Renting a Room - Should I do a Cost Segregation Study
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Attorney · Salt Lake City, UT · Member since 2025 · 144 posts · 180 votes
1yYou're in a great position to make strategic tax decisions with your property, but whether to do a cost segregation (cost seg) study now or wait depends on a few key factors—especially how you're using the property and your overall tax strategy. A cost segregation study can significantly accelerate depreciation by breaking down your property into shorter-life components (like appliances, cabinetry, flooring, etc.), allowing you to claim larger deductions up front—potentially through 100% bonus depreciation if applicable for your tax year. However, timing is crucial when the property is only partially used as a short-term rental.
Right now, since you're living in the property and only renting part of it on Airbnb, you’re in what's called a “mixed-use” situation. This limits the depreciation you can take. Only the portion of the property used for rental (i.e., the guest room and any shared common areas used by guests) can be depreciated, and you would only be able to cost segregate and depreciate that specific percentage—not the entire structure. That reduces the value of doing a full cost segregation study at this stage because the tax benefits will be proportionally limited.
However, once you move out and convert the whole property to a short-term rental (STR), your depreciation deductions—including those from a cost seg study—would apply to the entire property. This would dramatically increase the allowable deduction and could generate a much larger paper loss, especially if you or your CPA can qualify the property as non-passive (e.g., by materially participating or if it meets certain STR exemptions from passive activity rules). This could offset W2 income, especially if your AGI is around $100K and you're actively involved in the property.
That said, there are still scenarios where doing the cost seg study now could make sense—especially if your current AGI and losses allow you to benefit from the deduction and you really need the cash flow this year. Just remember that once the bonus depreciation rules phase out further (as they're doing post-2023), you may not get as much of a punch from waiting. But if you're only depreciating a portion of the home now and expect to fully depreciate the house as a business asset later, waiting could be the better financial play.
Note: This information is for educational and informational purposes only and does not constitute legal, tax, financial, or investment advice. No attorney-client, fiduciary, or professional relationship is established through this communication.
9 Replies
- 1yJulio GonzalezPro MemberSpecialist · West Palm Beach, FL · Member since 2008 · 4k+ posts · 1k+ votes
There are several variables to consider here. If you're holding the property for less than two years, cost seg probably isn't a good route. Have you already obtained a detailed cost/benefit analysis quote for a study? Most cost segregation study companies provide the quote for free. If you need any help or have any questions, feel free to reach out!
- 1ySean O'KeefePro MemberCPA | Accepting new clients | 50 States · Member since 2022 · 1k+ posts · 871 votesBefore you get a cost seg I think you need to evaluate if you can leverage losses for tax savings.
Quote from @Kevin M.:
About 18 months ago I finished a renovation with a Homestyle loan ($160k pp, $90k renovations, $320k ARV). Its a 2 bed 1 bath SFH and I rent the other room through AirBnb. Guests have access to the entire house except for my bedroom. The plan is to purchase a new property in the next year or so then rent the full house as a STR. I have a W2 job to deduct losses against and I'm hoping my AGI should fall right around $100k including the losses from my Schedule C (side business).
I still have to file my 2024 taxes and have been struggling with whether I should do a cost seg study this year or not? Getting more back this year would really help me pay off a couple things and finance my next property but if its more beneficial to wait until I rent the entire house I can do that. Would love to get some thoughts and if anyone has a good CPA that I can engage to do the study. Thanks!
If you’re renting out rooms in your home and the rental portion isn’t a separate dwelling, your deductible expenses are limited to the amount of rental income (under § 280A(c)(5) of the tax code. There is an exception for short-term rentals (under § 280A(f)(1)(B) and § 1.280A-1(c)(2) of the tax code and treasury regulations).
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.*This post does not create a CPA-client relationship. The information contained in this post is not to be relied upon. Readers are advised to seek professional advice.
- Attorney · Salt Lake City, UT · Member since 2025 · 144 posts · 180 votes1y
You're in a great position to make strategic tax decisions with your property, but whether to do a cost segregation (cost seg) study now or wait depends on a few key factors—especially how you're using the property and your overall tax strategy. A cost segregation study can significantly accelerate depreciation by breaking down your property into shorter-life components (like appliances, cabinetry, flooring, etc.), allowing you to claim larger deductions up front—potentially through 100% bonus depreciation if applicable for your tax year. However, timing is crucial when the property is only partially used as a short-term rental.
Right now, since you're living in the property and only renting part of it on Airbnb, you’re in what's called a “mixed-use” situation. This limits the depreciation you can take. Only the portion of the property used for rental (i.e., the guest room and any shared common areas used by guests) can be depreciated, and you would only be able to cost segregate and depreciate that specific percentage—not the entire structure. That reduces the value of doing a full cost segregation study at this stage because the tax benefits will be proportionally limited.
However, once you move out and convert the whole property to a short-term rental (STR), your depreciation deductions—including those from a cost seg study—would apply to the entire property. This would dramatically increase the allowable deduction and could generate a much larger paper loss, especially if you or your CPA can qualify the property as non-passive (e.g., by materially participating or if it meets certain STR exemptions from passive activity rules). This could offset W2 income, especially if your AGI is around $100K and you're actively involved in the property.
That said, there are still scenarios where doing the cost seg study now could make sense—especially if your current AGI and losses allow you to benefit from the deduction and you really need the cash flow this year. Just remember that once the bonus depreciation rules phase out further (as they're doing post-2023), you may not get as much of a punch from waiting. But if you're only depreciating a portion of the home now and expect to fully depreciate the house as a business asset later, waiting could be the better financial play.
Note: This information is for educational and informational purposes only and does not constitute legal, tax, financial, or investment advice. No attorney-client, fiduciary, or professional relationship is established through this communication. - 1yAshish AcharyaBusiness MemberCPA, CFP®, PFS · FL · Member since 2017 · 5k+ posts · 3k+ votes
@Kevin M. Since you're currently using part of the property as your primary residence and renting out the other bedroom via Airbnb, your cost segregation opportunity is limited until the entire home is placed in service as a full rental. Right now, only the portion of the home used for rental (the guest room and share of common areas) qualifies for depreciation, and a cost segregation study wouldn’t generate meaningful benefits relative to the cost.
Once you move out and convert the entire property to a short-term rental, you'll be eligible to depreciate the full structure (excluding land) and can apply a cost segregation study to front-load deductions using bonus depreciation. If you actively participate and qualify under the STR material participation rules, you may be able to offset W-2 income with those losses, especially if your AGI stays near $100K and you meet the IRS tests.
Wait to do the cost seg study until you convert the property to a full STR, as that will maximize your benefit and make the study cost-effective. In the meantime, continue to depreciate the rental portion based on square footage and allocate common expenses accordingly. Additional bonus depreciation might come back at 100% in 2025 as well.
This post does not create a CPA-Client relationship. The information contained in this post is not to be relied upon. Readers should seek professional advice.
INVESTOR FRIENDLY CPA®5241 Reviews - 1yJason MalabuteBusiness MemberAccountant · Los Angeles, CA · Member since 2016 · 2k+ posts · 903 votes
If you’re living in part of your home and renting out a room on Airbnb, your depreciation benefits are limited to just the portion being rented. A cost segregation study wouldn’t be worth it yet. Once you move out and convert the whole property into a short-term rental, you can depreciate the full structure (except land) and use a cost seg study to accelerate deductions through bonus depreciation. If you meet the IRS material participation rules, you may even be able to offset W-2 income with those losses. So it’s best to wait until the property is fully used as a short-term rental before doing a cost seg study.
Malabute & Company CPAs525 Reviews - Dr · VA · Member since 2025 · 154 posts · 34 votes1y
1. if you only rent 1 single room in your house, you can get deduction for the expense for that particular room plus 15% extra for overall house
2. if Airbnb and whole house is use and planning to keep the property for long term, can do Cost Seg
3. Cost Seg is a current deduction for high income taxpayers
4. upon selling the property "Recapture" hits badly
5. if you're not in high income, just keep the Airbnb and participate actively to qualify for loss deduction
- Member since 2026 · 5 posts · 6 votes8mo
For a mixed-use property, cost segregation can only be applied to the rented percentage. I hired an engineered study in order to justify the cost for this specific scenario.
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