Measure the window opening and confirm the unit fits
Check that the window and frame are sturdy and level
Gather the mounting hardware, brackets, screws, and seal materials
Unpack the unit and remove any shipping materials
Attach the side panels if included
Install the mounting bracket or support bracket if required
Open the window and place the unit on the sill
Center the unit in the window opening
Lower the window sash onto the top of the unit
Secure the unit to the window frame with the provided screws
Extend the side panels to fill the gaps
Fasten the side panels to the window frame
Install any foam strips or weather sealing around the gaps
Tilt the unit slightly outward if recommended by the manufacturer
Tighten all hardware and confirm the unit is stable
Plug the unit into a properly rated outlet
Test the unit to ensure it powers on and cools properly
Close and lock the window if possible for added security