An insulating glass unit may include at least three panes of transparent material and at least two spacers positioned between different panes of the unit. For example, a first spacer may hold a first pane of transparent material a first separation distance from a second pane of transparent material and a second spacer may hold the second pane of transparent material a second separation distance from a third pane of transparent material. In some examples, the insulating glass unit is configured so that the first separation distance is greater than the second separation distance. In such examples, the insulating glass unit may have a comparatively larger first between-pane space and a comparatively smaller second between-pane space. In some applications, the insulating glass unit may exhibit thermal and sound insulating properties approximately equal to a triple-pane insulating glass unit while having size characteristics approximately equal to a double-pane insulating glass unit.