hell i fit 68watts (2x13w cfl, and 1x42w cfl) in a super small box... basically the more lights you can fit the better... the small the box, the more useable lumes i believe... like lets say you have a 1000w hps in a 1 square fot grow box, it would do better than if you had a 1000w hps in a closet... you get what i am saying? i hope i make a lil sense...