using any hid lighting i would recommend getting a good inline fan, being a 400 watt i would use atleast a 4" fan maybe a 6" depending on temps. good fans are fantech, vortex, can fan, ect. i would also recommend trying to exhaust the light to a complete other room than your grow box is in. you will be circulating the hotter air with the cool air

the best thing about using quality inline fans is you can also hook up aircooled hoods and carbon filters to the same fan(knockout most security and ventilation problems with 1 major purchase)
texas grass Reviewed by texas grass on . Cooling in small spaces A wooden box with dimensions 36"x20"x60" (25 cubic feet) sits inside a closed space measuring 37"x61"x93" (121 cubic feet). The closed space is used for storage and so actually has less room than that available. Is it possible to use a 400 watt HPS light with hood inside the wooden box and still maintain optimal temperatures? Preliminary tests suggest that temperatures easily exceed 100°F within the box, using 2-3 80mm fans each on intakes and outtakes. The light itself generates most of Rating: 5