What is a kWh?
kWh stands for kilowatt-hour, and is a unit that tells how much energy is used in one hour. Kilo means a thousand. So for example, if you have a 1000 watt oven on for one hour, you have used 1 kilowatt-hour. For a light bulb, which may only consume 10 watt, it will take 100 hours (just over 4 days) before you have used 1 kWh.