Solar Calculator for Hawaii: Costs, Incentives & ROI
Hawaii offers the most compelling residential solar economics of any state in the United States, driven by electricity rates that are roughly three to four times the national average — averaging approximately forty-four to forty-seven cents per kilowatt-hour for residential customers across the island utilities — combined with an abundant tropical solar resource that delivers five to seven peak sun hours per day across most of the state. The result is payback periods of four to six years for typical residential solar installations, the fastest return on investment available to homeowners anywhere in the country. Hawaiian Electric Company, known as HECO, serves Oahu and is the dominant island utility; Maui Electric serves Maui, Molokai, and Lanai; and Hawaii Electric Light Company serves the Big Island. The original net metering program for residential customers was phased out by the Hawaii Public Utilities Commission in 2015 due to grid capacity constraints on Oahu, replaced by the Customer Self-Supply program and the Smart Export option. Under Customer Self-Supply, a solar system is sized to cover the home's own consumption rather than export surplus to the grid, which requires careful system sizing coordinated with the installer and utility. The Smart Export program allows net export but credits excess generation at a lower avoided-cost rate rather than the full retail rate, making self-consumption the economically optimal strategy for most Hawaii solar homeowners. Hawaii's residential installations typically carry a higher per-watt installed cost than the mainland due to ocean freight costs for panels, mounting hardware, and inverter equipment. The federal Investment Tax Credit of thirty percent remains the primary financial incentive, and the combination of ITC plus Hawaii's extraordinary electricity rates makes solar the most economically rational home improvement available to virtually any Hawaii homeowner with a suitable roof.
Incentive data updated: May 2026(may be outdated)
Average Solar Cost in Hawaii
Average installed solar costs in Hawaii typically range from $3.00 to $3.50 per watt before incentives, reflecting the state's elevated logistics costs for panels and hardware shipped across the Pacific, higher labor rates relative to Sun Belt markets, and the specialized inverter and rapid-shutdown requirements imposed by Hawaii utilities on systems interconnecting to their grids. A standard six-kilowatt residential system costs approximately $18,000 to $21,000 before the federal Investment Tax Credit — roughly twenty to thirty percent above mainland averages. The thirty-percent federal ITC reduces the net cost to approximately $12,600 to $14,700 for a six-kilowatt system. Despite the higher installed cost, Hawaii's extraordinary electricity rates mean that even at $3.25 per watt installed, a homeowner paying forty-five cents per kilowatt-hour recoups the after-ITC investment faster than a California homeowner with a twenty-five-cents-per-kilowatt-hour rate and a $2.80 per-watt installed cost. Hawaii does not currently offer a state-level residential solar income tax credit comparable to New York's twenty-five percent credit, though the state has historically offered various incentive programs. Homeowners should verify current state-level programs with the Hawaii Energy office or their installer. Battery storage paired with solar is particularly valuable in Hawaii under the Customer Self-Supply model, as it allows homeowners to shift excess daytime solar generation into evening hours, further reducing grid electricity purchases at Hawaii's high retail rates.
- Avg. installed cost
- $3.25/W
- Typical 6 kW system
- $18,000–$21,000
Top Solar Incentives in Hawaii
Live incentive data not currently available for Hawaii. See the federal incentive guidance via our Solar Tax Credit Calculator.
Electricity Rates in Hawaii
Hawaii's residential electricity rates are the highest of any state in the United States by a substantial margin, averaging approximately forty-four to forty-seven cents per kilowatt-hour for residential customers across the island utilities, compared to the national average of roughly thirteen to fourteen cents per kilowatt-hour. Hawaiian Electric Company customers on Oahu typically pay in the forty-three to forty-six cent range; Maui Electric customers on Maui pay comparable or slightly higher rates; and Hawaii Electric Light customers on the Big Island, which has a higher share of petroleum generation, have historically paid the highest rates of the three utilities. The structural reason for Hawaii's high rates is geography: the state has no connection to any mainland grid and must generate all electricity locally using a mix of oil, natural gas, wind, geothermal on the Big Island, and increasingly solar. The incremental cost of solar at today's installed prices is far below Hawaii's retail rate, which means every kilowatt-hour of solar self-consumption provides a direct financial benefit equivalent to avoiding a forty-five-cent grid purchase. Hawaii has aggressive renewable portfolio standards requiring the utilities to reach one hundred percent renewable energy by 2045, which is driving large-scale solar and wind development and has historically kept fuel costs elevated during the transition period. The high retail rate environment means there is essentially no scenario in which residential solar at current installed prices fails to be financially beneficial for a Hawaii homeowner with suitable roof access.
Peak Sun Hours in Hawaii
Hawaii's solar resource is exceptional and consistent by US standards, reflecting the state's tropical latitude between approximately eighteen and twenty-two degrees north — far closer to the equator than any continental US state. Oahu averages between 5.5 and 6.5 peak sun hours per day on a tilted surface, with Honolulu's south-facing locations often exceeding six peak sun hours annually. Maui averages similarly, with the dry leeward side of Haleakala receiving the strongest irradiance. The Big Island of Hawaii presents the most dramatic internal variation of any island: the windward Hilo side receives heavy rainfall and cloud cover that limits solar resource to approximately 4.5 to 5.5 peak sun hours, while the dry Kona coast on the leeward side consistently delivers 6.0 to 7.0 peak sun hours per day — among the highest annual solar irradiance values in the entire United States. Molokai and Lanai average 5.5 to 6.5 peak sun hours per day on their leeward sides. The consistent tropical sunshine with minimal seasonal variation means Hawaii solar systems produce at a high fraction of nameplate capacity year-round, unlike continental systems that experience significant winter production dips. Panel tilt optimization in Hawaii favors shallower angles closer to flat given the high solar elevation angle, and NREL PVWatts captures this by using the optimal tilt for each island's latitude in its production estimates.
Example ROI for a 6 kW System
- Estimated annual savings
- $2,400
- Payback period
- 4.5 years
- 25-year net savings
- $48,000
Run a personalized estimate with your ZIP code using the Solar ROI Calculator.
Major Cities in Hawaii
- Honolulu96813
- Hilo96720
- Kailua-Kona96740
- Kahului96732
- Pearl City96782
Common Questions About Solar in Hawaii
What happened to net metering in Hawaii?
Hawaii's original net metering program for residential customers was phased out by the Hawaii Public Utilities Commission in October 2015 following concerns that the program had been oversubscribed on Oahu's grid and that the full-retail-rate credit created a cost-shift to non-solar ratepayers. New residential solar installations after the phase-out date are served under two alternative programs: Customer Self-Supply, in which the system is sized to cover the home's own consumption and exports little or no power to the grid, and the Smart Export program, which allows net export but credits excess generation at a lower avoided-cost rate rather than the full retail rate. The economic implications are significant — under Customer Self-Supply, the financially optimal strategy is to size the system to approximately one hundred percent of annual consumption and pair it with battery storage to maximize self-consumption of excess daytime generation during evening hours. Existing customers on the legacy net metering program are grandfathered on their current tariff for a defined period. Homeowners should confirm the specific program terms applicable to new installations with Hawaiian Electric or their island utility before contracting.
Is solar worth it in Hawaii given the high installed cost?
Yes, substantially so. Despite Hawaii's installed costs running twenty to thirty percent above mainland averages, the state's extraordinary electricity rate of approximately forty-four to forty-seven cents per kilowatt-hour means each kilowatt-hour of solar self-consumption avoids an exceptionally high cost. A six-kilowatt system generating roughly eight thousand to ten thousand kilowatt-hours per year on Oahu — at forty-five cents per kilowatt-hour avoided — produces thirty-six hundred to forty-five hundred dollars of annual savings, achieving payback in four to six years even at a post-ITC installed cost of fourteen thousand to fifteen thousand dollars. No other state produces comparable payback speed for a standard residential solar investment. The addition of battery storage extends this advantage by shifting excess daytime solar into evening hours, further reducing high-rate grid purchases. Hawaii homeowners who own their home and have a suitable south or west-facing roof with reasonable shade clearance will find solar to be one of the highest-returning investments available, outperforming most conventional financial instruments on an after-tax basis within the first decade.
Does battery storage make sense with solar in Hawaii?
Battery storage is particularly valuable in Hawaii, for two reasons. First, under the Customer Self-Supply program that governs most new installations, the utility does not compensate exported excess generation at the full retail rate, making self-consumption the financially optimal strategy — and battery storage allows homeowners to shift excess midday solar generation into evening peak-consumption hours rather than exporting it at the lower avoided-cost rate. Second, Hawaii's high electricity rates mean that every kilowatt-hour stored and self-consumed instead of purchased from the grid saves approximately forty-five cents, producing a high return on the battery investment. Lithium-ion battery systems sized for a single evening cycle — typically ten to thirteen kilowatt-hours of usable capacity — are often cost-effective in Hawaii even without federal or state battery incentives, though the federal ITC of thirty percent applies to battery storage installed simultaneously with or as part of a solar system, which further improves the economics. Hawaiian Electric and the other island utilities also have resilience programs and export incentive structures that homeowners should review with their installer.
What are peak sun hours like on different Hawaiian islands?
Hawaii's solar resource varies primarily by the wet-dry geography of each island rather than by north-south latitude, since all islands are within five degrees of latitude of each other. On Oahu, the leeward (south and west facing) side of the Waianae and Koolau ranges — including Honolulu, Pearl City, and Ewa Beach — receives five and a half to six and a half peak sun hours per day, while the windward northeast coast receives more cloud cover and somewhat lower production. Maui's leeward side between Kahului and Kihei delivers consistently strong production, averaging five and a half to six and a half peak sun hours per day. The Big Island presents the most dramatic contrast: Hilo on the rainy windward coast averages four and a half to five and a half peak sun hours, while Kailua-Kona on the dry leeward coast averages six to seven peak sun hours per day — among the highest values in the entire United States. Molokai and Lanai both have favorable leeward solar resources averaging five and a half to six and a half peak sun hours. Use the ZIP-code-level calculator above for a production estimate specific to your island location.