In one paragraph
Madison SPECS is a specialty engineering firm focused on commercial cost segregation, particularly larger and more complex properties. Both firms produce IRS ATG-aligned studies using RSMeans 2024 cost data and MACRS classification per Rev. Proc. 87-56. Madison SPECS sends licensed engineers on-site, runs a 4–6 week engagement, and is built for $5M+ commercial work — high-end office, industrial, hospitality, and specialty real estate where on-site engineering judgment materially affects the schedule. Cost Seg Smart is built for residential and small-commercial under $5M — SFR, STR, condo, multifamily 2–4 unit, and small office/retail — using the same methodology applied to structured property data instead of an on-site visit. Studies start at $495 and ship in under 60 minutes.
At a glance: residential $500K STR comparison
| Dimension | Cost Seg Smart | Madison SPECS |
|---|---|---|
| Price (residential $500K) | $795 | Often won't quote (commercial focus) |
| Price (commercial $3M) | $1,895 | ~$8,000–$15,000+ |
| Turnaround | Under 1 hour | 4–6 weeks typical |
| Site visit | No (remote observation) | Yes (engineer on-site) |
| Methodology | RSMeans 2024 + MACRS | RSMeans + MACRS + on-site engineering |
| Property focus | Residential, STR, small MF, small commercial | High-end commercial, industrial, hospitality |
| Form 3115 lookback | Included | Included |
| Best fit | Under $5M, residential, STR, small MF | $5M+ commercial with specialty assets |
Methodology overlap (both firms)
The underlying technical machinery is the same. Both use:
- RSMeans 2024 construction cost data as the primary cost basis, calibrated by regional cost multipliers.
- MACRS classification per Rev. Proc. 87-56 for asset class lives (5-, 7-, 15-, 27.5-, or 39-year recovery).
- IRS Cost Segregation Audit Techniques Guide (Pub 5653) as the 13-element quality framework defining what a defensible study contains.
- Form 3115 §481(a) lookback support for properties owned 2+ years without a prior cost-seg study.
- Licensed engineer attestation on every report.
The difference is what feeds the methodology. Madison SPECS uses an on-site engineer's first-hand observations of the property — measuring custom finishes, identifying specialty MEP, evaluating ground-up specialty construction. Cost Seg Smart uses structured property data — county assessor records, RentCast property API, OSM building classification, satellite imagery, and the RSMeans cost library applied algorithmically. For high-end commercial properties with specialty assets that aren't well-represented in public data, the on-site approach captures details ours can't. For typical residential and small-commercial, the structured-data approach produces the same MACRS classification result.
Where Cost Seg Smart wins
- Residential rentals. Madison SPECS is built for $5M+ commercial work; their pricing model often won't quote a $400K SFR or $750K STR. We're built specifically for that segment — same methodology, study starts at $495.
- Small multifamily and small commercial under $5M. The break point where on-site engineering judgment materially affects the schedule is around $5M for typical commercial. Below that, structured-data analysis produces the same MACRS classification at a fraction of the cost and time.
- Portfolio investors with multiple residential properties. Each property is a fresh order, ~60 minutes, $495–$1,895. A residential portfolio of 10+ properties simply isn't economic at Madison SPECS pricing.
- STR owners on event-driven properties. The high-FF&E-density properties (Pacific Beach, Old Town Scottsdale, East Austin, Joshua Tree) are exactly where engineering-grade RSMeans classification matters. We score them the same way; pricing is residential-tier.
- Speed-sensitive filings. 60-minute turnaround vs. 4–6 weeks. If your CPA needs the schedule for a return that's already in extension, we deliver in time.
Where Madison SPECS wins
- High-end commercial over $5M. Class-A office, industrial with specialty MEP, hospitality with food-and-beverage build-out — these benefit from on-site engineering judgment that captures custom assets and specialty construction not visible in public data.
- Ground-up commercial new construction. When the building was custom-built recently, engineering observation of the actual construction details (vs. relying on assessor records that may not reflect the new build) materially affects the schedule.
- Specialty industrial and manufacturing. Custom equipment, process plumbing, specialty electrical — these are exactly the cases where on-site engineering is genuinely necessary, not optional.
- Hospitality and resort properties. Food-and-beverage build-out, FF&E in guest rooms, specialty fixtures — the on-site engagement model captures details that drive higher accelerated allocation than a remote analysis would identify.
- Properties where you specifically expect IRS examination. Both firms produce ATG-aligned reports. If the property is large enough that you want maximum defense-in-depth (extra exhibits, expanded methodology, dedicated audit-response retainer), Madison SPECS's larger engagement model accommodates that.
How to decide
Three questions to ask:
- Is the property over $5M with specialty assets, hospitality, or ground-up commercial new construction? → Madison SPECS.
- Does the property have unusual MEP, custom finishes, or specialty industrial equipment that requires on-site engineering judgment? → Madison SPECS.
- Otherwise (residential, STR, small MF, small commercial under $5M)? → Cost Seg Smart. Same methodology, dramatically lower study fee, faster turnaround.
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/.
costsegregationreviews.com tracks how major firms differ on methodology — Madison SPECS included — which is a useful editorial cross-check before committing to either side.
Last reviewed: May 2026. Maintained by the Cost Seg Smart Editorial Team. Madison SPECS is the registered trademark of Madison SPECS LLC. No affiliation. This comparison is informational; both firms produce IRS ATG-aligned engineered cost segregation studies. Confirm pricing and scope directly with each vendor.