Grilles do not have the damper normally found on registers. Find the best floor registers, wall registers, and air returns for you home by understanding the sizes and installation needs. Most residential grilles and registers are rated at 20-30 NC. You can measure NC using an inexpensive sound meter costing less than $100. Measure the existing air duct opening and take note of the width and length measurements. Most often the dimensions are read as width x height. Do not measure the old register or vent. If the exact center of the ceiling is already occupied by a light, the register can be moved a little toward an exterior wall. Floor register measurements are … Now the downside of going to small with your register is that it is too loud. Shop sidewall & ceiling registers and a variety of heating & cooling products online at Lowes.com. Pull the vent forward and out of the opening. Most registers I size are about the same sq/in's as the duct or a little less. 2220 (or jet No. I bought a house in June. Measure the size of the air duct opening. The openings are rectangular and are roughly cut in the drywall. There is not enough drywall for screws to grab onto. An air return is a vent grille that is usually located either in a hallway or in the ceiling, and its purpose is to extract air from a room and recycle it through the system to further condition it by cooling or heating. For my example I’m going to use an 8- x 8- x 8-inch sheet metal fitting called a ceiling register box, or C box, just to layout the dimension you’ll need. So we measure the back, not the front. Air registers & grilles are ordered by the size of the actual duct opening in the wall, floor or ceiling that the vent will fit into or cover, not the overall size of the existing vent cover! If you are ordering a wall return air grille or return air filter grille, please note that these are directional. Big rooms with oversized registers can have hot spots away from the register. Find sidewall & ceiling registers at Lowe's today. The exceptions to this rule are with floor registers. This measurement is simply defined as the grille or registers sound, measured in decibels (or dB) minus 10 decibels. I am looking for the air to be pushed out hard so that it creates airflow in the room. For months I've been trying to determine how to securely mount the ceiling registers in the basement. The first two dimensions are always the length of the sides of the duct fitting, and the round collar is always the third dimension. CFM = Vk x Ak *RETURN AIR REGISTERS/GRILLES — RSFA and RTFA SUPPLY DIFFUSERS 1. A four-way register near the middle of the room is another possibility. Locate the register or grille you are replacing and note if it is for a wall, ceiling or floor. For example, a room 15 feet long and 10 feet wide has a gross ceiling area of 150 square feet -- 15 times 10 = 150. Remove the screws that hold the vent in place. Determine the length and width of the ceiling in a rectangular room by taking measurements from corner to corner. 2. The front of a register is actually going to measure a little bit bigger, but we would still refer to it as a 10 x 6. To measure, turn on the system, measure … For measuring Vk an Alnor deflecting vane velometer with Jet No. As a result, the register screws simply go into the gap between the duct/vent and the drywall. Having your registers in the ceiling frees up floor space and gives you more options for arranging your furniture. Multiply the length by the width to obtain the gross ceiling area. determined by measuring the outlet velocity in feet-per-minute (FPM) and multiplying by an area factor (Ak). 2. 2220-A to which a 9/16” space has been fitted) is used.