Solar payback · HI
Is solar worth it in Hawaii?
A 7 kW rooftop system near Honolulu produces about 11,351 kWh a year. Priced against 6 current residential tariffs in Hawaii, payback runs from 5 years on the best of them to 16 on the worst.
Why the tariff matters more than the panels
Two households in Hawaii with identical roofs and identical systems can see paybacks 5 and 16 years apart, purely because they are on different tariffs. Solar produces at midday; households consume in the evening. Only 47% of what these panels make is used as it is made — the rest is exported, and what an exported kWh earns is set by the tariff and by state net metering rules, not by the hardware.
That is why the figures here are computed hour by hour against each real tariff rather than by taking a bill and assuming solar removes a share of it. How this is modeled →
Payback by tariff in Hawaii
7 kW system at $3.00/W, household using 1000 kWh a month, no incentives. A range means the export credit is not filed with the tariff and the outcome depends on net metering rules — 6 of 6 tariffs here belong to a utility that reports residential net metering.
| Utility | Tariff | Structure | Annual saving | Payback |
|---|---|---|---|---|
| Hawaiian Electric Co Inc | SCHEDULE TOU-R RESIDENTIAL TIME-OF-USE SERVICE - Three Phase - Closed Rate | Time-of-use + tiered | $2,028–$4,279 | 5–10y |
| Hawaiian Electric Co Inc | SCHEDULE R RESIDENTIAL SERVICE - Single Phase | Tiered | $1,981–$4,168 | 5–11y |
| Hawaiian Electric Co Inc | SCHEDULE R RESIDENTIAL SERVICE - Three Phase | Tiered | $1,981–$4,168 | 5–11y |
| Kauai Island Utility Cooperative | D Residential Service | Flat | $1,821–$3,879 | 5–12y |
| Hawaiian Electric Co Inc | SCHEDULE ARD TOU R - Residential Time of Use - Single Phase | Time-of-use | $1,299–$3,873 | 5–16y |
| Hawaiian Electric Co Inc | SCHEDULE ARD TOU R - Residential Time of Use - Three Phase | Time-of-use | $1,299–$3,873 | 5–16y |
Your roof, your numbers
Change the usage, system size and installed cost, and every Hawaii tariff is priced again.
What would change this
Your roof. Production is modeled for Honolulu on a south-facing array at 20° tilt. Shading, orientation and pitch all move it, and solar resource varies within Hawaii itself.
Your usage pattern. A household at home during the day self-consumes more and exports less, which shortens payback wherever export credit is poor.
Rising rates. These figures hold today's prices flat. Electricity prices have been rising, and every rise shortens payback — so treat these as a conservative bound.
State and local incentives. Not included here, and in some states they are worth more than the federal credit was. Check your state energy office before deciding.
Guides to solar payback
All guides-
Why a smaller solar system pays back faster
Doubling your panel count does not double your savings. On a real Georgia Power tariff, a 3 kW system pays back in 13 years and a 12 kW system takes 21 to 41 — and past a certain size, extra panels cannot save you anything at all.
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Where homes net-meter rooftop solar, and where almost none do
Utilities report 5.5 million net-metered home solar systems, 41 per 1,000 households. Hawaii has 233; Tennessee and Alabama almost none.
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Solar in 2026, without the federal tax credit
Section 25D ended on December 31, 2025. A home solar system bought in 2026 gets no federal credit at all — not a reduced one — and most payback advice still online predates that.
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When is electricity most expensive? It depends on your utility
Across 95 utilities with time-of-use rates we found 49 different weekday peak windows. Nearly all include 5 to 6 pm; little else is shared.
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Does each extra kWh cost more? It depends where you live
Of 84 utilities with tiered residential rates, 43 charge more per kWh as usage rises, 23 charge less, and 11 do both: rising in summer, falling in winter.