It is very difficult to accurately determine how much it costs to run a heater within your own environment. It depends largely on the type of house, size of room and quality of insulation. However the maximum the heater will cost will per 1 unit of electricity per hour, per kilowatt of heat. For example, if you have a 1500W heater the maximum it will use is 1.5 energy units per hour. However the unit will cycling on and off so the unit while off will not consume any electricity. Electric heaters heat only the room you are in and not the entire house, providing extra heat only where required and helping to optimize energy consumption. Electricity costs vary across suppliers. If you check your bill you will be able to find out how much you are paying per unit of electricity.