How to Install a Window AC Unit: Step-by-Step Guide

Published April 18, 2025

Installing a window air conditioner is easier than it sounds. With a few tools and a little patience, you can cool your space in under an hour. Here’s how:

Step 1: Measure the Window

Before purchasing a unit, measure the width of your window to make sure it fits. Most window ACs are designed for standard double-hung windows.

Step 2: Prepare the Area

Clear the window sill, clean the area, and make sure the window is secure. Have a helping hand ready if your unit is heavy.

Step 3: Install the Mounting Brackets

Follow the manufacturer’s instructions to attach any mounting hardware. These brackets will support the AC and help with stability.

Step 4: Insert the AC Unit

Carefully lift the AC unit and slide it into the window. Lower the window sash to rest securely on the unit, locking it in place.

Step 5: Seal and Secure

Extend the side panels to cover any open gaps. Use weather stripping or foam to seal the edges and prevent air leaks. Secure the unit with screws if necessary.