Do I need a CPA to benefit from cost segregation?

Yes. A cost seg study produces a report, but your CPA is the one who implements it on your tax return. I coordinate between you, the cost seg firm, and your CPA to make sure everything aligns.

Can I do a cost seg study on a property I already own?

Yes. You can perform a "look-back" cost seg study on properties you already own. Your CPA files a Form 3115 (change in accounting method) to claim the missed depreciation in the current tax year without amending prior returns.

What if bonus depreciation is being phased out?

Bonus depreciation has been phasing down. In 2026, it’s at 20% for assets placed in service. However, the accelerated depreciation from reclassification (5, 7, 15-year recovery periods) still provides significant value even without 100% bonus depreciation.

Is cost segregation only for expensive properties?

Generally, properties under $300K–$400K may not generate enough savings to justify the study cost. But every situation is different — that’s what the estimate tool is for.

Cost Segregation for Hawaiʻi STRs (2026 Guide)

Last updated: January 2026 · 12 min read · Written by Hawaiʻi STR Advisor

What Is Cost Segregation?

Cost segregation is an IRS-approved tax strategy that allows real estate investors to reclassify certain components of a building from real property (27.5-year depreciation) into personal property or land improvements (5, 7, or 15-year depreciation). This accelerates depreciation deductions, putting more money back in your pocket during the early years of ownership. For STR investors in Hawaiʻi, this can mean tens or hundreds of thousands in accelerated deductions — depending on the property value and your tax bracket.

Why STR Investors Have a Unique Advantage

Short-term rental investors have a unique advantage when it comes to cost segregation: the 7-day rule. Under IRS rules, if the average rental period of your property is 7 days or less, it’s generally not treated as a "rental activity" for passive loss purposes. This means that if you materially participate in managing the STR, the depreciation deductions from a cost seg study can potentially offset your active W-2 or business income — not just passive rental income. This is a significant distinction that many investors and even some CPAs overlook.

How a Cost Seg Study Works

A qualified cost segregation firm sends an engineer to inspect the property (or reviews detailed plans and records). They identify and reclassify building components: cabinetry, flooring, landscaping, plumbing fixtures, electrical systems, and more. The result is a detailed report that your CPA uses to adjust your depreciation schedule. The study itself typically costs between $5,000–$15,000 depending on property value and complexity, but the tax savings often exceed 10–20x the cost of the study in the first year alone.

Hawaiʻi-Specific Considerations

Hawaiʻi has unique factors that affect cost segregation strategy. State tax conformity with federal depreciation rules, island-specific building materials and construction methods, and the distinct regulatory environment for STRs on each island all play a role. Additionally, Hawaiʻi’s General Excise Tax (GET) and Transient Accommodations Tax (TAT) obligations should be factored into your overall investment analysis alongside the cost seg benefits.

When to Get a Cost Seg Study

Timing is critical. Ideally, you want to have the cost seg study completed in the same tax year that the property is placed in service. The “placed-in-service” date is when the property is ready and available for its intended use — not necessarily when you close on it or when you first receive a guest. If you’re buying a turnkey property, this may be the close date. If you’re renovating, it’s when renovations are substantially complete. Getting the study done before year-end ensures you capture the maximum first-year deductions.

Is a Cost Seg Study Worth It?

For most STR properties valued above $400K, the answer is almost certainly yes. The general rule of thumb: if the cost of the study is less than 10% of the first-year tax savings, it’s a no-brainer. For a $1M property in the 37% tax bracket with material participation, first-year bonus depreciation deductions could exceed $200K — translating to $74K+ in federal tax savings alone. Compare that to a $7K–$10K study fee and the ROI is obvious.

Educational only; not tax or legal advice. Consult your CPA before making decisions.