Want to know the largest names in heating and cooling right now? From equipment makers like Carrier, Daikin, and Lennox to major service contractors like EMCOR and Comfort Systems USA, these companies shape what gets installed in homes and commercial buildings across the country. They’re also leading the push toward high-efficiency systems, heat pumps, and smarter building controls. This list highlights the largest HVAC companies in the U.S. by size and explains what makes each stand out.
State of the HVAC Industry
The HVAC industry is changing fast. A major driver is electrification, with more homes and buildings switching to high-efficiency heat pumps rather than older fuel-based systems.
At the same time, companies are working through a refrigerant transition, with new A2L refrigerants and updated safety rules that affect how systems are made, installed, and serviced.
Another major boost is coming from the data center boom, as these buildings require powerful 24/7 cooling systems. On top of all that, more customers want lower energy bills, better indoor air quality (IAQ), and smart controls that help manage comfort, airflow, and building performance.
Top 10 largest HVAC companies in the U.S.
Note: This list ranks the largest HVAC companies operating in the U.S., including both major equipment manufacturers and large mechanical contractors/service providers, based on publicly available revenue and scale.
10. AAON, Inc.
- Revenue: $1.2006B
- Employees: 4,812
- CEO: Matt J. Tobolski
- Founded: 1988
AAON is a U.S.-based HVAC manufacturer best known for commercial heating and cooling equipment built for large buildings. It also has a strong specialty business through BASX, which makes equipment used in data center cooling, including fast-growing liquid cooling demand tied to data center applications.
9. Modine Manufacturing Company
- Revenue: $2.4B
- Employees: 11,400
- CEO: Neil D. Brinker
- Founded: 1916
Modine is a major name in thermal management, with a strong presence in commercial heating and cooling. Lately, it has been expanding quickly in data center cooling, and even highlights data center-driven growth as a key part of its Climate Solutions business.
8. Lennox International Inc.
- Revenue: $5.34B
- Employees: 14,200
- CEO: Alok Maskara
- Founded: 1895
Lennox is a major U.S. HVAC brand focused on residential and light commercial heating and cooling. It’s best known for premium systems sold through an extensive dealer network, as well as strong products for comfort, efficiency, and home climate control.
7. Rheem Manufacturing Company (incl. Ruud)
- Revenue: $6B
- Employees: 14,000
- CEO: Chris Peel
- Founded: 1925
Rheem is one of the biggest HVAC makers in the U.S., and it’s also a major name in water heating. Along with its Ruud brand, Rheem sells heating and cooling equipment through a large network of contractors and distributors across North America.
6. Comfort Systems USA, Inc.
- Revenue: $6.87B
- Employees: 18,300
- CEO: Brian Lane
- Founded: 1997
Comfort Systems USA is one of the top mechanical contractors in the country and has become especially well-known for large commercial projects. It has strong exposure to data center projects, as well as to industrial work and other high-growth HVAC installation and service markets.
5. Trane Technologies
- Revenue: $19.8B
- Employees: 45,000
- CEO: Dave Regnery
- Founded: 1913
Trane Technologies is one of the biggest HVAC companies serving the U.S. market. They have major brands across both heating and cooling systems and large commercial solutions. Trane also has a huge footprint in refrigeration and cold chain through Thermo King, which helps explain its massive scale compared to smaller HVAC-only competitors.
4. EMCOR Group, Inc.
- Revenue: $14.57B
- Employees: 40,400
- CEO: Anthony J. Guzzi
- Founded: 1987
EMCOR is one of the biggest U.S. names in mechanical contracting and building services. It delivers large HVAC work for complex projects, plus integrated building systems that cover everything from installation to ongoing service and facility maintenance.
3. Carrier Global Corporation
- Revenue: $22.5B
- Employees: 48,000
- CEO: David Gitlin
- Founded: 1915
Carrier is one of the most recognized HVAC leaders in North America, with a strong footprint in residential systems, commercial HVAC, and broader building climate solutions. The company can be traced back to Willis Carrier and the start of Carrier Engineering Corporation in 1915, helping shape modern air conditioning.
2. Daikin (Daikin North America/Goodman)
- Revenue: $30B
- Employees: 98,162
- CEO: Masanori Togawa
- Founded: 1924
Daikin is one of the world’s largest HVAC companies, with a significant footprint in the U.S. through Goodman and Amana systems, as well as growing commercial solutions. It also operates a large U.S. network through Daikin North America, including major manufacturing and distribution capacity.
1. Johnson Controls International
- Revenue: $23.2B
- Employees: 94,000
- CEO: Joakim Weidemanis
- Founded: 1885
Johnson Controls is a building tech heavyweight. It covers HVAC equipment through York, plus building controls and large smart-building platforms that help manage energy use, comfort, and safety. As demand for efficient cooling in large facilities grows, their building systems and HVAC solutions are becoming increasingly important for data centers and other high-demand sites.
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