As with the design of all elements of Unity Temple, the design of the art glass – or “patterned glass” as he called it – was the original work of Frank Lloyd Wright, and reflect Wright’s idea of organic architecture: the visual pattern and logic of each detail evolves consistently from shape and form present in the larger plan. Motifs in the Unity House art glass laylights, for example – rectangles with a yellow-green core and yellow outer corners, and a square with yellow-green core, brown corners and yellow sides – are like miniature plans of Unity House and Unity Temple.

Similarly, the geometric patterns of the Unity House laylights embody Wright’s principle of design based on the nature of materials. Most of the glass in Unity House laylights is opaque white; their motifs around the edges are in green, brown, and yellow tones used on the interior wall finishes. Their rectangular and square shapes are conventionalized forms, such as the pattern of leaves against the sky. Wright wrote of his art glass designs: “What architectural decoration the buildings carry is… conventionalized to the point where it is quiet and stays as a sure foil for the nature forms from which it is derived.” A colleague of Wright’s noted that geometric patterns are particularly appropriate in colored glass because of the crystal quality of the material, material which does not lend itself to naturalism.

There are no laylights in the entrance foyer. Instead, the six doors at both the east and west entrances contain panels of clerestory art glass.

The art glass of the Unity Temple auditorium has its own pattern and rhythm. Beams in both directions across the ceiling create a grid of twenty-five deep bays, in which are set the art glass laylights. As an expression of Wright’s ingenuity and deep sense of subtle mystery, the design of the panels is identical, but each panel is oriented in a different direction. The east-west panels are oriented in either an east or west direction; the north-south panels are oriented only toward the south.                 

The art glass in Unity House and Unity Temple was made by the Temple Art Glass Company of Chicago, a company that created art glass for other of Wright’s work of this period. The process used by the company entailed fusing chromatic material into the molten glass, rather than applying color to the glass by enameling or other modes of painting, which ensured a richer, saturated coloration. The technique replicated the method of medieval glassmakers, advocated by William Morris, whose ideas influenced Wright.

By contrast, the glass panels were assembled using a technology that was quite new and fused bands of copper to the glass edges. The copper strips were thinner than previously used hand-soldered cames – the grooved lead rod used to hold together panes of glass – avoiding interference with the art glass design, and creating, as described by Wright scholar Joseph Siry, “an elegant linear pattern of metal as a frame for the squares and rectangles of colored glass.” The combined use of traditional and modern technology exemplifies Wright’s ideal of the art and craft of the machine.

All of the windows in Unity Temple and Unity House that are original are in excellent condition, and a priority of the restoration was to preserve the original materials whenever possible. Glass was replaced only if it was not possible to salvage the original came, and only when original broken pieces were missing or damaged beyond repair. Reglazed panels were created to match precisely the original panels, including the color, design of the matrix, and method of soldering.