Electricity use guide
How much does a portable space heater cost to run?
Using a planning draw of 1,500 watts for 3 hours a day, this example uses 4.50 kWh daily. At the June 2026 monthly average U.S. residential rate of $0.1834 per kWh, that is about $0.83 per day or $301.23 per year.
- Daily electricity
- 4.50 kWh
- Monthly cost
- $25.10
- Annual electricity
- 1642.5 kWh
- Annual cost
- $301.23
Calculation for this example
1,500 W ÷ 1,000 × 3 hr/day × 365 days × $0.1834/kWh = $301.23/yearElectricity use in kilowatt-hours equals watts divided by 1,000, multiplied by runtime. Cost equals that energy use multiplied by the price per kWh.
What changes the actual cost?
- Actual draw can change with the model, power setting, workload, age, and standby behavior.
- For the closest estimate, use the wattage on the nameplate or manual and measure daily runtime over a typical week.
The example is a labeled planning estimate, not a specification for every model. Its national average rate includes fixed-charge and tax revenue; no separate fees are added. It is not the exact additional charge for using this appliance on your tariff.
Hourly, daily, and annual running costs
These fixed examples use residential electricity prices from the June 2026 monthly average, not your selected calculator rate. All longer periods assume the example schedule every day; seasonal equipment will differ. Values below one cent display as <$0.01.
| Period | Energy kWh | Cost $0.1834/kWh |
|---|---|---|
| One hour at stated power | 1.500 | $0.28 |
| Day at example schedule | 4.500 | $0.83 |
| Week (7 days) | 31.500 | $5.78 |
| Average month (365 ÷ 12 days) | 136.875 | $25.10 |
| Year (365 days) | 1642.500 | $301.23 |
Compare state-average rates Virginia, Washington, California, and Hawaii
Scroll sideways to compare all rates. With the table focused, use Left and Right arrow keys.
| Period | Energy kWh | U.S. average $0.1834/kWh | Virginia $0.1722/kWh | Washington $0.1491/kWh | California $0.3474/kWh | Hawaii $0.5272/kWh |
|---|---|---|---|---|---|---|
| One hour at stated power | 1.500 | $0.28 | $0.26 | $0.22 | $0.52 | $0.79 |
| Day at example schedule | 4.500 | $0.83 | $0.77 | $0.67 | $1.56 | $2.37 |
| Week (7 days) | 31.500 | $5.78 | $5.42 | $4.70 | $10.94 | $16.61 |
| Average month (365 ÷ 12 days) | 136.875 | $25.10 | $23.57 | $20.41 | $47.55 | $72.16 |
| Year (365 days) | 1642.500 | $301.23 | $282.84 | $244.90 | $570.60 | $865.93 |
Source: U.S. EIA residential electricity prices. These averages include fixed-charge and tax revenue, so they are not your utility’s marginal price for an additional kWh.
Full power is not the same as all-day use
Electric resistance heating turns incoming electrical energy into heat at the point of use. A thermostat can switch the heating element off between calls for heat. The 1,500-watt example therefore describes an active heating load, not a claim that every heater consumes that much continuously.
U.S. Department of Energy: electric resistance heating supports the operating guidance; the wattages and schedules here are illustrative inputs, not measurements supplied by that source.
A worked example you can adapt
If a heater draws 1,500 watts for two active hours, it uses 3 kWh. At $0.20/kWh that session costs $0.60. If it is switched on for four hours but heats for only half that time, the same 3 kWh estimate applies; fan and standby loads may add a little more.
Ways to make your estimate more useful
- Record time actually heating, not simply time switched on.
- Use a shorter seasonal schedule when heating is needed only in winter.
- Compare delivered heating needs before comparing costs with a heat pump; the technologies do not use electricity in the same way.
A common question
Does a lower-wattage heater always cost less to heat a room?
It costs less per active hour at the same rate, but may need to run longer. Compare total kWh required over the same period and comfort conditions, not just the label wattage.
Get a result for your appliance
Enter the wattage from your appliance label, your typical schedule, and the electricity rate from your bill. The calculator shows daily and annual energy, cost, source details, and the arithmetic used.
Calculate your portable space heater cost