Most cost conversations about commercial solar start with a number that’s already out of date. The federal tax credit changed its qualification rules mid-2026. Depreciation rules changed too, in a way that actually makes the math better for most businesses, not worse. If you’re pricing out a commercial system this year, the real cost picture depends on three things: the price per watt, whether your project still qualifies for the 30% tax credit under the current rules, and how depreciation applies to your specific project timeline.
Here’s what actually drives the price of a commercial solar installation right now, and how to run your own numbers instead of relying on a generic quote.
H2: What Commercial Solar Actually Costs Per Watt
Commercial systems are priced in dollars per watt of DC capacity, and the number depends heavily on system size, roof type, and electrical scope. The U.S. Department of Energy’s most recent published cost benchmarks put commercial rooftop installations in the range of roughly $1.40 to $1.80 per watt DC before any incentives are applied, with the spread driven mostly by racking type, electrical infrastructure, and project complexity rather than the panels themselves.
For a 100-kilowatt system — a reasonable size for a mid-size warehouse or retail building — that translates to roughly $140,000 to $180,000 installed, before incentives. A cold storage facility or grocery store running a larger rooftop array will see the per-watt price drop somewhat as the system scales, since fixed costs like permitting and interconnection get spread across more capacity. Get a site-specific quote rather than applying these benchmarks directly; roof condition, existing electrical service capacity, and shading all move the number in ways a general benchmark can’t capture.
The 30% Tax Credit Still Applies to Commercial — But the Rules Changed in July 2026
Here’s what hasn’t changed: the federal Investment Tax Credit under Internal Revenue Code Section 48E is still 30% for qualifying commercial solar projects. What changed is the timeline for qualifying.
Under the One Big Beautiful Bill Act, projects had until July 4, 2026 to establish “beginning of construction” — generally through the Physical Work Test described in IRS Notice 2025-42 — in order to lock in a four-year window to complete the project (generally by the end of 2030). That deadline has now passed. For any commercial project beginning construction after July 4, 2026 — which, as of this writing, means essentially any new project starting now — the credit is still available, but the project must be placed in service by December 31, 2027 to claim it. There’s no extension built into that date.
This matters for planning purposes more than it changes the credit amount itself: a business starting a commercial solar project today is working with roughly an 18-month runway to get the system installed and operational if it wants to claim the 30% credit. That’s a tight but workable window for a straightforward rooftop system; it’s a real constraint for a large ground-mount or multi-building project that needs permitting, utility interconnection approval, and equipment lead time. Projects also now need to account for foreign-sourcing content requirements that phase in under the same law — worth raising directly with your installer, since equipment selection affects eligibility.
Depreciation Now Works Differently Than It Used To
Before 2025, commercial solar equipment was typically depreciated using the Modified Accelerated Cost Recovery System (MACRS) over five years — a meaningful tax benefit, but one that took several years to fully realize. That changed under the same 2025 legislation. The IRS and Treasury Department confirmed permanent 100% bonus depreciation for qualifying property acquired after January 19, 2025, which means a business can generally deduct the full depreciable cost of a commercial solar system in the year it’s placed in service, rather than spreading it across five years.
There’s one wrinkle worth flagging rather than glossing over: when you claim the 30% ITC, the depreciable basis of the system is reduced by half the value of the credit before depreciation is calculated. In practical terms, that means you’re depreciating roughly 85% of the system’s cost, not 100% of it — still a substantial first-year deduction, just not quite the full price tag.
Running the Real Numbers: A Simplified Example
Take a $160,000 commercial system (100 kW at roughly $1.60/watt). The 30% ITC reduces your federal tax liability by $48,000, dollar for dollar, assuming sufficient tax liability to use it (unused credit can generally be carried back three years or forward for future years). The depreciable basis drops by half the credit amount — $24,000 — leaving roughly $136,000 eligible for depreciation. With 100% bonus depreciation, a business with sufficient taxable income could deduct that full $136,000 in year one.
Between the credit and the first-year depreciation deduction, many businesses recover a substantial share of the system’s cost through tax benefits alone in the first year, on top of whatever the system saves on utility bills going forward. The exact recovery depends entirely on your business’s tax position — how much taxable income you have to offset — so these figures are illustrative, not a projection for your specific business. A CPA who’s looked at your actual financials is the right person to run this for your situation.
What Actually Determines Your Price
Beyond the base per-watt number, a few factors move commercial solar pricing more than people expect:
- Roof type and condition. A flat commercial roof with ballasted racking is generally less expensive to install on than a roof requiring extensive structural reinforcement or a full tear-off first.
- Electrical service capacity. If your building’s existing electrical panel and service can’t handle the added capacity, a service upgrade adds real cost that a per-watt estimate won’t reflect.
- System ownership structure. A Power Purchase Agreement (PPA) shifts who claims the tax credit and depreciation — the PPA provider does, not your business — in exchange for no upfront capital cost. That’s a different financial calculation than ownership, not just a different price tag.
- Financing. Cash purchase, a commercial loan, and PACE financing (which ties repayment to a property tax assessment) all change your effective cost of capital and how quickly the system pays for itself.
If you want an accurate number instead of a rule-of-thumb range, that requires an actual site assessment — Pacific Solar has built commercial systems for grocery chains, cold storage facilities, and industrial operations across the Central Valley, and we’re glad to walk through what your specific building, roof, and tax situation actually look like.
Want a real number instead of a benchmark range? Contact Pacific Solar for a site-specific commercial solar quote.
Frequently Asked Questions
Is the commercial solar tax credit still 30% in 2026? Yes. Section 48E hasn’t changed rate-wise — what changed is the deadline for qualifying, since the July 4, 2026 safe-harbor window has now passed for new projects.
What if my business can’t use the full tax credit this year? Unused credit can generally be carried back three years or forward, subject to the usual IRS rules — worth confirming the specifics with your CPA.
Do I still get the tax credit if I sign a PPA instead of buying? No. Under a PPA, the provider owns the system and claims the ITC and depreciation, not your business.
How fast do I need to move to still qualify for the credit? Any project beginning construction now needs to be placed in service by December 31, 2027 to claim it — there’s no extension built into that date.