Every room with an intake and exhaust has either positive or negative air pressure.
Positive Air Pressure: Means the the pressure inside the room is greater than out side.
More intake than exhaust. This is good to reduce heat due to the insulation properties of air as well as reduced dust as no air is being sucked in by the opening of the room other than the intake of course.
Negative Air Pressure: Means the the pressure inside the room is less than out side.
More exhaust than intake. This is good to reduce smell as no air leaks leave the room other than through the exhaust.(which should already be filtered).
IMO grow rooms/cabs/cases whatever should be Negative Air Pressure.
Just my
Aim High