Q   What is a Solar Hot Water System?
A A system which turns cold water into hot water with the help of heat contained in the Sun’s rays is called a solar water heating systems (SHWS)
What is possible max. temperature of water  that can be attained in the solar water heating system?
A Around 60o to 90o C. The rise in temperature depends on

  • Solar Radiation

  • Weather Conditions

  • Solar collectors’ system efficiency.

Can it be installed anywhere?

Yes, it can be installed on Rooftops,  Building terrace,  Open ground


There should be : – No shading, – South orientation of the collectors, – Collector Tilt = Latitude or + 10o thereof , – Over head tank  with its bottom water outlet at least 8″ above the hot water tank of a solar water heating system.

Does it generate hot water on all days and in all seasons of the year?

It generates hot water on : -Clear sunny day (Max.), – Partially cloudy day: Moderate,

- Rainy or heavily overcast day -Nil, – Average 300 days in a year  (330 days in Gujarat & Rajasthan)

Can we use any type of water such as municipality treated water, bore well water or tank water?
A Only soft and potable water recommended – Hard water can reduce efficiency over time & damages collectors
What should be the type of material to be used for hot storage tanks?
A Stainless Steel  or copper for small tanks, Mild steel tank with anti-corrosive coating inside for large tanks
Q What about pipelines?
A Galvanized steel pipes of class B or C are normally used. Copper pipes can also be used. Heat resistant plastic piping, if available, can also be used.
Are there different types of collectors? If so, how to select the best one?

Yes, the best collectors are those with

  • high quality material for long life, say 10-15 years,(check out our page on Solar Water Heaters)

  • good workmanship to make collector water-proof and dust-proof,

  • high efficiency

Q   You said that the hot water will be available for 300 days in a year. How about the rest of the days?

SHWS can be provided with back up heating system by

- Electrical heater or – Boilers run on furnace oil/fire wood/coal or one bathroom should have elec. heater.

How much money do we have to spend for maintenance?

Maintenance is minimal :

-Periodic glass cleaning, -Check for leakages and valve functioning

Q Are there any governmental incentives, subsidies, loans etc.?


  • Soft loan from IREDA & some banks repayable over 5 to 8 years at low interest.

  • 100% depreciation tax relief for profit making companies

  • Limited subsidy  on  innovative solar systems.

Q   How much does a solar hot water system cost?

a) Domestic System (100 LPD at 60o C )

c) Rs. 17,000/- to Rs. 22,000/- as per quality

b) Non domestic System ( Range 60o to 90o C ): Rs. 130/- to 170/- per unit(100 lpd)

Q What about Payback?
A The chart explains all! FAQ.ht5