Difference b/w KW & KWh

It is a common misconception to be confused between kW and kWh. Let us break it down one by one. 

kilo watt kW stands for kilowatt. A kilowatt is simply a measure of power. For example, a 10,000 watt electric shower is often referred to as a10kW shower. 

However, 

kilowatt hour (kWh) is a measure of energy. In other words, it is the work performed by appliances during a given period of time. 

So a 2000 watt drilling machine needs 2,000 watts (2 kW) of power to work, while requiring 2 kWh of energy in an hour.

Therefore, any device that is left for standby over night or for long hours accounts for energy consumption in your electricity bill.

Formula

Ex- The TV runs 5 hours of a day and consumes 80-400 watts of power. So the total energy consumed by the TV is measured by the product of time and power consumed.

Energy (in kWh ) = Power (kW) X Time (24).

Energy = 400 x 5 /1000

Energy = 2 kWh