Space heater vs. oil-filled radiator: running cost
A space heater is cheaper to run: about $148 a year versus $165 for an oil-filled radiator at typical use and 17.99¢/kWh, a $16 difference.
| Space heater | Oil-filled radiator | |
|---|---|---|
| Typical watts | 1,500 W | 1,500 W |
| Watt range | 750–1,500 W | 600–1,500 W |
| Typical use | 6 hours a day for 5 months a year | 8 hours a day for 5 months a year |
| Energy per year | 825 kWh | 916 kWh |
| Cost per hour | 16¢ | 13¢ |
| Cost per day | 97¢ | $1.08 |
| Cost per month | $29.67 | $32.94 |
| Cost per year | $148 | $165 |
| Per year in Hawaii (43.51¢) | $359 | $398 |
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What drives the difference
- Space heater: Nearly all plug-in space heaters draw 1,500 W on high, the most a standard 15-amp outlet can safely supply. Every model converts electricity to heat at the same 100% rate, so the thermostat setting and hours matter more than the brand.
- Oil-filled radiator: Oil-filled radiators are electric resistance heaters with a sealed oil reservoir; they use the same 1,500 W on high as any space heater but cycle less often because the oil keeps radiating heat.
Ways to cut either cost
Stores heat in oil so it holds room temperature on its lower 600-900 W settings and cycles less.
See options on AmazonWarms your body directly at about 100 W instead of heating the whole room at 1,500 W.
See options on AmazonKeeps you warm overnight at about 60-80 W average instead of heating a bedroom at 600-1,500 W.
See options on AmazonWe may earn a commission from qualifying purchases. It never changes the numbers we show. Disclosure.
Frequently asked questions
Which costs more to run, a space heater or an oil-filled radiator?
At typical use and the U.S. average rate (17.99¢/kWh), an oil-filled radiator costs about $165 a year versus $148 for a space heater. That's $16 more.
How many watts do space heater and oil-filled radiator use?
A space heater typically draws 1,500 W (range 750–1,500 W). An oil-filled radiator draws 1,500 W (range 600–1,500 W). Watts alone don't decide cost. Hours of use, cycling and standby matter just as much.
Rates: EIA, 12 months ending 2026-07. Methodology.