Lamp Efficiency
You want task lighting for its energy efficiency. Therefore, use efficient lamps. Until recently, there was a strong temptation to use incandescent lamps and fixtures for task lighting because these were the only kind that allowed precise aiming at short range. However, the inefficiency of incandescent lamps cancels the advantage of accurate aiming.
For most applications, only fluorescent lighting offers good lamp efficiency. Much of the bother and innovation involved in the preceding discussion stems from the need to make the light distribution of conventional fluorescent lighting more controllable.
Compact fluorescent lamps may prove to be a breakthrough. They combine most of the efficiency potential of fluorescent lighting with the aiming capability of incandescent lamps. The best compact fluorescent lamps are perhaps 70% to 80% as efficient as the best conventional fluorescent lighting, and they have all the other advantages of fluorescent lighting.
For these reasons, base your initial task lighting designs on compact fluorescent lamps. Consider installing them in large reflector fixtures, as described previously.
HID lamps are almost point sources, so you can combine them with reflector fixtures to tailor the light distribution pattern accurately. Consider HID lighting for task lighting of large areas, especially where the fixtures cannot be installed close to the tasks. Color rendering, previously a serious weakness of HID lighting, has been greatly improved in recent years.
HID lighting is not suitable for small task areas, because small HID lamps are substantially less efficient than fluorescent lamps in small wattages. Also,remember that HID lamps cannot be turned on and off at short intervals.