What's in a Light Bulb?

Hugh Vandivier
Written by Hugh Vandivier
Updated January 26, 2016
yellow utility light with bulb
You use them all day, every day, but do you know what a light bulb is made of? (Photo by Katelin Kinney)

Are you curious about what's behind compact fluorescent lights (CFLs) and light-emitting diodes (LEDs)?

Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.
light bulb infographic LED incandescent CFL

The Energy Independence and Security Act of 2007 sparked the ongoing phase-out of incandescent bulbs, and increased use of compact fluorescent lights (CFLs) and light-emitting diodes (LEDs). Here's a look at those technologies:

Waste not, watt not

When we just had incandescent bulbs, a watt was a reasonable unit of measure to compare the intensity of light. So you knew that 100-watt bulbs were brightest, followed by 75-watt, then 60-watt bulbs, and so on. But a watt is a unit of power, not brightness. Those incandescent bulbs convert only about 5% of the energy they use into light.

Lumens are a better measure of brightness. A lumen is unit of measure for light perceived by your eye. So while an LED bulb may only emit 10 watts of energy, it can glow up to 44 percent brighter than a 60-watt incandescent bulb.

Graphic by Jake Ziolkowski

RELATED: Angie's List Guide to LED Lights

Need professional help with your project?
Get quotes from top-rated pros.