Starting on the left and going right, place the measuring tape on the side of the window. Hold it as level and straight as possible.
Place measuring tape on the left side of window opening, as shown below. Your tape measure should be resting against the part of the window that creates a continuous TRACK up one side, across the top, down the other side and falls behind the LIP at the bottom.
Then, measure to the right side and subtract about 1/16'. You need a little bit of 'wiggle room' in your width measurement so that the screen will be easy to put in and remove.
Take this same measurement at the top of the window, the middle of the window, and the bottom of the window. Write down the smallest of the three measurements.
This measurement is your window screen 'Width'.
First, check for a TOP TRACK at the top of the window. The TRACK will be a U-shaped channel that the screen will slide up into.
Next, find the LIP at the bottom of the window. This lip will be directly below the top TRACK. The bottom of the screen will fit behind this lip to hold it in place.
The aluminum window shown in the picture above has an inside lip and outside lip (inside for insect screen; outside for solar screen). If yours is similar to the picture sure and find the one on the outside, the 'outside lip'.
Now that you've located the tracks, let's start measuring!!
Insert the tape measure into the TOP TRACK you found earlier. Make sure the tape measure fits all the way to the top of the track. Hold it downward as straight as possible.
Make sure the measuring tape is as far up into the TRACK as possible, see below.
Note: when measuring the HEIGHT, make sure that you measure about 1/16'-1/8' ABOVE the top of the bottom lip, and provide the measurements to the nearest 1/16'.
Take this same measurement on the right side of the window, the middle of the window, and the left side of the window. Write down the smallest of the three measurements.
This measurement is your window screen 'Height'.
When measuring for your Crossbar location, place the tape measure on the top of the bottom lip (as shown above) and measure to the middle of the where the two windows meet (called the Meeting Rail). Round this measurement to the nearest inch. See below.
This measurement is your window screen 'Crossbar Height'.
Window Screen Resource Center
The resources below provide information and articles meant to educate and answer any questions you may have related to window screens.