Why are houehold electricty bills calculated in KW/h not Joules?
If you have a 1000W heater and leave it on for 2 hrs you use 2kwh of energy. if you get charged 10c/kWh then it will cost you 20c to run the heater for this time So it is much easier for the average person to calculate how much an appliance will cost them to run using kWh. To do the same calculation in Joules, they would have to convert from hours to seconds (since it is unlikely that they would use the appliance for only a few seconds) and they would also need to know the relationship between power and energy.
