How do you count windows?

We count each window pane (separate piece of glass) as a window. Frequently there are at least two window panes installed side by side. For French cut windows they are divided into many small panes. In cases like French panes, where the pieces are smaller than one square foot, we will sometimes count two or three panes of glass as one window. If a window is large (over 4’ X 4’) it could be counted as two windows.