The main difference between a return grille and a supply grille is the direction of the airflow. A return grille is designed to allow air to flow from a room back into the heating and cooling system, while a supply grille is designed to allow air to flow from the system into a room.
* A return grille is typically installed in a wall or ceiling, and it has a filter or screen that captures airborne pollutants and allows only clean air to flow back into the system. The filter helps to improve the indoor air quality by removing dust, pollen, and other contaminants from the air.
* A supply grille, on the other hand, is typically installed in a wall or floor, and it does not have a filter. The grille allows air to flow from the system into the room, providing ventilation and temperature control.
* Another difference between a return grille and a supply grille is the size and shape. Return grilles are typically larger and square or rectangular in shape, while supply grilles are smaller and round or oval in shape.
* Additionally, return grilles are usually located in the center of a wall or ceiling, while supply grilles are typically located near the edges of a wall or floor.
Overall, the main difference between a return grille and a supply grille is the direction of the airflow and the presence of a filter. Return grilles are used to improve the indoor air quality, while supply grilles are used to provide ventilation and temperature control.