EMCOR Group is electrical and mechanical construction. One of the world's largest specialty construction firms, EMCOR designs, installs, operates, and maintains complex mechanical and electrical systems. These include systems for power generation and distribution, lighting, voice and data communications, fire protection, plumbing, and heating, ventilation, and air-conditioning (HVAC). It also provides facilities services, including management and maintenance support. Through about 75 subsidiaries and joint ventures, the company serves a range of commercial, industrial, institutional, and utility customers. EMCOR operates primarily in the US (some 85% of sales), Canada, and the UK.