In one paragraph
Seneca Cost Segregation and Cost Seg Smart both produce engineering-based cost segregation studies that follow the IRS Cost Segregation Audit Techniques Guide. Seneca works with rental, commercial, owner-occupied business, new-build and renovation property across all 50 states, reviewing each property virtually or on site. It publishes no fee schedule (its own comparison page gives starting points of about $2,000 for residential and typically $3,500 for commercial): per their FAQ, fees depend on square footage, property type and complexity, and they provide a free, no-money-down proposal before a study. Per their homepage, most studies are completed in 2-4 weeks, with rush prioritization available for deadlines. Their site states a common feasibility threshold of $300K+ property value (How It Works; the homepage says $450,000) or $500,000 in improvements, and their featured single-family case study is a $370,000 purchase. Cost Seg Smart's automated studies work from satellite imagery, county assessor records, and structured property data, with quality checks, within 1–2 business days, starting at $495 for residential under $300K basis and $995 for commercial. In our view, Seneca is a reasonable fit if you want a per-property quote, an optional on-site review, and their written money-back terms. Cost Seg Smart is the fit if you want a published fixed price and a 1–2 business day schedule, especially for residential, STR, small multifamily, and well-documented commercial property.
Disclosure: Cost Seg Smart operates this comparison and is one of the firms compared here. See the methodology page for our standalone documentation. Seneca details on this page were checked against senecacostseg.com on 2026-11-02; tell us at research@costsegsmart.com if anything has changed.
Cost Seg Smart in brief
- Cost Seg Smart is an engineered cost segregation provider for residential, short-term-rental, multifamily and commercial property, with residential studies from $495 and commercial from $995.
- Cost Seg Smart delivers most residential studies in 1–2 business days, remotely, using remote observation together with public government construction cost data.
- Cost Seg Smart classifies components under MACRS per Rev. Proc. 87-56 and documents every study against the 13 quality elements of the IRS Cost Segregation Audit Techniques Guide (Pub 5653), including Form 3115 §481(a) catch-up schedules for properties owned two or more years.
- Cost Seg Smart prices a sub-$300K residential study at $495 and delivers it in 1–2 business days; Seneca Cost Segregation publishes no fee schedule (fees are quoted per property after a free proposal; its own comparison page says fully engineered residential studies start at about $2,000) and states that most studies are completed in 2 to 4 weeks.
At a glance: Seneca Cost Segregation vs Cost Seg Smart
| Dimension | Cost Seg Smart | Seneca Cost Segregation |
|---|---|---|
| Price (residential under $1M) | $495–$995 | No fee schedule; free proposal first. Its own comparison page says fully engineered residential studies start at about $2,000Source, checked Nov 2, 2026: senecacostseg.com/seneca-cost-segregation-vs-engineered-tax-services, senecacostseg.com/help. Conditions: A starting point, not a quote: fees depend on square footage, property type and complexity, and the residential figure scales with the property. You pay only if you proceed after the free estimate. |
| Price ($1M–$5M commercial) | $3,295–$4,995 | No fee schedule; free proposal first. Its own comparison page says commercial studies typically start at $3,500Source, checked Nov 2, 2026: senecacostseg.com/seneca-cost-segregation-vs-engineered-tax-services. Conditions: Priced to the complexity of the work; no property-size band is stated. |
| Turnaround | 1–2 business days | 2–4 weeks for most studies (FAQ); can prioritize for a deadline (no published timeframe)Source, checked Nov 2, 2026: senecacostseg.com/help, senecacostseg.com/seneca-cost-segregation-vs-engineered-tax-services. |
| Site visit | Every study is priced as a remote study, and when a walkthrough would improve it, we do it with you on a video call at no charge. For commercial and 5+ unit property, an in-person site visit is available as an add-on for $895, travel included, throughout the contiguous United States and Washington, DC, for buildings up to 20,000 sq ft. Residential rentals (1–4 units): an in-person visit by an independent field data collector, $595 throughout the contiguous United States and Washington, DC, travel included. Larger buildings, Alaska and Hawaii are by quote. | Virtual or on-site review, depending on the property and preferenceSource, checked Nov 2, 2026: senecacostseg.com/about-us. |
| Methodology | Public government construction cost data + MACRS + ATG | Engineering-based analysis; cost-data source not namedSource, checked Nov 2, 2026: senecacostseg.com/how-it-works. |
| Audit defense | Quality-checked before delivery + free CPA methodology support, no expiry | Seneca AuditDefense: responds to IRS questions; refunds 100% of the fee if Seneca caused an issue resulting in a >5% depreciation adjustmentSource, checked Nov 2, 2026: senecacostseg.com/about-us. |
| Form 3115 lookback | Included | Supported (Form 3115 catch-up, per their FAQ)Source, checked Nov 2, 2026: senecacostseg.com/help. |
| Best fit | Residential / STR / small MF / sub-$2M commercial | Per their site: investment property worth at least $450,000, or $500,000+ of improvements, held 3+ yearsSource, checked Nov 2, 2026: senecacostseg.com, senecacostseg.com/how-it-works. |
| Specialty signal | Automated pipeline, speed, transparent pricing | Free no-money-down proposal, virtual or on-site review, conditional money-back guaranteeSource, checked Nov 2, 2026: senecacostseg.com/help, senecacostseg.com/about-us. |
| Free revision policy | Free for 12 months after first delivery (36 months for your CPA's requests), then $195 per round; corrections of our errors always free (original scope of the study) | Not publishedSource, checked Nov 2, 2026: senecacostseg.com/help. |
| CPA coordination | Included: written answers, and calls or meetings with your CPA as needed | Works with your accountant; shares a draft for review (per Seneca FAQ)Source, checked Nov 2, 2026: senecacostseg.com/help. |
Methodology overlap (what each firm publishes)
Both firms reclassify building components into shorter recovery periods and follow the IRS audit guide. Where the two differ in what they publish:
- Construction cost data. Cost Seg Smart uses public government construction cost data with regional cost multipliers. Seneca does not name a cost-data source on its site.
- Recovery periods. Both reclassify qualifying components into 5-, 7- and 15-year property instead of 27.5 or 39 years. Cost Seg Smart classifies under MACRS per Rev. Proc. 87-56; Seneca describes the same reclassification without citing the revenue procedure (How It Works).
- IRS Cost Segregation Audit Techniques Guide (Pub 5653). Seneca states it follows the ATG (About Us). Cost Seg Smart documents every study against the guide's 13 quality elements.
- Prior-year property. Per their FAQ, past depreciation can be reclaimed with Form 3115 without amending prior returns. Cost Seg Smart produces the §481(a) catch-up schedule under DCN 7.
- Quality-checked deliverable. Seneca describes engineers who assess each property; its site does not state a PE stamp or signed attestation. Cost Seg Smart includes quality checks.
What differs is the labor model and the pricing model. Seneca reviews each property virtually or on site and quotes each engagement individually. Cost Seg Smart's pipeline is built around structured-data observation at published fixed prices. In our view, an on-site review matters most for specialty build-outs (commercial kitchens, hotel furnishings, spa and pool installations, medical or manufacturing equipment) and matters little for well-documented property types.
When Cost Seg Smart may be the better choice
When should I choose Cost Seg Smart over Seneca Cost Segregation?
- You want the price before you start. Seneca quotes each property individually and publishes only starting points (about $2,000 residential, typically $3,500 commercial). Our pricing is published (residential from $495, multifamily 2–4 from $995), so the Year-1 return on the study fee is known up front. Seneca also states a common feasibility threshold of $300K+ property value (its homepage says $450,000), so smaller rentals may fall below their range.
- Well-documented commercial. Office, retail and mixed-use property that is well documented (county assessor records, RentCast property API, standard commercial subtype) rarely needs an on-site review, in our view.
- Speed-sensitive filings. 1–2 business day turnaround vs the 2–4 weeks Seneca states for most studies (they offer rush prioritization but publish no rush timeframe). If your CPA needs the schedule for a return on extension, the gap can be decisive.
- Portfolio operators. A 5–10 property portfolio in an afternoon at published per-property prices, vs individually quoted engagements.
- Buyers weighing audit-defense terms. Seneca's money-back guarantee applies only if Seneca caused an issue resulting in a >5% depreciation adjustment. Cost Seg Smart provides quality checks + free written methodology support to your CPA for the life of the study; compare the two sets of terms against the price difference.
When Seneca Cost Segregation may be the better choice
When should I choose Seneca Cost Segregation over Cost Seg Smart?
- You want someone on site. Seneca offers virtual or on-site review depending on the property, timing and your preference (About Us). For specialty build-outs such as commercial kitchens, hotel furnishings, or spa and pool installations, first-hand observation can change the allocation, in our view.
- You want a free proposal first. Per their FAQ, Seneca provides a no-money-down proposal before a study is done, so you see the fee for your specific property before committing.
- You want a written money-back condition. Seneca AuditDefense states that Seneca will respond to IRS questions about its studies and refund 100% of its fee if, in an audit, Seneca is found to have caused an issue resulting in a >5% adjustment to depreciation (published terms).
- You found Seneca through its educational content. Their post Can I Do My Own Cost Segregation Study? covers the DIY question; if you arrived that way, their paid engagement is a natural next step.
Questions worth asking Seneca and us
Whichever firm you choose, these questions show what a study covers. Each answer below is what a Cost Seg Smart study does today.
- Where does the land value come from, and does the report say which source was used? Cost Seg Smart: We set land from your own documents or from public county records where they exist, check assessor figures for reliability, and the report names the source we used.
- Does it read your closing statement, or do you type the numbers in yourself? Cost Seg Smart: Upload your settlement statement and any itemized invoices or cost schedules and we read them: capitalizable closing costs go into your basis, documented costs are classified line by line, and a cost document we cannot read holds the study for review instead of being skipped.
- On a condo, does it count your share of the shared outdoor site improvements, or only the unit? Cost Seg Smart: Where a residential condo unit includes an ownership interest in the common elements, the study may allocate a conservative portion of the unit's existing basis to the shared outdoor improvements it identifies, such as parking, landscaping and fencing, as 15-year property. It reallocates basis you already have; it does not add any. Pools, clubhouses, gyms and other building amenities are not included. Condominium law normally gives each unit an undivided interest in the common elements, so the share is included even if you did not know you held one.
- Does the schedule reconcile to your depreciable basis, and what happens if it does not? Cost Seg Smart: Every component schedule adds up to your depreciable basis to the cent, and a study that does not is automatically blocked before delivery.
- What is checked before the report reaches you, and what happens when a check fails? Cost Seg Smart: Every study is automatically quality-checked before delivery, and a study that fails a check is held rather than sent.
How to decide
Three questions to ask:
- Does your property need an on-site review? For specialty build-outs, Seneca's on-site option may be worth a quoted fee. For residential, STR, small multifamily, or standard commercial, in our view the on-site visit rarely changes the schedule materially.
- Do guarantee terms matter to your purchase? Seneca refunds its fee only if it caused an issue resulting in a >5% depreciation adjustment. If you are comfortable with quality checks + free CPA response on examiner requests, Cost Seg Smart's terms cover the audit-defense scope.
- Do you need the schedule this month or this week? Cost Seg Smart's usual 1–2 business day turnaround vs the 2–4 weeks Seneca states for most studies is the deciding factor on speed.
If you want to see the math on a specific property before deciding, our free calculator gives a Year-1 estimate in 30 seconds. Full methodology details are at /methodology/, pricing tiers at /cheap-cost-segregation/.
Every Seneca cell in the table above names its source page on senecacostseg.com, checked on 2026-11-02.