Quote Originally Posted by qdavid
What Zandor said. If, for example, you use 4 cfls. Is the wattage really 4x150W (incandescent equivalents) or 4x42W (the real rating)? Lumens, color, and overall coverage of lights are the keys.
try not to use the incandescent equivalents. They dont mean anything, all they are is a marketing thing so people can replace the bulbs in their house and buy ones that are the same brightness. When we talk about HPS we dont say their incandescent equivalents because everyone knows they have higher efficiency.

so, if you are trying to figure out the Watts/sq ft you must use the actual watts. and each different light as a different optimum. I prefer to use the lumens/sq ft.