Thatz for sure... I started indoors with a couple of 150W HPS, then I got a 400W MH, and now I'm running 3 250W HPS, and that old 400W MH at the same time-all of which r in a CO2 enriched closet with beautiful ventilation and ac control, and itz only 4'X2', but with room for 8 5-gallon buckets...