Comfort Systems USA, Inc. engages in the provision of mechanical and electrical contracting services. The company is headquartered in Houston, Texas and currently employs 18,300 full-time employees. The firm operates through two segments: Mechanical and Electrical. The Mechanical segment includes HVAC, plumbing, piping, and controls, as well as off-site construction, monitoring and fire protection. The company also installs connecting and distribution elements, such as piping and ducting. The Electrical segment includes installation and servicing of electrical systems. The company builds, installs, maintains, repairs and replaces mechanical, electrical and plumbing (MEP) systems throughout its 47 operating units with 178 locations in 136 cities across the nation. The company is engaged in offering engineering, design-assist and turnkey, direct hire construction services of modular systems serving the advanced technology, power and industrial sectors. The company also provides mechanical construction services to the commercial and industrial sectors.