When it comes to window ACs, you need to measure the width and height of the window opening as well as the square footage of the area you want it to cool.
Manufacturers usually list the acceptable size range of the window and the maximum square footage the AC can cater to on the box. So, make sure all the measurements are correct and in line with the manufacturer’s specifications.
For the window, open it as far as possible and use a tape measure to measure the window from top to bottom and side to side.
Meanwhile, for the square footage of the area you want to cool, ask someone to hold the tape measure against a wall. Then, extend the tape to the opposite side of the wall to determine the length. Repeat the process to figure out the width.
Once you have the length and width, multiply the two measurements, and you’ll get the square footage. So, for instance, if the area is 13 feet long and 12 feet wide, it is 156 square feet.