How much does an oil-filled radiator cost to run?

The formula

cost = watts × hours ÷ 1,000 × price per kWh

Worked example: 1,500 W × 8 h ÷ 1,000 = 12 kWh a day. 12 kWh × $0.1816 = $2.18 a day, or about $65.38 over 30 days.

How many watts does an oil-filled radiator use?

Most are rated 600 to 1,500 W. The exact figure is on the label on the back or bottom.

• The owner's manual for the D-7-H oil-filled radiant heater sold at Lowe's lists three power settings on a 120 V outlet: 600 W (I), 900 W (II) and 1,500 W (III), with a separate thermostat dial that cycles the heater on and off once the room reaches temperature.
• Honeywell's HZ-789 manual lists 900 W on its constant LO setting and 1,500 W (12.5 A, 5,118 BTU an hour) on HI. In its EnergySmart mode the heater picks the power level itself and drops to standby, drawing only a few watts, once the room reaches the set temperature.
• Honeywell says the radiator needs 10 to 15 minutes to reach full heat output. The oil keeps releasing heat after the elements switch off, which is why the room feels steady, but it does not change how much electricity a kWh of heat takes.
• DOE says electric resistance heating turns all of the electricity it uses into heat. A 1,500 W oil-filled radiator, a 1,500 W ceramic space heater and a 1,500 W baseboard all deliver the same heat for the same kWh.

Cost at different electricity prices

Per month (30 days) and per year (12 such months). Real use is usually seasonal. Average residential prices for August 2026 from the same EIA table. Your utility's rate, including delivery charges, may differ. Check the price per kWh on your bill.

Ways to pay less

1. Let the thermostat do the work Heat the room on high, then turn the thermostat dial down until it clicks, as the D-7-H manual describes. From then on the heater only runs when the room cools. Hours with the elements on are what you pay for, so a radiator that cycles half the time costs half as much as the table's figures.
2. Drop to a lower setting once the room is warm Switching from 1,500 W to 900 W cuts the hourly cost from about $0.27 to $0.16 at 18.16¢/kWh. Honeywell notes the LO setting uses less electricity and is meant to hold a room at temperature.
3. Use the timer at night Because the oil holds heat, a radiator set to switch off an hour or two before you get up keeps the room warm for a while after it stops. DOE says turning the thermostat down 7 to 10°F for 8 hours a day can save as much as 10% a year on heating.
4. Heat one room, not the house A radiator pays off when it lets you turn the central thermostat down and heat only the room you are in. Running it alongside a furnace that is still set high only adds to the bill. Close the door to keep the heat where you are.
5. Seal the drafts first DOE estimates sealing air leaks can save 10 to 20% on heating and cooling bills. A drafty room keeps the radiator on high and stops the thermostat from ever cycling it off.

Safety. Plug the radiator straight into a wall outlet, never an extension cord or power strip, and keep it at least 3 feet from beds, curtains, furniture and anything else that can burn (CPSC, Honeywell). Don't leave it running unattended. The oil is sealed in at the factory: never open the fins or try to refill them.