How much it costs to run a space heater

The cost in every state

The table prices a 1,500-watt heater running flat out at each state's average residential electricity price over last winter, November 2025 to March 2026. Winter prices are the right ones for a heater: in many states summer rates are higher, so the annual average would overstate the cost.

Why your heater probably costs less than the table says

The table assumes the heating element is on every minute, which only happens in a room that never warms up to the heater's thermostat setting. Most heaters with a thermostat switch the element off once the room reaches the set temperature and back on as it cools, so over an evening it may only be heating half the time or less. Set the percentage in the calculator to match. If the heater has no thermostat, or the room is drafty and it runs constantly, leave it at 100.

The low setting halves the draw on most models. At the U.S. winter price, 750 watts for eight hours costs $1.06 a day instead of $2.12.

Every space heater is equally efficient

An electric resistance heater turns the electricity it uses into heat, all of it, whether it is an oil-filled radiator, a ceramic heater or a fan heater. Each kWh becomes 3,412 Btu of heat in the room, and a 1,500-watt heater on high produces about 5,118 Btu an hour. A heater sold as "energy efficient" cannot make more heat from the same electricity. What differs is how the heat is spread: a fan moves warm air quickly, a radiator heats more slowly and stays warm after it switches off, and a radiant heater warms the people in front of it rather than the air. Those differences change comfort, and sometimes how long you leave the heater on, but not the cost per hour at the same wattage.

When a space heater saves money and when it does not

A space heater saves money when it lets you heat one room while the rest of the house stays cooler. Turning the central thermostat down by several degrees and heating only the room you are in uses less energy than heating the whole house to the same temperature.

It costs more when it replaces cheaper heat instead of reducing how much you heat. Heat from electric resistance is expensive per unit compared with a gas furnace or a heat pump in most states, because a heat pump delivers two to three units of heat for each unit of electricity and gas usually costs less per Btu. The heating fuel cost comparison shows what a million Btu of heat costs from each fuel in your state, and the heat pump vs. gas furnace calculator compares a whole winter. For any other appliance, the electricity cost calculator uses the same arithmetic.

One safety note that costs nothing: plug a space heater directly into a wall outlet, not an extension cord or power strip, and keep it away from bedding, curtains and furniture. A 1,500-watt heater draws close to the limit of a standard household circuit.