Energy
Estimate what a space heater adds to your electricity bill.
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Space heater cost guide
An electric space heater is one of the few appliances where the nameplate is exactly what you pay for: a 1,500 W heater draws 1,500 W the whole time its element is on, and all of it becomes heat. This calculator multiplies that wattage by the hours the element actually runs each day and by your electricity price, then shows the cost per hour, day, 30-day month, and 365-day year. Use it to decide whether heating one room with a plug-in heater beats running central heating for the whole house, to see what a heater under a desk adds over a winter, or to compare a 1,500 W convector with a 750 W setting. Most portable heaters in North America are capped at 1,500 W by the 15 A outlet; in 230 V countries 2,000 W and 2,500 W fan heaters and oil-filled radiators are common. Thermostat cycling matters: a heater set to hold a small room at 20 °C may run its element only 50 to 70 percent of the time, so enter element hours rather than switched-on hours.
Energy per day (kWh) = watts × element hours per day ÷ 1,000. Daily cost = kWh × rate. Monthly = daily × 30; annual = daily × 365; hourly = watts ÷ 1,000 × rate.
Worked example with the defaults: a 1,500 W heater running 5 hours per day at $0.16 per kWh. Per hour: 1,500 ÷ 1,000 × $0.16 = $0.24. Per day: 1,500 × 5 ÷ 1,000 = 7.5 kWh, and 7.5 × $0.16 = $1.20. Per 30-day month: $1.20 × 30 = $36.00. Per 365-day year: $1.20 × 365 = $438.00, the figure the calculator displays. For a heater used only through a 120-day heating season, the seasonal cost is $1.20 × 120 = $144.
Power is in watts on the element setting you use — a heater with “750/1,500” switches should be entered at the setting you actually run. Hours are hours per day the element is heating, which is less than the time the unit is switched on if it has a thermostat. The rate is currency per kWh from your bill. Results assume a 30-day month and a 365-day year; multiply the daily cost by the days in your heating season for a seasonal figure. Gas or kerosene heaters are not covered; their fuel is priced per therm, litre, or kilogram.
This is a modelled estimate, not a meter reading. Real consumption moves with weather, occupancy, appliance age, standing charges, and tariff structure, and equipment rarely runs at its nameplate rating. Use the figure to compare options against each other, then confirm against your own bill and the manufacturer's specification before committing to a purchase. On this page the figure rests entirely on power, hours per day, electricity rate, market / jurisdiction, effective date, data source, update owner and review date, so start there if the space heater cost returns something you did not expect.
Good to know: “energy-efficient” and “ceramic” space heaters do not use less electricity for the same heat — every resistive heater converts 100 percent of its watts to heat, so a 1,500 W ceramic, oil-filled, or infrared model all cost the same $0.24 per hour at $0.16 per kWh. The differences are in comfort and where the heat goes. The real savings come from heating one occupied room instead of a house, or from a heat pump, which delivers 2 to 4 units of heat per unit of electricity. Also avoid running a 1,500 W heater on the same 15 A circuit as another large load; the calculator will not warn you but the breaker will.
Energy results depend on tariffs, equipment behavior, region, weather, and installation assumptions. Verify rates and electrical decisions with the utility, manufacturer, or qualified professional.
Sources
How it works
Estimate what a space heater adds to your electricity bill. This tool explains the calculation so you can adjust the assumptions to match your situation.
Worked example
With Power = 1500 W · Hours per day = 5 hours · Electricity rate = 0.16 $/kWh → $438.00 / year (estimated electricity cost). Change an input above and this example updates with your numbers.
Common questions
A 1,500 W heater uses 36 kWh in 24 hours of continuous running, which is $5.76 at $0.16 per kWh. With a thermostat cycling the element 60 percent of the time, expect about 21.6 kWh or $3.46. Over a 30-day month continuous use would be roughly $173.
A space heater is cheaper only when it lets you heat one room and turn the rest of the house down. Heating the whole home with several 1,500 W heaters at $0.16 per kWh costs far more than a gas furnace or a heat pump, which produces 2 to 4 kWh of heat per kWh of electricity.
No. Both convert every watt into heat, so a 1,500 W oil-filled radiator and a 1,500 W fan heater cost the same per hour of element time. The oil unit heats more slowly and keeps radiating after it cycles off, which can feel more comfortable and lets a thermostat cycle less often.
At 1,500 W for 5 hours a day and $0.16 per kWh, about $36 per 30-day month. Eight hours a day is about $58, and running it around the clock roughly $173. Enter your own tariff and hours to see the figure for your home.
A small heat pump (mini-split or reverse-cycle air conditioner) is the cheapest, delivering 2 to 4 units of heat per unit of electricity. If you must use a resistive heater, use the lowest setting that keeps the room comfortable, close the door, and put it on a timer so the element runs only when you are there.