The US HVAC & Plumbing Industry: A Structural Overview

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The US HVAC and plumbing services-and-distribution complex is the set of US activities that install, maintain, and supply the equipment and systems that move air, heat, and water through buildings — the contractor trade that performs the installation work, and the merchant-wholesale channels through which equipment and supplies move from manufacturers to the trade. Together these activities employ roughly 1.5 million people across approximately 122,000 employer firms and a larger sole-proprietor tail. The complex is defined by three six-digit NAICS codes: plumbing, heating, and air-conditioning contractors (NAICS 238220),plumbing and heating equipment and supplies wholesalers (NAICS 423720)for the hydronics side, and warm-air heating and air-conditioning equipment and supplies wholesalers (NAICS 423730). Adjacent industries — HVAC equipment manufacturing, household appliance repair, refrigeration equipment wholesale, and general residential remodeling — operate under different dynamics and sit outside the scope of this page and of the references built around it.

The HVAC and plumbing services-and-distribution complex is a recurring focus for mid-market private-equity buy-and-build for three structural reasons. First, it is profoundly fragmented at the firm level: roughly 90% of contractor employer firms have fewer than 20 employees (U.S. Census SUSB, 2022), and the median firm is small, local, and labor-bound. The distribution side is meaningfully more consolidated than the trade it supplies but remains fragmented relative to other manufacturing supply channels, with roughly three-quarters of wholesale firms under 20 employees. Fragmentation of this depth is the precondition for platform consolidation: a small geographically-bounded operator base provides a deep bolt-on pipeline (Hammer, Knauer, Pflücke & Schwetzler, 2017).

Second, labor is the binding operating constraint, and labor markets in skilled trades have repriced materially over the past several years. Average annual wages for HVAC and plumbing contractors compounded roughly 16% between 2021 and 2024 (BLS Quarterly Census of Employment and Wages); distribution wages on both the hydronics and warm-air sides moved at similar rates from a higher base. Wage compounding of that magnitude is structural rather than cyclical, and it shifts the operating economics of any consolidation strategy whose pro-forma assumes a stable contractor wage curve. The complex is also one of the few mid-market industries where the labor constraint is binding on both the trade and the supply channel simultaneously.

Third, the complex sits inside a residential and nonresidential construction cycle whose volume is cyclical but whose composition shifts more slowly. New residential construction permits (U.S. Census Bureau Building Permits Survey) and existing-home sales drive the contractor side; equipment shipments tracked by the Air-Conditioning, Heating, and Refrigeration Institute statistical release provide an industry-native indicator that is not derivable from federal sources. The interaction of fragmentation, labor repricing, and cyclical demand makes the complex a defensible setting for structured operating analysis, and a complicated one to underwrite from averages alone.

The scope excludes HVAC equipment manufacturing (NAICS 333415 and adjacent — a supplier industry operating under different dynamics, not a buy-and-build target in this complex), household appliance repair (a smaller industry with household-skew and scope contamination), refrigeration equipment wholesale (NAICS 423740 — operationally distinct), building-cleaning services, and general residential remodeling. The three included codes are the complete services-and-distribution complex named in the scope: nothing else is added by judgment.

The contractor industry is the largest of the three by every measure: approximately 107,000 employer firms operating 109,600 establishments and employing 1,176,800 people in 2022 (U.S. Economic Census, 2022). It performs the installation, replacement, and maintenance work — residential and nonresidential — that makes equipment usable in a building. Output is the value of construction work performed, $297.6B in 2022. Payroll represents 27 cents of every output dollar, the highest payroll share of any of the three industries in the complex and a structural fact of the trade: a contractor business is, fundamentally, a labor business.

Operationally, the contractor side splits between residential and nonresidential work. The two are distinct populations: residential pays lower wages (approximately $67,000 average annual in 2024 versus $91,000 for nonresidential), turns inventory more slowly, and runs on smaller project sizes. Nonresidential operates closer to a commercial-construction service-trade model with larger projects, more complex specifications, and higher wage rates that reflect the work content. BLS QCEW employment data shows residential and nonresidential moving at different rates across the 2021–2024 window: residential led 2022, nonresidential led 2023 and 2024, the full-window growth almost identical (+10.8% vs +10.4%). Treating the two as one industry obscures the most informative structure on this side.

Buy-and-build strategies on the contractor side typically focus on regional density and route-density economics: a platform builds out a metropolitan-area footprint of 5–15 locations, then layers on bolt-on operators in adjacent geographies. The fragmentation of the firm base supports this approach — the ten largest states hold 53% of contractor firms (Census SUSB, 2022), but no state dominates: the largest single-state share is 10%. Consolidation is a market-by-market exercise rather than a national one.

The hydronics distribution industry comprises wholesale merchants of plumbing fixtures, pipe, fittings, and hydronic heating equipment: the wet side of the supply channel. The 2022 Economic Census reports 2,554 employer firms operating 6,747 establishments and employing 87,600 people. Output is sales, $97.8B in 2022. The industry is more consolidated than the contractor trade it supplies — 75% of firms have fewer than 20 employees against 90% on the contractor side — but remains fragmented relative to the wholesale supply channels of other building-systems industries.

Operationally, hydronics distribution is working-capital intensive: inventory turnover is the central efficiency metric, branch-level inventory mix is the operating challenge, and accounts receivable balances reflect the contractor-customer payment cycle. Payroll represents 6.3% of sales — a wholesale-distribution structure rather than a service-trade one. Wages are distinctly higher than contractor wages (approximately $92,000 average annual in 2024) because the work content is different: branch counter staff, outside sales, and quotation labor are priced above field installation rates. Equipment prices for the hydronics product bundle are tracked by BLS Producer Price Index series WPU1054 (plumbing fixtures and fittings), which compounded approximately 12% between 2021 and 2024 — the equipment-price reset is a structural feature of the period, not a forecast.

Buy-and-build strategies on the hydronics side typically focus on geographic expansion of a regional platform: the operating efficiencies are in branch-network density, supplier-rebate consolidation, and integrated quotation systems. The customer base is the contractor trade — the segment described in the previous section — and platform purchasing power vis-à-vis manufacturers is the operating rationale most often cited for consolidation on this side.

The warm-air distribution industry comprises wholesale merchants of furnaces, central air conditioners, heat pumps, ventilation equipment, and related supplies: the dry side of the supply channel. The 2022 Economic Census reports 2,072 employer firms operating 6,427 establishments and employing 81,100 people. Output is sales, $96.6B in 2022 — almost identical in scale to hydronics, slightly smaller in firm count. The two distribution industries are similar in shape but serve different equipment categories with different cyclical dynamics: hydronics is more tied to plumbing and bathroom replacement; warm-air is more tied to new construction and equipment replacement cycles.

Warm-air distribution pays the highest wages of the three industries in the complex — approximately $112,000 average annual in 2024, almost twice the residential-contractor wage — reflecting the technical specification content of the work and the historically tight labor markets for HVAC-specific knowledge. Equipment unit shipments are tracked directly by AHRI: central air conditioners shipped 5.6 million units in 2024, air-source heat pumps 4.1 million units, gas warm-air furnaces 3.1 million units. The shipment data is industry-native — it is not derivable from federal sources — and provides a higher-frequency current-conditions indicator than the annual or quinquennial federal series.

Buy-and-build on the warm-air side mirrors the hydronics approach in structure but differs in cyclical exposure: warm-air sells into both replacement and new-construction demand, and is more directly exposed to residential building permit volume than hydronics. Heat-pump shipment growth (+14% in 2024) and a multi-year regulatory tightening of efficiency standards have created within-period shifts in product mix that compound the underlying labor-and-construction cycle.

Several operating themes recur across the three industries in the complex. The contractor-distributor gradient is the structural fact of the complex: payroll share of output runs 27 cents per dollar on the contractor side and 6–8 cents on the distribution side, an unbridgeable structural gap that reflects two fundamentally different business models. The same gradient appears in wage levels, inventory turnover, working-capital intensity, and overhead structure. Operators on one side should not be benchmarked against operators on the other; consolidators acquiring across the gradient are integrating two operating models, not one.

The residential–nonresidential signature on the contractor side is the second consistent theme. Residential and nonresidential contractors operate within the same six-digit NAICS code but report fundamentally different wage structures, employment dynamics, and project economics. The classification of a target as residential or nonresidential — and the implication for which side of the labor-cost curve it operates on — is the most consequential structural diligence question on the contractor side.

Fragmentation is the third recurring theme. The contractor side has approximately 107,000 employer firms and a sole-proprietor tail of multiples larger; the two distribution industries together count under 5,000 employer firms but operate roughly 13,000 establishments. Branch-level fragmentation is the structural condition under which platform strategies are built, and the gradient from 90%-under-20 (contractors) to 70%-under-20 (warm-air distribution) describes the consolidation runway available on each side. The structural reference for this complex maps fragmentation at full code-by-code granularity using Census County Business Patterns.

Geographic dispersion in the HVAC and plumbing complex tracks population and construction activity. The contractor industry appears in essentially every U.S. county, with density that follows residential and commercial building volumes. The distribution industries are more concentrated by establishment than the contractor side — branches cluster in metropolitan areas where the contractor customer base is dense — but still appear in roughly two-thirds of U.S. counties. Ellison and Glaeser (1997) provide the foundational methodology for measuring geographic concentration; that framework, applied to the three industries in the complex, shows them as substantially less concentrated than typical manufacturing industries (which cluster around resource bases or historical agglomerations) and as broadly tracking population. No region dominates the complex; consolidation in the industry is a market-by-market exercise.

These geographic patterns matter for buy-and-build pipeline. The Add-On Density Atlas — when published for this complex — maps the contractor-side establishment density at county granularity and overlays a five-year drift layer that shows where the establishment base is filling or thinning. The distribution industries, with their lower-but-still-substantial county coverage, are mapped on the same basis, with the branch network density displayed alongside the contractor density that supports it.

Industrial Patterns publishes three modules for each industry it covers. Operating Benchmarks reports the distribution of operating outcomes across the peer set on four metric families — margin behavior, labor elasticity, capital efficiency, and overhead. The inaugural HVAC and Plumbing edition (2024) is the first of these. Industry Structure Reference describes the structural condition across seven dimensions — population and composition, size structure, geography, concentration, dynamics, payroll-and-wage structure, and current conditions. Add-On Density Atlas maps establishment density and five-year drift at county granularity. The three modules are designed to be read together — the operating layer, the structural layer, and the geographic layer of the same named industry complex.

Each module is presented as a distribution of observed patterns across the peer set, not as a single industry average. Where a source suppresses a cell at fine granularity, the gap is shown rather than imputed. The references do not rank industries, score them, or characterize any structure as attractive — they report what the data reports.

Read “What is Operating Benchmarking? A Reference Guide” next →

Air-Conditioning, Heating, and Refrigeration Institute. (2024). AHRI statistical releases: Central air conditioner and heat pump shipments, gas warm-air furnace shipments, residential water heater shipments. https://www.ahrinet.org/analytics/statistics

Bureau of Labor Statistics. (2024). Quarterly Census of Employment and Wages, private national employers, NAICS 238220 / 423720 / 423730. https://www.bls.gov/cew/

Bureau of Labor Statistics. (2024). Producer Price Index — finished consumer goods and intermediate materials, HVAC and plumbing-fixture series. https://www.bls.gov/ppi/

Bureau of Labor Statistics. (2024). Occupational Employment and Wage Statistics, May 2024 — building-equipment contractor industry group. https://www.bls.gov/oes/

Bureau of Labor Statistics. (2024). Job Openings and Labor Turnover Survey — construction sector openings, hires, and separations. https://www.bls.gov/jlt/

Ellison, G., & Glaeser, E. L. (1997). Geographic concentration in U.S. manufacturing industries: A dartboard approach. Journal of Political Economy, 105(5), 889–927. https://doi.org/10.1086/262098

Hammer, B., Knauer, A., Pflücke, M., & Schwetzler, B. (2017). Inorganic growth strategies and the evolution of the private equity business model. Journal of Corporate Finance, 45, 31–63. https://doi.org/10.1016/j.jcorpfin.2017.04.006

Internal Revenue Service Statistics of Income. (2022). Corporation Source Book — minor industry detail for NAICS 238220 and wholesale grouping covering 423720 and 423730. https://www.irs.gov/statistics/soi-tax-stats-corporation-source-book

Scholes, L., Wright, M., Westhead, P., Bruining, H., & Kloeckner, O. (2009). Family-firm buyouts, private equity, and strategic change. Journal of Private Equity, 12(2), 7–18. https://jpe.pm-research.com/content/12/2/7

Syverson, C. (2011). What determines productivity? Journal of Economic Literature, 49(2), 326–365. https://doi.org/10.1257/jel.49.2.326

U.S. Census Bureau. (2022). Economic Census — NAICS 238220 / 423720 / 423730. https://www.census.gov/programs-surveys/economic-census.html

U.S. Census Bureau. (2024). Statistics of U.S. Businesses — firm and establishment counts by enterprise employment size. https://www.census.gov/programs-surveys/susb.html

U.S. Census Bureau. (2024). Building Permits Survey — new residential construction. https://www.census.gov/construction/bps/

U.S. Census Bureau. (2024). County Business Patterns — establishments and employment by county and NAICS. https://www.census.gov/programs-surveys/cbp.html

U.S. Census Bureau. (2023). Nonemployer Statistics — sole-proprietor tail at 4-digit industry brackets. https://www.census.gov/programs-surveys/nonemployer-statistics.html