DECISION GUIDE
Space Heater Electricity Cost Calculator
Space heaters draw a lot of power in a small package. Thermostat cycling, insulation and the heat setting determine how often the element runs.
Direct answer: The editable 1,500 W preset at 75% thermostat duty costs about $0.21 per scheduled hour. At 6 hours per day it costs about $1.24 per day and $37.34 per 30-day month at the U.S. average rate.
Editable estimate
Calculate and compare
Results update as you type.
kW × effective runtime × rate. Effective runtime = hours/day × duty cycle.
Baseline vs scenario
Compare two annual energy-use estimates.
Old vs new appliance payback
Use annual kWh for both models. Leave rebate at $0 unless you have a confirmed amount.
Simple payback = net upfront cost ÷ annual electricity-cost savings. Excludes financing, maintenance, rate changes and time value of money.
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Ways to lower this cost
See all savings tips →750 W VS 1,500 W
Compare 1, 4, or 8 energized hours
At the same rate, a 1,500 W resistance heater uses twice the electricity of a 750 W setting while energized. The table assumes 100% energized time; use the calculator duty-cycle input when the thermostat cycles.
| Daily energized time | 750 W energy / cost | 1,500 W energy / cost |
|---|---|---|
| 1 hour | 0.75 kWh / $0.14 | 1.50 kWh / $0.28 |
| 4 hours | 3.00 kWh / $0.55 | 6.00 kWh / $1.11 |
| 8 hours | 6.00 kWh / $1.11 | 12.00 kWh / $2.21 |
Wattage describes electrical input, not the comfort result for a specific room. Insulation, air leakage, room size, and thermostat cycling determine how long heat is needed.
Review insulation and air-sealing tips before comparing heater settings.
Space heater cost quick answers
How much does a space heater cost per hour?
Multiply heater kW by thermostat duty cycle and your electricity rate. The current 1,500 W preset is about $0.21 per scheduled hour at 75% duty.
How many kWh does a 1,500 W heater use?
It uses 1.50 kWh for each full energized hour. Four energized hours use 6.00 kWh and eight use 12.00 kWh.
Does 750 W always heat more cheaply?
It uses less electricity while energized, but it also supplies less heat. Compare comfort and required runtime, not wattage alone.
What should I measure?
Use the label or a safe plug-in meter and model thermostat duty cycle instead of assuming continuous operation.
DOE Energy Saver guidance · source reviewed August 2026.
RATE COMPARISON
How your rate changes the cost
Same appliance inputs, using May 2026 EIA residential averages.
Make the estimate more accurate
- Use the wattage printed on the heater label; many full-power models are 1,500 W.
- A plug-in energy meter captures thermostat cycling better than a guessed duty cycle.
- Compare room heating with whole-home heating before relying on a portable heater.
Presets are estimates. Use your model label, an EnergyGuide annual-kWh figure or a safe meter reading when available. Compare old and new appliance payback.