Carrying Forward Unused Solar Tax Credits — A Landlord's Guide

TL;DR: A solar tax credit that's bigger than your tax bill for the year isn't wasted. Most residential and business energy credits are nonrefundable, which means any unused portion carries forward to a future tax year rather than being lost. The rules for how long you can carry it, and whether the credit even applies to your equipment's placed-in-service date, have changed recently — confirm the current version on IRS.gov before you file.

_Last reviewed: August 2026 · 7 min read_

You installed solar panels, expected a nice credit, and then found out your tax liability wasn't big enough to use all of it in one year. That's a common problem, and it's not a lost cause. Here's how carryforward actually works for landlords and homeowners.

Okoniq Property Hub keeps a running log of energy-improvement costs, placed-in-service dates, and credit amounts claimed each year, so a multi-year carryforward doesn't turn into a guessing game at tax time.

What does it mean to "carry forward" a solar tax credit?

It means the part of the credit you couldn't use this year moves to next year's return instead of vanishing. Nonrefundable credits can only reduce your tax bill down to zero — they can't generate a refund beyond what you owe. If the credit is larger than your liability, the excess rolls forward and reduces next year's bill, and the year after that if needed.

This is different from a deduction, which lowers taxable income, or a refundable credit, which can produce a check even at zero liability. Solar credits fall into the nonrefundable category, which is exactly why carryforward exists as a mechanism. The specific number of years you're allowed to carry the credit, and whether newer legislation has changed eligibility for equipment placed in service after a certain date, are details you should confirm directly on IRS.gov or with a CPA — this is an area where rules have shifted recently, and stating an old number here would do you more harm than good.

How is a rental property's solar credit different from a homeowner's?

The path depends on whether the property is your residence or a rental you operate as a business. Homeowners generally claim a residential clean energy credit on their personal return. Landlords who install solar on a rental property typically look at the business energy credit rules instead, tied to the property being used in a trade or business.

That distinction matters for record-keeping and for how the credit interacts with depreciation. If you're deciding whether a solar installation counts as a capital improvement versus a repair for tax purposes, the capitalize vs expense decision tree walks through the four questions that settle it — and a rooftop solar array is almost always a capital improvement, not a deductible repair.

How does carrying forward a credit interact with bonus depreciation?

They stack, but you have to track the basis reduction carefully. Under the One Big Beautiful Bill, qualified property acquired after January 19, 2025 can qualify for 100% additional first-year depreciation, made permanent — no more phase-down schedule. If your solar equipment qualifies as depreciable business property on a rental, you may be able to depreciate the full cost in the year it's placed in service while also claiming an energy credit on the same asset, subject to a basis adjustment that reduces the depreciable basis by a portion of the credit claimed.

This is one of those situations where two tax benefits touch the same dollar, and getting the order of operations wrong overstates your deduction. Read how bonus depreciation actually works now before you assume the old 40%-phasing-to-20% schedule still applies — it doesn't. And the form that reports both regular depreciation and any bonus depreciation election is Form 4562; see Form 4562 depreciation explained for how landlords fill it out correctly.

| | Residential clean energy credit | Business energy credit (rental) | |---|---|---| | Who claims it | Homeowner, personal return | Landlord, business return | | Interacts with depreciation | No | Yes — basis adjustment required | | Carryforward if unused | Rolls to future years | Rolls to future years, general business credit rules | | Confirm current figures | IRS.gov, before filing | IRS.gov, before filing |

What records do you need to justify a multi-year carryforward?

You need the original invoice, the placed-in-service date, the credit amount claimed in year one, and a running total of what's carried forward each subsequent year. If an auditor pulls your return three years after installation, they'll want to see the paper trail connecting the original purchase to the current-year credit you're claiming — not just a number on a form. The audit trail checklist covers what examiners typically ask for and how to keep it organized without drowning in paperwork.

Keep the manufacturer's spec sheet, the contractor's invoice showing the installation date, and a copy of every prior-year return where you claimed a piece of the credit. If you're also depreciating the equipment on a rental, cross-reference the Form 4562 entries year over year so the carryforward math lines up with the depreciation schedule.

What happens if I sell the rental property before using the full credit?

Selling before you've absorbed the full carryforward complicates things, and the answer depends on which credit you're using and current statute. Some credit carryforwards are tied to the taxpayer, not the property, meaning you may still be able to use the remaining balance on future returns even after the sale — but this is exactly the kind of detail where a stale number or assumption from a few years ago can be wrong today. Don't rely on memory or a forum post. Confirm with a CPA before you close, especially if depreciation recapture is also in play; the depreciation recapture at sale post explains how recapture is calculated separately from any leftover credit.

FAQ

Do unused solar tax credits expire?

Nonrefundable credits generally carry forward rather than expire outright, but the exact number of years allowed and any sunset provisions depend on the specific credit and current law. Confirm the carryforward window on IRS.gov before assuming it's indefinite.

Can I claim a solar credit on a rental property I also depreciate?

Often yes, but the credit reduces the depreciable basis of the equipment, so you can't claim the full cost as both a 100% credit and a 100% depreciation deduction on the same dollars. Track the basis adjustment on Form 4562.

What's the difference between a tax credit and a tax deduction for solar?

A credit reduces your tax bill dollar for dollar; a deduction only reduces taxable income, which is worth less depending on your bracket. That's why an unused, nonrefundable credit carrying forward is more valuable to protect than a missed deduction.

Does installing solar count as a repair or a capital improvement?

It's a capital improvement in nearly every case, since it adds value and a new system to the property rather than restoring something that broke. That classification affects whether you depreciate the cost or try to expense it immediately.

Do I need a CPA to handle a multi-year solar credit carryforward?

You don't strictly need one, but the interaction between the credit, bonus depreciation, and any sale of the property has enough moving parts that a CPA familiar with current energy-credit rules is worth the fee for most landlords.

<div class="glass rounded-2xl p-5 mt-7 max-w-4xl border border-red-400/30 bg-red-500/5"> <div class="flex items-start gap-3"> <span class="text-2xl flex-shrink-0">⚠️</span> <div class="flex-1 min-w-0"> <p class="text-red-200 text-sm font-bold">Not tax advice</p> <p class="text-slate-300 text-xs mt-1 leading-relaxed"> This post assumes a general understanding of nonrefundable federal energy credits and how they interact with bonus depreciation for rental property, without stating a specific credit percentage, carryforward year count, or eligibility cutoff date since those have changed recently and weren't independently verified here. It does not account for your state's credits or rebates, your entity type, or legislation passed after July 2026. Tax rules change and depend on your specific situation. Talk to a licensed CPA before acting on anything here, and confirm current figures on IRS.gov. </p> </div> </div> </div>