GE Lighting 73156 Energy Smart Spiral CFL 10-Watt (40-watt replacement) 520-Lumen T3 Spiral Light Bulb with Medium Base, 5-Pack 40-watt replacement uses only 10-watts 520 lumens providing cozy, relaxing light Lasts 9.1 years based on 3 hours per day usage Estimated yearly energy costs $1.20 based on 3 hours per day $0.11 per kWh $33 in energy savings over the life of the bulb based on 3 hours per day usage