Comfort Systems USA, Inc. provides mechanical and electrical installation, renovation, maintenance, repair, and replacement services for the mechanical and electrical services industry in the United States. It engages in the design, engineering, integration, installation, and start-up of mechanical, electrical, and plumbing (MEP) systems; and renovation, expansion, maintenance, monitoring, repair, and replacement of existing buildings. The company offers its services for heating, ventilation, and air conditioning (HVAC) systems, as well as plumbing, piping and controls, off-site construction, electrical, monitoring, and fire protection.