Every time you turn on an incandescent lamp you’re seeing about 3.5 percent of the energy you’re paying for to power it up…But before we all run out and start specifying low pressure sodium lamps for the stage, we might want to take into consideration that their color rendering index (CRI) is zero…Lamp efficacy only tells part of the story. The luminaire efficacy should also be taken into account, and its efficacy can vary wildly…Designers can’t completely plug the energy leaks, but in many instances they can make them smaller.
— Richard Cadena, from Focus on Fundamentals, PLSN, April 2008
