Hawaii payback by island: about 7.9 years before incentives
Same 7.49 kW system at $23,519 cash, no battery, before the state tax credit. Each island has its own power price and its own export credits, so each gets its own figure.
Typical 7.49 kW system, $23,519 cash, simple payback before incentives
| Island and utility | Yearly savings | Simple payback before incentives | If 28% to 55% of the power is used at home |
| Oahu (Hawaiian Electric) | $3,068 | 7.7 years | 6.6 to 8.8 years |
| Hawaii Island (Hawaii Electric Light) | $2,968 | 7.9 years | 6.6 to 9.5 years |
| Maui (Maui Electric) | $2,621 | 9.0 years | 7.2 to 11.2 years |
Swipe the table sideways to see every column.
Statewide, weighted by the homes each utility serves, the figure is about 7.9 years. Kauai (KIUC) has no figure yet. The $5,000 state credit, if it reaches you, comes off the price and shortens each payback; these figures leave it out because Act 24 no longer promises it. If it does reach you, the payback is about 6.0 years on Oahu, 6.2 on Hawaii Island, 7.1 on Maui and 6.2 statewide. A battery that holds a midday kWh until 5 p.m. earns 19.4¢ more on Oahu (32.9¢ minus 13.5¢), and about 30¢ more if your home uses it instead. Price the battery as its own line, with its own payback.
How we calculated this
- Oahu output: 7.49 kW × 1,621 kWh per kW = 12,141 kWh a year.
- Price for power used at home: Oahu’s 12-month average of 44.75¢ (EIA, September 2025 to August 2026), less the $15.41 monthly customer charge and Green Infrastructure Fee, leaves 41.50¢ a kWh.
- Export credit: 14.45¢ a kWh, the 13.5¢ daytime, 32.9¢ evening and 18.9¢ overnight rates weighted by when panels produce (89%, 3% and 8% of output).
- Savings: 40% used at home × 41.50¢, plus 60% sent out × 14.45¢ = $2,015 + $1,053 = $3,068 a year. The 40% is a modeled share, not a measured Hawaii average; at 28% to 55% the payback runs 6.6 to 8.8 years.
- Payback: $23,519 ÷ $3,068 = 7.7 years. With every export at the 13.5¢ daytime rate it is 7.8 years.
- No upkeep and no future price rises are counted. No financing or panel aging.
- Hawaii Island and Maui use the same steps with their own prices and credits: 44.26¢ and 11.24¢ on Hawaii Island, 42.84¢ and 7.42¢ on Maui.
- Not modeled: the state tax credit or its $3,500 refundable version, Kauai, or any battery.
Run your own Hawaii numbers