

From the inside of your home, measure the width of the opening:
Top, Middle, and Bottom.

Identify the narrowest measurement and subtract 1/4 inch. This will serve as the width of the window you'll order.
Measure the height of the opening: Left side, Middle, Right side.

Identify the shortest measurement and subtract 1/4 inch. This will serve as the height of the window you'll order.
If you are unsure of your final measurements, we recommend you consult with a qualified installer.