How Much Electricity Does a Space Heater Use?
The typical space heater draws 1,500 watts on high — as much as fifty LED TVs running at once. Run it 8 hours a day and it uses 360 kWh a month: about $54 at $0.15/kWh, and easily the biggest single line on a winter bill.
Cost by usage pattern
The formula: watts × hours ÷ 1,000 = kWh, then × your rate. For a 1,500 W heater at $0.15/kWh:
| Usage | kWh/month | Cost/month | Cost/winter (5 mo) |
|---|---|---|---|
| 2 h/day (evening takeoff of chill) | 90 | $13.50 | $68 |
| 4 h/day (home office, workday) | 180 | $27 | $135 |
| 8 h/day (main room, all evening) | 360 | $54 | $270 |
| 12 h/day | 540 | $81 | $405 |
| 24/7 | 1,080 | $162 | $810 |
On low (750 W), halve everything. At higher electricity rates, scale up: at $0.30/kWh the 8-hour pattern costs $108/month. Get your exact number with the AC / heater running cost calculator.
The uncomfortable truth about "efficient" space heaters
Every plug-in resistive heater — ceramic, oil-filled, infrared, "eco" models, the $400 designer ones — converts electricity to heat at exactly 100%. A $25 heater and a $400 heater produce identical heat per watt. What differs is distribution (fan vs radiant), noise, and thermostat quality. A good thermostat matters because it cycles the heater off once the room is warm: a thermostat-controlled heater might average 60% duty cycle, cutting the table above by 40%.
What actually cuts the cost
- Heat the person, not the room. A 200 W heated throw or heating pad at your desk replaces a 1,500 W heater for a tenth of the cost.
- Use the thermostat and a timer. Set a target temperature instead of running on high, and don't heat empty rooms.
- Zone heating done right: a space heater beats central heating only when you're heating one room and turning the rest of the house down. Two or three space heaters usually cost more than the furnace they replace.
- The real upgrade is a heat pump. A small mini-split delivers the same heat for roughly a third of the electricity (COP ≈ 3). If you're space-heating every day all winter, run the numbers in the heat pump savings calculator — the payback often surprises people.
Safety notes worth repeating
Space heaters draw 12.5 A — near the limit of a 15 A circuit. Plug them directly into the wall (never a power strip or extension cord), keep 3 ft of clearance, and don't run them unattended or while sleeping.
Related tools
- Appliance Running Cost — this math for any device.
- Electricity Bill Calculator — see the heater inside your whole bill.
- Appliance Wattage Chart — wattages for 60+ appliances.