What's the difference between a kilowatt and a kilowatthour?

Answer:

A kilowatt measures the amount of energy at any single time, and a kilowatthour measures it over time. For example, a light bulb uses 100 watts. If you use it for an hour, you use 100 watthours. If you use 10 light bulbs, you place 1000 watts of demand on the system, or one kilowatt. If you use 10 light bulbs for one hour, you use one kilowatthour. Your bill is based on a kilowatthour, how much electricity you use over time multiplied by your electricity rate.