Energy Use Comparison
To produce the same amount of light (roughly 800 lumens, equivalent to a traditional 60-watt bulb), each technology uses very different amounts of electricity. An incandescent bulb uses 60 watts, a CFL uses 13 to 15 watts, and an LED uses 8 to 10 watts. That means an LED uses roughly 85 percent less electricity than an incandescent and 35 percent less than a CFL for the same brightness.
The energy difference adds up quickly. A single 60-watt incandescent bulb running 5 hours per day costs approximately $11 per year at 10 cents per kWh. An equivalent LED costs about $1.80 per year. Over 30 bulbs in a typical home, the annual savings from switching entirely to LED is $250 to $300.
Lifespan Comparison
Incandescent bulbs last approximately 1,000 to 1,200 hours. At 5 hours per day, that is roughly 7 to 8 months. CFL bulbs last 8,000 to 10,000 hours, or about 4 to 5 years at the same usage rate. LED bulbs last 25,000 to 50,000 hours, or 14 to 27 years. The LED you install today may well be the last bulb you ever put in that socket.
Total Cost of Ownership
When you factor in both purchase price and electricity costs over 25,000 hours (the typical LED lifespan), the comparison is stark. An incandescent requires approximately 21 replacements over that period at $1 each, plus $150 in electricity — totaling roughly $171. A CFL requires about 3 replacements at $3 each, plus $28 in electricity — totaling approximately $37. An LED costs $2 to $5 once, plus $18 in electricity — totaling roughly $20 to $23.
The LED costs 88 percent less than incandescent and 40 percent less than CFL over its lifetime. There is no scenario where incandescent or CFL lighting costs less than LED.
Light Quality
Early LEDs produced harsh, bluish light that many people found unpleasant. Modern LEDs are available in warm white (2700K), soft white (3000K), bright white (4000K), and daylight (5000K) color temperatures that match or exceed the quality of incandescent light. Dimmable LEDs are widely available and work with most dimmer switches, though some older dimmers may need replacement for smooth dimming.
The Bottom Line
Replacing all remaining incandescent and CFL bulbs with LEDs is the simplest, fastest, and highest-return energy improvement you can make. At $1 to $3 per bulb, the payback period is measured in weeks, not years. Use our electricity calculator to see how lighting costs compare to other categories in your electricity bill.