In Hawaii, a 2.6-kW system for an average home costs about $5,937 after incentives in 2026, saves about $1,471 in the first year and pays back in 3.9 years.
| Item | Amount |
|---|---|
| Solar, 2.64 kW × $3.46/W | $9,134 |
| Federal credit (0%) | $0 |
| State incentive | −$3,197 |
| Net cost | $5,937 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $5,937 | $1,471 | 3.9 yr | $44,207 |
| Rates rise 5.6%/yr (2020–25 pace) | $5,937 | $1,471 | 3.8 yr | $64,479 |
| Rates stay flat | $5,937 | $1,471 | 4.1 yr | $28,711 |
| Survey price $3.6/W (LBNL) | $6,178 | $1,471 | 4 yr | $43,967 |
| Add 13.5-kWh battery | $16,589 | $1,975 | 7.7 yr | $50,748 |
| Size to 100% of use instead | $8,906 | $2,206 | 3.9 yr | $66,311 |
Verdict: at average Hawaii numbers, solar is a strong investment in 2026 — payback takes 3.9 years, leaving you $44,207 ahead after 25 years. The main reasons: the most expensive electricity in the country; strong sun (the 4th-best yield of 51); export credits below retail (exports earn ~50% of retail), so only the solar you use yourself earns full value; a state incentive worth about $3,197. Pay cash if you can: Berkeley Lab found loan-financed systems priced about $1.50/W above cash installs in 2025, which can add years to the payback.
Net metering and exports in Hawaii: No net metering for new customers; Hawaiian Electric 'Smart Renewable Energy Export' net billing with island- and time-varying export credits; credits expire after 12 months.
Battery: a 13.5-kWh battery at the Hawaii average of $789/kWh adds $10,652 and shifts about 2,445 kWh a year from low-paid exports to your own use; payback becomes 7.7 years.
EnergySage's Hawaii page lists a 10.2-year payback. Its method is not fully published; ours uses EIA's Jan–Aug 2026 price, 40% self-use and the state's export credit, 3%/yr rate growth and 0.5%/yr panel aging, with no federal credit.
The full method, material data and tips are on the main solar payback calculator page.