Oil filled radiator running costs
Working out the running costs of oil filled electric radiators is not as straightforward as you might think.
Like all electric heaters, oil filled radiators are 100% efficient, so all the electricity they consume is converted directly into heat. However, they don’t normally run at full power all the time, so the actual power consumption of the radiator will depend on the room size and temperature rather than the maximum power output of the heater.
The heating elements in an oil filled radiator heat the oil, which in turn releases its heat into the room. The heating elements keep the oil at its operating temperature by automatically switching on and off as required. If the room is very cold, the heating elements will be switched on for a greater proportion of the time. Once the room is heated to the desired temperature, the radiator will not need to consume as much power to keep it there. Especially if the room is well insulated.
A more powerful radiator is able to heat the oil more quickly, so its heating elements will be switched on for less time than a lower powered radiator, but ultimately consume the same amount of energy and have the same running cost.
A more powerful radiator is able to heat a larger room than a lower powered one because its heating elements are more powerful (so it can heat the oil more quickly) and more fins (so the oil can release its heat more quickly).
Calculating the maximum oil filled radiator running costs
When it is first switched on, an oil filled radiator will run at full power trying to heat its oil to operating temperature. If the radiator cannot heat the room to the desired temperature, perhaps because the room is too large for the radiator size or not well insulated, it will continue to run at full power. This is the worst case for calculating running costs.
You can calculate the maximum running cost by looking at the maximum power output of your oil filled radiator and the cost per unit of electricity from your latest bill. The power output of an oil filled radiator is measured in Watts. 1,000 Watts = 1KW, which is one unit of electricity.
Example 2KW oil filled radiator running cost
If your radiator is rated at 2KW and you use it for five hours each day, it will use a maximum of 10 units per day. If you multiply the number of units by the cost you pay for each unit, you will know the maximum running cost for your oil filled radiator. The actual running cost will not be more than this.