Solar water heaters use the sun's thermal energy to heat water. These units are usually designed to serve as pre-heaters for conventional storage or tankless water heaters. A solar collector absorbs thermal energy from the sun and transfers this heat to water in a storage tank or water entering a tankless water heater.

Note that all solar energy systems manufactured or sold in Florida must meet the standards established by the Florida Solar Energy Center and display accepted results of approval performance tests. See Florida law (section 377.705, Florida Statutes) and http://www.fsec.ucf.edu/en/industry/testing/STsystems/ratings/  for more information. Also, see the Solar Rating and Certification Corporation (SRCC) Web site at http://www.solar-rating.org/ . SRCC is a non-profit organization whose primary purpose is the development and implementation of certification programs and national rating standards for solar energy equipment.

Source: UF/IFAS Energy Efficient Homes: Water Heaters; Wendell A. Porter, Hyun-Jeong Lee, and Kathleen C. Ruppert, 2008.