Watt Explained: What Electrical Power Tells You About Light
What Is Watt?
Watt (abbreviation: W) is the physical unit for electrical power. For light sources, the wattage indicates how much electrical energy the light source draws – in other words, how much electricity it consumes. However, the wattage says nothing directly about the brightness of a light source.
Watt and Brightness – A Common Misconception
With incandescent lamps, the wattage was a reliable indicator of brightness: a 60-watt incandescent lamp was brighter than a 40-watt one. This was because all incandescent lamps had a similar luminous efficacy.
With LEDs, the situation is different. A 7-watt LED can be just as bright as a 60-watt incandescent lamp – at a fraction of the energy consumption. The actual brightness is stated in lumens. Anyone wishing to compare the brightness of different light sources should therefore look at the lumen value, not the wattage.
Conversion Guide: Incandescent Lamp to LED
| Incandescent Lamp | LED (approx.) | Luminous Flux (approx.) |
|---|---|---|
| 25 W | 3–4 W | 250 lm |
| 40 W | 5 W | 470 lm |
| 60 W | 7–8 W | 806 lm |
| 75 W | 9–10 W | 1,055 lm |
| 100 W | 12–13 W | 1,521 lm |
Frequently Asked Questions (FAQ)
How many watts do I need for my LED?
The better question is: how many lumens do I need? The required brightness depends on the room and the intended use. The wattage only indicates energy consumption.
Does a dimmed LED consume fewer watts?
Yes. When dimming, the power consumption decreases and so does the electricity usage.
In Summary:
The wattage describes the energy consumption of a light source, not its brightness. For comparing brightness, the lumen value is decisive. At Leuchtenland.com you will find all the relevant technical data for every light source – from wattage and lumens to colour temperature.