Energy-efficient lighting involves so much more than removing lamps (light bulbs or tubes) or reducing wattage. To be truly efficient, lighting must be used to its best advantage in given situations. This guide explains how to analyze your current situation, nonenergized systems that come into play, how to decide on a retrofit or complete renovation of your lighting system, the cost-effectiveness of various system options, and how to acquire systems. In addition to other illustrations, tables and charts depict some of the most common systems now in use and indicate the impact of various changes, e.g., how energy consumption is affected by changing lamps and ballasts or by installing a new luminaire in the existing space. But the benefits of better lighting are not restricted to energy savings – there are significant bottom-line benefits to be derived from lighting improvements. The three major systems involved in lighting are discussed in detail, including human systems, nonenergized systems, and energized systems. A list of sources for further assistance and a glossary Placeholderalso are provided.