My GH is attached to a concrete block shed with one open side. At
present a solid wooden door connects the two. Exhaust fans are to be
installed at the end opposite the door. Charley's Greenhouse says I
should probably not put a motorized intake shutter on a door that is
going to open and shut. I have read of shutters opened by fan draft,
but do not know how to predict if my fan draft would be sufficient to
open such shutters (placed in the door).

What kind of shutter would be advisable?
Or could I perhaps put in a door with clear glass panels for winter and
screen panels for summer, as I have at the fan end of the GH? Thanks.
T-L