Mechanical contracting services install, maintain, and repair heating, ventilation and air conditioning (HVAC) equipment, HVAC controls, and HVAC ductwork within a building. A mechanical contracting service may also install industrial-grade chillers, boilers, and other mechanical systems. HVAC controls include intelligent heating controls, central heating controls, air conditioning controls, pressure ventilation controls, HVAC zone controls and HVAC noise controls. Mechanical contracting services and mechanical contractors also install and maintain HVAC ductwork, which includes pipe or closed conduits made of sheet metal, fiberglass board, or other suitable material for conducting air to and from an air handling unit.