Step 2: Measure the duct opening in your floor, wall or ceiling. (Width in inches -by- height in inches)
Note: The width (W) is always expressed first, followed by the height (H) dimension. Many of our vent grilles include directional patterns so it is critical to provide both dimensions in their respective order.
Step 3: Match the wall opening size to the correct vent cover size. The width and length of your opening should match the width and length of specific register/grille you require. This is the opening (inside) measurement. Outside size of register/grille will be bigger than opening size this accompanies the outside border portion of the cover.
Note: The actual dimension of the grille or registers interior dimension will be slightly smaller than the rough opening dimension - this is to ensure that the damper assembly fits comfortably through the vent hole opening. The grille frame is slightly larger than the industry standard to ensure coverage for both the rough opening and the paint/trim line commonly found when removing old cover grilles.