Exit signs that use more energy-efficient light sources and retrofit kits for converting signs offer the potential for energy savings. However, signs using energy-efficient light sources can vary widely in power characteristics, visibility, and readability. Exit Signs to identify performance concerns and help specifiers select products that save energy and can be seen in clear-air and smoke conditions. Technology Overview Light source technologies. Exit sign formats.
Matrix signs use arrays of small light sources, usually LEDs, to form the lettering.
Factors affecting visibility and readability. An exit sign may be easily visible, but still not be easily read if, for example, its letters are not uniformly luminous. Factors affecting a sign's visibility include its total luminance, its mounting location, its color scheme, and obstructions and visual distractions including decorations, other signs, and glare from other light sources or windows. Luminance contrast between letters and backgrounds also varies widely among signs and a sign may have a different luminance contrast in a lighted environment than in a dark one. An imaging photometer measured luminances of the sign faces for all the products except the radioluminescent signs, which produced luminances too low to measure accurately.