Lumen-pro-Watt-Rechner — Formel

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)

    • Lösungsbeispiel

    800 lumens from a 10 watt LED.

    1. Efficacy = 800 / 10 = 80 lm/W
    2. Annual cost at 8hr/day: 10W x 8 x 365 / 1000 x $0.15 = $4.38