光效计算器 — 公式
## Luminous Efficacy
**Efficacy = Lumens / Watts**
Higher efficacy means more light per unit of energy.
### Efficacy Benchmarks
- Below 20 lm/W: Poor (incandescent)
- 50-70 lm/W: Good (CFL)
- 80-120 lm/W: Very good (modern LED)
- Above 120 lm/W: Excellent (high-efficiency LED)
**Efficacy = Lumens / Watts**
Higher efficacy means more light per unit of energy.
### Efficacy Benchmarks
- Below 20 lm/W: Poor (incandescent)
- 50-70 lm/W: Good (CFL)
- 80-120 lm/W: Very good (modern LED)
- Above 120 lm/W: Excellent (high-efficiency LED)
计算示例
800 lumens from a 10 watt LED.
- Efficacy = 800 / 10 = 80 lm/W
- Annual cost at 8hr/day: 10W x 8 x 365 / 1000 x $0.15 = $4.38