Daylight was the primary means of illuminating the Arts and Industries Building (AIB); the architects did not originally anticipate nighttime tours of its interior or exhibits. As such, daylight played a major part in shaping the building’s design. Windows and clerestories flooded the volumes of the exhibit spaces with natural light; the tops of display cases were glass to allow the ambient natural light to illuminate the collection pieces on display. The AIB consisted of 90,000 square feet of floor area lit by 1,170.58 square meters (12,600 square feet) of glass.
The AIB’s building site, adjacent to the Smithsonian Institution on the National Mall, made proper daylighting of the structure somewhat of a challenge. Cluss and his fellow architects responded by varying the heights of the different roof elements of the building; the different heights found in the halls, ranges, courts, and pavilions allowed each space to receive natural light from high windows, clerestories, and skylights (while also helping to define the character of the building exterior). Engineers also varied the sizes of the exterior windows, and the materials used within them; this allowed for different diffusions of light depending on window location.