1. What is Luminous Efficacy?

Luminous efficacy measures how efficiently a light source produces visible light, expressed in lumens per watt (lm/W). It indicates how much visible light is produced for a given amount of electrical power consumed.

2. How Does the Calculator Work?

The calculator uses the efficacy formula:

Where:

• \( Lumens \) — Total visible light output
• \( Watts \) — Electrical power consumed

Explanation: Higher efficacy values indicate more efficient lighting, producing more light with less energy.

3. Importance of Efficacy Calculation

Details: Calculating luminous efficacy helps in comparing different lighting technologies, estimating energy costs, and making environmentally friendly lighting choices.

4. Using the Calculator

Tips: Enter lumens (light output) and watts (power consumption) values. Both must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is a good efficacy value?
A: Incandescent bulbs typically have 10-17 lm/W, CFLs 35-60 lm/W, and LEDs 80-150+ lm/W. Higher values indicate better efficiency.

Q2: How does efficacy relate to energy savings?
A: Higher efficacy means more light per watt, reducing electricity consumption for the same light output.

Q3: Is efficacy the same as efficiency?
A: Efficacy specifically measures light output per power input, while efficiency is a broader term for output/input ratios.

Q4: Why do efficacy values vary between light sources?
A: Different technologies convert electricity to light with varying efficiency due to their fundamental operating principles.

Q5: Can efficacy be greater than 683 lm/W?
A: The theoretical maximum is 683 lm/W for pure green light at 555 nm wavelength, but practical white light sources are much lower.