What ended, precisely
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025. A homeowner who purchased and installed by the end of 2025 could still claim it on that return. A cash or loan purchase now receives nothing from it.
That is roughly a third of the historical federal support for a residential system, removed. It is not a reduction or a phase-down, it is an expiry.
The consequence for reading quotes is immediate. Any calculator, guide or sales projection built before 2026 assumes the credit, and a projection that still applies it is overstating your return by close to the size of the credit.
Ask any installer directly whether their savings model applies a federal residential credit, and if so, ask for the version without it. Comparing one quote that includes it against one that does not is comparing two different worlds.
The state credit is now the main event
The Hawaii RETITC under HRS Section 235-12.5 gives 35 percent of the actual cost of a residential photovoltaic system, capped at $5,000 per system, and it has no scheduled repeal.
A residential system for these purposes is defined by capacity: 5 kW of total output. So an installation larger than 5 kW may comprise more than one system, each with its own $5,000 cap, with one Form N-342 filed per system.
That definition is now worth real money in a way it was not when it sat alongside a 30 percent federal credit. A homeowner who assumes a single $5,000 ceiling on a 10 kW installation may under-claim by thousands.
The credit can be carried forward indefinitely, or you can elect to have it refunded in the year claimed in exchange for a 30 percent reduction. Which is right depends on your Hawaii tax liability, so take the system cost and system count to a tax professional.
Where 30 percent still exists, and who gets it
Section 48E, the commercial Clean Electricity Investment Credit, survives at 30 percent and is available to third-party owners of residential systems under leases and power purchase agreements. The provider claims it, not you.
That is why third-party ownership is being promoted more heavily in 2026 than it was before. It is the remaining route by which a 30 percent federal credit touches a residential rooftop, and the party claiming it is the provider.
Whether any of that value reaches you depends entirely on the rate you are offered, which is a commercial decision rather than a rule. Ask what the provider claims, ask what portion is reflected in your rate, and ask for the comparison against a cash purchase on the same system.
Ask also who then owns the system, because under a lease or power purchase agreement you generally do not, and that affects whether you can claim the Hawaii RETITC at all. Losing a $5,000-per-system state credit to gain an indirect share of a federal one is a trade worth seeing in numbers.
Costing it out at Hawaii electricity prices
Strike the federal residential credit from any Waipahu quote that shows it, because Section 25D expired for property placed in service after December 31, 2025.
Rebuild from the RETITC at 35 percent capped at $5,000 per 5 kW system, Bring Your Own Device Plus at $400 per kW of committed battery capacity if storage is included, and the correct Smart Renewable Energy track, since Customer Grid-Supply, Customer Grid-Supply Plus, Smart Export, Customer Self-Supply and the Standard Interconnection Agreement are all closed to new customers.
Then add the Oahu residential average of 40.54 cents per kWh in 2025, which is the largest and most durable item in the calculation and the one that does not depend on any programme staying open.
Ask for that version in writing. An installer working Hawaii seriously in 2026 will already have it, and reluctance to produce it is informative in itself.