How Much Electricity Does a Light Bulb Use?
An LED bulb uses 8-12 watts, a CFL uses 13-15 watts, and an incandescent uses 60 watts for equivalent brightness. Running a 10W LED for 5 hours daily costs about $0.30 per month. Incandescents cost 6x more to run. Calculate your savings with the Power Cost Calculator.
Key Takeaways
- LEDs are 75-80% more efficient than incandescents.
- Smart bulbs use 0.
- Dimmed LEDs use proportionally less energy.
Explanation
LEDs are 75-80% more efficient than incandescents. A 10W LED produces the same light as a 60W incandescent. At $0.16/kWh, running an LED 5 hours daily costs $2.92/year vs $17.52/year for incandescent.
CFLs fall between LEDs and incandescents in efficiency. A 13W CFL equals a 60W incandescent. However, CFLs contain mercury and have shorter lifespans than LEDs.
Switching all bulbs in a home from incandescent to LED can save $100-200 per year on electricity. LEDs also last 15-25 years vs 1 year for incandescents.
Lumens, not watts, measure actual brightness. A standard 800-lumen bulb replaces a 60W incandescent. When shopping for LEDs, look for the lumens rating rather than wattage to ensure equivalent brightness. A 100W-equivalent LED produces about 1,600 lumens while drawing only 15-17 watts.
LED color temperature affects ambiance but not energy use. Warm white (2700K) LEDs use the same wattage as daylight (5000K) LEDs at the same lumen output. Choosing between warm and cool tones is purely a preference decision with no energy penalty either way.
Outdoor and specialty bulbs have different efficiency profiles. LED floodlights (BR30/BR40) use 10-15 watts to replace 65-100W incandescent floods. LED tube lights replacing 4-foot fluorescent tubes use 15-18 watts versus 32-40 watts for the fluorescent, saving 50% while eliminating the ballast that causes flickering and buzzing in aging fixtures.
Dimming LEDs reduces electricity consumption proportionally. An LED dimmed to 50% brightness uses approximately 50% of its rated wattage. However, not all LEDs are dimmable, and using a non-dimmable LED on a dimmer switch can cause flickering and premature failure. Always check that both the bulb and dimmer switch are rated as compatible.
Things to Know
- Smart bulbs use 0.5-1W on standby for WiFi connectivity.
- Dimmed LEDs use proportionally less energy.
- Halogen bulbs are slightly more efficient than incandescents but still far below LEDs.