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> Today’s garden-variety incandescent bulbs aren’t much different from the ones Thomas Edison sold more than a century ago. They still waste 90 percent of their
by monochromatic 12y ago
> Today’s garden-variety incandescent bulbs aren’t much different from the ones Thomas Edison sold more than a century ago. They still waste 90 percent of their power, delivering roughly 16 lumens per watt. Fluorescent tubes do a lot better, at more than 100 lm/W, but even they pale next to the best LEDs. The current state-of-the-art white LED pumps out around 250 lm/W, and there’s no reason why that figure won’t reach 300 lm/W.
If 16 lm/W is 10% efficiency, why isn't 300 lm/W an impossible 187.5% efficiency?
- jacobolus 12y agoOne guess: incandescents pump out lots of infrared radiation, compared to LEDs, and also a lot more red light. Lumens, as a unit, are normalized to the sensitivity of human cone cells, so the same amount of radiant flux in the green part of the spectrum is “more luminous” than in the red or violet parts of the spectrum, and infrared doesn’t count at all. As a result, I’m not sure there’s any obvious way to measure an efficiency percentage in terms of lumens/watt.