{"id":3777,"date":"2021-02-06T06:37:52","date_gmt":"2021-02-06T06:37:52","guid":{"rendered":"https:\/\/climesense.com\/?p=3777"},"modified":"2022-05-25T17:31:19","modified_gmt":"2022-05-25T17:31:19","slug":"size-return-air-grill","status":"publish","type":"post","link":"https:\/\/climesense.com\/size-return-air-grill\/","title":{"rendered":"How to Size a Return Air Grille"},"content":{"rendered":"\n

You definitely need to know how to size a return air grill if you want your HVAC system to function properly. Here is a step-by-step guide.<\/p>\n\n\n\n

Most of the issues that you might have with your heating and cooling duct system involve the return side — the duct itself, the air filter, or even the grill covering the duct. When the grill is the problem, it is typically because it is the wrong size and does not allow proper airflow. But how do you size a return air grill correctly?<\/p>\n\n\n\n

What is a Return Air Grille and Why is it Important?<\/h2>\n\n\n\n

Properly called a grille<\/em> (not grill) or less commonly, a vent, this is the ‘face’ that covers your duct system. Supply grilles cover the openings where the heated or cooled air is pushed out into the rooms, and return grilles do the same where air is drawn back into the system for recirculation.<\/p>\n\n\n\n

Although they often look very similar, there are two easy ways to identify which is which — placement and air pressure. Supply grilles are usually installed in the ceiling, while return air grilles are most-often installed in the floor or on the lower part of a wall. For a simple test, hold a tissue close to the grille, and the positive or negative airflow will eliminate any doubts.<\/p>\n\n\n\n

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Typically made of aluminum or plastic, a return grille usually holds a replaceable filter in place. The purpose of a filter grille is to keep debris, dust, and allergens from being sucked back into your ductwork and your HVAC unit’s blower assembly.<\/p>\n\n\n\n

What Happens if the Return Air Filter Grille is the Wrong Size?<\/h2>\n\n\n\n

If your return grille is not the right size, it reduces the effectiveness of your entire system. If it is too small for the capacity of your HVAC unit, the unit becomes “starved for air” and cannot provide an adequate supply of heated or cooled air. If it is too large or improperly installed, it may allow debris to pass through.<\/p>\n\n\n\n

How to Tell if a Return Air Grille is the Wrong Size<\/h2>\n\n\n\n

Filter grilles are undersized far more often than they are oversized. If the grille is too small, either physically in relation to the size of the return duct or in terms of airflow capacity in relation to the entire system, there are a few tell-tale signs<\/a> :<\/p>\n\n\n\n