Photometry Basics

Luminaire Efficacy Calculator

Calculate system luminous efficacy in lumens per watt using luminaire output and input power.

Inputs

Results

Total system power -- W
System efficacy -- lm/W
Comparison band --
Calculation details
Total system power
-- W
System efficacy
-- lm/W
Comparison band
--
Important notes
  • Comparison bands are indicative and are not a product certification or procurement decision.

Formulas

  • \(\displaystyle \eta = \frac{\Phi}{P_{\mathrm{system}}}\)
  • Use system lumens and system watts where the product data provides them.

Calculate system luminous efficacy in lumens per watt using luminaire output and input power.

Luminaire Efficacy Calculator is a planning aid. Keep the target source, product data, measurement method, and project assumptions with the result. Confirm compliance, installation, certification, and safety decisions with the responsible professional.

FAQs

Which power should be used?

Use the complete system input power where available, including a separate driver input when it is not already included.