Solar Water Heating System ( S.W.H ) is the conversion of sunlight into heat, for water heating, using a solar thermal collector . A variety of configurations are available at varying cost to provide solutions in different climates and altitudes. S.W.H's are widely used for residential and some industrial applications. An estimated one million residential and 200,000 commercial solar water-heating systems have been installed in India. How SWH works? A Solar Water Heater comprises of an array of solar collectors to collect solar energy and an insulated tank to store hot water. Both are connected to each other. During the day time, water in solar collectors gets heated which is either pumped or flown automatically on thermosyphon principle to the storage tank. Hot water then stored in the tank can be used for various applications.   Types of Solar Water Heating Systems Two types of Solar Water Heaters are available. One based on flat plate collectors and the