Assumes 3%/yr rate increases, 0.5%/yr panel degradation and no federal tax credit (the 30% §25D credit ended for systems installed after Dec 31, 2025). How we calculate
Data approachEIA rates · NREL sun hours · 2026 federal policy · methodology
A modeled 6 kW solar system in Hawaii costs about $18,000 installed at $3.00 per watt and saves roughly $2,640 in year one, a simple payback of about 6.8 years. Real-world pricing runs higher: EnergySage’s March 2026 Hawaii average of $3.28 per watt puts the same system near $19,700 and payback near 7.5 years. The 30% federal homeowner credit ended for systems installed after December 31, 2025. Hawaii’s 35% state credit (up to $5,000) still applies to qualifying 2026 systems, but the law changes for 2027 and the credit sunsets after 2030.
Electricity rates drive Hawaii’s solar math. EIA data for March 2026 show Hawaii’s average residential rate at about 42.2¢/kWh, against 18.6¢ nationally, more than double. Our model uses a slightly lower 40.8¢/kWh, which keeps savings estimates conservative. Every kilowatt-hour you make and use at home therefore saves far more than on the mainland, even though exported power earns much less. The full model is on our methodology page, and state data is on the Hawaii solar page.
Data visualization
Hawaii vs U.S. residential electricity price, March 2026. Hawaii averaged about 42.2¢/kWh against 18.6¢/kWh nationally. Source: EIA Electric Power Monthly Table 5.6.A, 2026.
Chart summary: Hawaii’s average residential price in March 2026 was about 42.2¢/kWh, roughly 2.3 times the 18.6¢ national average. Our 40.8¢ model rate sits just below the EIA figure. Source: EIA Electric Power Monthly, Table 5.6.A (March 2026 data, released May 21, 2026).
💰 System Cost
What Do Solar Panels Cost in Hawaii in 2026?
A 6 kW system costs about $18,000 installed at our $3.00-per-watt model price, with no federal credit for 2026 installations. Market quotes are often higher, so treat the model price as a baseline.
System size
Panels (400 W)
Installed cost at $3.00/W
Federal credit (2026)
Hawaii RETITC (35%, max $5,000)
Net after state credit
4 kW
10
$12,000
$0
$4,200
$7,800
6 kW (modeled)
15
$18,000
$0
$5,000
$13,000
8 kW
20
$24,000
$0
$5,000
$19,000
Assumptions: $3.00/W is our modeled installed price. EnergySage’s Hawaii average was $3.28/W in March 2026. The RETITC column assumes you have enough Hawaii income tax liability to use the credit and qualify under the current rules (see the next section). Excludes batteries.
Data visualization
Modeled Hawaii solar cost by system size. A 6 kW system costs $18,000 at $3.00/W and nets $13,000 after the $5,000-cap state credit. Source: Green Energy Calculators model, 2026.
Chart summary: At $3.00/W, installed cost rises from $12,000 for 4 kW to $24,000 for 8 kW. The state credit is worth 35% on the 4 kW system ($4,200) but hits the $5,000 cap on 6 kW and 8 kW, so it lowers the larger systems’ cost by a smaller share (28% at 6 kW, about 21% at 8 kW). Source: Green Energy Calculators model, methodology.
For a market check, EnergySage reported an average Hawaii price of $3.28 per watt in March 2026, or about $27,136 for the 8.27 kW average system before incentives, with quotes ranging from roughly $23,100 to $31,200. Hawaii homes also tend to use less electricity than the national average, roughly 500 kWh a month versus about 890 kWh nationally per EIA, so lower-use homes may need only 3–5 kW. Shipping costs, coastal salt-air requirements, island permitting and older low-pitch roofs can add cost. Set a target size first with the solar system size calculator, then get at least three written quotes from licensed Hawaii installers.
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🏛️ Incentives
Which Solar Incentives Are Still Available in Hawaii in 2026?
For a system you own and install in 2026, Hawaii’s RETITC is the main incentive: 35% of PV cost, capped at $5,000 per system. The federal homeowner credit is gone, and the state credit was rewritten in 2026.
Incentive
Status for a 2026 install
Value on an $18,000 system
Federal §25D credit (30%)
Ended after Dec 31, 2025
$0 (a 2025 install would have received $5,400)
Hawaii RETITC (state income-tax credit)
Available for 2026; changed by Act 24 from 2027
Up to $5,000 (35% = $6,300, capped at $5,000)
Lease / PPA (§48E, claimed by the system owner)
Only if construction began by July 4, 2026 or placed in service by Dec 31, 2027
Depends on the contract price
Utility programs
Hawaiian Electric BYOD Plus (battery)
See the battery section
Sources: IRS guidance on §25D and the 2025 federal budget law; Hawaiʻi State Energy Office RETITC page. This is not tax advice; confirm with a tax professional or the Hawaii Department of Taxation.
What Act 24 changed. Governor Josh Green signed SB 3125 as Act 24 on May 21, 2026. According to the state energy office and press reports, it adds a $40 million annual statewide cap on RETITC credits, new eligibility and certification requirements, and a sunset after 2030. The caps start with 2027. On June 12, 2026, Executive Order 26-02 exempted systems placed in service in 2026 from the cap if the taxpayer can show they relied on the credit before May 21. The Garden Island reported that the order covers the cap but not the new income limits. The state energy office says guidance and filing instructions are still being developed.
What that means for you:
Installing in 2026: keep your signed contract, deposit records, permit dates and in-service date together. If you signed after May 21, 2026, ask a tax professional whether the exemption covers you.
Planning for 2027 or later: treat the state credit as uncertain. A statewide pool and a 2030 sunset mean the 35%-up-to-$5,000 formula may not be available.
Unused credit: earlier Hawaii analyses note that excess RETITC can carry forward to future years. Confirm the current rule with the Department of Taxation.
Who can still claim a federal credit? Hawaii homeowners whose systems were completed in 2025 claim 30% on their 2025 return. Businesses, and owners of leased or PPA systems, may use §48E if construction began by July 4, 2026 or the system is placed in service by December 31, 2027. With a lease or PPA, the owner claims the credit and may pass part of it through a lower monthly price. Compare the price per kWh against 40.8¢ and check the escalator. See our federal solar tax credit guide for the full timeline, and check DSIRE for other programs.
⚖️ Policy & Net Metering
How Do Hawaii’s Export Rules Affect Solar Savings?
Hawaiian Electric closed retail net metering to new customers in 2015. New systems now enroll in the Smart DER tariff, which launched on April 1, 2024 with an export option and a non-export option. Export credits vary by island and time of day and are generally well below the retail rate, so solar pays off mostly by powering your own home. Hawaiian Electric’s Smart Renewable Energy Export page lists current rates and notes that they are updated every three years.
Our model treats Hawaii as a low-export state and assumes a right-sized system removes about 60% of your bill in year one (a 0.60 offset). That offset is our modeling assumption, not a utility figure. In practice:
Size for self-consumption. Match production to what the home uses during daylight, plus what a battery can store, rather than to your total annual kWh.
Shift loads to midday. Running laundry, dishwashers, water heating, pool pumps and EV charging while the sun is up turns 40.8¢ grid purchases into solar you produce yourself.
Confirm your program in writing. Ask the installer which tariff your system will be enrolled in, what it pays for exports and whether time-of-use pricing applies.
Customers on older programs, including Customer Grid-Supply, Customer Grid-Supply Plus and Smart Export, keep their terms for a period but may be moved to the Smart DER program later, so check before expanding an existing system. The solar net metering calculator models different export rates.
🔋 Storage & Usage
Why Does Battery Storage Make Sense in Hawaii?
A battery lets you use your own afternoon solar in the evening instead of buying grid power at about 40.8¢/kWh. Because Hawaii’s retail rates are high and daytime export credits are low, storage can be worth more here than in most states. Homeowner-owned batteries installed in 2026 get no federal credit, because §25D ended along with the solar credit. Installed prices vary widely by product and island, so get written quotes.
Illustrative math. Suppose a battery shifts 9 kWh a day of solar that would otherwise be exported. That is about 3,285 kWh a year. If the export credit were about 15¢/kWh (an assumption for illustration; actual rates vary by island and time block), each shifted kWh avoids roughly 26¢ of the difference between the 40.8¢ you would buy and the credit you would forgo. The gain is about $850 a year. That helps the payback but does not by itself cover a battery’s cost, so many owners buy for backup power as much as for savings.
Hawaiian Electric’s BYOD Plus program pays customers who add a new battery and commit to exporting stored energy during a daily window. Hawaiian Electric’s program page lists an upfront incentive of $400 per kW committed, plus monthly export credits. Enrollment capacity is limited by island and terms can change, so read the contract before signing.
A battery also keeps refrigeration, lighting, medical devices and communications running during an outage. The battery storage calculator helps size a system. Ask your installer whether battery costs affect the state credit, and confirm with the Department of Taxation.
📈 Payback Period
What Is the Solar Payback Period in Hawaii?
About 6.8 years for a 6 kW cash purchase at $3.00 per watt with no tax credit, or about 7.5 years at EnergySage’s $3.28 per watt Hawaii average. A full $5,000 state credit cuts those to about 4.9 and 5.6 years.
Worked example (modeled, not a real customer):
Input / result
No state credit
With $5,000 RETITC
System size
6.0 kW
6.0 kW
Peak sun hours (model input)
6.0
6.0
Annual production (kW × sun × 365 × 0.82)
~10,775 kWh
~10,775 kWh
Rate × bill offset
40.8¢ × 0.60
40.8¢ × 0.60
Year-1 savings
~$2,640
~$2,640
Out-of-pocket cost at $3.00/W
$18,000
$13,000
Simple payback (flat savings)
~6.8 years
~4.9 years
25-year bills without solar (3%/yr increases)
~$160,300
~$160,300
25-year net savings
~$71,900
~$76,900
Data visualization
Cumulative cash flow for a modeled 6 kW Hawaii system, Years 0–25. Net gain reaches about $71,900 without and $76,900 with the state credit, assuming 3% yearly rate increases and no federal credit. Source: Green Energy Calculators model, 2026.
Chart summary: With 3% yearly rate increases and 0.5% yearly panel degradation, cumulative cash flow turns positive during year 7 without the state credit (about 6.4 years of actual breakeven) and during year 5 with it (about 4.7 years). By year 25 the modeled net gain is about $71,900 without the credit and about $76,900 with it. The headline 6.8- and 4.9-year paybacks use flat first-year savings, so they are slightly more conservative. Source: Green Energy Calculators model.
Price sensitivity (6 kW, no escalation, same savings):
Installed price
Cost
Payback, no state credit
Payback, $5,000 state credit
$3.00/W (our model)
$18,000
~6.8 years
~4.9 years
$3.28/W (EnergySage Hawaii average, Mar 2026)
$19,680
~7.5 years
~5.6 years
By monthly bill (no state credit, $3.00/W):
Monthly bill
System size
Installed cost
Year-1 savings
Payback
25-yr net savings
$125
2.0 kW
$6,000
~$900
~6.7 yrs
~$24,700
$250
4.1 kW
$12,300
~$1,800
~6.8 yrs
~$49,100
$350
5.7 kW
$17,100
~$2,520
~6.8 yrs
~$68,800
Assumptions: system sized to annual usage at 40.8¢/kWh and 6.0 sun hours; year-1 savings = bill × 12 × 0.60; 3% annual rate escalation; 0.5% annual panel degradation; no federal credit. Sun hours vary by island and microclimate, and windward areas such as Hilo typically get less than leeward sites, so check your installer’s production estimate. Very small systems often cost more per watt, which lengthens payback.
Until the end of 2025, a 6 kW system with both the federal and state credits paid back in under 4 years in our model. Losing the federal credit adds about two years, but Hawaii’s high rates keep payback short compared with most states. Run your own numbers in the solar savings calculator.
No, not for a system you own. The 30% federal Residential Clean Energy Credit (§25D) ended for expenditures after December 31, 2025, and the IRS treats an expenditure as made when installation is complete. If your system was finished in 2025, claim it on your 2025 return with Form 5695. Leased and PPA systems may still qualify for the owner's commercial §48E credit if construction began by July 4, 2026 or the system is placed in service by December 31, 2027.
At our modeled $3.00 per watt, a 6 kW system costs about $18,000 and an 8 kW system about $24,000. Market data runs higher: EnergySage reported a Hawaii average of $3.28 per watt in March 2026, or about $27,100 for the 8.27 kW average system, before incentives. Island logistics, permitting and roof condition all affect price, so compare at least three written quotes in dollars per watt.
Yes, but it is changing. The RETITC is worth 35% of PV cost, up to $5,000 per system. Act 24, signed May 21, 2026, adds a $40 million annual statewide cap, new eligibility and certification rules, and a sunset after 2030. Executive Order 26-02 exempts qualifying 2026 systems from the cap, but reportedly not from the new eligibility rules. Confirm your case with the Hawaii Department of Taxation or a tax professional.
No. Hawaiian Electric closed retail net metering to new customers in 2015. New systems enroll in the Smart DER tariff, which has an export option with time-varying credits and a non-export option. Export credits are set by island and time of day and are generally well below the retail rate, so solar pays most when you use the power yourself or store it in a battery.
About 6.8 years in our model for a 6 kW cash purchase at $3.00 per watt, and about 7.5 years at EnergySage's $3.28 per watt Hawaii average, with no state credit. A 6 kW system at 6.0 sun hours produces roughly 10,775 kWh a year, which saves about $2,640 at 40.8¢/kWh with a 0.60 bill offset. Using the full $5,000 state credit cuts payback to about 4.9 to 5.6 years.
Hawaii solar by electric bill
See system size and payback for common monthly bills in Hawaii.
46.28¢/kWh — Hawaii average residential price. Source: EIA Electric Power Monthly, Table 5.6.B (year-to-date through July 2026), residential average retail price (July 2026) (EIA)
Solar production
6 peak sun hours/day × 0.82 system derate. Approximate state-average daily solar resource (peak sun hours) based on NREL solar resource data (NSRDB); not location-specific — use NREL PVWatts for an address-level estimate. (NREL PVWatts)
Installed price
$3.00 per watt before incentives. Blended 2026 US residential installed price used by this site; EnergySage marketplace reported about $2.60/W (mid-2026); full-market medians are higher.
Federal tax credit
$0 for homeowner-owned systems installed in 2026 — the 30% §25D credit ended Dec 31, 2025 (IRS)
Net metering
Low export credit (battery usually needed) — solar assumed to offset 60% of the bill. Hawaii closed retail net metering in 2015; current Smart Export / self-supply options favor pairing solar with a battery.
Estimates only — not tax, legal or financial advice. Get at least three installer quotes and confirm incentives with your utility and a tax professional.