Bonus Depreciation: Residential Rental vs. Commercial Property

The One Rule That's Identical for Both

Section 168(k) bonus depreciation doesn't ask what kind of building a component sits inside. It asks one question: does the property have a recovery period of 20 years or less? A cabinet in a single-family rental and a walk-in cooler's electrical hookup in a restaurant both answer that question the same way, yes, and both qualify for the identical bonus rate. Under the 2025 OBBBA law, that rate is 100% for qualifying property acquired after January 19, 2025.

Writing the rule around the asset rather than the building type keeps a classification argument, residential or commercial, from ever becoming a gate an owner has to clear before reaching the deduction that actually moves a return. A component either carries a recovery period of 20 years or less or it doesn't; the building around it never enters that particular calculation.

5-Year7-Year15-Year27.5/39-Year Shell

1. 1Carpet and flooring
2. 2Cabinets and appliances
3. 3Curtains
4. 4Lamps and light fixtures

1. 1Bedroom furniture
2. 2Sofa and armchairs
3. 3Coffee table
4. 4Dining table and chairs

1. 1Driveway and walkway
2. 2Fencing
3. 3Landscaping
4. 4Deck

1. 1Roof
2. 2Exterior and load-bearing walls
3. 3Foundation
4. 4Central HVAC

5-Year: carpet and flooring, cabinets, appliances, light fixtures, curtains

7-Year: furniture

15-Year: driveway, fencing, landscaping, deck

27.5/39-Year Shell: roof, load-bearing walls, foundation, central HVAC

Where They Split: The Building's Own Schedule

Residential rental property, a building where 80% or more of gross rental income comes from dwelling units, depreciates its structural shell over 27.5 years. Commercial and other nonresidential real property depreciates its shell over 39 years. That difference sits entirely outside the bonus depreciation question; it governs only the portion of the building a cost segregation study does not reclassify.

The line isn't always obvious at a glance. Small multifamily properties, typically four units or fewer held as rentals, generally fall under residential rules the same as a single-family home would, while a five-unit building or a mixed-use property with ground-floor retail can shift toward nonresidential treatment depending on the specific income mix. That determination sits with the owner's CPA, working from the building's actual rent roll rather than its unit count alone.

Side by Side: Two Real Studies

Two benchmark studies our engineering team produced show how the identical rule plays out differently across property types: a single-family rental in Montgomery County, Pennsylvania, and a commercial office/warehouse building.

Both studies ran the identical bonus depreciation rule against the components they found. The residential property's smaller fee against a smaller basis produced a far bigger multiple; the commercial property's larger basis produced far bigger absolute dollars on a smaller multiple, the pattern we describe as a smaller multiple, far bigger dollars, for large commercial buildings.

Turnaround differs by the same split. A residential study like the one in this table normally takes 1 to 2 weeks, 2 to 3 weeks during tax season. A commercial study runs 4 to 6 weeks during tax season and typically 2 to 3 weeks in January and February, reflecting the larger site engineering a commercial building requires.

Why the Bucket Mix Looks Different

A single-family rental's reclassified basis leans toward finishes: flooring, cabinetry, appliances, decorative lighting, window treatments, plus the site work around a house, a driveway, landscaping, a patio. A commercial building, depending on type, often carries more of its reclassified basis in 15-year land improvements, parking lots, site utilities, exterior lighting, at a scale a single-family lot doesn't have, plus specialty electrical and plumbing serving commercial equipment. How the mix shifts by property type breaks this down across more categories, restaurants, medical offices, warehouses, and multifamily.

A mid-rise office building shows a third pattern between those two extremes: a $2,971,345 basis producing $479,220 in first-year deductions, a 39.9:1 ratio against a $12,000 fee. That basis leans on common-area finishes, elevator-serving equipment, and a parking structure a mid-rise carries, a different mix again from a warehouse's simpler shell or a single-family home's cabinetry and flooring.

Why the Ratio Runs Backwards From the Dollars

Real commercial samples in our benchmark set run 24:1 to 67:1 in deductions-to-fee, while short-term rental studies at a lower residential fee routinely run 100:1 and higher. That's not commercial property underperforming; a commercial study fee reflects a bigger, more complex building, and the first-year dollars it produces are correspondingly larger even at a smaller multiple.

Put dollars next to ratio and the pattern is easy to see: the residential property's 135:1 multiple sits on $174,905 in first-year deductions, while the office/warehouse building's 33.4:1 multiple sits on $330,674, nearly double the dollars at a quarter of the ratio. Neither number is more "correct" than the other; they're measuring different things about buildings of very different scale.

The wider benchmark set shows the same pattern from a different angle. A free-standing restaurant identified $599,678 in first-year deductions against a $2,804,440 basis, a 66.6:1 ratio on a $9,000 fee, while a medical clinic identified $241,839 against a $1,404,500 basis, a 24.2:1 ratio on a $10,000 fee. Two similar fees, a $357,839 gap in first-year dollars, driven entirely by basis and bucket mix, not by a different bonus depreciation rate.

What Doesn't Split: Where the Deduction Comes From

Whether the building is a single-family rental or a mid-rise office, the first-year deduction always comes from the same two sources: the current year's depreciation on newly reclassified components under bonus rules, and, on a property already owned for years, a section 481(a) catch-up for the depreciation missed in prior years, claimed through a Form 3115 look-back study. Neither source cares whether the building is 27.5-year or 39-year property, because both sources are defined at the component level described throughout this page, not at the building-classification level.

The Practical Takeaway for an Owner Choosing Where to Look First

An owner deciding whether a cost segregation study is worth commissioning on a specific property is really asking about basis and bucket mix, not building type. A high-basis commercial building and a modest single-family rental can both produce a strong result; they just produce it on different scales and different multiples. The underlying bonus depreciation rule treats both the same way from the moment a study identifies the components.

The building-type question is worth asking for a different reason: it sets expectations for what kind of result to expect, a residential rental more likely to land a triple-digit multiple on modest dollars, a large commercial building more likely to land a smaller multiple on a much bigger number. Both are the same rule doing the same job on different-sized buildings.

Frequently asked questions

Does a commercial property get a higher bonus depreciation rate than a residential rental?

No. The rate is identical, 100% for qualifying property acquired after January 19, 2025 under current law, regardless of whether the building itself is residential or commercial. The rate attaches to the component's recovery period, not the building's classification.

Why do residential rental studies show higher deductions-to-fee multiples than commercial studies?

Residential studies typically carry a lower flat fee against a smaller building basis, which produces a bigger ratio even when the dollar total is modest. Commercial studies carry a larger fee against a larger, more complex building, producing bigger absolute dollars at a comparatively smaller multiple.

Do multifamily properties follow the residential or commercial rules?

It depends on the building. Small multifamily properties, typically four units or fewer held as rentals, generally follow residential rules if 80% or more of gross rental income comes from dwelling units; larger multifamily and mixed-use buildings can involve nonresidential treatment depending on the specific facts, a question for the owner's CPA.

Does the type of building change which components a study looks for?

The categories, 5-year, 7-year, and 15-year property, are the same list either way. What changes is which categories show up in meaningful amounts: a restaurant's kitchen-serving electrical looks different from a single-family home's cabinetry, even though both get evaluated against the identical classification rules.

Is a cost segregation study worth it on a smaller residential rental if a commercial building produces bigger dollars?

The two aren't in competition for the same money; each property is evaluated on its own basis and its own components. A modest residential property with a fee well under a commercial study's cost can still produce a large multiple relative to what it cost, even though the absolute dollars are smaller than a large commercial building would produce.

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