Federal Investment Tax Credit (ITC) for Arizona Solar Installations

The federal Investment Tax Credit (ITC) is the primary federal financial mechanism reducing the net cost of solar photovoltaic installations across the United States, including Arizona. This page covers the ITC's statutory basis, how the credit is calculated and applied against federal tax liability, common scenarios specific to Arizona residential and commercial projects, and the decision boundaries that determine eligibility. Understanding the ITC is foundational to evaluating the full economics of any Arizona solar project, alongside state-level programs detailed in Arizona Solar Tax Credits and Incentives.

Definition and scope

The Investment Tax Credit for solar energy is established under Internal Revenue Code Section 48 (commercial) and Section 25D (residential), as modified by the Inflation Reduction Act of 2022 (Pub. L. 117-169). The credit reduces federal income tax liability dollar-for-dollar by a percentage of the eligible installed cost of a qualifying solar energy system.

For residential installations, Section 25D governs, and the ITC rate is 30% of the total system cost for systems placed in service from 2022 through 2032 (IRS Notice 2023-29; IRS Form 5695 Instructions). The rate steps down to 26% in 2033 and 22% in 2034, unless Congress acts to extend or modify the schedule.

For commercial and business-owned systems, Section 48 applies, with the base credit rate at 30% for projects meeting domestic content and prevailing wage/apprenticeship requirements under the Inflation Reduction Act. Systems that do not meet those conditions may qualify for a lower baseline rate. The commercial credit is fully transferable and can be monetized through direct pay in certain circumstances, per IRS guidance.

Scope limitations of this page: This page addresses the federal ITC as it applies to Arizona-based solar installations. It does not address Arizona's separate state income tax credit (governed by A.R.S. § 43-1083.01 for residential), Arizona's sales tax exemption, or property tax exemptions — those fall under distinct statutory frameworks. The ITC is administered by the U.S. Internal Revenue Service (IRS), not by Arizona's Department of Revenue or any Arizona utility. Situations involving partnerships, REITs, tax-exempt entities, or passive activity limitations fall outside the scope of this page.

How it works

The ITC reduces the amount of federal income tax owed in the tax year the system is placed in service — meaning the system is installed, passes inspection, and is operational. For Arizona residential systems, this typically aligns with the date a utility interconnection approval is received and the system is energized, a process detailed under Arizona Utility Interconnection Process.

The credit is non-refundable under Section 25D for residential filers: if the credit exceeds tax liability in the year of installation, the unused portion carries forward to subsequent tax years. Under Section 48 for commercial systems, carryback and carryforward provisions apply per IRC §39.

Eligible costs include:

Solar PV panels and modules
Inverters (string, microinverter, or power optimizer)
Racking, mounting hardware, and structural attachments
Wiring and electrical balance-of-system components
Battery storage systems when charged exclusively by solar, per IRS guidance effective from the Inflation Reduction Act (standalone storage becomes eligible for the ITC in 2023 under Section 48)
Installation labor costs (permits, inspection fees, and installer labor)
Sales tax on eligible equipment

Costs not included in the ITC basis: roof repair or replacement undertaken separately from the solar installation, structural upgrades unrelated to mounting, and landscaping.

The credit is claimed on IRS Form 5695 (residential) or IRS Form 3468 (commercial) as part of the annual federal income tax return for the year the system is placed in service.

For a technical grounding in what components constitute a complete system, see the Arizona Solar Equipment Components Guide and the conceptual overview of how Arizona solar energy systems work.

Common scenarios

Scenario 1 — Residential homeowner, system fully owned:
An Arizona homeowner purchases and owns a 10 kW rooftop system with a total installed cost of $28,000. The 30% ITC yields a $8,400 federal tax credit. If the homeowner's federal tax liability in the installation year is $6,000, $6,000 is applied in year one and $2,400 carries forward to the following year.

Scenario 2 — Residential homeowner, loan-financed system:
Financing through a solar loan does not disqualify the ITC. The homeowner retains ownership of the system, allowing the 30% credit to apply to the full system cost. Lease and power purchase agreement (PPA) arrangements differ substantially; a comparison is provided in the subsequent section.

Scenario 3 — Commercial Arizona business, owned system:
A Phoenix-area commercial property owner installs a 150 kW ground-mounted system under Section 48. If the project meets prevailing wage and apprenticeship requirements under IRS Notice 2022-61, the 30% rate applies. Without meeting those requirements (projects under 1 MW may qualify for an exception), the base credit could differ. Commercial owners should review Residential Solar vs. Commercial Solar in Arizona for classification distinctions.

Scenario 4 — Adding battery storage:
An Arizona homeowner adds a battery storage system to an existing solar installation. Under the Inflation Reduction Act, standalone batteries placed in service after December 31, 2022, qualify for the ITC independently, provided they meet minimum capacity requirements. Previously, batteries were only eligible when charged entirely by co-located solar.

Decision boundaries

Ownership vs. third-party arrangements:
The ITC under Section 25D is available only to the system owner. Homeowners who enter into a solar lease or PPA do not own the system — the third-party developer does, and the developer claims the commercial ITC (Section 48). This is the single most consequential eligibility boundary in residential solar financing. The Arizona Solar Financing Options page covers the structural differences across ownership models.

Placed-in-service requirement:
A system that has been purchased but not yet inspected, approved, and energized does not qualify for the ITC in that tax year. Arizona's permitting and inspection framework — which requires municipal or county building permit issuance and final inspection sign-off before a utility will issue interconnection approval — directly governs when a system is considered placed in service.

Tax liability threshold:
The residential ITC is non-refundable. Homeowners with insufficient federal tax liability to absorb the credit in one year must carry it forward. Retirees with low taxable income, for example, may take multiple years to fully utilize a large credit. The commercial credit under Section 48 has broader monetization options including transferability.

New construction vs. existing homes:
The ITC applies to solar systems installed on new construction as well as existing homes. However, for new construction the placed-in-service date must coincide with when the homeowner occupies the residence — not the builder's construction completion date.

Geographic scope of this page:
The ITC is a federal credit with national applicability. This page frames the ITC specifically in the context of Arizona installations, Arizona permitting timelines, and Arizona utility interconnection procedures. The regulatory context for Arizona solar energy systems provides additional framing on how federal, state, and utility-level rules interact. The Arizona solar authority home situates the ITC within the broader Arizona solar decision landscape.

Interactions with Arizona Public Service, Salt River Project, and Tucson Electric Power net metering billing — which affect the financial model alongside the ITC — are addressed separately under Arizona Net Metering Policies and Utility Billing.

References

📜 6 regulatory citations referenced · ✅ Citations verified Feb 28, 2026 · View update log