Hawaii solar calculator
Size a Hawaii home solar system from your electric bill — kW, panel count, roof area, true cost with no federal credit for 2026 installs, and payback.
Quick answer: At $0.520/kWh and 5.8 peak sun hours, a $200/month bill needs about 2.87 kW — 7 × 410 W panels covering ~14 m². Gross cost is ~$9,830 with no federal credit for systems installed after 2025, offsetting $2,400 a year for a ~4.1 year payback.
Your details
Ballpark, not gospel. Sized at 78% real-world output with the Hawaii sun-hour average — confirm shading, roof angle and Hawaiian Electric's Smart Export terms with a local installer before buying. The calculator values all generation at your retail rate; exports earn time-varying credits, not full retail, so real savings track self-consumption and batteries (batteries also unlock the rich 5–9 p.m. export window).
The 30% credit ended — what changed
The residential clean energy credit (26 U.S.C. § 25D) gave homeowners a 30% credit on solar installed from 2022 through 2025. The July 2025 tax law ended it: no credit is available for property placed in service after December 31, 2025. That is why every figure on this page is ~30% higher than pre-2026 guides show. If your system went live by the end of 2025, tick the box above to see the credit applied; leased systems may still benefit because the leasing company claims the commercial credit. Source: IRS — Residential Clean Energy Credit.
Typical Hawaii system sizes by monthly bill
| Monthly bill | System size | Panels (410 W) | Net cost (no 2026 federal credit) | Payback |
|---|---|---|---|---|
| $100 | 1.64 kW | 4 | $5,617 | 4.7 years |
| $200 | 2.87 kW | 7 | $9,830 | 4.1 years |
| $300 | 4.51 kW | 11 | $15,447 | 4.3 years |
Computed at $0.520/kWh, 5.8 peak sun hours and $3.42/W installed, with no federal credit for 2026 installs. Run your exact bill above.
Solar in Hawaii: the details
Solar cost in Hawaii
Solar is expensive to install in Hawaii — but you need so little of it. The EnergySage marketplace averaged about $3.42 per watt installed in 2026, with market quotes typically landing $2.91–$3.94/W — at the top of the $2.50–$3.50/W national band. A typical ~3 kW system grosses only around $10,300, with no federal credit for 2026 homeowner installs.
What moves the number: shipping, roof type, and permitting on each island. High per-watt costs melt away because the system is tiny and the rates are enormous.
Export rules: getting paid for surplus power
Hawaiian Electric closed net metering in October 2015. New systems join the Smart Renewable Energy Export tariff, which pays time-varying credits instead of full retail.
On Oahu: 13.5¢/kWh by day, 32.9¢ from 5–9 p.m., and 18.9¢ overnight. Daytime exports — when your panels actually produce — are the cheapest credits, which flips the economics toward self-consumption and evening discharge.
Practical takeaway: in Hawaii, a battery isn't an accessory — it's how you move cheap daytime solar into the 32.9¢ evening window. Size the battery for your 5–9 p.m. load.
Hawaii solar incentives
Hawaii's Renewable Energy Technologies Income Tax Credit is one of the strongest state incentives left: 35% of system cost, up to $5,000 for residential solar. One warning: 2026 legislation (SB 2135) threatened to cap or end the program — confirm its status with a tax professional before counting the $5,000.
Is solar worth it in Hawaii?
Verdict: yes — one of the fastest paybacks in the US. At ~52¢/kWh, a $200 bill needs only a 2.87 kW system, paying back in ~4.1 years. Layer the 35% state tax credit (up to $5,000) on top and it's shorter still — though SB 2135 put the program under threat in 2026, so confirm it before counting on it. A battery to catch the 32.9¢/kWh evening export window is nearly mandatory.
Questions people actually ask
Straight answers, no fluff. Then run your own numbers above.
How many solar panels do I need in Hawaii?
It follows your bill. At the Hawaii average of $0.520/kWh and 5.8 peak sun hours, a $200/month bill needs about a 2.87 kW system — roughly 7 × 410 W panels covering ~14 m² of roof.
What is the average cost of solar panels in Hawaii in 2026?
The EnergySage marketplace averaged about $3.42 per watt installed in 2026, with market quotes typically $2.91–$3.94/W — at the top of the national $2.50–$3.50/W band. A typical ~3 kW system grosses around $10,300, with no federal credit for 2026 homeowner installs — before Hawaii's 35% state tax credit.
Does Hawaii have net metering?
Not since October 2015, when Hawaiian Electric closed it. New systems join the Smart Renewable Energy Export tariff, earning time-varying credits — on Oahu, 13.5¢/kWh by day, 32.9¢ from 5–9 p.m., 18.9¢ overnight — instead of full retail.
Does Hawaii offer any solar tax credit or rebate?
Yes — Hawaii's Renewable Energy Technologies Income Tax Credit gives 35% of system cost up to $5,000 for residential solar. Caution: 2026 legislation (SB 2135) threatened to cap or end the program, so confirm its status before counting on it.
Is the 30% federal solar tax credit still available?
Not for homeowner purchases anymore. The residential clean energy credit (26 U.S.C. § 25D) is not available for property placed in service after December 31, 2025, under the July 2025 tax law (Public Law 119-21). Systems installed by the end of 2025 can still claim 30%, and leased systems may still benefit because the leasing company claims the commercial credit instead. (Source: IRS — Residential Clean Energy Credit.)
Is solar worth it in Hawaii?
Verdict: yes — one of the fastest paybacks in the US. At ~52¢/kWh, a $200 bill needs only a 2.87 kW system, paying back in ~4.1 years. Layer the 35% state tax credit (up to $5,000) on top and it's shorter still — though SB 2135 put the program under threat in 2026, so confirm it before counting on it. A battery to catch the 32.9¢/kWh evening export window is nearly mandatory.
Figures last checked October 2026. Sources: residential rate and sun-hour averages via kilowattkit.com and unboundsolar.com's US sun-hours map, EIA Electric Power Monthly, NREL PVWatts/NSRDB, DSIRE, Hawaii Public Utilities Commission; IRS — Residential Clean Energy Credit.
More US solar calculators
Compare other states: Texas, Florida, California, Arizona, North Carolina, Alabama, Alaska, Arkansas, Colorado, Connecticut, Delaware, Georgia, Hawaii, Idaho. And the national US solar calculator for country averages.
Comparing quotes? The solar cost calculator breaks down cost per watt and the solar ROI calculator maps your payback year by year. Going deeper: installation cost guide, how net metering works, how much you can save with solar and the solar batteries guide.