Will depreciating my Airbnb over 27.5 years trigger an audit?

The classification itself is not a flag, but it is a standard adjustment when short-term rentals do get examined, because the booking history makes it easy to prove. The exposure compounds at thousands of dollars per year of excess deduction. Filing Form 3115 to fix it voluntarily avoids the accuracy-related penalty conversation entirely.

Does 39-year depreciation kill the short-term rental loophole?

No. The loophole is a passive-loss rule under §469 and Treas. Reg. §1.469-1T(e)(3)(ii)(A); it does not depend on the recovery period. Most of a first-year loss comes from cost segregation and 100% bonus depreciation on 5- and 15-year property, and none of that changes when the building itself runs 39 years.

My guests average 35-day stays. Do I use 27.5 or 39 years?

Stays of 30 days or more are not transient under the Treas. Reg. §1.48-1(h) standard, so the income counts as dwelling-unit income. If that income is 80% or more of the building's gross rental income for the year, the building is residential rental property under §168(e)(2)(A) and depreciates over 27.5 years.

Is the 80% test measured in nights or dollars?

Dollars. §168(e)(2)(A) compares gross rental income from dwelling units to total gross rental income from the building, taxable year by taxable year. A building can pass in a year dominated by month-long tenants and fail the next year when weekend bookings take over.

Does the 39-year life apply to my furniture and appliances too?

No. Furniture, appliances, and similar personal property are 5-year MACRS property regardless of how the building is classified, and land improvements are 15-year. The 27.5-versus-39 question affects only the building itself, which is why a cost segregation study recovers most of the difference.

The Journal / Real Estate Tax

Short-Term Rental Depreciation: 27.5 or 39 Years? The Average Stay Decides.

By Ewan Morkel, EAJuly 19, 20266 min read

An Airbnb with average guest stays under 30 days is nonresidential real property: 39-year depreciation, not 27.5. The 80% test that decides it, what misclassifying costs each year, and the Form 3115 fix if you have been doing it wrong.

A couple closes on a mountain cabin in March 2026, lists it on Airbnb, and hands the bookkeeping to software that files the building as residential rental property: 27.5-year depreciation, 3.636% of the building basis every year. Their average guest stays four nights. That default is wrong, and it is wrong in the direction the IRS cares about. Whether a short-term rental is depreciated over 27.5 or 39 years turns on a definition in §168 that most owners, and a surprising number of preparers, have never read, and a four-night rental fails it.

The test

Why most short-term rental depreciation runs 39 years.

The statutory chain is short. IRC §168(c) gives residential rental property 27.5 years and everything else in real estate 39. Residential rental property is defined in §168(e)(2)(A): a building where 80% or more of the gross rental income for the taxable year is rental income from dwelling units. A dwelling unit is a house or apartment used to provide living accommodations, but not a unit in a hotel, motel, or other establishment where more than half the units are used on a transient basis. A whole-home Airbnb is a one-unit establishment, so if the home runs transient, 100% of its units do. For the meaning of transient, the IRS has leaned for decades on Treas. Reg. §1.48-1(h), which treats accommodations as transient when the rental period is normally less than 30 days. The test is annual, per building, and measured in dollars of gross rental income, not in nights booked.

The same house can flip categories. Rent it to traveling nurses on 60-day contracts and the income comes from a dwelling unit again, so it is back to 27.5 years, assuming the 80% test passes for the year. A mixed calendar does the math on dollars: if 85% of the year's rents came from month-plus tenants and 15% from weekenders, the building stays residential for that year.

The wrong rule

The 7-day rule answers a different question.

Owners conflate this with the seven-day test because both live in short-term rental articles. Treas. Reg. §1.469-1T(e)(3)(ii)(A) says a property with average stays of seven days or less is not a rental activity for passive-loss purposes, which is the engine behind the short-term rental loophole. That regulation decides the character of your losses. It says nothing about depreciation. The recovery period comes from §168 and its 30-day transient standard, so a cabin with four-night average stays is both things at once: eligible for the loophole and stuck with 39-year depreciation. I still see returns claiming the loophole and 27.5 years together, which is the one combination the two rules cannot produce.

One Airbnb house misclassified at 27.5 years, tax year 2026.

Purchase price: $800,000
Land (not depreciable): $200,000
Building basis: $600,000
Average guest stay: 4 nights
Correct recovery period: 39 years
Correct annual depreciation (39-year straight line): $15,385
What 27.5-year treatment claims instead: $21,818
Annual overstatement: $6,433

Tax year 2026. Steady-state straight-line amounts on the building only; the placed-in-service year is lower under the mid-month convention of §168(d)(2). Land value from the purchase allocation. Stays averaging four nights are transient under the 30-day standard, so the building fails the §168(e)(2)(A) dwelling-unit test.

The consolation

Cost segregation blunts most of the damage.

The 27.5-versus-39 question only governs the building shell. A cost segregation study typically carves 20% to 30% of a short-term rental's basis into 5-year personal property (furniture, appliances, carpet) and 15-year land improvements (driveways, landscaping, the hot tub pad), and those classes keep their lives no matter how the building is classified. They are also eligible for 100% bonus depreciation, which the One Big Beautiful Bill Act made permanent for property acquired after January 19, 2025 (OBBBA §70301). On the $800,000 cabin above, a study that moves $180,000 into short-life classes deducts that $180,000 in year one either way. The 39-year life only slows the leftover shell, which is real money but not the headline.

The fix

Two wrong years is a method, and methods need Form 3115.

If you filed one return at 27.5 years, amend it. Once you have filed two, the wrong life is an established accounting method, and the fix is a Form 3115 method change with a §481(a) adjustment that picks the excess depreciation back up as income, spread over four years when the adjustment is unfavorable. Filed proactively, this is routine paperwork with no penalty conversation. Found on exam, it is the same math plus interest and accuracy penalties on every open year. The mechanics run just like catching up missed depreciation, pointed in the other direction. At $6,433 of annual overstatement and a 32% bracket, each year of exposure is roughly $2,059 of tax, so a five-year-old error is a $10,000 problem that gets cheaper the day you fix it and more expensive every April you do not.