My current setup has me running a 400w HPS (external ballast) in an unfortunately quite small cabinet (36"w x 18"D x 40"H) and I am obviously running quite warm, which is my own stupidity. It's just been set up and the exhaust is an EcoPlus 180cfm blower with passive intakes from the room via drilled holes. I have to keep the door open with a box fan blowin in to keep it in the 80's. I am considering building an exhaust and passive intake into a window that would allow me to pull in outside air while the 180cfm EcoPlus blower is pushing warm air out the window. Would it be feasible to pull a large amount of heat from the sealed hood using this method? Would very cold outside air (as the temperatures drop this winter) cause any issues with the bulb or hood? I am hoping to move this to a larger space right now, but for the time being I need to make do with the metal cabinet. If I have to I'll get a 265 or 465 EcoPlus as well and use one for the hood and one for the box. But I'm curious about the cooling efficiency of a sealed hood and how much of a difference it makes in the overall heat buildup if most of the effort is going into pulling heat away from that bulb as it's generated. Thanks!