to reduce manufacturing lead times to as short as 18 days.