A kilowatt-hour (kWh) is a unit of energy that measures how much electricity is used over time. It represents the amount of energy consumed when a device that uses one kilowatt of power runs for one hour. For example, if you have a light bulb that uses 100 watts, it would take 10 hours of use to consume one kWh of energy. Electricity bills often show the total kWh used in a month, helping you understand your energy consumption. By knowing how many kWh your appliances like refrigerators or air conditioners use, you can make smarter choices to save on your electricity bill.