The deeper the vent, the better airflow and a stronger product.
This is true for large louver vents.
When the wall depth into the attic allows,
most framers and contractors choose the 4" or 6" deep.
It is for the added strength and stability of the vent.
Since the louvers are horizontal, the height is the determining factor for the best depth.
With the bottom louver blocking more air than any other louver,
consideration is focused on it in sizing for the best air penetration.
A height of 12" or less have better airflow from the 1" depth.
Height of 13" to 23" is good for the 1" depth and 2" depth.
24" to 36" is better for the 2" and 4" depth.
37" and up is rated best at the 4" and 6" depth.
The louver spacing controls the airflow.
Louvers are faced at 1" tall each.
So, the 1" deep vent louvers are spaced 1" apart.
2" deep are spaced 1 1/2".
A 4" deep has spacing of 2".
And the 6" deep has 2 1/2" spacing.
One more consideration is the wall depth.
With potential of studs and framing,
the wall depth allowance may not accommodate a deeper vent.
In this case, measure to the available depth.
This will be the maximum depth to fit.
Also, the deeper the vent, the harder for rain to blow into the attic.
Onyx Xteriors will customize any vent as ordered.
This guide is to advise to the best net free air,
as well as the toughest vent product.