Are Oil Filled Radiators Cheap to Run

Running Costs For 2023 UK Price Cap


Oil filled radiators are extremely popular in the UK. In fact, they are one of the most popular portable electric heaters that are sold in the UK. Due to their popularity, you may be wondering are oil filled radiators cheap to run?

Below, I will show you the exact cost of running an oil filled radiator…

The cost of running an oil filled radiator will depend on how much your electricity supplier charges you for 1 kilowatt of electricity an hour.

As of 2023, with the new UK price cap, the cost is around £0.28p for 1 kilowatt of electricity an hour.

Oil filled radiators come in various heat outputs, and the cost to run these heaters will differ. They usually come in the following:

  • 800 Watts
  • 1000 Watts
  • 1500 Watts
  • 2000 Watts
  • 2500 Watts
  • 3000 Watts

1 kilowatt an hour is the equivalent to using 1000 watts an hour. Now, let’s calculate the running cost per hour of the oil filled radiators with the heat output mentioned above.

  • 800 Watts = £0.22p
  • 1000 Watts = £0.28p
  • 1500 Watts = £0.42p
  • 2000 Watts = £0.56p
  • 2500 Watts = £0.70p
  • 3000 Watts = £0.84p

These figures are rounded to the nearest even figure, and I have ignored decimals to make it easier.
Now I will show you the formula you need to use to work out the running cost of oil filled radiators.

You convert watts to kilowatts per hour

  • 800 Watts = 0.8 kWh
  • 1000 Watts = 1 kWh
  • 1500 Watts = 1.5 kWh
  • 2000 Watts = 2 kWh
  • 2500 Watts = 2.5 kWh
  • 3000 Watts = 3 kWh

You take the kilowatt-hours and times it by the cost of your kWh of electricity, the formula looks like this:

  • 0.8 × 0.28 = £0.22p

If you run an 800 watt oil filled radiator, it will cost £0.22p an hour, if you are on a good fixed traffic that is not affected by the current price cap, you would do something like this if you are paying £0.21p

  • 0.8 × 0.21 = £0.17p

You would pay £0.17p an hour to run an 800 watt oil filled radiator.

Because an 800 watt oil filed heater is cheaper than the others, that does not mean this is the right heater for you, as that size oil filled radiator may take longer to heat a room. The size of the room will determine what size oil filled heater you will need to run.

How to Select the Right Wattage Oil Filed Heater to Run in a Room?

The calculation below will help you select the right oil filled heater to run in a room to ensure it provides adequate heat, and actually warms the room to nice comfortable levels. The below figures are for the average insulated solid brick wall terraced house.

Room size in square meters x 100 watts per square meters

  • 500 watts can heat up to 5 square meter room
  • 600 watts can heat up to 6 square meter room
  • 800 watts can heat up to 8 square meter room
  • 1000 watts can heat up to 10 square meter room
  • 1200 watts can heat up to 12 square meter room
  • 1500 watts Can heat up to 15 square meter room
  • 2000 watts can heat up to 20 square meter room
  • 2300 watts can heat up to 23 square meter room
  • 2500 watts can heat up to 25 square meter room
  • 3000 watts can heat up to 30 square meter room

The figures above a rough estimate as to what you will need, if you have a modern property with excellent insulation, low ceilings. Instead of a 1,500 oil filled heater, you may be able to run a 800-1000 watt oil filled radiator instead.

If you live in an older property with high ceilings, instead of a 1,000 watt heater, you may need a 1,500 heater, and if you have old single glazed sash windows, 2,500 watts is what you may require to keep the room warm.

Now you know the cost to run an oil filled radiator in the UK, to help you find the best one, see our best oil filled radiator guide here, or learn how oil filled radiators work here.