This is an excellent product.- I use a 1oo Lpd evacuator vacuum tube solar water heater manufactured and marketed by V.GUARD, a company based in Kerala with sales and servicing network all over India.

It did not give me any troubles for the last 9 months. Quite sufficient for normal use of my family of 4 members. Depending on availability of sunshine, you can use it for nearly 300 days in a year in Kerala and much more number of days in other places where cloudy weather is not very frequent.
Save precious electricity. There is also an option for connecting it to the domestic electric supply and use the in-built electric heater  when solar light is not available for heating, This is quite useful in rainy days when there is little or no sunshine.

Can be installed in independent houses, villas and roof tops of flats as well. You need a direct water connection from an overhead water tank . Excellent installation and after-sales support.
One good idea is to connect the hot water outlet to your normal geyser storage tank ( if you already have one) and store the heated water in the geyser ( remember to disconnect the electric connection to the geyser). You can store hot water overnight in your geyser storage tank without spending any cost for electric heating !

Purchase Price (INR):

18000