Real Estate Tax Calc
5-year and 7-year personal property
The highest-value reclassifications move building components to 5-year or 7-year property, where they can be paired with bonus depreciation for a large first-year deduction. Examples of 5-year personal property: specialty or decorative light fixtures (distinct from the building's base electrical), removable flooring installed over a subfloor (carpet and luxury vinyl plank tile), casework (non-structural built-in cabinets), outlet receptacles installed specifically for equipment, security and surveillance systems, and window treatments. Examples of 7-year personal property: freestanding office furniture, certain food-service equipment, and specialized fixtures in restaurants or retail.
The key question for any component is whether it is a structural component of the building or something that could be removed without damaging the building. Items serving a general building function (load-bearing walls, central HVAC, general plumbing) stay at 27.5 or 39 years.
15-year land improvements
15-year property includes all improvements to land that are separate from the building structure. Common items: parking lots and paved driveways, sidewalks, curbing and gutters, landscaping (including grading for drainage), exterior freestanding lighting, fencing, swimming pools, decorative water features, retaining walls, site utilities placed outside the building footprint, and outdoor signage bases. These components use the 150% declining balance method and are eligible for bonus depreciation.
In a typical suburban office building or retail center, 15-year land improvements alone may represent 8–15% of total project cost — and they depreciate at roughly twice the speed of 39-year property.
What stays at 27.5 or 39 years
Structural and mechanical components that serve the building as a whole remain at the building's standard recovery period: load-bearing exterior and interior walls, concrete slab or structural floor, roof structure and decking, central HVAC system (air handling units, ductwork, chillers serving the whole building), elevators and escalators, fire suppression (sprinklers), plumbing mains and risers, and the general building electrical distribution system. These are the non-negotiable long-life assets that cost segregation cannot touch.
How the engineer actually finds these components
A defensible study is not a spreadsheet estimate — it is an engineering-based analysis following the methodology in the IRS Cost Segregation Audit Techniques Guide. The engineer reviews construction blueprints, the general contractor's cost breakdown (AIA pay applications, change orders), the purchase-price allocation, and, ideally, performs a physical site inspection to measure and document each component. For an existing building bought without detailed cost records, the engineer reconstructs costs using recognized estimating references (such as RSMeans data) and photographs to support each reclassification.
The output is an asset-by-asset schedule: every reclassified item, its estimated cost, its recovery period (5, 7, or 15 years), its Code section (1245 or 1250), and the documentation supporting the number. This paper trail is the point — it is what lets your CPA place the assets on the correct schedules and what defends the allocations if the IRS examines the return. A 'rule of thumb' percentage with no engineering support is exactly what an auditor disallows.
Typical reclassification percentages by property type
How much of a building shifts to shorter lives depends heavily on property type. As rough ranges from engineered studies: apartment buildings typically move 20%–35% of depreciable basis into 5-, 7-, and 15-year property; office buildings often land around 25%–40%; retail and restaurants frequently reach 30%–50% because of specialty finishes, signage, and dedicated equipment; and hotels, medical, and manufacturing facilities can exceed 50% thanks to heavy specialty systems. Simple single-tenant warehouses sit at the low end because they are mostly structural shell.
These are planning ranges, not promises — the actual result turns on the specific building's finishes and the quality of the cost records. A property with more decorative, tenant-specific, and site improvements yields a larger reclassification than a plain box.
Why the 1245 vs. 1250 label matters at sale
Every reclassified component carries a Code-section label that determines how it is taxed when you sell. The 5- and 7-year personal-property items are Section 1245 property: their depreciation is recaptured as ordinary income at your regular rate — no 25% cap. The 15-year land improvements are Section 1250 property, but because they use the 150% declining-balance method (and often bonus depreciation), they can generate 'additional depreciation' that is also recaptured as ordinary income, with the balance falling into the 25%-capped unrecaptured Section 1250 gain.
The trade-off is deliberate: cost segregation converts slow 27.5-/39-year deductions into fast ones, accepting some ordinary-rate recapture later in exchange for years of tax deferral and time-value benefit. The study report, by preserving each component's original cost and class, is what lets you compute that recapture correctly — and it is essential if you later do a partial disposition or a 1031 exchange.
Bonus depreciation supercharges the reclassified components
Reclassification is valuable on its own — a parking lot on a 15-year schedule beats a 39-year one — but the real firepower comes from pairing it with bonus depreciation, which applies to property with a MACRS recovery period of 20 years or less. That covers every 5-, 7-, and 15-year component a study identifies, but never the building shell itself. Under the One Big Beautiful Bill Act, 100% bonus depreciation was permanently restored for qualifying property acquired and placed in service after January 19, 2025 (IRS Notice 2026-11 provides interim guidance and a transition election back to the prior 40% rate for the first year).
The effect is dramatic. If a study reclassifies $300,000 of components on a newly acquired property, 100% bonus lets you deduct the entire $300,000 in year one instead of spreading it over 5–15 years. Two cautions: the passive activity loss rules still limit whether you can use the resulting loss against non-rental income unless you qualify as a real estate professional or have a qualifying short-term rental; and used-property bonus is available only if you did not previously use the property and did not acquire it from a related party.
Don't overlook Qualified Improvement Property
Studies on nonresidential buildings often surface Qualified Improvement Property (QIP) — improvements made to the interior of an existing commercial building after it was first placed in service (excluding enlargements, elevators/escalators, and internal structural framework). Thanks to the CARES Act fix, QIP has a 15-year recovery period and is bonus-eligible, rather than being trapped in 39-year real property. QIP is distinct from land improvements (it is interior work) but is another category that pulls large dollars out of the 39-year class. Interior renovations of stores, offices, and medical suites are prime QIP candidates.
When a study is worth it — and audit defense
An engineered study typically costs a few thousand to $15,000+ depending on property size and complexity, so it makes sense when the accelerated deductions comfortably exceed the fee and you can actually use the deductions given the passive-loss rules. As a rough screen, buildings with a depreciable basis above roughly $500,000 usually justify a study, especially with 100% bonus in effect. You can even run a look-back study on a property you have owned for years and claim the cumulative missed acceleration via a Form 3115 accounting-method change — no amended returns needed.
Whatever you do, keep the full report, the asset schedule, and the supporting cost documentation permanently. Cost segregation is on the IRS's radar; an engineered, well-documented study following the Audit Techniques Guide is defensible, while an aggressive, unsupported allocation is an invitation to have the deductions unwound with interest and penalties.
Frequently asked questions
What is the most commonly reclassified item in a residential cost seg study?
Land improvements (parking, fencing, landscaping, exterior lighting) are the most reliably reclassified, since the 15-year vs. 27.5-year distinction is straightforward. Interior finishes like carpet are also common.
Can HVAC be reclassified in a cost seg?
Only if the HVAC unit serves a specific piece of equipment or a discrete area exclusively — not the building as a whole. A dedicated server-room cooling unit may qualify; a central building HVAC system does not.
Is a cost segregation study required to claim these categories?
No, you can self-classify obvious items like parking lots without a study. For complex or large properties, an engineered study provides the documentation needed to defend the allocations if audited.
How much of a building can be reclassified to shorter lives?
It depends on the property type. Apartments typically reclassify 20%-35% of depreciable basis, office buildings around 25%-40%, retail and restaurants 30%-50%, and hotels, medical, or manufacturing facilities sometimes more than 50%. Simple warehouses fall at the low end because they are mostly structural shell.
Do reclassified components qualify for bonus depreciation?
Yes. Bonus depreciation applies to property with a recovery period of 20 years or less, which covers all 5-, 7-, and 15-year components a study identifies (but never the building shell). 100% bonus was permanently restored for qualifying property acquired and placed in service after January 19, 2025 under the One Big Beautiful Bill Act. Passive activity loss rules still govern whether you can use the resulting loss.
How are reclassified components taxed when I sell?
The 5- and 7-year personal-property components are Section 1245 property, recaptured as ordinary income with no 25% cap. The 15-year land improvements are Section 1250 property; additional depreciation from the 150% declining-balance method or bonus is recaptured as ordinary income, and the rest is 25%-capped unrecaptured Section 1250 gain. Cost segregation trades some ordinary-rate recapture later for years of deferral now.
What is Qualified Improvement Property?
QIP is an improvement to the interior of an existing nonresidential building placed in service after the building itself, excluding enlargements, elevators/escalators, and internal structural framework. It has a 15-year recovery period and is bonus-eligible, so interior renovations of stores, offices, and medical suites can be pulled out of the 39-year class.
Sources
Educational information and estimates only. Not tax advice. Tax rules change and vary by situation; consult a qualified tax professional before acting.