The present disclosure provides an air grille assembly for use especially with air conditioning and heating ducts, having a detachable grille constructed of a relatively thick material, such as wood, synthetic wood, vinyl or the like. The grille can mount against the structure and be coupled to a housing of thinner material that can fit in a standard-sized opening, and leave enough room for a standard-sized filter commensurate with such opening. Further, the disclosure can also provide an air grille assembly having a detachable grille with an exposed exterior frame with no movable or visible hardware, and can be removed from a housing by lifting the grille frame straight up or over, angling out the bottom and then sliding in the opposite direction. The grille assembly can be coupled into a structure's opening, and can include flanges to help ensure proper mounting without the use of special tools.