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What is LED luminous efficacy (lumens per watt)?
- By Lumistrips LED Professional
- May 16, 2020
Luminous efficacy measures how effective a light source produces visible light. It is the ratio of luminous flux to electric power, the value of lumens per watt (lm/w).
For example, the light output (luminous flux) of a 1 Watt LED can be very bright for high efficacy or barely visible for low.
The luminous efficacy is one of the defining factors of LED performance.
Top performance LEDs, with the highest luminous efficacy, have 220 lumens per watt (lm/w), such as the Nichia 757G LEDs. High performance LEDs, like those from many other manufacturers, have 150-200 lm/w. At the far end, we have the low performance LEDs with an efficiency of less than 99 lumens per watt.
| Top performance LED | High Performance LED | Good Performance LED | Low Performance LED |
| 220 lm/W | 150-200 lm/W | 100-149 lm/W | 50-99 lm/W |
The other light sources on the market today have the following luminous efficacy:
| Category | Type | Overall luminous efficacy (lm/W) |
|---|---|---|
| Incandescent | 15, 40, 100 W tungsten incandescent (230 V) | 8, 10, 13 |
| 5, 40, 100 W tungsten incandescent (120 V) | 5, 12, 17 | |
| Halogen incandescent | 100, 200, 500 W tungsten halogen (230 V) | 16, 17, 19 |
| 2.6 W tungsten halogen (5.2 V) | 19 | |
| Halogen-IR (120 V) | 17–24 | |
| Tungsten quartz halogen (12–24 V) | 24 | |
| Photographic and projection lamps | 35 | |
| Arc lamp | Carbon arc lamp | 2–7 |
| Xenon arc lamp | 30–50 | |
| Mercury-xenon arc lamp | 50–55 | |
| Ultra-high-pressure (UHP) mercury-vapor arc lamp, free mounted | 58–78 | |
| Fluorescent | 32 W T12 tube with magnetic ballast | 60 |
| 9–32 W compact fluorescent (with ballast) | 46–75 | |
| T8 tube with electronic ballast | 80–100 | |
| PL-S 11 W U-tube, excluding ballast loss | 82 | |
| T5 tube | 70–104 | |
| Gas discharge | 1400 W sulfur lamp | 100 |
| Metal halide lamp | 65–115 | |
| High-pressure sodium lamp | 85–150 | |
| Low-pressure sodium lamp | 100–200 |
For a high energy efficacy lighting installation, we also have to consider how the light output is transmitted to the required area. The is called illuminance (light falling on a surface) and is based on the fixture design and light source viewing angle.
At Lumistrips you will find many LED strips and modules with the highest useful lumens, because of the directed beam angle and also by using LEDs with the highest luminous efficacy on the market, the Nichia 757G LEDs.
