Solar water heater

The Climax water heater, first invented in the 1890s, was a turning point for practical solar energy. It is said that during that period one third of the homes in Pasadena, Calif., used solar hot-water heaters to avoid the expense of coal. The solar hot-water industry then thrived in the 1920s building boom in Florida. But then the government froze the use of copper during World War II, which dealt a blow to solar thermal, according to Home Power magazine. Then cheap electricity and new electric hot-water heaters stopped all growth until the 1970s.