Solar-control glass needn't mean just green any longer. PPG Industries says it has developed a new, neutral gray colored solar-control glass it claims will be an automotive industry first.

PPG installed the new gray glass in a demonstration BMW AG Z3 roadster at this January's North American International Auto Show in Detroit. The company has applied for a patent for what it believes could replace green-colored glass for the majority of automotive applications.

PPG says increased emphasis on glass as a design element led to the development of the VistaGray technology, which transmits approximately 48% of the sun's total energy (the highest-performance green glass transmits 45%), versus about 58% for typical green solar-control automotive glass and 81% for clear glass.