The short answer: at 17¢ per kilowatt-hour, a 1,500-watt heater running continuously for eight hours costs about $2.04 per day or $61.20 over 30 days. The actual result depends on the heater setting, thermostat cycling, local rate, taxes, fees, room conditions, and how long it really draws power.
The inputs used
- Rated power: 1,500 watts on the high setting
- Use: 8 hours per day
- Electricity rate: $0.17 per kilowatt-hour (kWh)
- Month: 30 days
- Winter example: 90 days
These are example inputs, not a national average or a forecast for a particular home.
Step 1: convert watts to kilowatts
Electric utilities charge for kilowatt-hours, so the heater's watt rating must first be divided by 1,000.
Step 2: find energy used per day
A kilowatt-hour measures power used over time. Multiply the heater's kilowatts by the hours it draws that power.
Step 3: apply the electricity rate
Multiply daily energy use by the example rate.
$2.04 × 30 days = $61.20 per month
$2.04 × 90 days = $183.60 for 90 days
What if the heater does not run continuously?
A thermostat may cycle the heating element off after the room reaches its target. If the element draws full power for an average of four hours during an eight-hour window, the energy portion of this example is cut in half:
180 kWh × $0.17 = $30.60 per month
That is a scenario, not a guarantee. A cold or drafty room may keep the element on longer. A lower setting may also change power draw, but the label or manual—not the word “low”—is the reliable place to find wattage.
Three useful comparisons
| Scenario | Monthly kWh | At 17¢/kWh |
|---|---|---|
| 1,500 W × 8 hours/day | 360 kWh | $61.20 |
| 1,500 W × 4 powered hours/day | 180 kWh | $30.60 |
| 750 W × 8 hours/day | 180 kWh | $30.60 |
The last two rows land at the same number because each uses the same total energy. Cutting either power or powered time in half cuts this simple energy estimate in half.
Why this is not a heating-system comparison
This example estimates the heater's electricity use only. It does not prove that a portable heater is cheaper or more expensive than a furnace, heat pump, boiler, or other whole-home system. Those systems use different fuels and efficiencies, and a portable heater may or may not allow the central thermostat to be lowered. Comparing them fairly requires the energy used by both options under the same weather and comfort conditions.
Redo the estimate with your bill
- Find the heater's watts on its label or manual.
- Find your electricity price per kWh on a recent utility bill. If the bill has tiered prices or separate delivery charges, use the best marginal rate you can identify.
- Estimate powered hours—not merely the hours the heater is plugged in.
- Calculate more than one scenario so the result is a range rather than false precision.
Limitations worth keeping visible
- The 17¢ rate is illustrative and may not match your location or billing plan.
- Taxes, fixed customer charges, demand charges, and time-of-use pricing are not included.
- Thermostat cycling and measured wattage can differ from the rated maximum.
- This case does not estimate insulation, outdoor temperature, room size, or heat loss.
- Money not spent on electricity is only “saved” if it is not shifted to another cost.
Sources and further help
- U.S. Energy Information Administration: Measuring electricity — watt, kilowatt, and kilowatt-hour definitions used in the calculation.
- U.S. Consumer Product Safety Commission: Portable-heater safety — current placement, outlet, and shutoff guidance.
- U.S. Energy Information Administration: Electric Power Monthly — current electricity price data.
External resources are provided for context. Everyday Totals is not affiliated with these agencies.
Use your heater, rate, and schedule
The appliance calculator replaces every example input and shows daily, monthly, and annual estimates.
Calculate my electricity cost