A kilowatt hour is a unit of energy commonly used to measure electricity consumption. It is the equivalent of using a kilojoule every second for an hour. Therefore, a kilowatt hour is 3.6 million joules.
A nutritional Calorie, or kilocalorie, is commonly used in food labeling. It is equal to 4.184 kilojoules. The average American consumes about 2,700 kilocalories per day.