It costs no more and no less. 70W HPS is = to 70W (3*23W)CFL in Cost.
It yields more per watt though if that answers your Q.
The thing with CFL's is, walking into home depot and walking out with CFL's SEEMs less conspicuous. But if you really think about it, Walking out with 1 HPS every 6 months is much less so.
The only REAL hard part about the HPS is getting your fixtures above say 150W. The 150 is about as big as it gets in HD or Lowes. They carry the bulbs for larger lamps but not the fixtures.
I ordered mine online taking a HUGE risk. Don't order EB@Y what ever you do. I chose Am@zon, but I won't be able to tell you if they decide to bust down my door for a suspicious purchase(it has happened to people before ie. eb@yers).
I got it delivered to my address right before I moved, I also used the anonymous prepaid creditcard.
Zcomp Reviewed by Zcomp on . CFL vs. HPS I'm currently planning my grow, which will be in an attic. It's not my house so I can't exactly start drilling holes everywhere, but I think regardless it's a little drafty so it may ventilate itself! Haha. There is a window which I could use though. But my question is: CFL bulbs REALLY are attractive because of how low their watt usage is - but can you really go the whole grow with CFL bulbs? I would like some tips on this, as well as the pros and cons. If an HPS is just simply better, then Rating: 5