Comfort Systems USA, Inc. is a provider of commercial, industrial and institutional heating, ventilation, air conditioning (HVAC), mechanical and electrical contracting services. Its segments include Mechanical and Electrical. The Mechanical segment includes HVAC, plumbing, piping, and controls, as well as off-site construction, monitoring and fire protection. It also installs connecting and distribution elements, such as piping and ducting. The Electrical segment includes installation and servicing of electrical systems. It builds, installs, maintains, repairs and replaces mechanical, electrical and plumbing systems throughout its over 50 operating units with 190 locations in 142 cities throughout the United States. It is engaged in offering engineering, design-assist and turnkey, direct hire construction services of modular systems serving the advanced technology, power and industrial sectors. It also provides mechanical construction services to the commercial and industrial sectors.