High pressure sodium lights

smppro said:

Great info Roseman, i myself prefer the 42w cfls, i think that they are the most efficient. I think another important thing when using CFLs is the space they are in. I think that a tight box works best, this allows you to get plenty of reflection of the near by walls making the cfls much more effective. I have a cfls box that is 24"x18"x32", i have 4 42w cfls mounted at the top(parallel to the ground) Not only can i produce 3-4oz of dense bud but the bud on the botton gets nice and tight too without having to have the bulbs a couple inches away. Oh yeah i also have a 400w hps box so i know what i dense bud look like.

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On the post a page back, Ed Rosenthal says he likes and prefers the 42 watt bulbs too.

Oh, as a side note, I'd like to note that lumens don't physically add up like that. Were that the case a few CFLs would be brighter than the sun - don't we wish! You have to get into things like photon flux density and such to really determine the quality of the light you're using. 2700 lumens at two feet away from the lamp won't get any higher adding more lamps at the same height, the meter will still read 2700. At least with CFL you can just have them on individual lines and hang them where they're needed, so you can sustain a much larger plant just by putting a few bulbs around it.

Ed might be a little outdated in his ballast knowledge, however. If you get Energy Star rated stuff, it has to be 85% or better in efficiency, not the 70-80% that Ed's talking about. I've got 90% rated ballasts for my T5HO, so the 432w pulls 475 at the outlet. I've tested that with my kill-a-watt meter. My old 400w HPS uses 480 at the ballast, so that's more like 78% efficiency. But it's not Energy Star rated, so that would figure.

I have a 7x7x8 room =49sft I am going to use a 1000 watt HPS light will that meet my needs?