ELECTRICITY, EXPLAINED
How much does a 1,500-watt space heater cost to run?
BillMellow editorial · Updated October 25, 2026
A 1,500-watt heater drawing its full stated power uses 1.5 kWh in one hour. At an illustrative $0.18 per kWh, that is $0.27 per operating hour. Four full-power hours a day cost $32.40 over 30 days.
Formula: 1.5 kW × operating hours × your variable $/kWh rate. Replace the example rate with the applicable charges from your own bill.
Space heater running cost at different rates
Every row below assumes a 1,500-watt draw throughout the entered operating time. The monthly column assumes four hours per day for 30 days. These are calculation scenarios, not state averages or available utility offers.
| Example rate | 1 hour | 4 hours/day | 30 days at 4 hours/day |
|---|---|---|---|
| $0.12/kWh | $0.18 | $0.72 | $21.60 |
| $0.18/kWh | $0.27 | $1.08 | $32.40 |
| $0.25/kWh | $0.375 | $1.50 | $45.00 |
| $0.35/kWh | $0.525 | $2.10 | $63.00 |
The fractional-cent hourly figures are shown before rounding; daily and monthly totals use the unrounded calculation. Your bill may use a different rounding method.
How much does eight hours a day cost?
At a continuous 1.5 kW draw, eight operating hours use 12 kWh. At the $0.18 example rate, that costs $2.16 for one day or $64.80 for 30 identical days. Two full-power operating hours would use 3 kWh and cost $0.54 per day or $16.20 over 30 days.
These are arithmetic scenarios, not recommended heater schedules. Follow the product’s operating and safety instructions. Cost alone is not a reason to run equipment unattended or use an unsuitable power setup.
A thermostat changes the operating time
Four hours between switching a heater on and off may not equal four hours at 1,500 watts. A thermostat can interrupt the heating element, and a lower setting can draw a different amount of power. Use measured kWh, or the time it actually draws the entered power, rather than assuming every elapsed hour is a full-power hour.
For example, if a suitable measurement reports 3 kWh during an evening, use that 3 kWh directly. At $0.18/kWh, the variable energy cost is $0.54. Do not multiply that measured energy by the evening’s hours again.
Which rate should you use?
Include the variable supply and delivery charges that apply to the use. Keep recurring flat fees separate. If your plan has time-of-use periods, calculate each period’s energy at its own price. If it has tiers, the extra heater use may cross a tier boundary.
The simple appliance tool uses one flat variable rate. A public tariff record can help identify a rate, but it may be historical and does not establish your exact plan. Confirm the current charges with the provider. See supply versus delivery charges and time-of-use electricity.
Does a space heater lower the whole-home bill?
This calculation estimates the heater’s added electricity cost. It does not prove that using it lowers total heating cost. That comparison depends on what heating it replaces, the fuel and equipment involved, the rooms heated and the household schedule.
Compare the whole bill and daily usage before claiming a saving. Use our electric bill comparison to review what changed, and keep safety and equivalent comfort separate from the energy arithmetic.
For the power-to-energy relationship, see US EIA unit definitions. All prices and schedules on this page are illustrative inputs.
Keep exploring
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- kW vs. kWh: what is the difference?
- Electricity supply vs. delivery charges
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