I would think you would be able to figure that out from the
Zone Information in the .eio file.
! <Zone Information>,Zone Name,North Axis {deg},Origin X-Coordinate
{m},Origin Y-Coordinate {m},Origin Z-Coordinate {m},Centroid X-Coordinate
{m},Centroid Y-Coordinate {m},Centroid Z-Coordinate {m},Type,Zone
Multiplier,Zone List Multiplier,Minimum X {m},Maximum X {m},Minimum Y
{m},Maximum Y {m},Minimum Z {m},Maximum Z {m},Ceiling Height {m},Volume
{m3},Zone Inside Convection Algorithm
{Simple-Detailed-CeilingDiffuser-TrombeWall},Zone Outside Convection
Algorithm {Simple-Detailed-Tarp-MoWitt-DOE-2-BLAST}, Floor Area
{m2},Exterior Gross Wall Area {m2},Exterior Net Wall Area {m2},Exterior
Window Area {m2}, Number of Surfaces, Number of SubSurfaces, Number of
Shading SubSurfaces, Part of Total Building Area
Using the origin Z coordinate and the ceiling height would give you a
good approximation. Or even just hte maximum z coordinate.
The .eio file can be totally or selectively put into a spreadsheet for
working on.