How To Measure Floor Vent Size

Most vent faceplates are large enough to support the register and cover the entire hole.

How to measure floor vent size.

You could also use a 4 x10 floor register if your hole measured 4 1 4 x 10 1 2. A register is measured by the size of its louvers which is the bottom of the register that fits into the ventilation duct. Remove screws holding the vent in place. The flush mount no frame is also ordered by measuring the duct size.

Measure the size of the air duct opening. For floor registers they follow the same rules as return grilles where you state the dimension parallel to the louvers first. For example a 4 x 10 flush mount wood register has an overall size of 6 x 12. Pull the vent forward and out of the opening.

Measure the duct opening in your floor wall or ceiling. Locate the register or grille you are replacing and note if it is for a wall ceiling or floor. For sizing please use the duct size and reference the overall frame size for installation. Length in inches by height in inches this is your duct opening size.

To measure your register properly remove the existing register from the floor wall or ceiling in which it is installed. However the overall size of the opening must be considered. The width and length of your opening should match the duct opening sizes. The length l is always expressed first followed by the height h dimension.

Remove the screws that hold the vent in place. Then measure the length and width of the air duct opening. Measure the opening in your floor wall or ceiling. If your hole measures 3 7 8 x 9 7 8 you should be able to use a 4 x 10 floor register depending on the style.

Note if the register or grille you are replacing is for a wall ceiling or floor. How to measure and replace a floor register. Take out the existing floor register and measure the length width of the opening in inches all registers will be listed in inches.