The type of the opening is based on the family category for the opening and in what element it is contained in:
If it is a Window it will have a type of OperableWindow.
If it is a Door it will have a type of NonSlidingDoor.
If the opening is contained in a Roof it will have a type of FixedSkylight.
If it is a Curtain Wall Panel, the opening will default to a type of FixedWindow. If the material specified for the family, and the material transparency is less than 3%, the opening will be ignored as a solid panel.
An opening of the category Openings will have the type of Air.