Space heater cost formula?
kWh = (W ÷ 1,000) × hours × days; cost = kWh × $/kWh.
This calculator estimates electricity cost for a portable space heater from watts, hours per day, days, and $/kWh.
Energy (kWh) = (watts ÷ 1,000) × hours/day × days. Cost = kWh × rate. A common default is a 1,500 W heater running 6 hours/day.
Follow the manufacturer’s instructions for clearance and placement, and do not block heater vents. This page estimates operating cost only—it does not size a furnace or heat pump.
Concise answers for common searches — definitions, steps, and comparisons.
kWh = (W ÷ 1,000) × hours × days; cost = kWh × $/kWh.
Often about 750–1,500 W.
Convert watts to kilowatts, multiply by hours per day and days for kWh, then multiply by your electricity rate.
Formula
kWh = (watts ÷ 1,000) × hoursPerDay × days; cost = kWh × pricePerKwh. Defaults often use 1,500 W, 6 hours/day, 90 days, and $0.16/kWh.Use the nameplate (typical portable heaters about 750–1,500 W). Default example is 1,500 W.
Enter how many hours the heater runs each day (0.5–24).
Set the period length and your $/kWh from the utility bill.
Review estimated cost for the period and total energy use.
Input
watts 1500 · hours 6 · days 90 · rate 0.16Output
810 kWh · about $129.60(1500÷1000)×6×90 = 810 kWh; 810×0.16 = 129.60.
Input
watts 1500 · hours 6 · days 30 · rate 0.16Output
270 kWh · about $43.20(1500÷1000)×6×30 = 270 kWh; 270×0.16 = 43.20.
Common real-world scenarios where this tool saves time.
1,500 W, 6 hr/day, 90 days at $0.16/kWh → about 810 kWh and roughly $130.
Lower hours/day (for example 2–3) to estimate lighter supplemental heating costs.
Change watts only to see how heater size affects the same runtime and rate.
Step-by-step chains that connect related tools for common tasks.
Estimate portable heater cost, then compare central heating load tools if you are planning a system.
| Hours/day | Days | Approx. cost |
|---|---|---|
| 3 | 30 | ~$21.60 |
| 6 | 30 | ~$43.20 |
| 6 | 90 | ~$129.60 |
Keep clearances, do not block vents, and follow the manufacturer’s instructions for placement and cord use.
Run 750 W vs 1,500 W scenarios at your hours and rate to budget supplemental heat.
Enter realistic run hours. Many heaters cycle or are used only in evenings.
Enter electrical watts from the heater nameplate, not BTU/hr heating load.
Replace the default $/kWh with your bill’s energy charge for a closer estimate.
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kWh = (watts ÷ 1,000) × hours per day × days. Multiply by $/kWh for cost.
Use the heater nameplate. Many portable units are 750 W on low and about 1,500 W on high.
Yes. Set days to 30 (or your billing-cycle length) with your watts, hours/day, and rate.
Thermostats and eco modes cycle the element off. This calculator assumes the entered watts for every counted hour.
No. It only estimates plug-in heater electricity cost. Use the Furnace BTU or Heat Pump Size calculators for equipment load planning.
Follow the manufacturer’s safety instructions. Keep vents unobstructed and use the heater only as directed for your model.
Space heater cost inputs remain local — EverydayTools does not collect space-heater-cost calculator entries.
Estimates only — not professional HVAC or energy audit advice. Actual bills vary with cycling, rates, and fees. Follow manufacturer safety instructions.
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Reviewed on 2026-06-28.
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Typical space heater: 750–1,500 W
30 for monthly, 90 for a summer season, 365 for annual