Solar payback in Hawaii

5.6 peak sun hours/day average. Residential electricity rate: 46.62¢/kWh.

Estimated payback by system size

Installed cost at 2.75$/W, accounting for 20% system-loss derate (inverter, wiring, soiling, temperature).

SystemAnnual kWhAnnual SavingsInstalled CostPayback
4 kW6,545 kWh$3,051.41$11,0003.6 years
6 kW9,818 kWh$4,577.11$16,5003.6 years
8 kW13,091 kWh$6,102.82$22,0003.6 years

Important notes

No incentives assumed: The federal residential solar investment tax credit ended after 2025. Some states and utilities still offer rebates or performance-based incentives; check with your utility.

Full self-consumption or net metering: Savings assume you use all generation on-site or export at retail rates via net metering. Some utilities buy surplus power at wholesale rates, which would reduce savings.

Your site specifics matter: Roof shade, orientation, system degradation, and your actual utility tariff (demand charges, time-of-use rates, fixed fees) can significantly change payback.

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Electricity rates in Hawaii