Question

Why don't we use Joule as commercial unit? How many Joule will make up 1kWh.

Answer 1

1 kwh is 3600000joules

that is 1kwh=3.6×10^6 J

Electricity meters measure the number of units of electricity used in a home or other building. Units (kilowatt-hours) are used instead of joules because a joule is a very small unit of energy. You wouldn't buy potatoes by the milligram!