Hawaii has the most expensive electricity in the United States — residential rates average $0.40–$0.46 per kWh on Oahu, reaching $0.47–$0.55/kWh on the Big Island and Maui. Those rates make Hawaii simultaneously the most expensive place to run a home on grid power and the most financially compelling place to go solar.
Stack a 35% state income tax credit on top of the 30% federal ITC, add outstanding solar resources (5.5–6.5 peak sun hours per day on most islands), and solar plus battery storage in Hawaii can achieve payback periods of 6–9 years — comparable to the best incentive stacks in New England, despite higher system costs.
This guide covers every Hawaii solar incentive in 2026, how the HECO export tariff affects system design, and full stacking examples for Honolulu, Maui, and the Big Island.
Hawaii Solar Incentive Summary
| Incentive | Value | Who Qualifies |
|---|---|---|
| Hawaii State Income Tax Credit | 35% of cost, capped at $5,000 (residential) | All Hawaii taxpayers who own their system |
| Federal ITC | 30% of system cost | All homeowners with federal tax liability |
| Total effective credit rate | Up to 65% of system cost | Both credits stack independently |
| HECO Smart Export credit | ~$0.14–$0.20/kWh | HECO/MECO/HELCO customers |
| County property tax exemption | 100% of added value | All Hawaii counties |
| No state sales tax on solar | N/A — Hawaii has a GET, but solar is exempt | Most installations |
1. Hawaii State Solar Income Tax Credit: 35%
Hawaii's state solar tax credit (Hawaii Revised Statutes § 235-12.5) is one of the most generous in the country:
- Rate: 35% of qualified costs
- Residential cap: $5,000 per system
- Commercial cap: $500,000 per system
- Carry-forward: Unlimited — unused credit carries forward to future tax years
This credit is calculated on the gross installed cost — before the federal ITC is applied. This is the most favorable possible calculation: you do not reduce your basis for Hawaii state purposes because you received the federal credit first.
Example for a $28,000 system:
- Hawaii state credit: 35% × $28,000 = $9,800 → capped at $5,000
- The credit is $5,000 regardless of system size above ~$14,300
Important: The $5,000 cap applies per permitted system. Some larger systems on larger homes are permitted as two separate installations (e.g., one array on each roof face with separate permits). In this case, each system qualifies for up to $5,000 — but this must be a genuine two-system installation, not a paper split. Consult your installer and a Hawaii tax professional before attempting this approach.
2. Federal Investment Tax Credit: 30%
The 30% federal ITC applies to the full installed cost of the solar system, including panels, inverter, battery storage (when charged at least 80% from solar), racking, and labor.
How federal and state credits stack in Hawaii:
The two credits are calculated independently and do not reduce each other's basis in Hawaii.
| Item | Amount |
|---|---|
| Gross system cost | $28,000 |
| Federal ITC (30% × $28,000) | −$8,400 |
| Hawaii state credit (35% × $28,000, capped) | −$5,000 |
| Total effective cost after both credits | $14,600 |
That is a 47.9% total credit rate on a $28,000 system — meaning nearly half your system cost is covered by tax credits. For systems where the 35% uncapped amount is under $5,000 (i.e., systems under $14,300 in gross cost), the effective combined rate is 65%.
3. HECO Smart Export and the Battery Storage Imperative
This is the most important thing to understand about Hawaii solar in 2026: Hawaii does not have traditional net metering.
Hawaiian Electric Company (HECO, serving Oahu), Maui Electric Company (MECO), and Hawaii Electric Light Company (HELCO, serving the Big Island) eliminated traditional NEM and Customer Grid Supply (CGS) programs in 2022–2023 as grid saturation on the islands made retail-rate export economically unsustainable.
Current export tariff: Smart Export (formerly known as Green Button Export)
- Exported solar gets credited at approximately $0.14–$0.20/kWh depending on island and time of day
- This is NOT the retail rate — retail residential rates are $0.40–$0.46/kWh
- Self-consumed solar is worth $0.40–$0.46/kWh (retail avoided cost)
- Exported solar is worth only $0.14–$0.20/kWh (Smart Export rate)
Consequence: Every kWh you consume directly from your solar panels is worth 2–3× more than every kWh you export to the grid. This creates a powerful economic incentive to maximize self-consumption and minimize export.
Battery storage becomes near-essential: A properly sized battery (Tesla Powerwall 3, Enphase IQ 10T, or Franklin aGate) stores excess daytime solar production and releases it at night — capturing the full $0.40–$0.46/kWh retail value instead of the $0.14–$0.20/kWh export rate. The economics of Hawaii solar + battery are dramatically better than solar alone.
For more on battery storage options and costs, see our home battery storage costs guide.
4. Hawaii Solar + Battery System Economics
Standard solar-only system (no battery):
- Daytime self-consumption: ~40% of production
- Daytime export: ~60% of production (worth $0.14–$0.20/kWh)
- Nighttime draw from grid: ~60% of total usage (at $0.44/kWh)
- Result: Moderate bill reduction; poor export economics
Solar + battery system:
- Daytime self-consumption: ~40% of production (direct)
- Battery charge: ~50% of production stored
- Battery discharge at night: covers ~50% of nighttime load
- Grid export: ~10% of production (minimal)
- Result: 85–95% energy independence; dramatically better economics
A 10 kW solar + 13.5 kWh Tesla Powerwall 3 combination is the most common Hawaii installation in 2026. Total cost before incentives: approximately $42,000–$50,000 (panels + inverter + battery + installation).
After incentives:
- Federal ITC (30% × $45,000): −$13,500
- Hawaii state credit (35%, capped at $5,000 for solar): −$5,000
- Battery eligible for federal ITC separately if over threshold: included above
- Effective net cost: ~$26,500–$32,000
Annual savings at 90% self-sufficiency: ~$4,000–$5,500/year Payback: 5.5–8 years — comparable to top incentive states despite higher system cost
5. Property Tax Exemptions in Hawaii
All four Hawaii counties offer property tax exemptions for solar energy systems. The specifics vary:
Honolulu (Oahu): Solar systems are exempt from real property tax assessment. The added value from your solar installation is excluded from your property tax bill entirely. With Honolulu property tax rates of ~$3.50/1,000 (residential), a $30,000 solar system exemption saves ~$105/year — or $2,625 over 25 years.
Maui County: Renewable energy systems are fully exempt from property tax. Maui's residential property tax rate is higher ($5.81/1,000 for owner-occupied), so the exemption is more valuable: a $30,000 system saves ~$174/year, or $4,350 over 25 years.
Hawaii County (Big Island): 100% exemption for renewable energy systems per Hawaii County Code. The Big Island's residential rate is $9.10/1,000 — one of the highest in the state. A $35,000 system saves ~$319/year or $7,975 over 25 years. This is one of the most valuable property tax exemptions in the state.
Kauai: Solar installations receive a property tax exemption. Kauai's residential rate is ~$3.05/1,000.
How to claim: Your installer typically provides documentation; you file with the county real property assessment division before the applicable tax year deadline. Ask your installer whether they include this paperwork as part of their post-installation service.
6. Kauai Island Utility Cooperative (KIUC)
Kauai operates on a separate grid from the other Hawaiian islands. KIUC — a member-owned cooperative — has a different solar program structure than HECO:
- Self-Supply program: No export allowed (batteries are effectively required to prevent export)
- Grid Export program: Limited enrollment, credit at avoided cost (~$0.12–$0.18/kWh)
- Net Energy Metering (legacy): Closed to new applicants
Kauai buyers should design solar systems specifically to minimize grid export. A properly sized solar + battery system (typically 8–12 kW solar + 10–27 kWh storage) with no grid export can achieve near-complete energy independence. With Kauai rates at $0.45–$0.55/kWh, even a self-supply-only configuration achieves excellent economics.
7. General Excise Tax (GET) Treatment
Hawaii does not have a traditional state sales tax — instead, it has the General Excise Tax (GET), typically 4% (4.5% in Honolulu with the surcharge). This GET is technically a tax on the seller's gross revenue, not the buyer — but it is nearly always passed through to consumers.
For solar installations, the situation as of 2026:
- Solar contractors pass through GET on most installations (effectively adds 4–4.5% to installed cost)
- Some large installers absorb the GET in their pricing — ask explicitly when comparing quotes
- The GET paid on your solar installation is included in the basis for both the federal ITC and Hawaii state credit — meaning even the tax you pay to install the system earns you tax credits
Net effect: The GET slightly increases your system cost, but that higher cost basis earns you more in credits (both 30% federal + 35% state), partially offsetting the tax burden.
8. Stacking Example: Honolulu, Oahu (HECO)
Household profile: 3-bedroom home in Honolulu, monthly usage 750 kWh, HECO residential rate $0.42/kWh
System design:
- Peak sun hours: 5.7/day (Honolulu)
- Solar: 9 kW (production-optimized for self-consumption)
- Battery: 13.5 kWh Tesla Powerwall 3
- Annual solar production: ~10,400 kWh
- Self-consumption (with battery): ~90% of production
Cost breakdown:
| Component | Cost |
|---|---|
| 9 kW solar system | $27,000 |
| Tesla Powerwall 3 | $12,000 (installed) |
| Total gross cost | $39,000 |
| Federal ITC (30%) | −$11,700 |
| Hawaii state credit (35%, capped) | −$5,000 |
| Net cost after incentives | $22,300 |
Annual savings:
- Solar self-consumption: 9,360 kWh × $0.42 = $3,931
- Residual grid draw (10% of usage): ~$378/year
- Net annual utility savings: ~$3,553/year
Payback: 6.3 years 25-year net savings (3% rate escalation): ~$88,000
9. Stacking Example: Kailua-Kona, Big Island (HELCO)
Household profile: 2,400 sq ft home near Kailua-Kona, monthly usage 950 kWh, HELCO rate $0.47/kWh
System design:
- Peak sun hours: 6.2/day (Kona side of Big Island)
- Solar: 11 kW
- Battery: 2× Tesla Powerwall 3 (27 kWh)
- Annual production: ~14,800 kWh
- Self-consumption: ~90% with two batteries
| Component | Cost |
|---|---|
| 11 kW solar | $33,000 |
| 2× Powerwall 3 (installed) | $22,000 |
| Total gross cost | $55,000 |
| Federal ITC (30%) | −$16,500 |
| Hawaii state credit (capped) | −$5,000 |
| Net cost | $33,500 |
Annual savings:
- Solar self-consumption: 13,320 kWh × $0.47 = $6,260
- Near-zero grid bill
- Net annual savings: ~$5,900/year
Payback: 5.7 years 25-year net savings: ~$140,000 (at 4% annual rate escalation)
10. Stacking Example: Lahaina/Wailuku, Maui (MECO)
Maui was devastated by wildfire in August 2023. Rebuilding has included significant solar + battery adoption as a grid resilience measure.
Household profile: Rebuilt home in Wailuku, monthly usage 800 kWh, MECO rate $0.43/kWh
System design:
- Peak sun hours: 5.9/day (central Maui)
- Solar: 9 kW + 13.5 kWh battery
| Component | Cost |
|---|---|
| 9 kW solar + battery (installed) | $40,000 |
| Federal ITC (30%) | −$12,000 |
| Hawaii state credit (capped) | −$5,000 |
| Net cost | $23,000 |
Annual savings: ~$3,800/year (90% self-sufficiency at $0.43/kWh) Payback: ~6.1 years
11. Hawaii vs. Other High-Rate States
| State | Avg Rate | Key Incentive | System Cost (Net) | Payback |
|---|---|---|---|---|
| Hawaii | $0.43/kWh | 35% state credit + 30% ITC | $22,000–$34,000 | 5.7–8 years |
| CT | $0.26/kWh | RSIP $0.20–$0.26/kWh × 6 yr | $16,000–$19,000 | 3–4 years |
| RI | $0.25/kWh | REF $0.20–$0.65/W rebate | $14,000–$18,000 | 5–7 years |
| MA | $0.25/kWh | SMART + 15% state credit | $10,000–$14,000 | 3–5 years |
| NY | $0.22/kWh | NY-Sun + 25% state credit | $12,000–$18,000 | 5–8 years |
| NJ | $0.19/kWh | SREC II 15-year income | $15,000–$20,000 | 4–5 years |
Hawaii has higher system costs (island logistics, labor, equipment shipping) and the battery requirement adds $10,000–$22,000. But the extreme electricity rates and outstanding sun resource produce payback periods competitive with most mainland high-incentive states.
12. Finding a Hawaii Solar Installer
Hawaii has a mature solar installer market — the state has had one of the highest solar penetration rates per capita in the U.S. for over a decade. Key considerations:
Verify NABCEP certification: Look for NABCEP-certified installers. Hawaii's industry is competitive; certified installers meet a higher standard than unlicensed contractors.
Get 3 quotes minimum: Installer pricing on the islands varies significantly (sometimes $0.50–$1.00/W between quotes). Island logistics (Maui, Big Island, Kauai) add cost vs. Oahu.
Battery storage included: Ask for quotes that include battery storage. Given the export rate economics, a solar-only quote in Hawaii is often not the most financially optimal configuration.
HECO/HELCO interconnection: Ask your installer how long interconnection approval takes. HECO's grid saturation issues have caused delays on some circuits in Honolulu; experienced installers know which feeders have capacity and can advise on system sizing to stay within grid limits.
Permit timeline: Honolulu has an automated solar permitting system (SolarAPP+) that can approve residential systems in 24–72 hours. Maui, Big Island, and Kauai have manual processes that typically take 2–6 weeks.
See our best solar companies guide and how to read your solar quote before meeting with installers.
13. Hawaii Solar: Step-by-Step Process
- Energy audit: Start with your last 12 months of HECO/HELCO/KIUC bills to establish baseline usage
- Battery assessment: Determine how much overnight and cloudy-day coverage you want (13.5 kWh Powerwall 3 covers a typical Honolulu home for one night)
- Get 3 quotes from NABCEP-certified installers; compare equipment, warranties, and interconnection experience
- Review the quote carefully — see how to read your solar quote for the full checklist
- Apply for HECO/MECO/HELCO interconnection (your installer submits on your behalf)
- Permit and install: Timeline varies by island (Honolulu fastest via SolarAPP+)
- PTO: Permission to Operate issued by utility after final inspection
- File IRS Form 5695 with your federal taxes for the ITC in the year you receive PTO
- File Hawaii Form N-342 with your state taxes for the 35% state credit
- Apply for county property tax exemption with your county assessment office
Key Takeaways
- 35% Hawaii state credit stacks on 30% federal ITC → effectively 47–65% of system cost covered
- No traditional net metering — Smart Export pays $0.14–$0.20/kWh vs. retail $0.40–$0.46/kWh
- Battery storage is the key to maximizing economics — self-consumed solar is worth 2–3× exported solar
- Payback: 5.7–8 years for solar + battery combinations in most Hawaii scenarios
- 25-year savings: $88,000–$140,000 depending on island and system size
- County property tax exemptions apply in all four counties (check your specific county)
For system sizing help, use our Solar System Designer — enter your details and get a complete parts list with Amazon affiliate links for DIY purchases. For more context on solar economics, see our payback period calculator, home battery storage costs, and solar energy storage explained.
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