When you purchase an Airbnb or short-term rental property, the IRS requires you to depreciate the building over either 27.5 years (residential rental property) or 39 years (nonresidential property, which includes STRs with average rental periods of 7 days or less). Under standard straight-line depreciation, a $600,000 building generates roughly $21,818 in annual depreciation for a residential property or $15,385 for a nonresidential STR. Those numbers are modest compared to the actual economic wear on individual building components.
A cost segregation study changes this by reclassifying specific building components into shorter recovery periods under IRC Sec. 168. The result is a dramatically accelerated depreciation schedule that can produce six-figure deductions in Year 1. For Airbnb owners who qualify under the STR exception and materially participate, these accelerated deductions can directly offset active income.
What a Cost Segregation Study Actually Does
A cost segregation study is an engineering-based analysis that identifies and reclassifies building components from their default recovery period into shorter MACRS recovery classes. Under IRC Sec. 168(e), personal property and land improvements have shorter recovery periods than the building structure itself.
The study separates the property into four categories. Five-year property under IRC Sec. 168(e)(3)(B) includes carpeting, appliances, certain electrical outlets and wiring dedicated to specific equipment, decorative light fixtures, and cabinetry not permanently affixed to the structure. Seven-year property includes furniture, office equipment, and certain specialized fixtures. Fifteen-year property under IRC Sec. 168(e)(3)(C) includes land improvements such as landscaping, sidewalks, driveways, fencing, patios, decks, and outdoor lighting. The remaining structural components stay at the building's default recovery period of 27.5 or 39 years.
For a typical Airbnb property, 20% to 35% of the purchase price (excluding land) can be reclassified into these shorter-lived categories. On a $500,000 building, that means $100,000 to $175,000 of the basis moves from a 27.5-year or 39-year schedule into 5-year, 7-year, or 15-year property.
Bonus Depreciation and the OBBBA
The real power of cost segregation comes from bonus depreciation under IRC Sec. 168(k). The One Big Beautiful Bill Act (OBBBA), signed into law in 2025, restored and made permanent 100% bonus depreciation for qualified property placed in service after the date of enactment. This means that all 5-year, 7-year, and 15-year property identified in a cost segregation study can be fully expensed in the year the property is placed in service.
Prior to the OBBBA, bonus depreciation had been phasing down: 80% in 2023, 60% in 2024, 40% in 2025. The restoration to 100% permanently eliminates the phasedown and provides certainty for investors planning acquisitions.
Year 1 Depreciation Example
Consider a real estate investor who purchases an Airbnb property for $800,000. After subtracting $150,000 for land value, the depreciable basis is $650,000. A cost segregation study identifies the following reclassifications:
Five-year property: $130,000 (20% of depreciable basis), including appliances, specialty lighting, built-in entertainment systems, removable cabinetry, decorative fixtures, and dedicated electrical circuits. Seven-year property: $32,500 (5%), including furniture, bedding platforms, and office equipment. Fifteen-year property: $65,000 (10%), including landscaping, the driveway, patio, fencing, and exterior lighting. Structural (39-year for STR): $422,500 (65%), the remaining building structure.
With 100% bonus depreciation, the Year 1 deduction on the reclassified property is $227,500 ($130,000 + $32,500 + $65,000). The remaining $422,500 generates an additional $10,833 in first-year straight-line depreciation on a 39-year schedule. Total Year 1 depreciation: $238,333.
Without cost segregation, the same property on a straight 39-year schedule would produce only $16,667 in Year 1 depreciation. The cost segregation study increases Year 1 depreciation by $221,666.
STR Classification and Why It Matters for Recovery Period
One detail many Airbnb investors miss is that STR properties with average rental periods of seven days or less are classified as nonresidential real property under IRC Sec. 168(e)(2)(B), which means the structural components depreciate over 39 years instead of the 27.5-year residential rate. This longer structural depreciation schedule actually makes cost segregation more valuable for STRs, because a larger proportion of annual depreciation shifts into the accelerated categories identified by the study.
The trade-off is straightforward. You accept a slightly slower depreciation rate on the structural components in exchange for the ability to treat the entire activity as non-passive (through the 7-day rule and material participation), which means the accelerated depreciation actually reduces your current tax liability rather than creating a suspended passive loss.
When to Order a Cost Segregation Study
The ideal time is the year you place the property in service. This captures the full Year 1 bonus depreciation benefit. However, if you purchased an Airbnb in a prior year and never completed a cost segregation study, you can still capture the benefit retroactively through a "look-back" study.
Under Rev. Proc. 2023-24 and IRC Sec. 481(a), you can file a change in accounting method using Form 3115 to claim the cumulative difference in depreciation as a one-time adjustment. This does not require amending prior-year returns. The catch-up deduction is taken entirely in the year of the accounting method change, creating a large current-year deduction.
Minimum Property Value
Cost segregation studies involve engineering analysis and professional fees, typically ranging from $3,000 to $8,000 depending on property size and complexity. As a general guideline, the study produces meaningful ROI on properties with a depreciable basis of $300,000 or more. Below that threshold, the accelerated depreciation benefit may not justify the study cost.
Common Components Reclassified in Airbnb Properties
STR properties often contain more reclassifiable components than traditional long-term rentals because of the hospitality-oriented furnishing and finishing. Typical items identified in an Airbnb cost segregation study include kitchen appliances (refrigerator, dishwasher, range, microwave), washer and dryer, hot tub or pool equipment, dedicated HVAC zones for specific rooms, accent lighting and decorative fixtures, removable shelving and cabinetry, built-in speakers and entertainment wiring, security cameras and smart home systems, outdoor fire pits and grills, patio furniture and pergolas, landscaping and irrigation systems, driveways and parking areas, and retaining walls under four feet.
Each of these items falls into a 5-year, 7-year, or 15-year recovery class and qualifies for 100% bonus depreciation under current law.
Integration with the STR Tax Strategy
Cost segregation does not operate in a vacuum. For the accelerated depreciation to offset active income, the property must meet two additional requirements. First, the average rental period must be seven days or less under Temp. Reg. 1.469-1T(e)(3)(ii)(A) so the activity is not treated as a rental activity. Second, the owner must materially participate under Temp. Reg. 1.469-5T to ensure the losses are non-passive.
When all three elements are in place, the Airbnb owner can deduct the full accelerated depreciation against business income, investment income, and other active sources. This combination is the foundation of every effective STR tax strategy.
AE Tax Advisors provides turnkey cost segregation studies for Airbnb and STR investors, including engineering analysis, IRC-compliant documentation, and integration with your overall tax plan. To find out how much Year 1 depreciation your Airbnb property can generate, call (631) 614-5762 or email team@aetaxadvisors.com for a free cost segregation estimate.