The formula
Electricity cost = power (kW) × hours of use × price per kWh. Appliances list power in watts, so divide by 1,000 to get kilowatts. Our electricity cost calculator does the math for any appliance.
Space heater example
Most portable space heaters draw 1,500 watts on high. At an electricity price of $0.17 per kWh, running one for 8 hours a day costs 1.5 × 8 × $0.17 = $2.04 a day, or about $61 a month. On the low setting (often 750 W), the cost is roughly halved.
Compare with other appliances
An electric blanket uses about 100 to 200 W, so 8 hours a night costs only $0.14 to $0.27 at the same rate, which is far cheaper than heating a whole room. An oil-filled radiator uses similar power to a fan heater but cycles on and off once warm. A heat pump can deliver two to four units of heat per unit of electricity, which is why it's much cheaper to run than resistive heaters.
Find your electricity price
Look at your bill for the price per kWh, including delivery charges. Prices vary greatly by region and time of day; some plans charge more at peak hours, so running heaters overnight may be cheaper.
Ways to save
Heat the room you're in rather than the whole house, close doors, use draft stoppers and insulate windows with film. Lowering the thermostat by 1°C (about 2°F) can noticeably reduce heating bills. A programmable thermostat avoids heating empty rooms.
Safety
Plug space heaters directly into a wall outlet, not an extension cord, keep them at least three feet (one meter) from anything that can burn, and choose models with tip-over and overheat shut-off. Never leave them running while asleep unless the model is designed for it.
Estimate your winter total
Add the monthly cost of each appliance you use more in winter: heaters, longer lighting hours, dryers. Knowing the total helps you budget and decide whether an upgrade such as a heat pump or insulation would pay for itself.
Frequently asked questions
How much does a 1500W space heater cost per hour?
About $0.26 per hour at $0.17 per kWh.
How do I calculate appliance electricity cost?
Watts ÷ 1,000 × hours × price per kWh.
Is an electric blanket cheaper than a space heater?
Yes, it typically uses about a tenth of the power.
Are heat pumps cheaper than space heaters?
Usually; they deliver 2–4 times more heat per unit of electricity.