Efficacy
The efficiency of a light source measured in lumens per watt (lm/W). Higher efficacy means more light for less electricity.
Efficacy is the spec that explains why LEDs dominate the lighting market. An incandescent bulb converts about 15 lumens per watt of electricity — the rest becomes heat. A typical LED achieves 100 lm/W, and high-end models exceed 150 lm/W. That's a 6-10x improvement in efficiency.
In practical terms, efficacy determines your electricity bill. Two LED bulbs might both produce 800 lumens, but one draws 8W (100 lm/W) while the other draws 11W (73 lm/W). Over 25,000 hours of rated life, that 3W difference adds up to real money — especially when multiplied across every fixture in your home.
Efficacy also tends to correlate with quality. Higher-efficacy bulbs usually have better LED chips and drivers, which means better color consistency and longer actual lifespan. It's one of those rare specs where the more efficient option is also the better-built one.
Specifications
| Incandescent | ~15 lm/W |
| CFL | ~60 lm/W |
| LED (typical) | ~100 lm/W |
| LED (high-end) | ~150+ lm/W |
