Clarence Kemp

Clarence Kemp was an American inventor who built and patented the world's first commercially sold solar water heater. In 1891, working from a manufacturing business he had founded in Baltimore, Kemp patented a device he called the Climax, which consisted of blackened metal water tanks enclosed in a glass-fronted box mounted on a roof, letting sunlight passively heat the water inside for household use. Kemp originally marketed the device as a seasonal convenience, but it found its strongest market in Southern California, where abundant sunshine and relatively costly fuel made solar heating economically attractive; by the late 1890s a substantial share of homes in Pasadena, California used Kemp's solar water heaters. The Climax is generally credited as the first commercially successful solar thermal product, predating the more efficient solar water heater designs that later built on its basic passive glass-box principle, and Kemp has been inducted into the National Inventors Hall of Fame for the invention.