What Is Qualified Real Property for Section 179?

Qualified real property under Section 179 is a defined set of improvements to nonresidential buildings that a business can deduct in full the year the work is placed in service, rather than depreciating it over decades. It covers four specific building systems — roofs, HVAC, fire protection and alarms, and security systems — plus a broader category called qualified improvement property (QIP), which is most interior work on a nonresidential building. For tax years beginning in 2026, a business can expense up to $2,560,000 of Section 179 property, including qualified real property, subject to a phase-out and a taxable income limit.¹

What Counts as Qualified Real Property

The statute splits qualified real property into two groups. The first is four named systems installed in a nonresidential building after the building itself was originally placed in service:¹

Roofs, including full replacements and significant roof work on a commercial building.
HVAC equipment — heating, ventilation, and air-conditioning systems serving the building.
Fire protection and alarm systems, such as sprinklers, smoke detectors, alarms, and suppression equipment.
Security systems, including surveillance cameras, access-control hardware, and alarm monitoring.

The second group is qualified improvement property: any improvement a taxpayer makes to the interior of a nonresidential building, placed in service after the building was first put to use.² Renovating a retail showroom, reconfiguring office space, or replacing flooring and lighting throughout a warehouse all fit. QIP is intentionally broad and captures most interior remodel work that isn’t in one of the excluded categories below.

Both new and used components qualify, as long as you acquire the property by purchase and not from a related party, by gift, or by inheritance. A used commercial HVAC unit from a liquidation sale is treated the same as a brand-new system.

When the Property Is Placed in Service

The placed-in-service date, not the purchase or construction date, controls which year you deduct. Property is placed in service when it is ready and available for its intended use, even if you haven’t started using it yet.³ A new HVAC system installed in November but not switched on until December is placed in service in November if it was operational and available then.

The Building Has to Be Nonresidential

Every category of qualified real property shares one hard requirement: the building receiving the improvement must be nonresidential real property. The code defines that as Section 1250 property that is not residential rental property and does not have a class life under 27.5 years.⁴ Offices, retail stores, warehouses, restaurants, and medical facilities all count.

A building becomes residential rental once 80 percent or more of its gross rental income comes from dwelling units. A new roof on an apartment complex is not qualified real property. Hotels and motels are treated as nonresidential when more than half the units are rented on a transient basis.

Property used mainly to furnish lodging is generally off-limits for Section 179, with exceptions for transient hotels and motels and for nonlodging commercial facilities inside a lodging property that are equally available to the public.

What Doesn’t Qualify

Three kinds of building work are specifically excluded from QIP and cannot be expensed under Section 179:²

Building enlargement — adding square footage, a new wing, or an expanded footprint.
Elevators and escalators, whether installed new or replaced.
Internal structural framework — load-bearing walls, columns, floors, and ceilings that form the building’s skeleton.

The structural framework exclusion trips people up. New drywall over existing framing qualifies as QIP; removing a load-bearing wall and installing a steel beam does not. The line is between finishing or updating the interior within the existing framework and altering the skeleton. Excluded work has to be capitalized and depreciated over the building’s standard 39-year recovery period.³

2026 Dollar Limits

The One, Big, Beautiful Bill (OBBB), signed in 2025, permanently doubled the Section 179 base limits and indexed them for inflation. Three caps apply for tax years beginning in 2026:

Maximum deduction: $2,560,000 across all Section 179 property, including qualified real property.
Phase-out threshold: the deduction shrinks dollar-for-dollar once total Section 179 property placed in service during the year exceeds $4,090,000.
Full elimination: the deduction disappears entirely at $6,650,000 in qualifying purchases.

Then there’s the taxable income limit. Your Section 179 deduction can’t exceed the total taxable income you earned actively running your business. If the business nets $200,000 and you placed $500,000 of qualified real property in service, your Section 179 deduction for the year tops out at $200,000. The unused $300,000 doesn’t disappear. It carries forward and can be deducted in a later year when there’s enough business income to absorb it.¹

Section 179 and Bonus Depreciation on the Same Property

Section 179 and bonus depreciation are separate mechanisms that can apply to the same qualified real property. Section 179 is an election you affirmatively make. Bonus depreciation applies automatically to eligible property unless you opt out.⁵ The OBBB restored the bonus rate to a permanent 100 percent for qualified property acquired after January 19, 2025, so for most property placed in service in 2026, bonus depreciation alone can wipe out the full cost.⁶ Qualified real property has a 15-year MACRS recovery period, which makes it eligible for bonus depreciation.³

Why bother with Section 179 when bonus is 100 percent? Flexibility. Section 179 lets you choose how much to expense on each asset, which is useful when you’re trying to shape taxable income across years. Bonus depreciation is all-or-nothing by class of property: full allowance or elect out. Section 179 also has no acquisition-date cutoff tied to January 2025.

When you use both on the same property, the IRS requires a fixed order. Apply Section 179 first, then bonus depreciation on the remaining basis, then regular MACRS on anything left.³ If you elect out of both, you depreciate over 15 years under MACRS.

One planning point worth keeping in mind: bonus depreciation has no taxable income cap, so it can create or deepen a net operating loss. Section 179 cannot. A low-profit year is often a reason to skip the Section 179 election and lean on bonus depreciation instead, generating a loss that can be carried to other tax years.

How to Make the Election

You claim Section 179 by completing Part I of IRS Form 4562, Depreciation and Amortization.⁷ List each item of qualified real property, its cost, and the amount you’re electing to expense. Only the business-use portion qualifies, and the property must be used more than 50 percent in your trade or business.⁸

You can make the election on your original return for the year the property was placed in service, or on an amended return filed within the time allowed by law, including extensions.⁹ If you missed the election on your original return, an amended return filed before the deadline can still preserve it. You can also revoke a previously elected amount, but you can’t make a fresh Section 179 election on those same revoked dollars for the same property.

Keep original invoices, contracts, completion certificates, and documentation of the date the improvement became ready for use. For a roof, your records should show the work was done on a nonresidential building already in service. For interior QIP, they should confirm the improvement didn’t involve enlargement or structural framework changes.

Recapture If Business Use Drops or You Sell

The first-year write-off comes with strings attached. If the property’s business use falls to 50 percent or less at any point during its recovery period, you have to recapture part of the deduction as ordinary income in the year the change happens.³ The recaptured amount is the difference between what you deducted under Section 179 and what you would have deducted under standard MACRS for the same period. Report recapture on IRS Form 4797, Sales of Business Property.

Selling or otherwise disposing of the property also triggers recapture. Gain attributable to prior Section 179 deductions is taxed as ordinary income, not capital gains. Destruction, theft, and other involuntary conversions count as dispositions too, so insurance proceeds on a destroyed asset can create a recapture event if they exceed the adjusted basis.³ If you’re not confident you’ll hold the property through its 15-year recovery period, weigh the first-year benefit against the recapture risk.

Check Your State Rules Before You Count the Savings

Federal Section 179 treatment does not automatically carry over to the state return. A significant number of states decouple from the federal limits and impose their own lower caps, some as low as $25,000. Others allow higher amounts but still well under the federal figure, and a few disallow a percentage of the federal deduction and require you to add it back over several years.

A business that expenses $500,000 of qualified real property federally might deduct only $25,000 on the state return, with the rest depreciated over a longer period. Check your state’s conformity before you build the Section 179 deduction into cash-flow projections. The gap can meaningfully change your actual tax savings.

1
Office of the Law Revision Counsel. 26 USC 179 – Election To Expense Certain Depreciable Business Assets
2
LII / Legal Information Institute. Definition: Qualified Improvement Property From 26 USC 168(e)(6)
3
Internal Revenue Service. Publication 946 (2024), How To Depreciate Property
4
LII / Legal Information Institute. Definition: Nonresidential Real Property From 26 USC 168(e)(2)
5
Internal Revenue Service. IRS, Treasury Issue Guidance on Making or Revoking the Bonus Depreciation Elections
6
Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One, Big, Beautiful Bill
7
Internal Revenue Service. About Form 4562, Depreciation and Amortization (Including Information on Listed Property)
8
Internal Revenue Service. 2025 Instructions for Form 4562, Depreciation and Amortization (Including Information on Listed Property)
9
eCFR. 26 CFR 1.179-5 – Time and Manner of Making Election