The definition of a louver HVAC is a system that uses adjustable slats or blades to control the amount of air that is allowed to pass through. Louvers are typically used in HVAC systems to control the amount of air that is allowed to enter a room or space. They are usually found in air ducts, air vents, and air grilles. Louvers can be adjusted to allow more or less air to enter a space, depending on the needs of the occupants. Louvers are an important part of an HVAC system, as they help to regulate the temperature and humidity levels in a space. They also help to reduce energy costs by controlling the amount of air that is allowed to enter a space. Louvers are available in a variety of materials, including metal, plastic, and wood, and can be used in both residential and commercial settings.