Running cost comes down to wattage, hours and your rate. In Hawaii the rate is 52.00 cents per kWh, which is 182.0 percent above the national average. Here is what that means for a air-source heat pump.
A air-source heat pump drawing 3,000 W costs $1.56 per hour in Hawaii. Run 8 hours a day that is $12.48 daily, $374 a month and $4,555 a year, which is $2,940 more than the same appliance at the US average rate.
Air-source heat pump cost at Hawaii rates
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Planning estimate. The rate box is prefilled with a regional average; the figure on your own bill is the one that matters. Power is draw while running, not while switched on.
Cost by hours used per day in Hawaii
| Hours/day | Energy | Per day | Per month |
|---|---|---|---|
| 1 h | 3.00 kWh | $1.56 | $46.80 |
| 2 h | 6.00 kWh | $3.12 | $93.60 |
| 4 h | 12.00 kWh | $6.24 | $187 |
| 6 h | 18.00 kWh | $9.36 | $281 |
| 8 h | 24.00 kWh | $12.48 | $374 |
| 12 h | 36.00 kWh | $18.72 | $562 |
| 24 h | 72.00 kWh | $37.44 | $1,123 |
Cost by wattage at 52.00 cents
| Rated power | Per hour | Per day | Per month |
|---|---|---|---|
| 1,200 W | $0.62 | $4.99 | $150 |
| 2,000 W | $1.04 | $8.32 | $250 |
| 3,000 W | $1.56 | $12.48 | $374 |
| 4,500 W | $2.34 | $18.72 | $562 |
| 6,000 W | $3.12 | $24.96 | $749 |
Find the row matching the nameplate on your own unit. Within a single appliance category the spread is often wider than the difference between categories, so the label is worth reading.
Heating season in Hawaii
Heating demand in Hawaii is limited to a handful of weeks, which is why electric resistance heat is more common and more tolerable here. Over a short season the running cost stays contained even at resistance-heating rates.
Why Hawaii pays what it does
Hawaii is a regulated market, so your utility is the only supplier and the rate is set through the state commission rather than by competition. Pricing tends to be steadier than in deregulated states, and there is no switching decision available. The levers are all on your side of the meter.
At 52.00 cents, Hawaii ranks 51 of 51 from cheapest to most expensive. The West regional average is 19.65 cents. Roughly half of any residential bill is transmission and distribution rather than generation, which is why rates keep climbing even when fuel prices fall.
How this compares across the country
The same air-source heat pump on the same schedule, in the cheapest and dearest states:
| State | Rate | Per month | Per year |
|---|---|---|---|
| Idaho | 12.35¢ | $88.92 | $1,082 |
| Utah | 12.96¢ | $93.31 | $1,135 |
| Hawaii | 52.00¢ | $374 | $4,555 |
| California | 33.25¢ | $239 | $2,913 |
| Hawaii | 52.00¢ | $374 | $4,555 |
Lowering the number in Hawaii
- Leave the thermostat alone. Heat pumps work best holding a steady temperature; deep setbacks trigger expensive resistance backup on recovery.
- Avoid emergency heat unless the pump has failed. That setting is pure resistance heating and costs several times as much.
- Keep the outdoor unit clear. Snow, leaves and shrubs against the coil cut capacity.
- Change filters regularly. Airflow restriction hurts a heat pump more than a furnace.
- Size for design temperature. Capacity falls as it gets colder, which is exactly when you need it.
Offsetting it with solar in Hawaii
This load uses about 24.00 kWh a day. Covering that would take roughly 17 standard 400 W panels at typical sun hours, an array of about 6.80 kW. Because it offsets electricity worth 52.00 cents rather than the national 18.44 cents, the same array is worth more here than the national payback figures suggest.
A heat pump delivers three or more units of heat per unit of electricity, which is what makes solar heating arithmetically possible at all. Full sizing, including battery and inverter requirements, is on the solar sizing page for this appliance.