Comfort Systems USA provides mechanical and electrical contracting services. Co.'s mechanical segment principally includes heating, ventilation and air conditioning, plumbing, piping and controls, as well as off-site construction, monitoring and fire protection. Co.'s electrical segment includes installation and servicing of electrical systems. Co. builds, installs, maintains, repairs and replaces mechanical, electrical and plumbing (MEP) systems throughout its operating units. Co. operates primarily in the commercial, industrial and institutional MEP markets and performs most of its services in industrial, healthcare, education, office, technology, retail and government facilities.