The type of electric heater that is cheapest to run can depend on a number of factors, such as the cost of electricity in your area and the efficiency of the heater. Some types of electric heaters are more energy-efficient than others, so they may be cheaper to run. For example, infrared heaters and ceramic heaters tend to be more energy-efficient than traditional convection heaters. Oil filled radiatords store their heat for longer after use making it an efficient option. It is also a good idea to look for a heater with a high energy efficiency rating and to use a programmable thermostat or timer to control when the heater is in use.