For the width, measure in three places and use the narrowest width. For height, use the shortest height for verticals.

On your notes clearly indicate which measurement is the width and which is the height. It is very common to transpose measurements. Try to always measure the width first, then height.

Inside or Recessed Mount
We recommend an inside mount whenever possible for a neater look. See the Sill Depth Chart below for the minimum sill depth needed for installation and the minimum needed for the product to be flush with the front.

When you specify an inside mount, provide us the window opening size. We will make about an 1/4" deduction on both sides so your products will operate properly and not rub against your window frame.

Outside Mount
Outside mounts hang outside the window opening either on the wood frame or above and beyond the wood frame. That will make your window appear bigger and hide unattractive windows. To ensure minimum light gaps and maximum privacy, add 4 to 5 inches on each of the four sides. Leave room for the mounting brackets, which are about 2-1/2" tall.

For outside mounts, specify the exact width and exact height you want the product to be. We will make your product the exact size you specify and we will not take any deductions. So you must add to the window opening measurement to allow for mounting brackets and the distance you want to go past the window.