Solar Panel Depreciation Life: MACRS, Bonus, and ITC Basis

For tax purposes, the depreciation life of solar panels is five years. The IRS classifies solar energy equipment used in a trade, business, or income-producing activity as five-year property under the Modified Accelerated Cost Recovery System (MACRS), regardless of the panels’ physical lifespan of 25 to 30 years.¹ For systems placed in service after January 19, 2025, 100% bonus depreciation lets most business owners deduct the full depreciable basis in year one instead of spreading it across the five-year schedule.

Why Five Years

The five-year recovery period comes from Section 168(e)(3)(B) of the Internal Revenue Code, which designates solar electric generating equipment, along with other qualified clean energy property, as five-year property.¹ Tax depreciation has nothing to do with how long the equipment physically lasts. Congress set the accelerated timeline as an incentive for clean energy investment.

The classification covers a full system: the panels, inverters, wiring, and the monitoring equipment. Energy storage (batteries) placed in service after December 31, 2024, qualifies for the same five-year MACRS treatment under Provision 13703 of the Inflation Reduction Act.¹ A solar-plus-battery install follows one depreciation schedule.

First-Year Expensing in 2026

The One Big Beautiful Bill Act (Public Law 119-21), signed July 4, 2025, restored 100% bonus depreciation for qualifying business property placed in service after January 19, 2025.² For most solar installations going in during 2026, that means the full depreciable cost comes off in the first tax year. Before the new law, the first-year percentage had dropped to 60% in 2024 and was scheduled to fall to 20% in 2026.

Bonus depreciation applies automatically unless you elect out of it. There is no cap on the dollar amount, and the business does not need to have taxable income in the year the deduction is claimed. A large first-year deduction can create a net operating loss that carries forward.

Section 179 as an Alternative

Solar equipment also qualifies for the Section 179 deduction. For 2026, the maximum Section 179 deduction is $2,560,000, with a dollar-for-dollar phaseout once total qualifying property placed in service during the year exceeds $4,090,000.² The main difference from bonus depreciation: Section 179 can only reduce taxable business income to zero. It cannot create a loss. If your business income is less than the cost of the system, bonus depreciation is usually the better route because it has no income limitation.

Some taxpayers use Section 179 up to their taxable income limit and apply bonus depreciation to the remaining basis. With 100% bonus depreciation available, the combination mainly matters if the bonus percentage phases down again in a future year.

The ITC Trims Your Depreciable Basis

If you claim the federal Investment Tax Credit on the installation, you cannot depreciate the full purchase price. Section 50(c) of the Internal Revenue Code requires you to reduce the depreciable basis of energy property by 50% of the credit amount.³ This is the most commonly overlooked rule in solar tax planning, and getting it wrong overstates the deduction.

For a $200,000 system claiming a 30% ITC, the math runs like this:

ITC amount: $200,000 × 30% = $60,000 credit
Basis reduction: $60,000 × 50% = $30,000
Depreciable basis: $200,000 − $30,000 = $170,000 (85% of original cost)

With 100% bonus depreciation, you deduct $170,000 in year one and receive the $60,000 credit on top. Form 3468 instructions state the rule plainly: “You must reduce the basis of energy property by 50% of the energy credit determined.”⁴

One caveat on ITC availability. The One Big Beautiful Bill Act terminates the Section 48E Clean Electricity Investment Credit for facilities that begin construction more than 60 days after enactment (roughly September 2025) or are placed in service after December 31, 2028.² Verify current eligibility before assuming the basis adjustment applies to your project.

When the Clock Starts

Both depreciation and the ITC run from the date the system is “placed in service,” which is not necessarily the day panels go on the roof. The IRS treats property as placed in service when it is in a condition of readiness and availability for its assigned function, weighing five factors for solar:

All required local, state, and utility permits and licenses have been obtained
Control of the system has been handed from the installer to the owner
Critical performance tests have been completed
The system has been synchronized with the power grid
The system has begun producing power on a regular basis

No single factor is controlling, but a system that has passed final inspection and is generating power generally meets the standard. If an installation wraps up in late December, confirm all five factors are satisfied before year-end or the deductions and credit shift into the following tax year.

How MACRS Works If You Don’t Take Bonus

With 100% bonus depreciation applied, the rest of the depreciation mechanics are academic. They become relevant only if you elect out of bonus depreciation, or if the bonus percentage phases down in a future year.

The default method for five-year property is the 200% declining balance method, which front-loads deductions. The IRS also applies the half-year convention, treating the property as placed in service at the midpoint of the year.⁵ The practical effect is that deductions actually span six tax years: a half year at the start, and the trailing half year in year six.

Watch for one exception. If more than 40% of all depreciable property you place in service during the year goes into service during October through December, the mid-quarter convention replaces the half-year convention. Solar jobs often close near year-end, and the mid-quarter rule produces a smaller first-year deduction for fourth-quarter property.

Who Can Depreciate the System

Depreciation is available only for solar equipment used in a trade or business or to produce income. Commercial buildings, warehouses, farms, and rental properties qualify. A system on your personal residence does not; this is a fundamental requirement of the depreciation rules, not a technicality you can work around.

Homeowners should also note that the Residential Clean Energy Credit under Section 25D is not available for property placed in service after December 31, 2025, per IRS guidance implementing the One Big Beautiful Bill Act.⁶

Mixed Business and Personal Use

When panels serve both business and personal purposes, such as a home with a dedicated office or a rented portion, the cost is split proportionally. If a home office occupies 15% of the home’s square footage, 15% of the system’s cost is eligible for depreciation. The remaining 85% is personal-use property. You cannot claim both depreciation and a tax credit on the same portion of the cost.

Recapture If You Sell or Convert the System

Taking a big first-year deduction is not free money if you later dispose of the system. Two separate recapture rules can claw back benefits.

Depreciation Recapture

Solar panels are personal property for tax purposes and fall under Section 1245. If you sell the system or the property it sits on, any gain attributable to depreciation previously claimed is taxed as ordinary income rather than at the lower capital gains rate.⁷ If you deducted the full $170,000 depreciable basis on a $200,000 system through bonus depreciation and later sold the property at a gain, up to $170,000 of that gain is taxed at ordinary rates. This is the trade-off for accelerated depreciation.

ITC Recapture

The ITC has a separate five-year vesting period. If you dispose of the system or change its use (for example, converting from business to personal use) before five full years, you must pay back a share of the credit on Form 4255:⁸

Within year 1: 100% recaptured
Year 2: 80%
Year 3: 60%
Year 4: 40%
Year 5: 20%
After five full years: none

The recaptured amount is added directly to your tax bill in the year of disposition. Selling two years in with an original $60,000 ITC produces an extra $36,000 of tax (60% of $60,000).

Where the Deduction Goes on Your Return

Depreciation is calculated and claimed on Form 4562, Depreciation and Amortization. This is where you specify the five-year recovery period, elect or opt out of bonus depreciation, and make any Section 179 election. The total then flows to the operating return:⁵

If you claim the ITC, also file Form 3468 (Investment Credit), and reflect the 50% basis adjustment on your depreciation schedule in Form 4562. Form 3468 instructions require an accounting of your basis in the energy property and a depreciation schedule showing the remaining basis after the credit.⁴

Keep every document that supports your depreciable basis and placed-in-service date: the installation contract, invoices, proof of payment, interconnection agreement, permit approvals, and the installer’s certificate of completion. Given the five-year ITC recapture window and audit risk, plan on holding these records for at least seven years after the system is placed in service.⁴

1
Internal Revenue Service. Cost Recovery for Qualified Clean Energy Facilities, Property and Technology
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Internal Revenue Service. One, Big, Beautiful Bill Provisions
3
Office of the Law Revision Counsel. 26 U.S. Code 50 – Other Special Rules
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Internal Revenue Service. 2025 Instructions for Form 3468
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Internal Revenue Service. 2025 Instructions for Form 4562 – Depreciation and Amortization
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Internal Revenue Service. FAQs for Modification of Sections 25C, 25D, 25E, 30C, 30D, 45L, 45W, and 179D Under Public Law 119-21
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Office of the Law Revision Counsel. 26 U.S. Code 1245 – Gain from Dispositions of Certain Depreciable Property
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Internal Revenue Service. Instructions for Form 4255 – Certain Credit Recapture, Excessive Payments, and Penalties
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Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship)
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Internal Revenue Service. Topic No. 414, Rental Income and Expenses
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Internal Revenue Service. Instructions for Form 1120 (2025)