This case study compares standard depreciation with cost segregation on a $1 million property. With 100% bonus depreciation, restored permanently by the Big Beautiful Bill, the difference is about $129,800 in first-year tax savings at a 37% rate, assuming the deduction is usable that year.
The property is a mixed-use building purchased for $1 million in February 2025, with land value at $200,000 and a depreciable basis of $800,000.
Under standard depreciation rules, the owner would claim $20,513 a year, spread evenly across 39 years. With cost segregation and 100% bonus depreciation, first-year depreciation on the same building reaches $371,282. That is $350,769 in additional deductions, on identical property, in the same tax year. The only thing that changed is how the building was classified.
The study moved $360,000 of the building into 5-, 7- and 15-year property, which qualifies for 100% bonus depreciation for property acquired and placed in service after January 19, 2025.
This analysis provides concrete numbers and implementation steps for investors considering cost segregation. The data reflects current tax law, including the Big Beautiful Bill provisions. Results on other properties depend on asset class, land allocation and the owner's tax situation.
What Is the Difference Between Cost Segregation and Regular Depreciation?
Regular depreciation writes off an entire building on a single 27.5-year or 39-year straight-line schedule. Cost segregation splits the building into components and moves the qualifying ones onto 5-, 7-, and 15-year schedules, where 100% bonus depreciation makes them deductible in year one. The total deduction over the life of the property is the same. What changes is when you receive it.
| Standard depreciation | With cost segregation | |
|---|---|---|
| Year 1 deduction | $20,513 | $371,282 |
| Recovery period | One schedule: 39 years for commercial, 27.5 for residential rental | Four schedules: 5, 7 and 15 years for reclassified components, with the remaining structure on 27.5 or 39 |
| Documentation required | Closing statement and a land-versus-building basis allocation | Engineering study with a property inspection, component-level cost detail, photographs and a report meeting the IRS Audit Techniques Guide |
| Audit exposure | Minimal. It is the default treatment | Manageable with an engineering-based study. Rule-of-thumb allocations and contingency fee arrangements are what draw examiner attention |
Figures reflect the $800,000 depreciable basis in the case study below. The rest of this article walks through how those numbers were reached.
Traditional Approach to Property Depreciation
How Standard Depreciation Works
Standard depreciation follows IRS-mandated recovery periods based on property classification. Residential rental properties depreciate over 27.5 years using straight-line method. Commercial properties require 39 years. The distinction matters significantly for tax planning.
For residential rental property to qualify for 27.5-year depreciation, at least 80% of gross rental income must come from dwelling units. All other rental properties fall under commercial classification at 39 years. This classification directly impacts annual deduction amounts and long-term tax strategy.
Consider our $1 million property example with $800,000 depreciable basis after deducting land value. Under commercial classification at 39 years:
- Annual depreciation: $20,513
- First-year tax savings at 37% rate: $7,590
- Total five-year tax benefit: $37,950
These calculations use a full year of straight-line depreciation for simplicity and assume no additional improvements; the mid-month convention reduces the first year slightly. The depreciation remains constant annually until the basis is fully recovered.
What's the difference between residential and commercial property depreciation?
The IRS distinguishes properties based on use and income source. Residential rental property generating 80% or more income from dwelling units qualifies for 27.5-year depreciation. This includes apartment buildings, single-family rentals, and duplexes used primarily for housing.
Commercial property encompasses office buildings, retail spaces, warehouses, and mixed-use properties not meeting residential criteria. Short-term rental properties operating like hotels also fall under commercial classification. The longer depreciation period significantly reduces annual deductions, making cost segregation particularly valuable for commercial property owners.
Breaking Down Property Components
What Cost Segregation Actually Does
Cost segregation services systematically identify and reclassify property components into shorter depreciation categories. Instead of treating the entire building as one asset, engineering-based studies separate components based on IRS guidelines. This reclassification accelerates depreciation deductions without changing the property's total depreciable basis.
How much falls into the shorter categories depends on the asset class. As a share of depreciable basis, total reclassification runs, for example, 27% to 38% for a single-family rental, 28% to 41% for an office building and 25% to 39% for industrial property, with the rest staying on the 27.5- or 39-year schedule.
Common 5-Year Property Items:
- Carpeting and vinyl flooring
- Window treatments and blinds
- Removable cabinetry and millwork
- Appliances and equipment
- Decorative lighting fixtures
- Security and communication systems
- Dedicated electrical for equipment
15-Year Property Examples:
- Parking lots and driveways
- Landscaping and irrigation
- Sidewalks and walkways
- Fencing and gates
- Site lighting and utilities
- Stormwater management systems
The Accelerated Depreciation Advantage
Permanent 100% bonus depreciation for qualified property means all 5-year, 7-year, and 15-year property identified through cost segregation can be fully deducted in year one. Properties with recovery periods of 20 years or less qualify for immediate expensing.
This lets investors claim much of a building's depreciation in year one rather than over decades.
How much of my property typically qualifies for accelerated depreciation?
It depends on the asset class, and it's measured against depreciable basis, not purchase price: for example, 27% to 38% for a single-family rental, 28% to 41% for an office building and 25% to 39% for industrial property.
Where a property lands within its class depends on specifics identified during the inspection. Factors include construction quality, finishes, site improvements, and special-use areas. Each property requires individual analysis to determine accurate reclassification potential.
Property Details
Quick Property Stats:
- Purchase Price: $1,000,000
- Land Value: $200,000 (20%)
- Depreciable Basis: $800,000
- Property Type: Mixed-use commercial
- Location: Denver metropolitan area
- Acquisition Date: February 2025
The 20% land value allocation reflects county assessor data and market comparables. The building includes retail space on the ground floor with office units above. Quality finishes and site improvements add to the reclassifiable share.
Standard Depreciation Scenario
Under traditional depreciation, the entire $800,000 depreciable basis follows a 39-year straight-line schedule. No distinction exists between structural components and personal property. Every element receives identical treatment.
Year-by-Year Breakdown (First 5 Years):
| Year | Annual Depreciation | Cumulative | Tax Savings (37%) |
|---|---|---|---|
| 1 | $20,513 | $20,513 | $7,590 |
| 2 | $20,513 | $41,026 | $7,590 |
| 3 | $20,513 | $61,539 | $7,590 |
| 4 | $20,513 | $82,052 | $7,590 |
| 5 | $20,513 | $102,565 | $7,590 |
| Total | $102,565 | $37,950 |
This approach provides consistent but small annual deductions. The owner must wait 39 years to fully recover the investment through depreciation deductions.
Cost Segregation with 100% Bonus Depreciation Scenario
R.E. Cost Seg conducted a detailed engineering study, including a property inspection and document review. With 100% bonus depreciation, the results are as follows.
Component Breakdown:
- 5-year property (25%): $200,000 - Security systems, removable fixtures, specialty electrical
- 7-year property (8%): $64,000 - Office furniture, data cabling, equipment
- 15-year property (12%): $96,000 - Parking areas, landscaping, exterior lighting
- 39-year property (55%): $440,000 - Building structure, permanent systems
Enhanced Depreciation Schedule with 100% Bonus:
| Year | Depreciation | Cumulative | Tax Savings (37%) |
|---|---|---|---|
| 1 | $371,282* | $371,282 | $137,374 |
| 2 | $11,282 | $382,564 | $4,174 |
| 3 | $11,282 | $393,846 | $4,174 |
| 4 | $11,282 | $405,128 | $4,174 |
| 5 | $11,282 | $416,410 | $4,174 |
| Total | $416,410 | $154,070 |
*Year 1 includes: $360,000 (100% bonus on 5, 7, and 15-year property) + $11,282 (regular depreciation on 39-year property)
The Bottom Line:
- First-year depreciation: $371,282 vs. $20,513 standard
- First-year tax savings: $137,374 vs. $7,590 standard
- Additional first-year benefit: $129,784
- Cost segregation study fee: from $2,730 (fully engineered, commercial)
- First-year return: roughly 48x the study fee
What happens if I sell the property after taking accelerated depreciation?
Depreciation recapture applies when selling property after claiming bonus depreciation. Section 1245 property faces recapture at ordinary income rates up to 37%. The time value of money often still favors taking the deductions early. A 1031 exchange can defer some or all of the gain on the real property, but Section 1245 recapture on personal property can still apply.
When Cost Segregation Makes Sense
Strategic Considerations for Investors:
- Acquisition after January 19, 2025 (for 100% bonus)
- Planning to hold property three years minimum
- Need for current year tax deductions
- High personal income tax bracket (32% or higher)
- Qualifying for real estate professional status
- Tax savings meaningfully outweigh study costs
While some advisors suggest $300,000-$500,000 as a rule of thumb, there's no strict property value threshold for cost segregation. The decision should be strategic, made between the investor and their CPA based on overall tax planning goals. R.E. Cost Seg has successfully completed studies on properties of various sizes, when the analysis showed meaningful tax benefits relative to study costs.
Permanent 100% bonus depreciation for property acquired and placed in service after January 19, 2025, applies to smaller properties too. A $300,000 single-family rental with $240,000 of depreciable basis, reclassifying 27% to 38%, could generate roughly $65,000 to $91,000 of first-year deductions, or about $24,000 to $34,000 of tax at 37% if the losses are usable.
The Real Decision Factor
Don't let property value alone determine your strategy. The key question is whether tax savings meaningfully exceed the study cost. Consider:
- A $300,000 property might generate $24,000 to $34,000 in first-year tax savings
- A fully engineered study starting at $2,320 represents roughly 7-10% of those potential benefits
- Every property deserves individual analysis based on its unique characteristics
R.E. Cost Seg works with CPAs to evaluate each opportunity strategically. Properties with extensive personal property, recent renovations, or specialized use areas often justify studies regardless of total value.
Steps to Implementation
Pre-purchase analysis: R.E. Cost Seg provides preliminary estimates before closing. These projections incorporate 100% bonus depreciation benefits for qualifying properties.
Engage qualified professionals: Engineering-based studies require specialized expertise. Qualified firms combine engineering knowledge with tax code understanding. Quality studies are easier to defend if examined.
Complete study within tax year: Studies must conclude before filing returns. Fully engineered studies are delivered within 15 to 20 business days of engagement, with the site visit scheduled early in that window. A Rapid Report delivers in 5 business days.
Document everything: Maintain all supporting materials including photos, invoices, and engineering reports. Comprehensive documentation supports depreciation positions during IRS examinations.
Can I apply cost segregation to properties I've owned for years?
Yes. A look-back requires a change in accounting method, which your CPA files using Form 3115. This allows catching up all missed depreciation in the current year without amending prior returns. Properties acquired before the Big Beautiful Bill still benefit from cost segregation through accelerated depreciation methods.
Understanding the Downsides
Key Risks to Consider:
Depreciation recapture represents the primary concern. Section 1245 property faces recapture at ordinary income rates upon sale. With 100% bonus depreciation, the entire amount of personal property becomes subject to recapture consideration.
IRS audit potential exists but remains manageable. Quality engineering studies following established methodologies are easier to defend if examined. R.E. Cost Seg provides full audit support with all studies.
Upfront study costs start at $2,320 for a fully engineered residential study and $2,730 for commercial, with a Rapid Report option from $950. Larger properties, portfolios, and buildings with specialized systems price above those starting points. In the case study above, first-year tax savings were roughly 48 times the study fee; results vary by property.
Future depreciation decreases after taking a 100% bonus. Only the 39-year structural components provide ongoing annual deductions. This front-loading requires careful tax planning for future years.
Getting the Benefit While Managing Risk
Best Practices:
Use IRS-compliant engineering-based studies exclusively. Avoid percentage-based estimates or rule-of-thumb allocations. Proper methodology supports defensible positions.
Maintain comprehensive documentation, including photos, floor plans, and invoices. Larger first-year deductions make documentation more important.
Consider 1031 exchanges when selling properties with significant recapture exposure. An exchange can defer some or all of the gain on the real property; Section 1245 recapture on personal property can still apply.
How does cost segregation affect a 1031 exchange?
Since 2018, Section 1031 covers real property only. The 5- and 7-year personal property identified in a study isn't part of the exchange, so its Section 1245 recapture can apply at the time of the exchange. Plan for this before exchanging.
Your Next Steps
In this case study, cost segregation with permanent 100% bonus depreciation produced about $129,800 more in first-year tax savings than standard depreciation, roughly 48 times the study fee.
Calculate your property's cost segregation potential with R.E. Cost Seg's free estimate tool.
