Watts, kilowatts and kilowatt hours
It' a matter of wattage and time of use
To understand your energy usage you need to understand how electricity is measured.
A watt is the standard measure of how much electricity is used at any 
moment. A kilowatt is simply 1,000 watts (kilo = 1,000). A kilowatt hour (kWh) is a kilowatt used for one hour.
On most appliances you can find the wattage on the nameplate. To calculate the kilowatts used by an appliance, divide the wattage by 1,000. So a 200 watt appliance would be 200 divided by 1,000 or 0.2 kilowatts. A 1,500 watt hair dryer would use 1.5 kilowatts.
Two good explanations can be found here:
michaelbluejay.com
Dollar Stretcher - author Gary Foreman
