the 400w should work well as long as u have the area ventilated so as heat doesnt damage the plant(s). I believe computers use a simular amount of electricity (400watt to over 550watt). I may be wrong on that..
Bonez87x Reviewed by Bonez87x on . yet another question about lights If someone were thinking of growing in a small 3'X3' area would a switchable 400W MH and 400W HPS light be a good place to start? Would smaller 250W size systems be better for that size of an area. Would it make a difference on the power bill as well? Rating: 5