I use 8 cfl, Just added a 70w hps for shitz and giggles. but the were grown to this using only cfl. I use a mix of four 26w 6500k and four 26w 3500k bulbs. I was intending to add 4 more 3500k bulbs for flowering but then i got this hps security light. I personally love the cfl's. Not to bad on heat, and in a small area they seem to work great. Looking forward to a harvest. That is about 6 weeks away. btw you can pic up the warm(3500k) cfl's at lowes 26w 4 pack for like 12 bucks