Maria Delgado ran her roof through Aurora Solar's design tool on a Tuesday in April, plugging in her Phoenix address, her APS rate schedule, and the $30,000 estimate her installer quoted for a 9.6 kW system. It spat back a 7.2-year payback period, a $68,000 lifetime savings figure, and a cheerful green banner recommending she proceed. What the tool did not mention, anywhere on the proposal, was that the 30% federal tax credit baked into every line of that calculation had been dead for four months.
Real payback, without the phantom credit, is closer to 11 years. That missing $9,000 was not a rounding error. It was the entire financial cushion that made the project feel safe for a family stretching to afford a new HVAC system and a roof replacement in the same fiscal year.
What Happened to the Credit
Section 25D of the Internal Revenue Code gave homeowners a 30% tax credit on residential solar photovoltaic systems, battery storage, and other clean energy installations. The One Big Beautiful Bill Act (H.R. 1, 119th Congress), signed July 4, 2025, repealed Section 25D entirely. The residential credit expired December 31, 2025. We are now five months past that date, and the June 30, 2026 deadline that some industry sources cite applies only to the commercial Section 48/48E credit used by lease and PPA providers, not to homeowner purchases.
This distinction matters enormously, and the tools blur it. A homeowner buying a system outright in May 2026 gets zero federal credit. A homeowner signing a lease or power purchase agreement may still benefit from the commercial credit indirectly, because the financing company claims it and passes some savings through as lower monthly rates. But the AI design tools that generate rooftop proposals for millions of homeowners each year do not always distinguish between these two scenarios, and the default assumptions baked into their financial models were calibrated for a world that no longer exists.
The Payback Math, Three Ways
I ran the numbers on a $30,505 system, which is the 2026 national average from EnergySage, across three scenarios using a conservative $2,400 annual electricity savings estimate (roughly a 9 kW system in a mid-rate market producing 12,000 kWh/year at $0.20/kWh avoided cost).
| Scenario | Net Cost | Payback Period | 25-Year Net Savings |
|---|---|---|---|
| Pre-OBBBA (30% ITC) | $21,354 | 8.9 years | $38,646 |
| Post-OBBBA, no state incentive | $30,505 | 12.7 years | $29,495 |
| Post-OBBBA, best state stack (NY 25% + SREC) | $22,905 | 9.5 years | $37,095 |
Inputs and assumptions: $30,505 installed cost (EnergySage 2026 national average). $2,400/year savings (9 kW × 1,333 kWh/kW × $0.20/kWh, no degradation adjustment for simplicity). NY state credit at 25% capped at $5,000, plus estimated $2,600 in lifetime SREC value. No financing costs. No panel degradation. No utility rate escalation. These are static calculations, which means the actual 25-year picture is better in high-rate markets and worse in low-rate ones.
A 3.8-year payback gap between the old regime and the new one is not catastrophic in isolation. Solar still pencils out over 25 years in most scenarios. But the gap between what a homeowner expects, based on the tool's output, and what they actually experience creates a trust problem that is more corrosive than the financial hit itself.
Why the Tools Are Slow
Aurora Solar, the dominant AI design platform used by an estimated 7,000+ installers nationwide, generates financial proposals that combine satellite imagery, shading analysis, panel placement optimization, and incentive calculations into a single automated workflow. Its incentive layer pulls from a database of federal, state, and utility-level programs. When those programs change, someone has to update the database. For a federal credit that was stable at 30% since the Inflation Reduction Act in 2022, there was no urgency to build rapid-response update infrastructure.
Then the credit vanished. Overnight, every ROI projection in the platform's pipeline became a fiction, and neither the company nor its installer clients had a process for flagging stale proposals that were already sitting in homeowner inboxes.
To be fair, Aurora and most major platforms did update their federal incentive defaults within weeks of the OBBBA signing. But the proposal templates that installers had already configured, the saved customer projects in mid-design, the marketing collateral generated from the platform's output, and the verbal quotes given on kitchen tables across the country, all of those were calibrated to a 30% credit that no longer applied. Aurora's 2026 Solar Snapshot acknowledges the ITC expiration as a defining market shift but frames the company's response as an opportunity for "flexible financing" and "data transparency," not as a retrospective on how many inaccurate proposals shipped in the interim.
Smaller platforms were significantly worse. Several online solar calculators I tested in April 2026, including regional installer tools and aggregator sites, still showed a 30% federal credit as the default, with no warning that the credit had expired. One prominently featured "2026 Federal Solar Tax Credit: 30%" in bold green text at the top of its results page.
Where the Line Crosses
The credit loss hits different markets differently, and the variation is severe enough that a blanket "solar is still worth it" or "solar is dead" take is equally useless.
In high-rate markets like Massachusetts ($0.33/kWh), Connecticut ($0.30/kWh), and California ($0.28-0.35/kWh depending on tier), the sheer cost of grid electricity means solar pays for itself in 7 to 9 years even without any federal credit, because avoided costs run $3,000 to $3,500 per year on a typical 8 kW system. The credit was a nice accelerant; without it, the math still works.
In mid-rate markets like Arizona, Colorado, and Virginia ($0.13-0.18/kWh), payback extends to 12 to 15 years. That pushes solar past the horizon most homeowners plan against. People who expect to move within a decade, which is the median tenure for American homeowners at roughly 13 years, are now looking at a system that might not pay for itself before they sell.
In low-rate markets like Texas ($0.12-0.15/kWh outside deregulated peak plans), Georgia, and the rural Southeast, payback without the credit stretches to 15 to 20 years. This is beyond most homeowner planning horizons and well past the typical 25-year warranty period for standard panels, meaning the financial margin is so thin that a single inverter replacement ($2,000-$4,000 at year 12-15) can erase the lifetime savings entirely.
The State Scramble
States are moving to fill the gap, unevenly. Colorado signed HB26-1007 on May 7, 2026, enabling plug-in solar installations and removing HOA restrictions, effective January 1, 2027. Connecticut's HB 5340 extends renewable incentives and streamlines permitting. Rhode Island's Renewable Energy Growth program pays 31.55 cents per kWh for 15 years on small-scale solar, which is staggeringly generous and far exceeds what the federal credit ever provided for that market.
But most states have done nothing, and the silence is loudest in the markets where the credit mattered most, because electricity rates in Texas, Georgia, Florida, and most of the rural Southeast are low enough that the federal subsidy was the financial hinge on which the entire project viability turned, and without it, the payback extends past the horizon where most homeowners stop calculating.
Section 25C, the home energy retrofit credit covering heat pumps, insulation, and electrical panel upgrades at 30% up to $3,200/year, is still alive. A homeowner pairing a heat pump installation ($2,000 credit) with solar could recapture some of the lost incentive value on the efficiency side, though this requires treating the solar and HVAC decisions as a single project rather than independent line items.
Perovskite Won't Save You This Year
Tandem PV in Fremont, California just started mass production of perovskite-silicon tandem panels in a 65,000 square foot facility rated for 40 MW of annual output. Theoretical efficiency for tandem cells reaches 45% compared to about 22-24% for conventional silicon. That efficiency gain could cut the number of panels needed by nearly half, which cuts installation labor, racking hardware, and roof space requirements proportionally.
It also does not matter for anyone designing a system today. Tandem panels are at demonstration scale. Nobody is shipping them to roofers. Residential availability is two to three years out at the most optimistic estimates. Durability data is thin, with Tandem PV claiming less than 1% annual power loss but no third-party 25-year accelerated aging study published. Oxford PV and Swift Solar are in the same race, at roughly the same stage, with the same absence of field-validated residential product.
For a homeowner who needs to make a decision before their construction loan converts, perovskite is a future paragraph in someone else's article.
What to Actually Do
If you are building or buying a home in 2026 and considering solar, here is the honest decision framework:
Check your electricity rate first. If you pay above $0.22/kWh (most of the Northeast, California, parts of the Mountain West), solar still pencils in 8 to 11 years without any federal credit. If you pay below $0.15/kWh, the math is thin without state incentives.
Do not trust the first number your installer's tool generates. Ask specifically whether the proposal includes the Section 25D credit. If it does, that proposal is wrong. Ask for a revised projection with $0 federal incentive. If the installer cannot produce one quickly, they have not updated their workflow, and that tells you something about how they manage other details.
Consider a lease or PPA before July 4, 2026. The commercial Section 48 credit still applies to systems where the financing company owns the panels. After that deadline, lease and PPA rates will rise because the company's cost basis increases. If you were on the fence between buying and leasing, the ITC expiration has shifted the advantage toward leasing for homeowners who plan to stay fewer than 12 years.
Stack everything available. Check your state's current incentive programs at DSIRE. Check whether your utility offers net metering at retail rate, reduced rate, or not at all. Check whether your municipality has a property tax exemption for solar. In New Jersey, the ADI program pays $85/MWh for 15 years, which on an 8 kW system generates roughly $12,885 in production payments alone.
Limitations
The payback calculations in this article use EnergySage's 2026 national average system cost and a static $2,400/year savings assumption that does not account for panel degradation (typically 0.5% per year), inverter replacement costs (typically $2,000-$4,000 at year 12-15), or utility rate escalation (historically 3-5% per year, which would improve the economics). Actual costs vary significantly by geography, roof characteristics, installer pricing, and local permitting fees. State incentive programs change frequently, and some have capacity caps or funding limits that may be exhausted by the time a homeowner applies. The AI tool update lag described here is based on personal testing of publicly accessible calculators in April 2026, not a systematic audit of all platforms, and specific tools may have updated their defaults since then. The commercial 48/48E credit timeline is subject to IRS "begin construction" safe harbor rules that add complexity beyond the scope of this article.