How much does it cost to run a space heater?
A 1,500 W space heater uses 1.5 kWh an hour, which costs $0.26 an hour at 17¢ per kWh — $2.04 for 8 hours on high, about $62.05 a month if you do that every day.
How to work it out
- 1,500 W ÷ 1,000 = 1.5 kW × $0.17/kWh = $0.26 an hour
- 1.5 kW × 8 h = 12 kWh × $0.17 = $2.04 a day
- 12 kWh × 365 days = 4,380 kWh a year = $744.60 ($62.05 a month)
Virginia Cooperative Extension lists portable heaters at 750–1,500 W, and Champion’s chart gives the same range; this page uses the top of it, a heater on high. Every watt becomes heat, so the only real question for cost is how many hours it actually runs.
Adjust for your project
More options: Days/yr
- Cost per hour
- $0.26
- Cost per month (average)
- $62.05
- Cost per year
- $744.60
- Energy per day
- 12 kWh
- Energy per year
- 4,380 kWh
The same appliance at other hours per day
| Hours used per day | Energy per day | Cost per day | Cost per month (average) |
|---|---|---|---|
| 1 | 1.5 kWh | $0.26 | $7.76 |
| 2 | 3 kWh | $0.51 | $15.51 |
| 4 | 6 kWh | $1.02 | $31.03 |
| 8 | 12 kWh | $2.04 | $62.05 |
| 12 | 18 kWh | $3.06 | $93.08 |
| 24 | 36 kWh | $6.12 | $186.15 |
What to know about space heater running costs
- The thermostat decides the hours. Eight hours “on” in a room that warms up quickly might be four hours of real heating. A plug-in usage monitor answers it in a day.
- Low setting is usually about half. Many 1,500 W heaters have a 750 W setting — the bottom of the extension service’s 750–1,500 W range — which halves the cost per hour.
- All electric heaters are equally efficient. Oil-filled, ceramic and infrared models all turn 1,500 W into 1,500 W of heat. They differ in how the heat feels and spreads, not in cost per hour.
- On batteries it is a huge load. 1.5 kWh an hour empties a typical 1 kWh power station in well under an hour — see how long a power station runs a space heater.
The current is on how many amps is 1500 watts at 120 volts — one heater can take most of a household circuit. If you are heating with a generator in an outage, the generator size and fuel are on the generator size calculator; for a propane heater instead, how long a 20 lb propane tank lasts for heating does the fuel side.
Different size? Use the full Electricity Cost Calculator.
What you’ll need
- Plug-in electricity usage monitorBudget price
Plugs in between the wall and a 120 V appliance and shows real watts and kWh over a day — the honest way to fill in a load list, especially for fridges that cycle on and off.
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Frequently asked questions
How much does it cost to run a space heater 24 hours?
On high for all 24 hours, $6.12 a day at 17¢ per kWh (36 kWh).
How much does it cost to run a space heater on low (750 W) for 8 hours?
About $1.02 a day — half the high-setting cost.
How much does a space heater cost per month at 20¢ per kWh?
About $73.00 a month for 8 hours a day on high.
Other common sizes
- The cost to run a window AC unit — $0.17 an hour at 17¢/kWh (10,000 BTU)
- The cost to run a dehumidifier — $1.60 a day at 17¢/kWh (12 hours)
- The cost to run a ceiling fan — $0.15 a day at 17¢/kWh (12 hours)
Sources
- Virginia Cooperative Extension, BSE-301: Estimating Appliance and Home Electronic Energy Use (2020) (opens in a new tab) — Wattage × hours ÷ 1,000 = kWh per day; watts = amps × volts when only amps are listed; a refrigerator runs at full wattage about a third of the time; typical nameplate wattages.
- Champion Power Equipment — Generator Wattage Chart (opens in a new tab) — Typical running and starting watts for household, RV and job-site appliances (a manufacturer’s planning chart — your nameplate wins).