1. What is a Lumen to Watt Calculator?

Definition: This calculator estimates the electrical power (watts) required for an LED light source based on its luminous flux (lumens) and efficacy.

Purpose: It helps consumers and lighting professionals determine appropriate LED wattage needed to achieve desired brightness levels.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( W \) — Electrical power (watts)
• \( L \) — Luminous flux (lumens)
• \( E \) — Efficacy (lumens per watt)

Explanation: The luminous flux is divided by the efficacy to determine the required electrical power.

3. Importance of Lumen to Watt Conversion

Details: Proper conversion helps in energy-efficient lighting design, accurate energy consumption estimation, and comparing different lighting solutions.

4. Using the Calculator

Tips: Enter the desired brightness in lumens and the LED efficacy (default 100 lm/W). Typical LED efficacy ranges from 80-150 lm/W.

5. Frequently Asked Questions (FAQ)

Q1: What is lumens efficacy?
A: Efficacy measures how efficiently a light source converts electrical power to visible light (lumens per watt).

Q2: What's a typical efficacy for LED bulbs?
A: Most modern LEDs range from 80-150 lm/W, with high-efficiency models reaching 200+ lm/W.

Q3: How does this compare to incandescent bulbs?
A: Incandescent bulbs typically have 10-17 lm/W, while LEDs are 5-10 times more efficient.

Q4: Where can I find lumen ratings?
A: Lumens are usually listed on lighting product packaging or specifications.

Q5: Why is my actual wattage slightly higher?
A: The calculation doesn't account for driver/ballast losses, which typically add 10-15% to the power consumption.