Looking to install side vents on side of my enclosed trailer 1 on each side , need ideas on where to mount them ? Both up high or both down low ? One low one high? Both at rear or both at front ? Front one side rear one side ?
Depends on your expected result of venting the interior of the trailer.
Roof vents allow the possibility of rain water entering the trailer at any time.
A side mounted vent facing forward will apply positive pressure to the interior of the trailer while traveling. If fairly well sealed, dust intrusion will be lessened to a large extent.
Such a vent, sitting still, will have the same effect as any other vent.