Steam and Air-Conditioning Supply — NAICS 22133

A rollup primer for both public-market and private investors. This is a pass-through level: the NAICS industry (5-digit) code 22133 contains exactly one child industry, 221330, so the two are effectively the same thing. Core figures below are U.S. federal statistics; company detail lives in the child primer.

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1. Overview

NAICS 22133 is the district-energy business — central plants that make steam, hot water, or chilled water and pipe it underground to many buildings (a downtown, a university, a hospital campus, a military base), sold as a metered utility service instead of each building running its own boiler and chiller. NAICS is the North American Industry Classification System, the federal code set used to organize business statistics.

Two features make it interesting to an investor. Each system is a local natural monopoly — once the pipes are in the street, no one builds a second competing grid — so cash flows are stable, contracted, and often inflation-linked. And the industry is in a decarbonization capital cycle: old fossil-fired plants are being swapped for electric boilers, heat pumps, and thermal storage, and new "thermal energy network" laws let regulated utilities build networked-geothermal systems. The catch for stock pickers: there is no pure U.S. public-equity play — the real owners are infrastructure funds, universities, hospitals, and municipalities [13][14][15].

2. What's inside — and why the group equals its one child

At the 5-digit level, NAICS breaks industries into 6-digit national industries. NAICS 22133 has a single 6-digit child, 221330 (also titled Steam and Air-Conditioning Supply) [1]. There is nothing in the group that is not in the child, so every statistic, company, and dynamic at this level is identical to 221330. The parent group above this is 2213 — Water, Sewage and Other Systems, inside Sector 22 (Utilities); the sibling codes there are water supply (221310) and sewage treatment (221320) [1].

For the full detail — scope boundaries, company profiles, contract economics, regulation, and outlook — read the child primer, 221330. The rest of this page is a summary and pointer.

3. Size (our ground-truth stats for this level)

These are the authoritative federal figures for NAICS 22133 — identical to 221330 because it is the only child.

This is a tiny, capital-intensive utility niche — roughly $21 million of revenue per firm — and average pay is high (~$115,000, 2023 payroll ÷ employment), consistent with a skilled utility workforce [3].

Read these numbers as an undercount. Federal business statistics understate district energy because integrated utilities code steam to their primary line and campus systems are coded to their parent institution. New York State shows only ~$28 million of 22133 revenue in the 2022 Census, yet Con Edison's steam operation alone booked $703 million in 2025 — because that combined electric/steam utility is classified under electric power, not here [2][9]. Universities, hospitals, and military base plants (the largest group by count) fall into education, health care, or government statistics [1]. The physical footprint is far larger than the $1.26 billion suggests: roughly 660 U.S. district-energy systems on 2012 data [6]. See 221330 §3 for the full physical baseline; no single current federal dataset captures total systems, capacity, and ownership at once.

4. The investable universe

Because the group is 221330, so is its investable universe. There are essentially no pure public plays. The only meaningful listed exposure is Consolidated Edison (NYSE: ED), which owns the largest U.S. district-steam utility (Manhattan) — but steam is only ~4% of a diversified electric-and-gas company [9]. Managers KKR (NYSE: KKR) and Antin (Paris: ANTIN) offer look-through fee economics through the funds that own Cordia and Vicinity, not the assets themselves [14][15].

The value actually sits in private and institutional hands: merchant platforms Vicinity Energy (Antin), Cordia (KKR), and CenTrio (QIC/Ullico); universities and hospitals that own captive campus plants; and municipal/federal systems [13][14][15][16]. Full ownership tables are in 221330 §4.

5. How the money works

Three revenue models, all present in the single child [9][19][17]:

• Rate-regulated (Con Edison steam): earn an allowed return on equity (ROE) on a rate base of invested capital; fuel is largely passed through. ConEd steam's authorized ROE is 9.25% but it earned only 6.65% in the year to December 2025 — it under-earns [10].
• Merchant/contract (Vicinity, Cordia, CenTrio, campus deals): long-term (20–50-year) energy-service agreements with a fixed capacity charge plus a commodity pass-through, often with take-or-pay minimums and inflation escalators [19].
• Campus concession / public-private partnership (P3): a private operator pays a large upfront sum to run an institution's utilities for 40–50 years [17].

Combined heat and power (CHP — plants that make electricity and capture the waste heat) adds power-market revenue where present; Inflation Reduction Act (IRA) tax credits (with cash "direct pay" for tax-exempt owners) improve decarbonization economics [16]. Detail in 221330 §5.

6. Demand drivers

Building-decarbonization mandates (e.g., New York City's Local Law 97, Boston's BERDO emissions charge), urban and campus density, reliability/resilience, cooling growth, and waste-heat reuse all support clean district energy — while efficiency, warm winters, and building-level heat pumps erode legacy fossil-heat volume (ConEd projects steam peak demand falling ~0.9%/year) [9]. See 221330 §6.

7. Regulation

State public utility commissions (PUCs) set rates for the regulated utilities (most visibly the New York Public Service Commission over ConEd steam); merchant systems run on negotiated contracts, not price regulation. The Federal Energy Regulatory Commission (FERC) matters only when a CHP plant sells power; the EPA's Clean Air Act rules drive fuel-switching spend. New thermal energy network (TEN) laws (New York's 2022 UTENJA and others) let utilities rate-base networked-geothermal systems — a structural growth avenue [11][20]. Full treatment in 221330 §7.

8. Consolidation

A local monopoly, nationally fragmented — the top 4 firms hold 69.4% of revenue, the top 8 82.4%, the top 20 94.6%, and the top 50 99.9% (the concentration index is suppressed); with only 59 firms it is an oligopoly of local monopolies [4]. Infrastructure capital is consolidating it: Antin bought Veolia's U.S. business ($1.25B, 2019 → Vicinity), KKR bought Clearway's ($1.9B, 2021 → Cordia), and Brookfield sold its platform for ~$4.1B (2021), alongside billion-dollar campus P3s [14][15][17][18]. See 221330 §8.

9. Risks

Stranded-asset risk from mandatory fossil-plant conversion; customer bypass and volume decline (the "fixed-cost spiral"); rate-case and contract-renewal risk; interest-rate/leverage sensitivity on long-dated cash flows; aging century-old mains; and customer concentration. Detailed in 221330 §9.

10. How to invest & outlook

Public-market investors have only diluted exposure — Consolidated Edison is the closest listed name, but its value tracks a whole electric-and-gas utility, not steam; KKR/Antin give manager economics only. No pure public play exists [9][14][15]. Private-market investors are the natural owners: infrastructure-fund platform buyouts, direct city/campus ownership, 50-year campus P3 concessions, municipal/project bonds, and the emerging regulated TEN channel [14][17][20].

Outlook (judgment): a slow-growing core with a decarbonization capital supercycle — flat-to-declining thermal volumes but rising capital intensity as operators replace fossil boilers with electric boilers, heat pumps, and storage. Upside optionality (building-performance mandates, IRA direct pay, thermal-network rate-basing, data-center waste-heat reuse) is real, and so are the risks (stranded assets, bypass, rate compression). Expect M&A to stay active [14][15][16][20]. Because this level is a single-child pass-through, the full investment case is the one in 221330 §10.

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Sources

1. U.S. Census Bureau / OMB, North American Industry Classification System — 22133 / 221330 Steam and Air-Conditioning Supply (2022) (single 6-digit child 221330; parent group 2213; Sector 22; adjacent codes). https://www.census.gov/naics/?input=221330&year=2022&details=221330
2. U.S. Census Bureau, 2022 Economic Census — Utilities Summary / Concentration, NAICS 221330, United States (receipts $1,263,307k; 59 firms; state detail). https://data.census.gov/table/ECNBASIC2022.EC2222BASIC
3. U.S. Census Bureau, County Business Patterns 2023, NAICS 221330 (118 establishments; 1,957 employees; $229,998k annual payroll). https://www.census.gov/programs-surveys/cbp.html
4. U.S. Census Bureau, 2022 Economic Census — Concentration Ratios, NAICS 221330 (CR4 69.4%, CR8 82.4%, CR20 94.6%, CR50 99.9%; HHI suppressed; 59 firms). https://www.census.gov/programs-surveys/economic-census.html
5. U.S. Energy Information Administration / ICF / IDEA, U.S. District Energy Services Market Characterization, 2018 (2012 data: ~660 systems). https://www.eia.gov/analysis/studies/buildings/districtservices/pdf/districtservices.pdf
6. Consolidated Edison, Inc., Form 10-K FY2025 (steam revenue $703M; steam ≈4% of consolidated revenue; steam peak demand ~-0.9%/yr). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001047862&type=10-K
7. Consolidated Edison, Inc., Form 10-K FY2024–FY2025 (steam authorized ROE 9.25%, actual 6.65% for 12 months ended 12/31/2025). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001047862&type=10-K
8. New York State Public Service Commission, Con Edison Steam Rate Plan, Case 22-S-0659. https://dps.ny.gov/pending-and-recent-electric-rate-cases
9. Vicinity Energy, Company overview (~19 systems, 12 cities; merchant platform). https://www.vicinityenergy.us/
10. Antin Infrastructure Partners / ION Analytics, Acquisition of Veolia's U.S. district energy (2019, $1.25B EV → Vicinity) and 2025 sale process. https://en.wikipedia.org/wiki/Vicinity_Energy
11. KKR / Clearway / Cordia, KKR acquires Clearway thermal business (~$1.9B, 2021), relaunched as Cordia. https://cordiaenergy.com/about-us/
12. QIC / Ullico / CenTrio, QIC and Ullico Complete Acquisition of CenTrio (400+ buildings). https://www.prnewswire.com/news-releases/qic-and-ullico-complete-acquisition-of-centrio-leading-us-district-energy-platform-301335780.html
13. ENGIE North America / Ohio State / University of Iowa, University energy public-private partnerships. https://www.projectfinance.law/publications/2021/august/university-energy-partnerships/
14. Brookfield Infrastructure, Sale of North American District Energy Business (2021, ~$4.1B aggregate EV). https://bip.brookfield.com/press-releases
15. District Energy St. Paul, 2025 Annual Report and Heating/Cooling Rates. https://www.districtenergy.com/
16. Internal Revenue Service / Treasury, Inflation Reduction Act — Section 48 / 48E ITC and Section 45Y PTC (CHP, geothermal, thermal storage; elective/direct pay). https://www.irs.gov/credits-deductions/elective-pay-and-transferability
17. U.S. Environmental Protection Agency, Title V permits / New Source Review / Boiler MACT / Greenhouse Gas Reporting Program. https://www.epa.gov/nsr
18. New York City, Local Law 97 (Climate Mobilization Act, 2019). https://www.nyc.gov/site/sustainablebuildings/ll97/local-law-97.page
19. City of Boston, Building Emissions Reduction and Disclosure Ordinance (BERDO). https://www.boston.gov/departments/environment/berdo
20. Building Decarbonization Coalition / NY Department of Public Service / Eversource, Thermal Energy Network legislation and pilots (NY UTENJA 2022). https://buildingdecarb.org/