Published September 2026. Deadlines described here reflect federal law as enacted. Consult your tax professional regarding your own eligibility.
The federal Investment Tax Credit for commercial solar does not phase down. It stops. For most projects starting today, the system must be complete and operating by December 31, 2027 — and that deadline is considerably tighter than the calendar makes it look.
This article works backward from that date using our own project timelines, so you can see where the real decision point falls.
First: Which Bucket Are You In?
The 2025 tax legislation created two different paths, separated by a single date. Which one applies to you depends on whether your project had begun construction by July 4, 2026.
| If Construction Began… | Deadline to Be Placed in Service | Why It Matters |
|---|---|---|
| On or before July 4, 2026 | December 31, 2030 | Four additional years. If you committed to a project before that date, you may already be protected and not realize it. |
| After July 4, 2026 | December 31, 2027 | No phase-down and no extension. After this date the credit is simply unavailable. |
If You Started Before July 4, 2026
This is worth checking rather than assuming. For solar projects at or below 1.5 MW — which covers essentially all commercial rooftop work, including every system we build — beginning construction could be established by incurring at least 5% of total project cost, not only by physical work on site.
That means a deposit, an equipment order, or a signed commitment made before July 4, 2026 may have secured your position, with until the end of 2030 to complete. If you paid anything toward a solar project in the first half of 2026, bring the documentation to your tax professional before you conclude you have missed anything.
If You Are Starting Now
Everything below applies to you. The system must be placed in service by December 31, 2027 — meaning complete and capable of producing power: installed, inspected, interconnected, and granted Permission to Operate by the utility.
Signed is not enough. Installed is not enough. The utility has to have said yes.
Working Backward From December 31, 2027
Our FAQ describes how a typical project progresses. Running those stages in reverse from the deadline produces the following.
| Stage | Typical Duration | Must Be Underway By |
|---|---|---|
| Permission to Operate | Often about a month; utility processing varies and cannot be guaranteed | End of November 2027 |
| Inspection by the AHJ | Scheduling dependent | Mid-November 2027 |
| Installation | Several days to several weeks by size and complexity | October 2027 |
| Permit review | Days in some jurisdictions, a month or more in others | August–September 2027 |
| Engineering and permit package | About one month | July–August 2027 |
| Initial evaluation of bills and site | About one week | July 2027 |
That chain describes a project where nothing goes wrong. It assumes the permitting authority is not backlogged, the installation schedule has an opening when you need it, and no utility-side work is required.
Where the Schedule Actually Breaks
Three things routinely consume more calendar than businesses expect.
Utility service upgrades. If your existing electrical service cannot accommodate the new generation, the upgrade carries its own engineering, its own utility queue, and its own timeline — frequently the longest single item in a project. We identify this need during evaluation and spell out the attendant timelines, precisely because discovering it late is what puts a deadline out of reach.
Permit review variation. Review times by the Authority Having Jurisdiction vary considerably. Some jurisdictions issue permits within days. Others require a month or more depending on workload, and workload in late 2027 is likely to be heavier than usual as projects converge on the same deadline.
The queue itself. We are one team and we do not subcontract our installations. We honor commitments to existing customers in the order they were made. As the deadline approaches, the calendar fills.
The Real Decision Point
Adding realistic margin to the chain above puts the practical decision point in spring 2027 for a straightforward project — and meaningfully earlier for any project that may involve a service upgrade.
December 31, 2027 is the legal deadline. It is not the date to begin the conversation. It is roughly nine months after the date to begin the conversation.
What This Means for Commercial Customers
We are direct about the role incentives play in our numbers. The payback periods we model — as short as three to four years on well-matched projects — assume the customer can use the federal credit and first-year depreciation. Our own materials carry that qualification: requires sufficient tax credit appetite.
The credit is 30% of system cost, with adder enhancements bringing some projects up to 50% where they are available, and commercial solar also qualifies for 100% bonus depreciation and MACRS 5-year accelerated depreciation. Together these substantially reduce net cost. Whether and to what extent your business can claim them is a question for your tax professional, and it is one worth answering early — because the answer also determines the right size for your system.
What does not change after 2027 is the underlying reason to install: a right-sized system reduces the electric bill every month for twenty-five years, and utility rates are not trending downward. The credit accelerates that return considerably. It is not the sole reason the investment works.
Our Design Philosophy
We would rather tell you in July 2027 that the schedule no longer allows a credit-qualifying project than take a deposit in October and hope. Every project we take on for the remainder of this window gets an honest timeline with the utility and permitting steps named explicitly.
If the credit matters to your numbers, the time to have the conversation is well before you think it is.
Request a free consultation and we will tell you candidly whether your project still fits the window.