Book 3, Question 42
Why Do LED Lights Use Less Power?
LED lights use less power because they make light in a tiny chip and waste much less energy as heat than old bulbs.
An LED makes light inside a tiny chip, so almost no energy is thrown away as heat. An old-fashioned bulb glows by heating a thin wire until it's white hot, and that wastes lots of energy. So the same brightness costs far less power with an LED!
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Quick answers
How much more efficient are LEDs?
A typical LED bulb makes about 83 lumens of light per watt, compared with about 16 for an incandescent bulb.
Sources: National Geographic, U.S. Department of Energy, BBC
From the book
Page from A Million Whys Book 3
More fun facts
- LEDs use less energy than both compact fluorescent and old incandescent bulbs.
- A typical LED bulb makes about 83 lumens of light per watt, compared with about 67 for a fluorescent bulb and 16 for an incandescent bulb.
- Most of the energy an LED uses becomes light, while old incandescent bulbs waste about 90 percent as heat.
- LEDs last about 30 times longer than incandescent bulbs.
- Many LED bulbs promise up to 25,000 hours of use.
- In the early 2000s, white LEDs gave only about 20 lumens per watt. Some LEDs today reach 150 lumens per watt or more.
Sources: National Geographic, U.S. Department of Energy, BBC
Questions kids ask
How long does an LED bulb last?
Much longer than old bulbs. LEDs last about 30 times longer than incandescent bulbs, and many promise up to 25,000 hours.