One kiloWatt hour has to do with the amount of energy being supplied or consumed in relation to the amount of time it is being consumed. One kiloWatt is 1000 Watts or 10 - 100 Watt light bulbs...
There is no set answer to this - there are too many variables... How many units are you using over a year ? What steps are you taking to reduce your consumption ? Which supplier are you using ? What...