Oil-filled radiator vs fan heater: which is cheaper?

The verdict

Per kilowatt-hour they are identical, and no electric resistance heater beats another. Both convert electricity to heat at 100%, which is not a quality claim but what resistance means, and there is no headroom above it. Two 1,500 W heaters with their elements energised for the same number of hours cost the same to the cent, whatever the box says about ceramic, infrared, micathermic or oil.

Side by side

Oil-filled radiator and space heater are costed by the same function from the same dataset, so the $33 between them is a difference in the appliances and not in how each was measured. Oil-filled radiator draws an average 675 W across the hours it runs; space heater draws 827 W across its own.

Both at 18.34¢/kWh, the EIA residential average for June 2026. Ten years is roughly the service life of either.

The assumptions behind those figures

Nothing above is a manufacturer’s claim. 1,500 W at 45% for 8 hours a day, 150 days a year, is where oil-filled radiator’s 810 kWh comes from; 1,500 W at 55% for 8 hours over 150 days is where space heater’s 992 kWh comes from. Both are rated 1,500 W, so every dollar of the difference above comes out of the duty-cycle row.

Change any of these on the appliance’s own page and every figure moves with it. The duty cycle is a property of the machine; the hours are a property of you.

What the gap is worth at your rate

Nothing here is a purchase decision, so there is no payback to compute. But $33 is the gap at the national average, and what it is worth to you depends on your rate — which varies more across the country than the difference between these two.

The gap in your state

The appliances are the same everywhere; the rate is not. The gap between these two is worth $96 a year in Hawaii and $24 in Nevada — 4× apart, on identical appliances.

A year of each, by state. Residential average price, EIA June 2026.

Questions

Other head-to-heads

• Heat pump vs electric furnace

  $1,230 a year apart

  Is a heat pump actually cheaper to run than electric resistance heat?

• Window vs portable air conditioner

  $32 a year apart

  Is a portable air conditioner more expensive to run than a window unit?

• Ceiling fan vs air conditioning

  $411 a year apart

  Can a ceiling fan replace air conditioning?

Source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, June 2026. U.S. Government work, public domain.

How every figure on this page is computed · Where the data comes from