How Much Does a Space Heater Cost to Run?
Short answer: a standard 1,500-watt space heater running 6 hours a day costs roughly $47 a month at the current US average electricity rate, but anywhere from $30 in the cheapest states to over $100 in Hawaii or California. It is the most expensive form of heat in your house. Price it at your state's exact rate.
Key takeaways
- The math is simple: 1.5 kW × hours × your state's rate. Nothing about a space heater is efficient or inefficient; they all turn 100% of electricity into heat.
- "Energy-saving" marketing on resistance heaters is physics-free. A $400 infrared unit and a $25 fan heater deliver identical heat per kWh.
- Running one 24/7 costs $110 to $380 a month depending on state. That pace can exceed whole-home gas heating.
- As spot heating for one room while the thermostat is lowered elsewhere, a space heater can genuinely save money. As primary heat, it is the worst option.
The exact math
Every resistance heater converts electricity to heat at 100% efficiency, so wattage and hours are the whole story; DOE Energy Saver documents the standard wattages. A "1500W" unit on full power draws 1.5 kWh every hour. At the US average residential rate that is about 26 cents an hour; in the priciest states it is over 50 cents an hour, using current EIA state rates.
Six hours a day for a month: 1.5 × 6 × 30.4 = 274 kWh. That is $31 a month at 11.5 cents (North Dakota), $47 at the US average, $97 in California, and $118 in Hawaii, using current EIA rates. Your thermostat behavior matters too: a unit cycling on a thermostat may only draw power half the time it is "on."
Why the "efficient space heater" does not exist
Resistance heating is already at the physical maximum: one unit of electricity in, one unit of heat out. Oil-filled, ceramic, infrared and "eco" models differ in how they distribute heat and how they cycle, which affects comfort, but not the cost per unit of heat. The only electric heating that beats 100% is a heat pump, which moves 2 to 3 units of heat per unit of electricity, as DOE Energy Saver explains. That difference is the entire subject of our heat pump vs gas furnace guide.
When a space heater saves money, and when it bleeds you
Saves money: heating one occupied room to comfort while the whole-house thermostat drops several degrees. Zone heating a home office can beat running the furnace for an empty house.
Bleeds you: as primary heating, or left running in unoccupied rooms. At 24/7 duty in an average-rate state a single unit costs about $190 a month, more than many homes' entire gas bill. If you are doing this because your central heating is broken or absent, the replacement math has probably swung in your favor; start with your state's page to see what you are paying per kWh.
Frequently asked questions
How much does a space heater cost to run per hour?
Wattage divided by 1,000, times your rate. A 1,500W unit at the US average is about 26 cents per hour on full draw; a 750W setting is half that.
Are oil-filled radiators cheaper to run than fan heaters?
No. Same wattage, same heat, same cost. Oil-filled units feel steadier because they store heat and cycle more slowly, which can suit thermostat use, but the per-kWh economics are identical.
Is it cheaper to run a space heater or central heating?
Per unit of heat, gas central heating and heat pumps are both far cheaper. A space heater only wins when it lets you avoid heating most of the house at all.