While new ways of producing light offer lots of design possibilities, it still makes sense to stick with the tried-and-true basics of light
layering that designers have long relied on to produce attractive, well-lit spaces. Light layering incorporates four specific types of lighting to create a well-lit environment: task, accent, decorative, and most important, ambient light. The rule here is that more than one light source is needed to illuminate a room properly. The challenge when working with new, energy-efficient types of lighting is that you have to go beyond light layering and understand how these new sources create light in order to use them correctly.
For example, CFLs, CCFLs, and ESLs (see "Low-Energy Lighting: The Latest Bulb Technologies" on the facing page) are omnidirectional sources of light. This means they throw light out evenly in all directions, which is what a standard household "A" lamp (like our old incandescent) does. That makes all of these types good sources of ambient and decorative lighting, and occasionally task lighting; but they are ineffective as accent lights.
LEDs, by contrast, are unidirectional, meaning that their light is projected out in
one direction. As a result, they can provide a very good source of accent lighting and task lighting, and occasionally ambient light if used correctly or if designed in a luminaire (fixture) that compensates for their unidirectional tendencies.
In addition to the differences in how they project light, these new light sources differ in the color (temperature) of light they produce. Other characteristics, such as resistance to temperature change, ability to dim, and available wattages, also can influence your decision on what type of bulb to use where.
Once you know the properties of these earth-friendly light sources, you can begin to include them more confidently to produce each of the layers of light that combine to produce a well-lit room.
