A Solar Water Heating system basically comprises of two components :

An array of solar collectors and an insulated tank, to store hot water. Consuming the solar energy, the water in the solar collector gets heated and is pumped to the storage tank, which can then be used for various purposes.

For a family of 4 members with 100 litres per day usage capacity can save up to 1500 units of electricity per year. The savings depend on the capacity of the system installed.