There are many differences between kWh and kW. The kWh refers to the amount of energy that you are using. Some may assume that this refers to the number of kilowatts that you use per hour, but this refers to the unit of measurement that may be needed to make different appliances run. kW stands for kilowatt. This is equal to 1000 watts.
This means that every time an appliance makes use of electricity, it requires a certain amount of kW of power. Take note that even if you turn off your television set, but you forget to remove the plug, the electricity will keep on moving and this will still make a difference with your electric bill.