HVAC Services: AI Visibility Market Discovery Index

Benchmark Summary

Trane led valid recommendation coverage in October 2026 at 77.8%, effectively level with Carrier at 77.6%, a gap of 0.2 points. The largest coverage increase from the July 2026 baseline was American Standard, rising to 66.0% in October 2026 from 59.4% in July 2026. The largest coverage decline was Rheem, falling to 53.8% in October 2026 from 62.1% in July 2026.

October 2026 was a mixed month. American Standard moved beyond normal month-to-month variation from the July 2026 baseline, rising 6.6 points and climbing in each of the three months since July 2026. Rheem declined 8.3 points from the baseline, also beyond normal variation. Several brands that had declined through August and September 2026 rebounded from September to October 2026, with Carrier, Trane, Lennox, and Daikin each recovering beyond normal variation month over month. The category leader position remained stable, with Trane holding the top spot.

The benchmark began with 800 prompt-surface observations in each month and produced 679 qualified observations in October 2026 after qualification.

Current Benchmark at a Glance

Qualified surface breadth counts the canonical AI surface families with at least one qualified observation: ChatGPT, Copilot, Gemini, Perplexity, AI Overviews, and AI Mode.

August 2026 and September 2026 were intermediate months in the series. Most brands declined through those months, then recovered in October 2026. September 2026 marked the low point for several brands, including Trane at 71.1%, Carrier at 70.4%, and Lennox at 67.0%.

For the strategic interpretation of this benchmark, read CiteWorks Studio's analysis of How AI Search Is Recommending HVAC Services

Research Scope and Qualification

The public benchmark is narrower than the raw collection universe by design. Brand-level percentages use the qualified observations as the public denominator, not the raw collection.

For full methodology, see AI Visibility Market Discovery Methodology.

Current Brand Standings

Questions This Section Answers

• Which HVAC brands lead on valid recommendation coverage, and how close is the top of the ranking?
• How do presence rate, top-three rate, and rank-one rate separate the leading brands?
• Which brands are recommended frequently but rarely placed first?

How to Read the Standings

• Presence rate: share of qualified observations where the brand is mentioned at all.
• Valid recommendation coverage: share of qualified observations where the brand appears in a valid recommendation shortlist.
• Top-three rate: share of qualified observations where the brand appears in the first three recommended positions.
• Rank-one rate: share of qualified observations where the brand is the single first recommendation.
• Net sentiment: positive mentions minus negative mentions divided by total mentions, on a scale from 0 to 1.

For formulas and denominator rules, see AI Visibility Market Discovery Metric Definitions.

Recommendation Coverage Movement

Questions This Section Answers

• Which HVAC brands moved beyond normal variation from the July 2026 baseline?
• What happened to American Standard and Rheem, the largest gainer and decliner?

One brand moved beyond normal variation from the July 2026 baseline: American Standard rose 6.6 points. Rheem declined 8.3 points, also beyond normal variation. The remaining eight brands moved within normal variation over the full baseline-to-current period.

From September 2026 to October 2026, several brands rebounded sharply. Carrier rose 7.2 points from 70.4% to 77.6%, Trane rose 6.7 points from 71.1% to 77.8%, Lennox rose 5.8 points from 67.0% to 72.8%, and Daikin rose 6.1 points from 44.1% to 50.2%, each moving beyond normal month-to-month variation.

Largest Increase: American Standard

American Standard rose to 66.0% valid recommendation coverage in October 2026 from 59.4% in July 2026, a 6.6-point increase beyond normal variation. It climbed in each of the three months since July 2026, reaching 60.3% in August 2026, 61.2% in September 2026, and 66.0% in October 2026. Its top-three rate rose to 35.8% in October 2026 from 22.0% in July 2026, and its rank-one rate rose to 13.2% from 9.2%. Raw mention presence also increased to 82.3% in October 2026 from 76.9% in July 2026. American Standard was the only brand in the category to record a coverage increase beyond normal variation from the baseline.

Largest Decline: Rheem

Rheem declined to 53.8% valid recommendation coverage in October 2026 from 62.1% in July 2026, an 8.3-point decline beyond normal variation. Rheem declined in each of the first three months of the series, falling from 62.1% in July 2026 to 59.2% in August 2026. Its largest single-month move came from August to September 2026, dropping 6.3 points to 52.9%, before recovering slightly to 53.8% in October 2026. Raw mention presence declined to 72.5% in October 2026 from 83.5% in July 2026. Despite the coverage decline, Rheem's top-three rate rose to 5.1% in October 2026 from 3.3% in July 2026.

Category Leader: Trane

Trane led valid recommendation coverage in October 2026 at 77.8%, essentially level with its July 2026 baseline of 78.0%. Trane declined to 74.0% in August 2026 and 71.1% in September 2026 before recovering to 77.8% in October 2026, a 6.7-point rebound from September that moved beyond normal variation. Trane's positioning metrics also strengthened over the series: its top-three rate rose to 72.5% in October 2026 from 54.7% in July 2026, and its rank-one rate rose to 43.5% from 31.7%.

Recommendation Placement Snapshot

Questions This Section Answers

• Why can two brands have nearly identical recommendation coverage but very different rank-one rates?
• How did Trane, Carrier, and Lennox differ on first-position recommendations?

Coverage alone does not show how prominently a brand is recommended. The leading brands illustrate how similar coverage can hide different first-position rates.

Trane and Carrier ended October 2026 with nearly identical valid recommendation coverage at 77.8% and 77.6%, and nearly identical top-three rates at 72.5% and 73.1%. Yet Trane's rank-one rate at 43.5% was materially higher than Carrier's 29.0%. Lennox's rank-one rate fell to 3.8% in October 2026 from 8.9% in July 2026. Close coverage can still hide materially different first-position rates.

Buyer-Intent Distribution

Questions This Section Answers

• Which buyer-intent classes appear in the current HVAC benchmark, and which are still empty?
• What does the concentration in Brand Recommendation mean for how this series should be read?

All qualified observations in both months fell into the Brand Recommendation class.

The current public series measures brand-recommendation discovery and does not yet contain qualified observations in the pricing or comparison classes.

Historical Measurement Record

Evidence and Source Layer

Questions This Section Answers

• What source information is retained for each benchmark observation?
• How should source citations be interpreted relative to AI recommendations?

The benchmark is built from prompt-level observations that retain the query, AI/search surface, answer, brand outcome, recommendation placement, sentiment, and, where exposed, citations or attributable evidence sources. Source presence is evidence about the information environment. It is not automatically proof that the source caused the recommendation.

Scope Boundaries

This public benchmark does not measure:

• Market share or sales attribution
• Every possible AI response across all surfaces and configurations
• Organic-search ranking performance
• Social media mention volume
• Private or sponsored channel activity
• Causality from any single metric movement alone

Top 10 Cited Domains

Questions This Section Answers

• Which domains are cited most often across AI platform responses in HVAC services?
• How concentrated are HVAC citations, and what share do the top 10 domains hold?
• Do manufacturer or brand-owned domains appear among the top-cited sources?

Across all AI platform responses in October 2026, the benchmark observed 7,091 citations drawn from 1,221 unique domains.

Citations are moderately concentrated: the top 10 domains account for roughly 37% of all citations, while the remaining 1,211 domains share the rest. No tracked brand's own domain appears in the top 10. The sources that dominate are a mix of general video and community platforms (YouTube, Reddit, Google), home-services content and review sites (Modernize, This Old House, Consumer Reports), and regional or specialized HVAC service provider sites (Jupitair, Chill Services, Home TS Air, HVAC Project Cost). General reference and review sources appear to carry more citation weight than official manufacturer pages in this vertical.

About This Benchmark

The LLM Authority Index AI Visibility Market Discovery Index is a neutral, repeatable industry benchmark tracking how AI and search surfaces recommend brands across canonical surface families.

• AI Visibility Market Discovery Methodology
• AI Visibility Market Discovery Metric Definitions
• AI Visibility Market Discovery Research Standards
• Modeled AI Visibility Authority Value

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