Electric Radiator Running Costs And Energy Usage


‘What is the running cost of your radiators’ and ‘ how do the running costs compare with X Company electric radiators’ are regularly asked questions.


The correct answer is “ The running costs depend on a number of factors” and “The running costs will be the same as X company electric radiators “ The factors affecting running costs are:  the electricity tariff at the property, the thermostat setting, the nature of usage ( on/off or continuous ) and the heat loss of the rooms and the property.


All electric resistance elements are 100% efficient at turning fuel input into heat output, therefore all electric radiators from all German radiator manufacturers have the same efficiency and the same running cost. The quality of the thermostat and timing controls can have an effect by ensuring only the heat wanted is produced at the times wanted. Our products have PI electronic thermostats  ( The most accurate available ) with an accuracy of +/- 0.2 deg C.


Let’s assume the average current electricity cost per kwh ( per unit ) of 12p. This means that a 1kw radiator would cost 12p per hour to run if heating at full power for the hour.


The next bit is where it gets a bit tricky to calculate. If the thermostat is set to 20 deg C for example, once the room reaches 20 degrees C the thermostat will turn the power off to the radiator. From this point onwards, the thermostat will ensure that the only heat emitted is enough heat to counteract the heat loss of the room and therefore keep the room at a constant 20 deg C. For example, if the room has a heat loss of 200 watts per hour, the 1kw radiator will only produce 200 watts of heat in that hour. That would mean only being on intermittently for a total of 12 minutes in each hour. At an electricity tariff of 12p per kwh this would cost 2.4p per hour.


If that same 1kw radiator was placed in a room that had less insulation, more outside walls, bigger windows and single glazing it would have to counteract a much bigger heat loss. It therefore would have to emit more heat per hour to maintain a steady state temperature and cost more to run. If this room has a heat loss of 800 watts per hour for example, then the radiator would have to produce 800 watts of heat per hour to counteract the heat loss and maintain a steady state temperature. This would mean being on intermittently for 48 minutes in each hour. At an electricity tariff of 12p per kwh this would cost 9.6p per hour.


It will always take more energy to heat a room to temperature than it will to maintain a room at a set temperature. Therefore on/off usage patterns will be more costly than maintaining a constant temperature or using ‘set back’ or ‘economy’ temperature settings rather than switching off completely when the room is not occupied.


In common with all heating systems, the thermostat setting affects the running cost, so rooms which are not occupied should be set to lower temperatures. According to the Carbon Trust, your heating cost will rise by 8% for every 1 degree the thermostat setting is increased above 19°C.



Our radiators, in common with all other electric radiators will cost differing amounts to run depending on the circumstances. All electric radiators will produce heat for exactly the same cost. The thermostat accuracy and time programming controls are important to ensure that only the heat required and no more is produced and that the heat is produced only at the time required and only in the rooms where it is required.