Running a 1,500-watt space heater 8 hours a day in Hawaii costs about $169.42 a month — $0.70 an hour on full power at Hawaii's average 46.41¢/kWh.
At 46.41¢/kWh — Hawaii average, Jan–Aug 2026 (EIA). That is 155% above the U.S. average of 18.19¢.
| Period | kWh | Cost |
|---|---|---|
| Per hour of use | 1.5 | $0.70 |
| Per day | 12 | $5.57 |
| Per month | 365 | $169.42 |
| Per season (1 mo) | 365 | $169 |
Normal mean temperature (NOAA, population-weighted). Highlighted months average below 60°F.
| Heat source | $ per million Btu | This much heat |
|---|---|---|
| Gas furnace, 95% AFUE | $53.22 | $66.29 |
| Heat pump (ENERGY STAR avg) | $54.99 | $68.49 |
| Gas furnace, 80% AFUE | $63.20 | $78.72 |
| Space heater / baseboard | $136.02 | $169.42 |
In Hawaii resistance heat costs 2.6× as much as gas heat from a 95% furnace. A space heater only saves money when it lets you turn the whole-house thermostat down several degrees and heat just the room you're in. A heat pump delivers the same heat for about $68.49 a month.
| Heater | Per hour | 8 h/day, month | 24 h/day, month | Season (1 mo, 8 h) |
|---|---|---|---|---|
| 750 W | $0.35 | $84.71 | $254.12 | $84.71 |
| 900 W | $0.42 | $101.65 | $304.95 | $102 |
| 1,500 W | $0.70 | $169.42 | $508.25 | $169 |
1.5 kW × 8 h = 12 kWh a day; × 30.42 days = 365 kWh a month; × 46.41¢ (Hawaii average, Jan–Aug 2026, EIA) = $169.42.
Because resistance heat costs 2.6× as much as gas heat in Hawaii, a space heater saves money only if it lets you turn the whole-house thermostat down and heat just the room you're in. If your home heats with electric baseboards or furnace strips, a space heater costs the same per Btu — the saving comes only from heating fewer rooms.
The average Hawaii home used 511 kWh a month in 2025 (EIA); this heater adds 71% to that while it runs.
The full method, material data and tips are on the main space heater cost calculator page.