Space heater cost calculator
How Much Does a Space Heater Cost to Run?
Calculate the hourly, daily, monthly, and annual electricity cost of running a space heater using your local electricity price.
Cost estimate
Calculate your electricity cost
Estimated energy use0 kWh/day
Estimated monthly energy0 kWh/month
Cost = watts ÷ 1,000 × hours used × electricity price.
Example
A quick way to sanity-check the result
With the example settings of 1,500 watts for 8 hours a day, the heater uses 12 kWh each day. Multiply that by your electricity price to estimate the actual cost.
Actual electricity use can vary with power settings, thermostat cycling, efficiency, standby use, and how the appliance is operated.
Why 1,500 watts is common
Portable heaters are high-power appliances.
Many plug-in space heaters are rated around 1,500 watts at their highest setting. At that draw, one hour of continuous operation uses 1.5 kWh. The hourly cost is therefore 1.5 times your electricity price in dollars per kWh.
At 16¢/kWh, one continuous hour is about 24 cents. Eight continuous hours would use 12 kWh and cost about $1.92.
Thermostat cycling
Being switched on for eight hours does not always mean eight hours at full power.
A thermostatically controlled heater turns its heating element on and off as the room reaches the set temperature. If the heater spends only half of an eight-hour period actively heating, its actual energy use can be much lower than a calculation that assumes a continuous 1,500-watt draw.
Room size, insulation, outdoor temperature, drafts, thermostat setting, and heater placement all affect how often the element runs.
When a space heater saves money
Heating one occupied room can reduce total heating use—but only in the right situation.
A portable heater may reduce overall energy use if it lets you meaningfully lower whole-home heating while keeping one occupied room comfortable. Running a space heater while the central heating system continues unchanged simply adds another electric load.
For the general calculation method behind this tool, see How to Estimate an Appliance's Electricity Cost.