I have 20 plants in right now, 14 in different stages of veg. on the 16hr side and 6 on the flowering side.I put a bathroom exhaust fan in upside down to pump 140cfm threw some carbon filters silently. as far as light, I have seen the best results from sylvaina 150watt (40w energy usage) energy efficient bulbs. Only 6 bucks a bulb and doesn't use much energy with good results.