I can tell you about mine.. I have two scrubbers one 12 lb honeywell and 1 3 1/2lb in a 5x5 room. I am useing the 3 1/2lb scrubber as the exaust for the room and the other bigger one just hanging in the room. although I havent started budding yet, I have 7, 40" tall plants and 7 clones 2weeks old and no smell outside the room... I guess it depends how well the room is sealed off too. Good luck dude, its a prob for me too.