LED's as a Primary Light Source

[ron101]

Mal is right Bev. Light wattage is a measure of electrical energy going into the bulb not a measure of the light energy coming out.

The laws of physics dictate that energy in a closed system must be conserved, meaning if you put 400W into a bulb, 400w worth of (various) energy must come out. Since MH bulbs run really hot, much of the 'wattage' that goes into the bulb is lost to thermal energy while LED's run really cool.

Wattage is really for electrical information not for optical. Like Mal said a 250w Iwaski has the same PAR as a 400w radium. Classifying them as 116 PAR bulbs would not tell you what ballast to use.