What type of project is this?
"French Pane" windows have an external grid that sits on the outside of the larger window and creates a look that actually makes one window out of many smaller individual panes.
As an example of French Panes: If a baseball went through the window, you would only need to replace one small square of glass, and not an entire window glass sheet.
Let us know about how many of your windows are in the "French Pane" category.
If all of your windows are storm-type windows, then you will only fill out this area. We count storm windows separate from regular "pane counts".
Measure your concrete area to be cleaned by the foot.