ABSTRACT
There are not fixed lines among the lighting of yesterday, today, and tomorrow, because they often overlap. Yesterday’s lighting is not only T12s with magnetic ballasts but also what is called first generation, basic grade, or 700 series full wattage T8s with generic electronic ballasts, which are still very common. Today’s lighting includes high performance T8s with high performance ballasts, and electronically ballasted CMH and LED, some of which are tunable. Tomorrow’s lighting will be LED or another type of SSL, mainly tunable with integral wireless controls, which are considerably less expensive than existing controls. Today, some people want to wait until LED products and controls are improved and less expensive before doing a retrofit or upgrade, but often the lost savings from waiting are never recouped.
