The True Cost of Running a Space Heater (Hourly, Monthly, Honestly)
Updated September 2026
Bottom line: A 1,500-watt space heater costs about 26¢ an hour at the national-average rate. That's $62 a month at 8 hours a day and over $180 a month if it never turns off. Every 1,500-watt unit makes exactly the same heat, whatever the box says. It saves money in one pattern only: heating the one room you're in while the whole-house thermostat drops several degrees. As a supplement with the thermostat left alone, it's pure added cost, and that's the January bill-shock story every single year.
The math, without the marketing
Watts are watts. 1,500 watts for one hour is 1.5 kWh, times your rate: 26¢ at the 17¢ average, 19¢ in the cheap-power states, 45¢ and up in the priciest ones. Our state pages do the local number.
Ceramic, infrared, quartz, oil-filled, 'eco', the $29 one and the $179 one: all of them convert electricity to heat at the same 100%. They differ in how the warmth is delivered (a fan, a radiant glow, a slow warm radiator) and in how well they control themselves. Never in heat per dollar. There is no efficient space heater. There are only heaters with better thermostats.
That thermostat is the one real feature. A unit that cycles off at a set temperature runs fewer hours than one blasting continuously, and fewer hours is the only lever you have. A thermostat, a timer, tip-over shutoff and a quiet fan. That's the whole legitimate shopping list.
A home office, in numbers
Say the office is 12 by 12 and you're in it nine hours a day. A 1,500-watt heater holding 68°F in a room that size, door shut, actually runs maybe half to 60% of the time once the room is warm. Call it 8 kWh a day, $1.36, or about $30 for a 22-day work month.
The other side of the ledger is the setback. Dropping the whole-house thermostat from 68 to 60°F for those same nine hours saves roughly 1% of heating cost per degree per eight hours, so around 9% of the monthly heating bill. On a $200 gas-furnace month that's $18 back against $30 spent. On a $400 electric-furnace or propane month it's $36 back, and the heater has paid for itself with change to spare.
So zone heating isn't automatically a win. It wins when the central system is expensive (electric resistance, propane, an old oil boiler) or the house is big and leaky, so a deep setback saves a lot. With cheap natural gas in a tight 1,500-square-foot house it's close to a wash, and what you're really buying is one warm room. Either way the savings come from the setback. The heater just makes the setback bearable.
The pattern that bites
The one that shows up in shocked January bills is the opposite arrangement: a heater added to a cold bedroom with the central thermostat untouched. That's stacking the most expensive heat in the house on top of an unchanged baseline. Two heaters run this way, evenings and overnight, add $100 or more to a monthly bill, and nobody remembers plugging in anything unusual.
A room that's cold while the rest of the house is fine is usually a duct, insulation or draft problem, and those have permanent fixes that cost less than one winter of plug-in heat. Check that the register is open and actually blowing, feel for drafts at the window and the outlet plates, and if the room sits over the garage, the floor insulation is the suspect.
Cheaper and safer ways to buy warmth
Per unit of heat, a heat pump (central or a mini-split) delivers the same warmth at roughly a third of resistance cost. If one already serves the room, use it and skip the plug-in entirely. Electric blankets and heated throws draw 50 to 150 watts and warm the person instead of the air, for 1 to 3 cents an hour. For TV and sleep hours that's the cheapest comfort watt in the house.
Safety is part of the cost equation. Plug heaters straight into the wall, because power strips and extension cords melt. Keep three feet of clearance from anything that burns. Don't run them unattended overnight; if all-night heat is non-negotiable, an oil-filled radiator on a low thermostat setting is the safer shape.
FAQ
How much does a space heater cost per hour?+
A 1,500-watt heater at the national-average rate costs about 26¢ an hour, roughly $62 a month at 8 hours a day. In high-rate states it tops 40¢ an hour. Check your state's page for the local number.
Are some space heaters cheaper to run than others?+
No. Every 1,500-watt heater produces identical heat. A built-in thermostat that cycles the unit instead of running it flat out reduces hours, and therefore cost. Branding changes nothing.
Is it cheaper to run a space heater or central heat?+
One room plus a whole-house setback: the heater wins, and by more if your central heat is electric resistance, propane or oil. Several heaters, or an unchanged thermostat: central heat wins clearly, and a heat pump at a third of the per-BTU cost wins by a mile.
Does the low setting cost half as much?+
Yes, 750 watts is about 13¢ an hour. It also makes half the heat, so the room warms more slowly and the heater runs longer to reach the same temperature. On a thermostat the cost per degree of warmth is the same either way; the low setting mostly keeps a small, already-warm room from overshooting.