HVAC is a specialized field integrating design, installation, and control systems. A contractor can design a system, select components, and analyze the building’s cooling and heating requirements. A building services designer or mechanical engineer can also analyze the system’s performance and design, and help with component selection. Specialty mechanical contractors and suppliers can design and install HVAC systems for buildings of all sizes. Regardless of size, HVAC systems must undergo building permits and code compliance inspections.

A typical HVAC system consists of an outdoor unit and an indoor unit. The outdoor unit contains a fan and circulates air through ducts. The air inlet unit is specially designed to let fresh air into a building. This air is routed to various rooms for different purposes, such as heating or cooling the building, removing dust, reducing humidity, or other uses. The central air system moves air through a network of ducts to keep rooms at the desired temperature and humidity.

HVAC systems are important parts of residential, large industrial, and office buildings. They can also be used in vehicles, hospitals, and marine environments. Depending on their size, HVAC systems regulate temperature and humidity, thereby maintaining a comfortable and healthy indoor environment.