How much does a space heater cost to run?
A 1500-watt heater costs about **28 cents an hour** to run, or **$2.21** for an eight-hour evening, at the US average tariff. This is by a wide margin the most expensive thing on this site. Every other appliance here — television, monitor, fridge, freezer, dishwasher, washer, dryer, air conditioner — averages **363 watts between all eight of them**. A single heater on its high setting draws four times that.
Work it out with your own tariff
Hours used per day
Watts, from the label on yours
Your rate, cents per kWh
| Period | Cost | Hours counted |
|---|---|---|
| One hour running | $0.36 | 1 hour |
| A full 24 hours on | $8.64 | 24 hours |
| A day of typical use | $8.64 | 24 hours |
| A month | $259 | 24 h/day × 30 |
| A year | $3,154 | 24 h/day × 365 |
1200 W × 24 h ÷ 1000 = 28.80 kWh × 30¢ = $8.64 for a day of typical use.
Calculated at 1200 W — the figure printed on the appliance, not a measurement of ours. Check the plate on yours and pick it above. Rate defaults to 18.44¢ (U.S. Energy Information Administration, 2026-05) — a national average, which is wrong for you specifically, so put your own in above.
The number on the plate is the number, and that is unusual
Everywhere else on this site the wattage comes from a measurement: a laboratory test under a defined procedure, published by a certification programme. Here there is no measurement, no certification, and no source to cite — and none is needed.
A space heater is a resistive load. Electricity goes in and essentially all of it comes out as heat; there is no compressor cycling, no motor under variable load, no efficiency to speak of. So the rating printed on the appliance is what it draws. 1500 W means 1500 W.
That is why this page asks you for the number instead of telling you one. Look at the plate or the box. Almost every plug-in heater sold in the US is 1500 watts on high and 750 on low, because a 15-amp household circuit will not carry much more than 1800.
But the thermostat means it is not on all the time
This is the caveat that matters most, and it is the same problem as the refrigerator page in reverse.
A thermostatic heater does not draw 1500 watts continuously. It heats until the room reaches the setting, then cuts out, then cuts back in. Over an evening in a well-insulated room it might run a third of the time; in a draughty room with the door open, nearly all of it.
So the hours you set below are hours of actual heating, not hours of the heater being switched on. If you leave it on all evening in a room it warms easily, your real cost is a fraction of the figure — and there is no way for us to know which case is yours, which is exactly why the hours are yours to set.
A heater without a thermostat, or one turned up so high it never reaches the setting, does draw its rating continuously. Those are the cases where the number below is literal.
What a season costs
Eight hours a day for a month at 1500 W comes to about $66. Across a four-month heating season, roughly $266.
Set against a heat pump or central heating, that comparison is where the interesting decision lives — and it is not one this page can make for you, because it depends on what you are heating instead, and on gas prices we do not publish. What this page can tell you honestly is the electricity cost of the heater alone.
On low, it is half
750 watts is about 14 cents an hour. The relationship is exactly linear, again because the load is resistive: half the watts, half the cost, half the heat.
The practical consequence is worth stating, because it runs against intuition: running a heater on low for twice as long costs the same as running it on high for half as long. There is no efficiency to be gained by choosing a setting. What changes is how fast the room warms, and — with a thermostat — how much of the time the element is actually drawing power.
What this does not account for
No source, and that is deliberate. Every other device on this site carries a citation to a measurement. This one does not, because the figure is the rating on your own appliance rather than anybody's test result. If a page quotes you a measured wattage for space heaters generally, ask what it could possibly have measured.
The thermostat is the largest source of error here. The calculator assumes the heater draws its rating for the hours you set. A thermostatic heater in a room it warms easily runs a fraction of that time, and your real cost is correspondingly lower. This cuts one way only: the figure is a ceiling, not an average.
Insulation, room size and outdoor temperature decide everything. The same heater in the same house costs different amounts in October and January. Nothing on this page models that, and any page that claims to is modelling your house without having seen it.
This is the electricity cost only. Whether a space heater is cheaper than turning up the central heating depends on gas prices, how many rooms you are heating, and the efficiency of the system you are not using. That comparison needs a gas price, which this site does not yet publish.
Oil-filled and ceramic heaters are the same arithmetic. The construction changes how the heat is delivered and how long the appliance stays warm after switching off, not how many watts it draws while on.
Worth reading next
Sources
- 01Electric Power Monthly, Table 5.3 — average price of electricity to ultimate customersU.S. Energy Information Administration ·
How these figures are produced: see our methodology.
Figures are calculated from published wattages and a published tariff, both dated above. They are good for comparing devices, not for predicting your bill: your rate, settings and usage all differ.