Generally, the most energy efficient types of home lighting are fluorescent and LEDs (light emitting diodes) lighting. However, use and appropriateness of the bulb for the fixture and conditions impact efficiency. To determine energy efficiency in lightbulbs, calculate the lumens per watt (lpW). To calculate the lumens per watt, find the number of lumens (output) on the package or on the bulb, and divide that number by the number of watts (input) used to produce those lumens. The number you get is a rating that describes the amount of electricity consumed for the amount of illumination (light emitted). For example, a 100 watt bulb that produces 1800 lumens will have an lpW of 18. The more lumens produced by a bulb per watt (energy used), the more efficient the lightbulb is and the more energy is saved. Be aware that as fluorescent bulbs age, their lumen output decreases, so you may find both a beginning lumen rating and an average lumen on the package. Incandescent bulbs have a typical rating of 5-22 lpW. Halogen incandescent bulbs have a typical rating of 12-36 lpW. Fluorescent tubes have a  rating of 75-100 lpW and compact fluorescents have rating of 27- 80 lpW. Light emitting diodes (LEDs) have a rating of 45-107 lpW. LEDs are expected to grow in popularity and availability. The following U.S. Department of Energy web links have more information about energy efficient lighting for your home: Types of Residential Lighting Energy Efficient Bulbs

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