Hawaii pays about 41.3¢ per kilowatt-hour for residential electricity and receives about 5.6 kWh per square metre per day of sunlight — 1st and 5th respectively among the 50 states and DC tracked here. Those two numbers set the ceiling on what rooftop solar returns in Hawaii, and they point in the same direction.
Where Hawaii sits against the rest of the country
Hawaii is 26.5¢/kWh above the median residential rate across this dataset (14.8¢/kWh) and 1.0 kWh/m²/day above the median insolation (4.6 kWh/m²/day). Under this site's standard assumptions, that combination puts Hawaii 1st of 51 for modeled payback speed, at 4.6 years against a dataset median of 13.5 years.
What actually drives payback in Hawaii
Hawaii ranks in the upper half on both inputs — 1st for electricity price and 5th for sunlight. Swap Hawaii's sunlight for the dataset median and payback moves to 5.6 years (0.9 years of swing). Swap its electricity rate instead and payback moves to 11.8 years (7.2 years of swing). The rate swap is the larger of the two, so what a kilowatt-hour costs is the input deciding the outcome in Hawaii.
State incentives on record
Recorded for Hawaii: Renewable Energy Technologies Income Tax Credit (RETITC) 35% of system cost capped per system size; Customer Self-Supply and Customer Grid-Supply Plus tariffs; some of the highest electricity rates in the US drive fastest payback.
No federal credit is applied above (Section 25D expired 31 December 2025), and export terms often matter more than the headline rate (net metering guide).
The modeled system, in numbers
At Hawaii's sunlight level a 7 kW array produces roughly 11,160 kWh a year, worth about $4,609 in first-year bill savings at 41.3¢/kWh against an assumed $22,400 installed cost. A ten-year payback at this sunlight level would require a residential rate of about 18.0¢/kWh, which Hawaii already exceeds.
States with comparable economics
Hawaii's closest analogues by modeled payback are California (5.9 years), Massachusetts (7.8 years), Connecticut (8.0 years). They arrive there from different rate and sunlight combinations, so their incentive rows are the useful comparison.
- California — modeled payback 5.9 years
- Massachusetts — modeled payback 7.8 years
- Connecticut — modeled payback 8.0 years
Hawaii-specific notes
Hawaii combines the highest residential electricity rate in this dataset with strong sunlight, which is why it ranks where it does above. Legacy retail net metering has been replaced by Customer Self-Supply and Customer Grid-Supply Plus tariffs, so the value of exported energy is lower than the retail rate assumed in the model.