How to Install a Window AC Unit

Joe CruzJoe CruzUpdated: Mar. 16, 2023

Installing a window air conditioner is an easy way to keep your cool.

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man inserting an air conditioner unit into a windowFamily handyman
Next Project
Time

An hour or less

Complexity

Beginner

Cost

$150 - $400

Introduction

With the summer temperatures on the rise, you may need to install a window air conditioner to keep your home cool— it’s easier than you think.

Tools Required

  • Scissors
  • Screwdriver

Materials Required

  • Appliance cord
  • Foam weatherstrip
  • Window Air Conditioner
  • Wood block

Project step-by-step (5)

Step 1

What type of window do you have?

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  • Casement windows that crank open and horizontal sliding windows don’t work as well for window air conditioners.
  • If you have a storm window, you may need to remove the screen or slide open the lower window.

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Step 2

Blocking

  • When installing the window air conditioner, you want to make sure it’s sitting level in the window opening.
  • You made need to add some blocks between the windowsill and the air conditioner near the front (and possibly toward the back) to assure that the unit is level. Typically, a 2×4 works well for this, but every situation is different.

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Step 3

Weatherstrip

  • Before moving forward, you’ll want to seal around the window. Cut, peel and stick 1-1/4-in. x 1-1/4-in. foam weatherstrip to the windowsill, as well as on top of the air conditioner or to the bottom of the window.

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Step 4

Install the air conditioner

  • Some window air conditioners are quite heavy — you may need a helper. If the air conditioning unit needs to be cleaned, do it now before it is installed.
  • With the window open, lift the air conditioning unit into the window opening until the wings are even with the window jamb, centering it in the opening.

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  • Lower the upper window down on top of the air conditioner, holding it in place.
  • Expand the air conditioner wings to close the gap on each side.

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  • (Optional) If you don’t mind putting holes in your window, secure the wings to the window.

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Step 5

Electrical Connection

  • If possible, plug your air conditioner into a designated 20 amp circuit.
  • If you need to run an extension cord, it’s always a good idea to use a heavy-duty appliance cord.

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Originally Published: July 07, 2022