Watts are a measure of electrical power used. It's not a measure of light given off. Unfortunately most people learned that a 100 Watt light bulb is so bright, and a 60 Watt light bulb is so bright, and so on. So they've got a little table in their heads which measure brightness in Watts, even though it's the wrong unit.
When newer lighting tech like fluorescent (CFL) and LED became popular, this became a problem. Because they're more efficient, they give off more light per Watt than an incandescent bulb. Or put another way, they use fewer Watts to produce the same amount of light.
Equivalent-watts were made up to bridge this gap.
■The Watts on the label of a light bulb is always how much power it uses. People in...