Solar energy for daily use in households is already a popular concept. For the present they are virtually confined to heating water, more than 600 homes in Bangalore city are already using this system, thereby doing with geysers (Fulkerson et al 1989). Solar water heating system is a simple device, works on the principle of black body radiation and green house effect. It generally involves use of flat plate collectors, storage tank, circulation system and appropriate controls and accessories. Solar water heaters can be broadly classified as (a) Thermosyphon or natural circulation, (b) forced circulation system. Usually thermosyphon units are used for domestic application (for capacity of 300 litres) and forced circulation is used in the case of industrial and commercial applications.