Mechanical contractors play an essential role in America’s trillion-dollar construction industry. Keep reading as we explore the largest mechanical contractors in the U.S. based on data from Engineering News-Record (ENR).
Top 50 largest mechanical contractors in the U.S.
Note: The “ENR rank” column indicates each company’s place on the magazine’s list of top 600 contractors in the United States.
A closer look at the 10 largest mechanical contractors in the U.S.
Next, let’s look at each of the top 10 biggest mechanical contracting companies in America.
#1. Comfort Systems USA
Comfort Systems USA is the country’s leading HVAC, electrical, and plumbing service provider. Based in Houston, Texas, Comfort Systems USA is publicly traded and boasts a market cap of $2.73 as of writing, according to Yahoo Finance.
The company operates in more than 140 locations across the United States through over 35 subsidiaries, including:
- ACI Mechanical
- BCH Mechanical
- Eastern Heating & Cooling
- Starr Electric Company
- TEC Industrial
According to Fortune, Comfort Systems USA employs over 12,000 Americans.
#2. ACCO Engineered Systems
Pasadena, California-based ACCO Engineered Systems is an employee-owned mechanical contracting company founded in 1934. Its services include:
- energy management
- engineering support
- mechanical equipment repairs
- mechanical retrofits
- preventative maintenance
Owler estimates the company’s annual revenue at $1 billion and its employee count at 3,000.
#3. Southland Industries
Next on our list of the largest mechanical companies in the USA is Southland Industries. The Garden Grove, California-based company reported annual revenue of $940 million in 2020.
Its service offerings include:
- sheet metal systems
- process piping
Owler pegs Southland Industries’ headcount at 1,200.
McKinstry is an acclaimed mechanical contractor based in Seattle, Washington. The firm got its start in 1960 as a plumbing contractor. It has since been recognized by ENR and even former U.S. President Barrack Obama as a forerunner among sustainable, environmentally-friendly mechanical contractors.
McKinstry is arguably best-known for its energy services in government, healthcare, and renewables. Owler estimates the company’s annual revenue at $600 million and its headcount at 1,529.
Nooter/Eriksen is among the most experienced mechanical contracting companies in the United States, with its amalgamated firms having been founded over 100 years ago. The Fenton, Delaware-based company operates worldwide, with offices in Europe, Asia, and the Middle East. It specializes in supplying heat recovery steam generators but also provides engineering and inspection services.
#6. Apollo Mechanical Contractors
Apollo Mechanical Contractors is a Native American-owned mechanical contractor founded in 1981. The company’s extensive list of service offerings also includes pre-construction, civil engineering, equipment installation, and preventative maintenance.
Apollo Mechanical Contractors provides service in many sectors, such as:
- high-tech manufacturing
- food processing
- industrial manufacturing
- mission-critical systems
Our next largest mechanical contractor is Harris, which was founded in St. Paul, Minnesota in 1948. This mechanical contracting company specializes in engineering, construction, and building controls. Harris boasts 11 regional offices and over 2,000 employees.
Its recent projects include the Minneapolis Marriott Southwest Hotel, Reagan National Airport’s new north concourse, and a certain company’s spaceship-shaped corporate campus in Cupertino, California.
#8. Limbach Holdings LLC
Limbach Holdings is a publicly-traded mechanical contracting company specializing in HVAC, electrical, plumbing, and control systems. According to Yahoo Finance, its current market capitalization sits at $114.2 million.
Limbach Holdings is based in Pittsburgh but has offices all throughout the United States, including Southern California. It employs more than 1,500 workers across the country.
Next on our list of the largest mechanical contractors in the U.S. is TDIndustries. The company, founded in 1946 and boasting $690 million in revenue, specializes in HVAC, mechanical, electrical, and plumbing services.
It’s 100% employee-owned and has ranked on Fortune Magazine’s list of the 100 best companies to work at for over two decades.
#10. Harder Mechanical Contractors
Last but certainly not least on our roundup of the largest mechanical contractors in America, we have Harder Mechanical Contractors. The firm got its start as a plumbing contractor in Portland, Oregon during the city’s massive World War II manufacturing effort. Following the war, Harder Mechanical Contractors continued adapting to the nation’s shifting needs.
Today, the company has locations all over the western United States, specializing in everything from plumbing to process piping, equipment installation, and modularization.
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