Watts are one way of measuring electricity and one (1) watt is equal to 1/746 horsepower. We're used to buying incandescent light bulbs based on their watts. When switching to the new compact florescent light bulbs (CFLs) or light-emitting diodes (LEDs), you will need to learn the equivalent watts which are significantly lower to produce the same/more light when using CFL or LED light bulbs.
For those who want a more technical definition, here's the definition we found for “how many watts does a light bulb use” at wiki.answers.
- Watts = Amps x Volts.
- Amps = Volts/Resistance.
- Measure the resistance of the bulb and divide it into the voltage the bulb uses, to get the amps drawn by the bulb.
- Multiply the amps by the volts to get the power the bulb draws. For example, a 120 volt bulb has 144 ohms resistance, Amps = 120/144 = .833 amps. .833 amps x 120 volts = 99.96 or a 100 watt bulb.