OK. Let's see if we can simplify how to measure an Octagon Vent.
You will not be measuring each of the 8 sides.
Look at the wall opening and determine if it appears to be a real octagon shape.
All 8 sides should be the same length.
The width will be horizontal across the center of the opening.
The height will be vertical up the center of the octagon opening.
These measures should come out close to each other.
Double checking the measures can be done by measuring the same on a diagonal.
This is what is called the "opening size".
For this the vent will be manufactured 1/4" per side smaller to install into the opening.
The vent would measure in the same manor.
First right across the middle.
Then up the middle for the height.
Measuring the octagon vent itself is called "tip to tip".
That just leaves the depth to be chosen for the 3 measures needed for ordering.
Still have unanswered questions?