Cold air return grilles sizes

December 3, 2021
Wall Return Air Grille

Registers are the vents that control air flow into a room from heating and cooling systems.

  • A louvered damper enables control of the air, which can be directed in at least one direction or in some cases up to as many as four, or diffused altogether.
  • Registers can be used in walls and ceilings so cold air can fall into a room, and in floors so heated air can rise.
  • If they become blocked, the air temperature in the room can be greatly affected.


Grilles are the vents through which air is pulled out of a room for circulation back to the central heating or cooling unit.

  • They have no dampers behind the slats to close off the flow of air.
  • They may be located in floors, ceilings or walls.
  • Placement assists circulation within a room, and an unobstructed flow is required for system efficiency.
  • Several small grilles may be utilized and located throughout the home, or one large grill may be positioned near the furnace.
  • Wall transfer grilles, door grilles and jump ducts are also helpful for maintaining a steady return air flow in homes that have a centrally located grille.

How to Measure for Replacement Registers and Grilles

Follow these measurement instructions for a snug fit.

  • Locate the register or grille you are replacing and note if it is for a wall, ceiling or floor.
  • Remove the screws that hold the vent in place. Pull the vent forward and out of the opening.
  • Measure the size of the air duct opening. Do not measure the old register or vent. Note the measurements as width and length as that is how they are packed and labeled.
  • Ensure the new register or grille covers the opening. If the opening is large, look for units with wide borders.
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