Energy Saving Compact Fluorescents. 100W Replacement. Energy Star. Uses only 23 watts. Light Output: 1600 Lumens. Energy Used: 23 Watts. Average Life: 8000 hours. Lasts up to 7 years. Saves 296 dollars in energy costs, as compared to using four 100 watt bulbs at 12c per KWH. To save energy costs, find the bulbs with the light output you need, then choose the one with the lowest watts.