Andrew Sarangan wrote:
Is it possible to cut out a window on a regular garage door? I need to
install a fresh-air intake grille for an exhaust fan, and the garage
door appears to be the best location.

I've seen it done in hangar and garage doors with a fine toothed blade
in a Sawzall. The best example involved plywood, bolted through the
waste section, with the whole sandwich cut as a unit.