Space heater electricity cost

Almost every plug-in space heater maxes out at 1,500 W — which makes it one of the most expensive ways to move heat around, per hour, of anything that plugs into a wall.

Short answer at the example rate of $0.17/kWh: a typical 1,500 W space heater running 8 hours a day, 30 days a month uses about 360 kWh and costs $61.20 a month. Put in your own wattage, schedule and rate below — 750 W is the low setting most heaters offer, 1,500 W is the high setting, and the 3,000 W row is two heaters in two rooms — a common winter setup that surprises people on the bill.

The $0.17/kWh default is a rough example rate — about the US residential average on EIA figures, and it moves over time. Type in the rate from your own electricity bill for numbers that mean anything for your home.

Low, typical and high — side by side

The default schedule is 8 hours a day for a 30-day month — a heater warming a home office through a workday, or a bedroom through the night. All three rows use that same schedule and the $0.17/kWh example rate; only the wattage changes.

The honest maths of electric heat

A space heater is not inefficient — nearly every watt becomes heat in the room. The problem is the price of the input: at typical residential rates, a kWh of electricity costs several times more than the same heat from a gas furnace and roughly three times more than from a heat pump, which moves heat instead of making it. The heater wins on exactly one axis: it heats only the room you are in.

So the comparison that matters is not heater vs heater. It is "1,500 W in this room" against "the whole central system running to keep every room warm" — if the space heater lets you turn the rest of the house down, it can come out ahead. If the central heating stays where it was, the heater is simply an extra 360 kWh a month looking for a reason.

Cutting the cost without cutting the warmth

Use the low setting once the room is up to temperature, close the door of the room being heated, and put the heater on a timer rather than letting it run into an empty room. Oil-filled models keep radiating after switch-off, which suits a regular schedule; fan models warm a cold room faster at the start. None of that changes the wattage — it changes the hours, and hours are where the money is.

Questions

How much does a space heater cost per hour?

On high (1,500 W) it uses 1.5 kWh an hour — about $0.26 at $0.17/kWh. On the low setting (750 W) about $0.13 an hour. Small numbers per hour; the cost arrives via the hours.

Is a space heater cheaper than central heating?

Only when it replaces heating the whole house — heating one occupied room with 1,500 W while the central system stays off or low can win. As a supplement on top of full central heating it is pure addition: electric resistance heat is among the priciest heat per unit, well above a heat pump or gas furnace in most regions.

Do ceramic, oil-filled or infrared heaters use less electricity?

No — all plug-in electric heaters convert electricity to heat at essentially 100% efficiency, so 1,500 W is 1,500 W of heat whatever the casing. They differ in how the heat feels and how evenly it spreads, not in the kWh.

Why did my bill jump if the heater is only on at night?

Eight hours a night at 1,500 W is 360 kWh a month — comparable to everything else in a small home combined. Night use also lands entirely in hours you would otherwise use almost nothing, so it shows up as a clean jump on the bill.

More appliances: the main calculator and whole-home list · every preset on one chart · how the formula works