Identify that your windows are Andersen windows by locating the logo. It should be in one of the corners.
Look for a series of letter and numbers under or near the logo. Write down those numbers on a sheet of paper.
Identify how your window opens. Casement and awning windows have a crank and open outwards. Double-hung and gliding windows are opened by sliding one sash past another.
For windows with a crank, identify the location of the hinges. Casement windows have hinges at the side, while awning windows have hinges at the top. For windows that slide open, identify the direction in which they slide. Double-hung windows slide vertically, while gliding windows move horizontally.
On the same sheet of paper you used in Step 2, record the type of window you have.
Measure the width of the visible glass (the portion of the glass you can actually see) from edge to edge. Write it down as well.
If you are measuring double-hung windows, determine if you need half screens or full screens.
Measure the height of the of the visible glass in the window. For double-hung windows, measure only one pane of glass if you have half screens; measure to the top of the second pane if you have full screens.
Call Andersen Windows at (888) 888-7020 to get help identifying the exact size of the window screen you need to replace, and to either order a new screen or find a store near you that sells replacement screens.