A cost-segregation study may accelerate depreciation on parts of a short-term rental. It separates eligible personal property and land improvements from the residential building. The study changes when basis is recovered; it does not create basis, improve cash flow, or guarantee that a tax loss is currently deductible.
The decision depends on the property's depreciable basis, asset mix, placed-in-service date, expected holding period, study cost, state law, and the owner's ability to use the resulting deduction. A large first-year depreciation figure can be worth little today when passive-activity or other loss limits suspend it.
This guide shows how to estimate deduction potential before ordering a study. It covers federal depreciation rules for a typical residential STR. Mixed-use buildings, commercial property, major renovations, and individual return positions require separate analysis.
What a Cost-Segregation Study Changes
A residential rental building is generally 27.5-year property. Land is not depreciable. Furniture, appliances, certain removable finishes, and some site improvements may have shorter recovery periods when their facts support a different tax classification.
A study allocates existing depreciable basis among those asset classes. It may move eligible costs from 27.5-year property into 5-, 7-, or 15-year property. Shorter-life property may also qualify for additional first-year depreciation.
The study does not change the purchase price or add a deduction that did not exist. Without acceleration, eligible basis is generally recovered over later years. Cost segregation moves some deductions forward and leaves fewer deductions for the future.
Basis Comes Before Asset Classification
Begin with the property's tax basis. Purchase cost and eligible acquisition expenses may enter basis. The total must then be allocated among land, the building, furnishings, equipment, and other acquired assets.
The purchase agreement, appraisal, county assessment, replacement-cost evidence, and facts about included furniture may inform the allocation. No single source automatically controls every component. An allocation chosen only to increase depreciation is difficult to defend.
Improvements made after acquisition have their own costs and placed-in-service dates. Repairs may be currently deductible when capitalization is not required. A study should not classify a previously deducted repair as depreciable basis.
Typical Recovery Periods in an STR
- Land: Not depreciable.
- Residential building: Generally 27.5-year property, including structural components that serve the building.
- Five- or seven-year property: May include eligible furniture, appliances, equipment, carpeting, decorative items, and other tangible personal property.
- Fifteen-year property: May include eligible land improvements such as certain fencing, paving, landscaping, and exterior site features.
These are categories, not automatic results. Attachment, function, permanence, and relationship to building operation matter. A light fixture that serves the building may differ from removable decorative lighting. Plumbing that serves the whole building may differ from equipment dedicated to a qualifying process.
The IRS Cost Segregation Audit Technique Guide describes study methods, asset classification, cost allocation, and the elements examiners review. The guide assists examiners and is not itself binding legal authority.
Qualified Improvement Property Is Often Misapplied
Qualified improvement property generally means an improvement to the interior of nonresidential real property after the building was first placed in service. A typical house or condominium operated as an STR is residential rental property, not nonresidential real property.
A kitchen remodel, bathroom renovation, floor replacement, or built-in cabinet in a residential STR is therefore not automatically QIP. Some separate components may qualify for shorter recovery periods under their own classification, but the residential renovation as a whole does not become 15-year QIP.
Building enlargements, elevators, escalators, and internal structural framework are excluded from QIP even in nonresidential buildings. The return preparer should establish the building type and the nature of each improvement before applying QIP treatment.
Current 100% Bonus-Depreciation Rule
Current law generally allows a 100% additional first-year deduction for qualified property acquired after January 19, 2025. The property must also be placed in service and meet the other requirements. Property acquired earlier may remain under the prior phaseout schedule.
IRS Notice 2026-11 provides interim guidance for the restored deduction. IRS Publication 946 explains recovery periods, conventions, placed-in-service rules, Section 179, and the special depreciation allowance.
Bonus depreciation generally applies to eligible property with a recovery period of 20 years or less. Land and the 27.5-year residential building do not qualify. A study can identify shorter-life components, but each component must still satisfy the bonus-depreciation rules.
The acquisition date and placed-in-service date answer different questions. A closing does not place a property in service when renovation or permitting prevents it from being ready and available for rent. Furniture and later improvements may also have separate dates.
A Hypothetical Deduction Estimate
Assume an investor purchases and places a furnished residential STR in service after January 19, 2025. The purchase price and eligible acquisition costs produce $500,000 of depreciable basis after land is removed.
- Residential building: $400,000.
- Eligible five- and seven-year property: $70,000.
- Eligible fifteen-year land improvements: $30,000.
Assume the $100,000 of shorter-life property qualifies for 100% bonus depreciation. The first-year bonus deduction is then $100,000. The building adds depreciation under the residential-rental convention; it is not simply a full-year $400,000 divided by 27.5 calculation.
Without the study, separately acquired furnishings should still receive their correct classification when known. A comparison that puts every dollar into the building can overstate the study's benefit. The useful comparison is the correct depreciation schedule before the study versus the corrected schedule after it.
At an assumed 35% marginal federal rate, an additional $100,000 deduction could have a simplified current federal tax effect of $35,000 if the entire deduction is allowed now. If the loss is suspended, the current effect may be zero. The deduction may become useful later under the rules that release it.
When the Deduction May Offset Wages
Cost segregation determines depreciation timing. It does not determine whether a loss is passive. Rental activities are generally passive under Internal Revenue Code Section 469.
A short-term rental may fall outside the rental definition when average customer use is seven days or less. The owner must also materially participate for the activity to become generally nonpassive. The loss must then survive basis, at-risk, personal-use, excess-business-loss, and other limits.
The STR tax mechanism connects depreciation, customer-use classification, material participation, and the remaining loss limits. Model those rules before treating accelerated depreciation as a current wage offset.
Estimate the Study's Real Benefit
Compare at least three schedules: no study, a reasonable study result, and a lower short-life allocation. For each schedule, calculate current federal tax, current state tax, suspended losses, future depreciation, and expected tax at sale.
Use the owner's expected marginal rates rather than multiplying every deduction by the highest bracket. A deduction may cross several tax brackets. State add-backs may also delay or eliminate the state benefit.
Subtract the study fee and added return-preparation cost. Then compare the after-tax present value of accelerated deductions with the future deductions given up. A larger first-year deduction is not automatically a larger lifetime deduction.
Holding Period and Sale Consequences
Depreciation lowers adjusted basis. Accelerating depreciation can therefore increase taxable gain when the property is sold. The tax character depends on the asset and the amount of prior depreciation.
Gain tied to Section 1245 personal property may become ordinary income up to the applicable recapture amount. Building depreciation can produce unrecaptured Section 1250 gain, generally subject to a maximum 25% federal rate.
A Section 1031 exchange may defer qualifying gain when every requirement is met. It does not erase basis history, and personal property transferred with the real estate may not receive the same treatment. Include the likely exit before deciding whether acceleration is useful.
State Conformity Can Change the Answer
States do not all follow federal bonus depreciation. Some require an addition to state income followed by later state deductions. Others use different depreciation schedules or loss limitations.
The property location, owner residence, entity structure, and filing obligations can involve more than one state. Calculate each state result rather than applying the federal percentage to an assumed combined tax rate.
What a Defensible Study Should Contain
- A clear description of the property and business use.
- Reconciliation to total depreciable basis.
- Identification and treatment of land and land improvements.
- Asset descriptions, classifications, recovery periods, and legal rationale.
- Source documents, photographs, drawings, invoices, and cost records.
- A documented method for estimating costs not separately invoiced.
- Placed-in-service dates and depreciation schedules.
- Identification of the specialists who prepared and reviewed the work.
A study fee alone does not establish quality. The report should explain how each material cost was identified and valued. Percentage estimates without property-specific support may be difficult to reconcile with the actual purchase.
Ask how the provider treats change orders, owner-provided furnishings, prior renovations, site work, indirect costs, and assets already listed separately. Confirm who will answer the return preparer's questions and support the classifications if examined.
When a Look-Back Study May Apply
An owner may commission a study after the property has been depreciated for earlier years. Correcting depreciation may require an accounting-method change rather than amending every prior return.
Form 3115 and a Section 481(a) adjustment may bring the cumulative difference into the year of change. Eligibility, procedural rules, and audit protection depend on the facts and current guidance. The return preparer should decide the filing method before the study is ordered.
Where STR Search Fits
STR Search evaluates markets and properties for acquisition. Its analysis can address demand, seasonal revenue, regulation, competition, operating costs, management, and likely capital needs.
STR Search does not classify assets, prepare a cost-segregation study, determine material participation, or file depreciation elections. A qualified study provider and return preparer perform those roles.
The acquisition should work without accelerated depreciation. Test debt service, reserves, repairs, replacement costs, management, and exit risk before adding a tax scenario.
Decision Checklist Before Ordering a Study
- Is the land and building basis allocation supportable?
- Are furnishings and other assets already listed separately?
- Which components could reasonably receive shorter recovery periods?
- Were the property and each improvement placed in service?
- Does each asset meet the bonus-depreciation requirements?
- Can the owner currently use the resulting loss?
- How does each relevant state treat the deduction?
- What study and return-preparation costs will be incurred?
- How long does the owner expect to hold the property?
- What gain and recapture may arise at sale?
Conclusion
A cost-segregation study can accelerate depreciation by separating eligible short-life assets and land improvements from a residential building. Its value comes from timing, not from creating new basis or improving property performance.
Estimate the correct starting schedule, likely reclassification, current loss usability, state treatment, study cost, future deductions, and sale tax. Reject percentages that are not supported by the specific property.
Before filing, have the return preparer review the study, acquisition documents, placed-in-service dates, depreciation elections, passive-activity treatment, basis, at-risk amount, personal use, and state adjustments. Keep the final report and supporting records with the depreciation schedules.
