Comparing Seneca Cost Segregation and Engineered Tax Services usually means you already have a property in mind, a tax deadline on the calendar, and two firms that both promise an engineering-based study. On paper they can look alike. In practice, they differ on speed, pricing transparency, guarantee terms, and the kind of owner each one is built to serve.
As co-founder of Seneca Cost Segregation and a real estate investor myself, I regularly work with owners and CPAs who are weighing a Seneca proposal against one from a larger, longer-established firm. I run one of the two firms in this comparison, so I have kept it to verifiable facts: Seneca’s figures come from our own records and published terms, and every ETS figure comes from ETS’s own published material.
What follows covers how each firm runs a study, how turnaround, fees, and audit protection stack up, and which firm tends to fit which kind of property. The goal is a decision you can defend to your CPA.
TL;DR — Seneca vs Engineered Tax Services
Here is where the two firms separate once you look past the shared “engineering-based” label:
- ●Faster delivery: Seneca delivers studies for every property type in 5 to 10 business days once the owner’s documents are in, against the 4 to 6 weeks ETS publishes for most studies.
- ●Lower starting prices: Seneca’s fully engineered residential studies start at about $2,000 and commercial studies typically start at $3,500, and you pay only if you move forward after the free estimate.
- ●Fee-refund guarantee: Seneca refunds 100% of its fee if its own error causes a depreciation adjustment above 5%, a written term ETS does not publish.
- ●Every property size: Seneca’s work runs from small Midwest single-family homes to multi-million-dollar manufacturing plants, while ETS cites roughly $500,000 of basis as the usual starting point.
- ●Scale and breadth: ETS brings 25 years, a reported 75,000+ studies, and research credit, 179D, and 45L work under one roof.
- ●Shared baseline: Both firms include audit support at no extra charge and follow the IRS Audit Techniques Guide.
Seneca and Engineered Tax Services at a Glance
The table below lines the two firms up on the points buyers weigh most.
ETS also appears in our wider roundup of the best cost segregation companies, which profiles seven firms that run engineering-based studies.
How Seneca Cost Segregation Approaches a Study
Seneca is a veteran-founded firm that does one thing: cost segregation studies for real estate owners across all 50 states. Since its founding in January 2024, its engineering team has assessed 10,200+ properties and analyzed more than $5B in cost basis, with an average first-year deduction of $171,000.
That work spans small Midwest single-family homes through multi-million-dollar mansions, long- and short-term rentals, small self-storage facilities through multi-million-dollar manufacturing plants, 120+ unit hotels, and office buildings over 40,000 square feet. Clients deal directly with the in-house team doing the work: a dedicated Project Manager, the Engineering team, and an Advisor, with no outside sales reps relaying messages between the CPA and the engineers.
Engineering Review and Head of Engineering Sign-Off
Every Seneca study is built by in-house engineers who identify, measure, and cost every component that makes up the property, so the client receives a full component breakdown along with the shorter-life assets. The work follows the IRS Cost Segregation Audit Techniques Guide, and the Head of Engineering signs off on each report before it reaches the client.
Every report passes through the same internal review, so quality does not depend on who picked up the file. Seneca also performs Qualified Production Property (QPP) studies for qualifying new construction.
That review step matters because the guide favors detailed engineering approaches over shortcut estimates. Our breakdown of engineering-based studies versus rule of thumb explains why examiners treat the two differently.
On-Site or Virtual Property Tours
Seneca clients choose between an on-site tour and a virtual one. Many commercial properties get an on-site visit from the engineering team, while a guided video walkthrough works well for most residential properties.
Either way, the preliminary estimate comes from Seneca’s engineering team, built from the information received about the property. Once the study starts, clients get real-time updates as it moves through defined stages, so nobody has to chase status.
AuditDefense and the Money-Back Guarantee
Seneca responds to IRS questions about its studies at no added cost. On top of that, its published guarantee refunds 100% of the study fee if an audit finds that a Seneca-caused issue led to a depreciation adjustment greater than 5%.
A written refund term gives you a defined remedy if the study is at fault, and Seneca’s record of zero IRS audits triggered or lost sits behind it.
How Engineered Tax Services Approaches a Study
Engineered Tax Services, often called ETS, is one of the longest-running firms in the field. The details below come from ETS’s own published material.
A Licensed Engineering Firm With a Long Track Record
ETS was founded in 2001 by Julio Gonzalez and is headquartered in West Palm Beach, Florida, with 26 offices nationwide. The firm holds Professional Engineering firm licenses in Florida and Texas.
ETS reports more than 75,000 completed cost segregation studies and over $2B in client tax savings. Those figures make it one of the most experienced names a buyer will encounter.
A Five-Phase Process and Tele-Engineering
ETS describes five phases: engineering analysis, cost allocation, tax classification, documentation and review, and a results walkthrough with the client and CPA. Its stated timeline for most properties is 4 to 6 weeks.
For owners who prefer not to host an inspector, ETS offers Tele-Engineering, a real-time video tour that the owner films on a phone or tablet while an ETS professional directs the shots.
A Wider Menu of Tax Incentives
ETS positions itself as a specialty tax firm rather than a cost segregation boutique. Alongside studies, it offers research and development tax credits, 179D energy deductions, 45L credits, 1031 exchange services, and insurance.
For an owner who wants several incentives handled by one provider, that breadth is a genuine advantage.
Turnaround Time and Filing Deadlines Compared
Turnaround is where the two firms differ most. Seneca delivers studies in 5 to 10 business days for every property type, complex commercial included, provided the client collaborates in a timely way, while ETS publishes 4 to 6 weeks for most properties.
The gap matters most when a return is on extension. A study that closes within two weeks of receiving your documents leaves your CPA time to review the fixed asset schedule, while a six-week study ordered in August can push the handoff uncomfortably close to the fall extension deadline.
Timing also affects the size of the deduction itself. Property acquired and placed in service after January 19, 2025 qualifies for 100% bonus depreciation under the One Big Beautiful Bill, so a faster study lets you claim that first-year benefit on the return you are filing now. Our guide to how long a cost segregation study takes covers what drives the timeline.
Study Fees and Property Size Compared
Seneca’s fully engineered residential studies start at about $2,000 and scale with the property. Commercial studies are priced to the complexity of the work and typically start at $3,500.
Both firms offer a free preliminary estimate before any fee is charged. At Seneca, the engineering team builds that estimate and proposal, and the client pays only after deciding to move forward.
ETS does not publish a fee schedule and quotes after a free analysis. The FAQ on its cost segregation page states that most professionally prepared studies run $3,000 to $12,000, depending on property size and complexity.
Property size is the second filter. ETS says studies generally make economic sense from roughly $500,000 of depreciable basis, while Seneca does not set a fixed minimum and has studied everything from small single-family rentals to large manufacturing plants. For a real number on your own property, the free Seneca calculator gives a quick estimate, and our page on what a cost segregation study costs explains the fee drivers.
Audit Protection Compared
Both firms include audit support in the study fee. ETS states that every study comes with full audit defense support at no additional charge, and Seneca responds to IRS questions about its studies at no added cost.
The difference is the written guarantee. Seneca’s published terms refund 100% of its fee if its own error causes an adjustment greater than 5%, and ETS does not publish a comparable refund term.
Our article on why audit defense matters covers what that protection should include. Neither firm can promise how an examination will end, so ask each one for its audit terms in writing.
Which Firm Fits Your Property
The right choice depends on the property, the deadline, and what else you need from a tax provider.
Single-Family, Short-Term Rental, and Small Multifamily Owners
Seneca is usually the better match here. Residential studies from about $2,000, no fixed minimum basis, and the option of a quick virtual tour suit owners of single-family rentals, small multifamily, and short-term rentals; our guide to a cost segregation study for short-term rentals shows how those studies work.
Investors Facing a Filing Deadline
Seneca has the edge whenever the calendar is tight. A 5 to 10 business day study, once the documents are in, fits inside an extension window with room for CPA review.
Large Commercial Portfolios and Multi-Incentive Projects
ETS is a strong fit for commercial projects where the owner also wants research credits, 179D, or 45L handled by the same team. Its national office network and long history suit owners who value a single provider for several incentives.
Commercial owners who only need cost segregation, from 120+ unit hotels to manufacturing plants, can expect a faster engagement with Seneca, with on-site tours available and direct access to the engineers doing the work.
Questions to Ask Both Firms Before You Sign
What we see consistently when investors bring us a competing proposal is that the turnaround and audit terms get far less attention than the estimate. Put the same questions to both firms:
- ●Methodology: Which engineering approach from the IRS guide does the study use, and who signs the report?
- ●Turnaround: How many business days from document handoff to final report, and is that date in writing?
- ●Fees: Is the quote a fixed fee, and what would change it?
- ●Audit terms: What does audit support cover, and is there a written refund term if the study is at fault?
- ●Deliverables: Will your CPA receive a fixed asset schedule ready for the return, plus support for any Form 3115 filing?
- ●Credentials: Does the team include members of the American Society of Cost Segregation Professionals or licensed engineers?
Our guide on how to choose cost segregation services goes deeper on reading two proposals side by side.
Frequently Asked Questions
Below are the questions we hear most from investors comparing Seneca and Engineered Tax Services.
Why Investors Choose Seneca
Our in-house engineers build every Seneca study, our Head of Engineering reviews each report before delivery, and audit defense comes standard, backed by 10,200+ properties assessed and zero IRS audits triggered or lost. If you are weighing Seneca against another proposal, request a free estimate and compare the numbers side by side.
Conclusion
Both firms deliver engineering-based studies that follow IRS guidance, so the choice comes down to fit. ETS brings decades of history and a wide menu of incentives, which suits large commercial owners who want one provider for several programs.
Seneca is the stronger choice for most residential, short-term rental, multifamily, and standard commercial owners: faster delivery, lower starting prices, a written refund guarantee, and a direct line to the team doing the work. Recovery periods under IRS Publication 946 apply the same way whichever firm runs the study, so speed and terms are where the real difference shows.
A free estimate is the simplest next step, and it puts a real number beside whatever proposal you already hold.
