Here's the one with the ventilation formula:

http://boards.cannabis.com/indoor-gr...-progress.html

The best three threads on lighting are the top three "stickies" in the Indoor Lighting section.

For my small space I found that it would cost me less $$$ to run a 400 watt HPS and get almost twice the lumens than my current CFL's.

Miss stinkyattic has a formula for determining your electricity cost in this "stickie". The formula is on page 4.

http://boards.cannabis.com/basic-gro...-dankness.html