How to Install a Portable Air Conditioner in a Sliding Window

Installing a portable air conditioner in a sliding window is straightforward when you understand the process. Most portable ACs come with window kits designed for this purpose, though some creativity may be needed for non-standard situations. This guide walks you through the installation process step by step.

Understanding Your Window Kit Components

Before beginning installation, familiarise yourself with the components included in your window kit. Most kits contain adjustable sliding panels, an exhaust hose connector, weatherstripping or foam tape, and installation hardware.

The sliding panels are typically two or three interlocking pieces that extend to fit various window widths. They connect together to form a continuous barrier filling your window opening while accommodating the exhaust hose connector.

The exhaust hose connector creates a circular or rectangular opening through the panel where your exhaust hose attaches. Some designs twist-lock into place, while others use snap-on collars.

Weatherstripping seals gaps between components and between the panel and window frame. This foam or rubber material compresses to create an airtight seal that prevents hot air from entering and cool air from escaping.

Measuring Your Window

Accurate measurement ensures proper fit and prevents unnecessary gaps.

Open your sliding window and measure the width of the opening when the window is positioned where you want it during AC operation. Most installations work with the window open approximately the height of the exhaust hose connector, typically 12 to 18 centimetres.

Note the total window width as well. Your adjustable panel must extend to fill this width completely. Most kits accommodate windows from 60 to 140 centimetres wide, but verify your kit's range against your window width.

Measure the height of the opening you are creating by opening the window partially. Ensure this height accommodates the exhaust hose connector with some clearance for the panel sections above and below it.

Preparing the Window Area

Clear the window area before installation. Remove any obstacles from the windowsill and surrounding floor space. Clean the window tracks of debris that might prevent proper sliding or sealing.

Position your portable AC unit where you intend to use it and measure the distance from the exhaust port to the window. Ensure the exhaust hose reaches comfortably without excessive stretching or sharp bends.

Assembling the Window Kit

Connect the adjustable panel sections according to your kit's instructions. Most panels slide together and lock at the desired width. Some kits include securing screws to prevent accidental adjustment after installation.

Install the exhaust hose connector in the designated opening of the panel. This typically involves pushing the collar through from one side and twisting or snapping a securing ring on the other side.

Apply weatherstripping to the edges of the panel that will contact the window frame. Place foam tape along the top edge where the panel meets the closed window, along the sides where panels meet the window frame, and around the exhaust connector if gaps exist.

Installing the Panel in Your Window

Open your sliding window to the required height. For most horizontal sliding windows, you will slide one pane behind the other to create the opening.

Place the assembled panel into the window opening. For horizontal sliders, the panel typically sits vertically in the gap between the window frame edge and the sliding pane. Adjust the panel width to fit snugly between the frame and pane.

Close the sliding window against the panel. The window edge should press firmly against the panel, compressing the weatherstripping to create a seal. The panel should be held in place by the window pressure.

Check for gaps along all edges. Add additional weatherstripping or foam tape where daylight shows through. Even small gaps allow significant air exchange that reduces cooling efficiency.

Connecting the Exhaust Hose

Attach the exhaust hose to the connector on your window panel. Most hoses twist-lock clockwise until they click into place. Others snap on and may benefit from additional tape securing.

Connect the other end of the exhaust hose to your portable AC unit's exhaust port. Follow the same connection method, ensuring a secure fit that will not disconnect during operation.

Arrange the hose to run as straight as possible from unit to window. Avoid kinks, sharp bends, and loops that restrict airflow. Keep the hose as short as practical, stretching only what is necessary.

Securing the Installation

Standard window kit installations rely on window pressure to hold the panel in place. For added security, consider supplementary measures.

Window security bars or locks can limit how far the window opens, preventing the installation from being pushed in from outside. Install these in the closed window's track to restrict movement.

Some users add screws through the bottom of the window frame into the panel bottom, preventing upward movement. Only do this if you are comfortable with minor permanent modifications to your window frame.

For sliding windows that open horizontally, installing a window lock bar in the closed portion's track prevents the window from being opened further.

Addressing Common Installation Challenges

Not all windows match the standard horizontal slider design. Adaptations may be necessary.

For double-hung windows that slide vertically, the same panel can work but installs horizontally across the bottom of the raised window. Support may be needed to hold the panel in place against gravity.

Casement windows that swing outward or inward require different approaches. Some users create custom plexiglass panels cut to fit the window opening with an appropriate exhaust hole. Others use doorway kit alternatives that work with patio doors.

Very wide windows exceeding your kit's maximum extension require panel extensions. Some manufacturers offer extension panels as accessories, or you can fabricate extensions from plywood or acrylic sheets.

Testing and Optimising Your Installation

With installation complete, test the system before relying on it.

Turn on your portable AC and feel around the window kit for air leakage. Warm air flowing in or cool air flowing out indicates gaps needing additional sealing.

Check that the exhaust hose connection at the window is expelling hot air. Place your hand near the outside opening to confirm airflow.

Operate the AC for thirty minutes and verify that your room temperature drops as expected. Inadequate cooling despite proper operation may indicate installation gaps or insufficient unit capacity.

If you are still selecting a portable AC unit, use our [portable air conditioner comparison tool](/) to find models that include comprehensive window kits suitable for your window type. Many manufacturers now offer enhanced kits designed for easier installation and better sealing.