The terms air diffuser, register, grille, and vent are often used interchangeably, but there are subtle differences between them.
- Air diffuser: This is a device that is installed at the end of an HVAC duct to distribute air into a room. It may have an adjustable damper to control the direction of airflow.
- Register: A grille that includes a damper to control the amount of air flowing through it is called a register. Registers are typically installed on the floor, wall, or ceiling and are designed to cover the duct opening.
- Grille: A grille is a decorative cover for an air duct that allows air to flow through while also preventing larger objects from entering the duct. Grilles are typically stationary and do not have adjustable dampers.
- Vent: An opening through which air can flow. In the context of HVAC systems, a vent is usually used to refer to the opening where the air is released into a room.
In summary, air diffusers, registers, and grilles are all devices that allow air to flow into or out of a room. The main difference between them is that air diffusers have adjustable dampers, while registers and grilles do not. Vents are openings through which air can flow, but they do not have dampers or grilles.
