Recently we looked at the way power companies calculate how much electrical energy we use in our homes. The Joule is too small a unit to measure household energy consumption, so suppliers work out our bills using a must larger unit called the kilowatt-hour (kWh).

I found this page on BBC Bitesize that has some information and a quiz to test your kWh knowledge. There is also a section on the kilowatt-hour at gcse.com.