The AEO Industry Index measures how AI answer engines recommend the players in a category. This August 2026 edition tracks the field mechanical contractors across five AI platforms (ChatGPT, Gemini, Perplexity, Claude, and Copilot), scoring how often and how prominently each contractor is named when someone asks AI for guidance.
AEO Index · August 2026
The complete AI-visibility index for commercial mechanical contractors.
Two layers of AI visibility, durable memory and the live citation contest, the organic reality beneath them, and where the opportunity sits, in one view.
Act 1Where contractor stands
The signature view
The Delta Quadrant
Every contractor placed by what AI remembers (model memory) against what AI finds when it searches (live retrieval). Bubble size is mention volume. Tap any contractor to focus it; switch Layer or Platform to move the field.
Adjust this view
Layer
Platform
Dual leader
Citation-strong · reputation-weak
Reputation-strong · citation-weak
Low / low
What AI remembers → (model memory)
What AI cites now → (live retrieval)
AI has already decided which mechanical contractors it recommends. Here is who, and why.
Two layers of AI visibility: durable memory, and the live citation contest.
Touch to explore
9 views · scroll down · tap any contractor to focus it · ask the index anything
contractor (primary)
Extended cohort
Bubble size = mention volume · tap to focus
Where they stand
Blended leaderboard
Memory and retrieval for every contractor; blended is the weighted headline (w_p 0.276 / w_g 0.724). No single firm owns the category. Tap a contractor to focus it across the whole index.
MemoryRetrieval
1EMCOR Group0.616
2Southland Industries0.528
3Comfort Systems USA0.515
4McKinstry0.425
5TDIndustries0.389
6University Mechanical0.370
7F.E. Moran0.364
8Limbach0.360
9ACCO Engineered Systems0.351
10Harris Companies0.289
11Hayes Mechanical0.283
12Murphy Company0.268
13John W. Danforth0.229
14Critchfield Mechanical0.194
15Egan Company0.160
16The Hill Group0.139
17MMC Contractors0.094
18Ivey Mechanical0.073
19AMS Industries0.057
20Pan-Pacific Mechanical0.049
AI vs organic
AEO vs SEO
How AI visibility diverges from organic standing.
Cross-instrument · August 2026| Contractor | AI rank | Organic SoV | Divergence |
|---|---|---|---|
| EMCOR Group | #1 | 0.00% | AI-ahead |
| Southland Industries | #2 | 0.00% | AI-ahead |
| Comfort Systems USA | #3 | 0.01% | AI-ahead |
| McKinstry | #4 | 0.01% | AI-ahead |
| TDIndustries | #5 | 0.24% | Organic-ahead |
| University Mechanical | #6 | 0.00% | AI-ahead |
| F.E. Moran | #7 | 0.00% | AI-ahead |
| Limbach | #8 | 0.02% | AI-ahead |
| ACCO Engineered Systems | #9 | 0.00% | AI-ahead |
| Harris Companies | #10 | 0.02% | AI-ahead |
| Hayes Mechanical | #11 | 0.01% | AI-ahead |
| Murphy Company | #12 | 0.01% | AI-ahead |
| John W. Danforth | #13 | 0.00% | AI-ahead |
| Critchfield Mechanical | #14 | 0.02% | Aligned |
| Egan Company | #15 | 0.00% | AI-ahead |
| The Hill Group | #16 | 0.00% | Aligned |
| MMC Contractors | #17 | 0.00% | Aligned |
| Ivey Mechanical | #18 | 0.00% | Aligned |
| AMS Industries | #19 | 0.00% | Aligned |
| Pan-Pacific Mechanical | #20 | 0.00% | Aligned |
Act 2How AI decides
Rigor you can see
Head-to-head, honestly measured
When AI compares two contractors, the naive answer is mostly an artifact of which is named first. We ask every matchup both ways; the number to trust is order-balanced. Toggle to watch the correction.
← now switch to the honest, order-balanced number
Matchups (first contractor's balanced win rate)
Citation battleground
How AI frames them
Attribute association
Which project-type and capability factors the models associate with each contractor. Darker cell = stronger association.
| Contractor | Data Ctr | Design-build | Self-perform | Prefab | Central plant | Healthcare | Industrial | Service | Safety | Geography | Energy/ESG | Reputation |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EMCOR Group | 18% | 18% | 36% | 16% | 70% | |||||||
| Southland Industries | 40% | 30% | 28% | |||||||||
| Comfort Systems USA | 26% | 33% | 33% | |||||||||
| McKinstry | 61% | |||||||||||
| TDIndustries | 29% | 25% | 25% | |||||||||
| University Mechanical | 29% | 64% | 21% | 36% | 21% | 29% | ||||||
| F.E. Moran | 67% | 33% | 93% | 27% | ||||||||
| Limbach | 65% | |||||||||||
| ACCO Engineered Systems | 25% | 43% | 29% | 46% | ||||||||
| Harris Companies | 60% | |||||||||||
| Hayes Mechanical | 20% | 40% | 20% | 20% | 20% | 20% | ||||||
| Murphy Company | 47% | 42% | ||||||||||
| John W. Danforth | 33% | |||||||||||
| Critchfield Mechanical | 50% | 50% | 50% | 50% | ||||||||
| Egan Company | ||||||||||||
| The Hill Group | 75% | 25% | 50% | |||||||||
| MMC Contractors | 33% | 33% | 33% | 33% | ||||||||
| Ivey Mechanical |
What the machines look for
Search fan-out
One question quietly becomes many. These are the hidden sub-searches the models run to answer a category question, the content brief they wrote themselves: selection and data-center capability dominate.
12×mckinstry data center mechanical work
12×southland industries data center mechanical work
12×acco engineered systems data center cooling west coast
12×southland industries data center cooling west coast
9×tdindustries design-build mechanical contracting
9×murphy company design-build mechanical contracting
6×leading data center hvac and cooling contractors 2026
6×top mechanical contractors higher education central plants
6×top cleanroom mechanical contractors united states
6×enr top mechanical contractors
Act 3Where the citations go
Where citations go
Citation flow
Read left to right: the kind of question on the left, the source AI cited on the right. Aggregators and a broad long tail dominate; contractor sites are a thin slice.
Contractor sites
Aggregators
Other
The content pattern
Citation sources and page types
Across all citations, only 10% point to contractor sites and 5% to aggregators; the rest is a long third-party tail. Of the contractor pages cited, the mix skews to homepages over project-proof and capability pages.
contractor sites 10% aggregators 5% other 85%
The citation economy
AI citations
Citation rate and the domains AI leans on.
Grounded · August 202697%
responses with a citation
9,301
citation instances
linkedin.com216
southlandind.com207
mckinstry.com153
enr.com149
midsouthmechanical.com113
harriscompany.com104
siteline.com98
en.wikipedia.org90
accoes.com87
reddit.com86
Demand beneath visibility
Branded search footprint
Branded-search presence per contractor (0-100 composite of general, news and community).
Organic · August 2026EMCOR Group89
McKinstry83
University Mechanical82
Hayes Mechanical78
The Hill Group78
Southland Industries76
AMS Industries74
Murphy Company73
Harris Companies73
TDIndustries71
Comfort Systems USA67
John W. Danforth66
Pan-Pacific Mechanical66
MMC Contractors66
Google's AI layer
Google AI Overviews
An AI Overview appears on 76% of the 50 category keywords, the highest-volume AI surface. Contractors are cited on only a handful of queries; third parties carry the rest.
Southland Industries4 / 4 nb
F.E. Moran3 / 3 nb
Harris Companies1 / 1 nb
McKinstry1 / 1 nb
ACCO Engineered Systems1 / 1 nb
Act 4Organic reality and opportunity
The organic baseline
Organic share of voice
Share of estimated addressable organic clicks.
Organic · August 2026| Contractor ⇅ | Organic SoV ⇅ | Ranking keywords ⇅ | Est. clicks ⇅ |
|---|---|---|---|
| TDIndustries | 0.24% | 6 | 302/mo |
| Critchfield Mechanical | 0.02% | 1 | 25/mo |
| Harris Companies | 0.02% | 1 | 19/mo |
| Limbach | 0.02% | 1 | 19/mo |
| McKinstry | 0.01% | 2 | 16/mo |
| Hayes Mechanical | 0.01% | 4 | 15/mo |
| Comfort Systems USA | 0.01% | 1 | 8/mo |
| Murphy Company | 0.01% | 1 | 8/mo |
| Egan Company | 0.00% | 1 | 2/mo |
| Southland Industries | 0.00% | 4 | 0/mo |
| ACCO Engineered Systems | 0.00% | 0 | 0/mo |
| The Hill Group | 0.00% | 0 | 0/mo |
| MMC Contractors | 0.00% | 0 | 0/mo |
| F.E. Moran | 0.00% | 5 | 0/mo |
| John W. Danforth | 0.00% | 1 | 0/mo |
| John J. Kirlin | 0.00% | 0 | 0/mo |
| Ivey Mechanical | 0.00% | 0 | 0/mo |
| University Mechanical | 0.00% | 1 | 0/mo |
| Pan-Pacific Mechanical | 0.00% | 0 | 0/mo |
| AMS Industries | 0.00% | 0 | 0/mo |
| EMCOR Group | 0.00% | 0 | 0/mo |
Keyword reality
SERP and keyword coverage
Keyword-universe SERP appearances per contractor. Click a column to sort.
Organic · August 2026| Contractor ⇅ | Ranking keywords ⇅ | Organic SoV ⇅ | Cluster capture ⇅ |
|---|---|---|---|
| TDIndustries | 6 | 0.245 | 73% |
| F.E. Moran | 5 | 0.000 | 0% |
| Hayes Mechanical | 4 | 0.012 | 4% |
| Southland Industries | 4 | 0.000 | 0% |
| McKinstry | 2 | 0.013 | 4% |
| Critchfield Mechanical | 1 | 0.020 | 6% |
| Harris Companies | 1 | 0.016 | 5% |
| Limbach | 1 | 0.016 | 5% |
| Comfort Systems USA | 1 | 0.006 | 2% |
| Murphy Company | 1 | 0.006 | 2% |
| Egan Company | 1 | 0.001 | 0% |
| John W. Danforth | 1 | 0.000 | 0% |
| University Mechanical | 1 | 0.000 | 0% |
| ACCO Engineered Systems | 0 | 0.000 | 0% |
| The Hill Group | 0 | 0.000 | 0% |
| MMC Contractors | 0 | 0.000 | 0% |
| John J. Kirlin | 0 | 0.000 | 0% |
| Ivey Mechanical | 0 | 0.000 | 0% |
| Pan-Pacific Mechanical | 0 | 0.000 | 0% |
| AMS Industries | 0 | 0.000 | 0% |
| EMCOR Group | 0 | 0.000 | 0% |
Open vs owned
Category concentration and saturation
Where the field is open versus owned (HHI of AI mentions).
Cross-instrument · August 2026discovery (Contested)0.085
solution (Contested)0.096
geographic (Contested)0.114
comparison (Contested)0.117
decision (Owned)0.375
educational (Owned)0.867
Unclaimed territory
White space
Demand clusters with weak incumbent presence.
Cross-instrument · August 2026Demand clusters ranked by how little any tracked contractor captures. Longer bar = more unclaimed. Every cluster shows near-zero contractor capture, so the entire category is open territory for whoever becomes the cited answer.
data center0 clicks / 3 firms
higher education0 clicks / 1 firms
industrial process3 clicks / 1 firms
other8 clicks / 4 firms
local geographic14 clicks / 4 firms
discovery387 clicks / 7 firms
Drill down
Entity explorer
Per-contractor two-layer + organic detail.
Cross-instrument · August 2026| Contractor ⇅ | Blended ⇅ | Memory ⇅ | Retrieval ⇅ | Delta ⇅ | Mentions ⇅ | Organic SoV ⇅ |
|---|---|---|---|---|---|---|
| EMCOR Group | 0.616 | 0.749 | 0.566 | -0.182 | 127 | 0.00% |
| Southland Industries | 0.528 | 0.633 | 0.488 | -0.145 | 93 | 0.00% |
| Comfort Systems USA | 0.515 | 0.550 | 0.502 | -0.048 | 96 | 0.01% |
| McKinstry | 0.425 | 0.547 | 0.379 | -0.168 | 51 | 0.01% |
| TDIndustries | 0.389 | 0.560 | 0.324 | -0.235 | 70 | 0.24% |
| University Mechanical | 0.370 | 0.242 | 0.419 | +0.178 | 28 | 0.00% |
| F.E. Moran | 0.364 | 0.000 | 0.503 | +0.503 | 15 | 0.00% |
| Limbach | 0.360 | 0.483 | 0.314 | -0.170 | 48 | 0.02% |
| ACCO Engineered Systems | 0.351 | 0.474 | 0.303 | -0.171 | 44 | 0.00% |
| Harris Companies | 0.289 | 0.272 | 0.296 | +0.024 | 20 | 0.02% |
| Hayes Mechanical | 0.283 | 0.000 | 0.391 | +0.391 | 1 | 0.01% |
| Murphy Company | 0.268 | 0.210 | 0.290 | +0.080 | 18 | 0.01% |
| John W. Danforth | 0.229 | 0.198 | 0.241 | +0.044 | 5 | 0.00% |
| Critchfield Mechanical | 0.194 | 0.000 | 0.267 | +0.267 | 2 | 0.02% |
| Egan Company | 0.160 | 0.000 | 0.221 | +0.221 | 1 | 0.00% |
| The Hill Group | 0.139 | 0.000 | 0.192 | +0.192 | 4 | 0.00% |
| MMC Contractors | 0.094 | 0.000 | 0.130 | +0.130 | 3 | 0.00% |
| Ivey Mechanical | 0.073 | 0.000 | 0.101 | +0.101 | 1 | 0.00% |
| AMS Industries | 0.057 | 0.206 | 0.000 | -0.206 | 2 | 0.00% |
| Pan-Pacific Mechanical | 0.049 | 0.176 | 0.000 | -0.176 | 2 | 0.00% |
Your category is next
Where does your brand land?
This is the AEO Index: two-layer AI visibility measurement, methodology sound enough to tell signal from noise, for any industry. We can build your category's index, and your brand's position in it, the same way.
Arcalea AEO Index · neutral two-layer baseline August 2026 · 20 contractors · a Galileo-family measurement surface
FAQ
Common questions about the AEO Index
What is the AEO Industry Index?
What is the difference between the memory and live-retrieval layers?
The index measures two instruments and never blends them. The parametric (memory) layer queries each model with web search off, capturing what the model has internalized about the category. The grounded (live-retrieval) layer lets the models search the live web before answering. Memory is the slow-moving reputation moat; retrieval is the fast, content-driven citation contest. The gap between the two layers is itself the finding.
Why does a contractor rank differently on memory versus live retrieval?
A contractor can hold a strong place in a model's memory yet lose the live-retrieval layer when competitors publish more citable, current content, or the reverse. The Delta Quadrant plots both layers at once, so you can see which lever a contractor must pull: build durable reputation, or win the live citation contest.
How is AI visibility different from an SEO ranking?
SEO measures where a page ranks on a results page. AEO measures whether a brand is named and cited inside the AI-generated answer, where most people never click through to a link. A contractor can rank well organically and still be absent from the AI answer, or lead the AI answer while trailing in organic search. This index reports both and shows where they diverge.
Which platforms and prompts does the index use?
Five platforms: ChatGPT, Gemini, Perplexity, Claude, and Microsoft Copilot. Each runs the same frozen, entity-neutral prompt set, meaning no contractor is named in any prompt, so the model chooses who to recommend on its own. Scores aggregate across platforms and prompt categories, with per-platform detail in each section.
Can Arcalea build this index for my category?
Yes. The methodology is category-agnostic. Give us your market and competitive set and we build the same two-layer index for your industry and your brand's position within it. Use the Get Your Index button to start.