Electricity Saving Tips For Homes And Offices

Solar Water Heater System – how it can help save on electricity bills

By on April 22, 2016
Hindi Translation: सौर वॉटर हीटर प्रणाली - यह बिजली के बिल पर बचत में कैसे मदद कर सकते हैं

Solar and renewable energy are quite popular these days. Through a lot of government support, marketing and subsidies solar products are quite popular these days in India. Many people want to adopt these technologies but are unaware of what to do and how to get it. We at Bijli Bachao thought that helping people understand they can adopt renewable sources at their homes could be of great help. So we start with this article on Solar Water Heater systems, providing most of the details one can have questions on.

What is solar water heater?

Solar water heater is a system that utilizes solar energy (or the energy from sunlight) to heat water. It has a system that is installed on a terrace or open space where it can get sunlight and the energy from the sun is then used to heat water and store it in an insulated tank. The system is not connected to electricity supply and thus does not have an on-off switch, but it uses the sunlight throughout the day to heat the water and store it in the storage tank. Water from the storage tank can then be used for any application as desired.

Different types of solar water heaters available in market

There are 2 types of solar water heaters that are available in Indian market:

1) FPC (Flat Plate Collectors) system: These are metallic type systems and have a longer life.

2) ETC (Evacuated Tube Collectors) system: These systems are made up of glass and are fragile.

Both these type of water heaters come with or without pump. Pump is used to move water from collectors to the storage tank. Those without pump use thermosyphon principle to move water from collectors to storage tank automatically.

How to decide on which type to buy

ETC systems are fragile but are cheaper. They are also very good for colder regions where the temperature is sub zero. In place where the water is salty, these systems require regular cleaning due to deposition of salt on the inner surface of glass tubes.

FPC systems are long lasting, as they are metallic. But they are expensive than ETC systems. They can work in colder regions with sub zero temperature but will need an anti freeze solution making the system expensive. In places with salty water a heat exchanger is required with FPC system to avoid scale deposition that can impact the heating capability of the system.

System without pump (thermosyphon) is ideal for domestic and small application users (as it is cheaper) provided water does not have high chlorine content. Those with pumps are good for industries.

How does the system perform on rainy/overcast days

Many people have concerns that solar systems will not work on overcast days. Well a system can still work if the overcast is not long (less than a day or two) as the system works on diffused radiation in the atmosphere. A solar system can also be integrated with an existing electric system that can act as a backup during the days when the overcast is long. The electric system can switch on if the water temperature from the solar water heater goes down below 40oC. Electric backup is not required in solar system if you have an existing electric water heater. In case you do not have an existing water heater, you can install an electric backup. You can also keep the two systems separate and use the electric system only when needed.

Maintenance requirements of solar water heater

  1. If you have ETC system then glass can break, as it is fragile. So the glass may need occasional replacement.
  2. Scaling happens on solar water heaters regularly especially if the water is hard. So the collectors need regular cleaning using acid.
  3. If the outside surface of water heater is painted, then it may need a repaint every 2-3 years to prevent corrosion.
  4. Occasional leakages could happen in the system and local plumbers can repair those.

Sizes of solar water heaters are available in the market

Solar water heaters available in market start from size of 100 ltr per day. The other sizes that are available are 200, 250, 300 and 500 lts per day. The maximum area required for the collectors to be installed on terrace/open area is:

Capacity (liters per day) Area in sq. m. for ETC system Area in sq. m. for FPC system

100

1.5

2

200

3

4

250

3.75

5

300

4.5

6

350

7.5

10

The liter per day mentioned above is liters of hot water at (60-70oC). A 100 liters size is suitable for a family of 4. You can check more on sizing of water heaters in our article: Choose the right sized water heater/geyser for electricity saving.

Savings that can be achieved using solar water heater

A 100-liter per day water heater can save yearly electricity units in various parts of India as per the table mentioned below:

Northern Region

Eastern Region

Southern Region

Western Region

Expected no. of days of use of hot water per year

200 Days

200 Days

300 Days

250 Days

Expected yearly electricity saving on full use of solar hot water (units of electricity)

1000

1000

1500

1250

The units used for water heating depend on the amount of water that is heated, so the number of unit increases proportionately as the size increases. You can use our calculator to find out how much do you pay per unit of electricity to evaluate savings: Online Electricity Bill Calculator – For all states in India.

Approximate cost of a system

Approximate cost of solar water heater systems are as mentioned below:

Capacity (liters per day) Cost of ETC system (in Rs) Cost of FPC system (in Rs)

100

15000

22000

200

28000

42000

250

34000

50000

300

40000

58000

350

62000

85000

(source: http://mnre.gov.in/file-manager/UserFiles/Guidelines_domestic_users_of_swh_cost_systems.pdf)

The cost above includes cost of collectors, insulated hot water storage tank, system piping, electrical backup, installation, etc with five-year performance guarantee as per the minimum technical specification laid down by MNRE. Costs towards piping from system to utility point, heat exchangers (if any), may be extra. In N-E & Hilly states, Remote areas and Islands, the cost may be higher by 15 to 20%. The above cost may vary from manufacture to manufacturer depending upon the salient features of their products.

Government subsidies that are available

Government provides subsidies to consumers who buy solar water heaters. The subsidies available are: 30% at cost to consumers in general category states and 60% at cost to consumers in hilly areas, north eastern states and islands limited to certain benchmarks: Rs 3000 per sq.m. for ETC and Rs 3300 per sq.m. for FPC systems.

How to get subsidy and get a solar system installed

The best source to get a solar system installed is your state nodal agency. Contact number of various state nodal agencies are available in MNRE website and also at http://www.mnre.gov.in/information/solar-water-heatres/. You can also get the same installed through an accredited channel partner of MNRE: list.

Using solar water heater is a win-win situation for consumers, utilities and the environment. Renewable energy is future and embracing the same makes a lot of economic and environmental sense.Water Heater Infographic

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  • Ashwin

    Which is the best cost effective system available in Bangalore, Karnataka based on user ratings and industry leading brands? Thanks

  • raheel shaaz
  • Amit Bajpayee

    Agni Solar Systems (P) Ltd. (ASSPL) is a dedicated solar company involved in marketing,sales and servicing of solar energy based products and systems such as solar water heaters, solar lanterns, solar street lights, solar home lighting systems, solar pumps, solar cookers and solar distillation systems under the Agni brand name.
    For details on different types of Agni solar products available in india and their prices, Call Us On 02066434111/ +919822648018

  • prasanna kumar k b

    Hi, We are the leading distributor of Sun Energy Solar water heaters ETC, in Kanakapura Main Road, Bangalore. Myself prasanna kumar and my contact number is 9986976900 / 9620294568…. Dealers or individual inquiries are welcome.

    Brief description about ETC solar is,

    It is estimated that an average household burns energy equivalent to 1 ton of coal in around 50 days. This in itself is a cause of concern. What is more astonishing is the fact that the largest percentage of this energy is spent by heating appliances like water heaters. Sunvik Solar with their farsighted vision have come up with a diverse range of solar water heaters each built with the sole purpose of fusing efficiency with cost effectiveness. This not only helps in cost cutting but also in saving the environment.

    Construction:
    The inner body has been constructed using stainless steel. This helps the storage tank to withstand the diverse climatic trends prevalent in the outdoor site where this is installed. Also steel does not get heated up easily thereby ensuring that the hot water remains so for a longer period of time. The presence of PUF or polyurethane foam also aids in this. PUF is extensively used to insulate the storage cylinder. The cylinder is red and color and has a capacity of 100 to 500 liters per day thereby making it an ideal alternative for families. It is also very compactly

    Type and Function:
    The Sun Energy Solar Evacuated Tube Collector 100 to 500 Liter Solar Heater is generally used in residences and homes and is hence a domestic type water heater. It can heat water up to a temperature of 85degrees making it one of the most efficient solar water heaters present in the market in this category.

    A guarantee of 5 year comes with this solar water heater by default. Other features include a powder-coated outer surface and pipes which inhibit blockages and scaling.

  • Manan

    I currently am in a need of new solar water heater installation. I have analyzed the current information available on this site as well as GOI site but I am not able to find the authorized dealer who can help me with sunsidized installation of the product. If you know whom to connect, I sincerely seek your help.

  • Akash Agrawal

    yes .you can use it for cooking as well..many industries and hotels are doing along with residential [email protected]

  • Sathyanarayana

    I have SwH but some days the water does not get heated at all. Can I connect 1 Lts geyser to the water coming from solar heater so that if the water is already hot I don’t have to switch the geyser else I will switch it on.

    • https://www.bijlibachao.com Abhishek Jain

      You can certainly do that. In fact that is the best solution.

  • Harpreet

    Is the water heated in FPC type of system useful for cooking purposes.

    • https://www.bijlibachao.com Abhishek Jain

      I doubt that it would be good. Although I am not sure.

  • Prakash H K

    I installed V Guard 200 LPD Evac Tube SWH in 2008 and am very happy. There has been no breakage or damage so far in spite of ice-storm. Also on cloudy days, the SWH gives reasonably hot water if there are white clouds overhead. Bangalore has very few days when there are completely dark rainy clouds all thru the day so we get 350+ days hot water from the SWH here in B’lore

  • Abhinandan Choudhary
  • Vijay Sharma

    Hi, I am looking for a ETC solar water heater and had inquired about a few of them in the market. Some dealers tell me that there is no difference between the quality of the tubes in companies like Supreme,Nutec,BOSCH etc. A replacement tube from BOSCH costs 640 while from Supreme costs 340. Can you tell me if the quality of the tube would matter across companies and so this should be one of the criteria for me in choosing the right company? In other words, does the efficiency of the heater depend on the quality of the tubes and would there be difference in the quality across these companies. I dont see any efficiency stats written for any solar heater for any company in their specifications.

    • Dhawal

      Hi Mr. Sharma,
      There is no difference in the tubes. So their efficiency is the same if they are a double-walled glass tube.
      Ideally, all are imported from China as there is no/very less manufacturers in India.
      Do you have a problem of tube breakages?

  • Abhinandan Choudhary
  • vinay kumar

    Training Opportunities
    A Career in Solar Energy the Fastest Growing Industry in the World
    Become a solar installer/integrator**
    Contact : 9312700996

  • Rama

    The person who has done the comparison for FPC and ETC has no idea of either type of solar technologies. These articles should be drafted by consulting with an expert from a manufacturing unit. I work in a unit where we manufacture both types and are perfectly aware of each of these type of water heater and can provide solution based on the scenario.

    Some FPC / ETC features are totally incorrect and are down played. Certain important ones are missing that will enable customers to make informed decisions.

  • Samden T

    Hello I have a small resort in Lamahatta Darjeeling ( altitude 5200 ft ) and I get decent amount of sunlight. I am planning to install a 200 lts solar water heater. Could you please let me know who I should contact. Nearest major town is Siliguri West Bengal.

    Thanks Samden

  • Ninad Bidkar

    Hello we have installed Solar water heater 200 lit per day on our home roof top, but i need to know whether i can get benefit on my yearly residential taxes ? can any body give me details pls?

    • Prakash H K

      You should ask your municipality/ elec board? In K’taka, we get Rs 50 rebate monthly, on Elec Bill, on submission of certificate given by SWH supplier. K’taka does not give any rebate on taxes.

  • Shibu

    Hi Team,

    I’m constructing a house in Bangalore and want to be energy efficient as much as possible; and your articles are helping me a lot. With respect to Solar Water Heater, one of the issue that I observed was the immediate availability of hot water on turning on the tap. Most of the time we have to waste atleast bucket full of water before we start to get hot water.

    How can we get hot water from Solar water heaters immediately on turning on the tap? Also is there any special plumbing material to be used to specifically for the hot water line.

    • Prakash H K

      Shibu, either the hot water pipe is too long OR made of material like metal OR is 0.75″ dia (many plumbers wrongly insist on using 0.75″ metal pipe for outside plumbing even for solar!). You should ask your plumber to instal 0.5″ CPVC plastic pipe direct from SWH to bathroom tap. Still there will be SOME cold water as no system has magical property of yielding hot hot water from the moment of turning the tap, BUT MUCH LESS! Also perhaps the SWH is positioned wrongly on rooftop, it may be moved closer to the bathroom?

    • Bijli Bachao Team

      Hi Shibu,

      Is it that the pipe from the water heater to the bathroom is too long? Most of the time the water in the pipe is cold. Also in general it is better to have a hybrid system (solar water heater + electric geyser). This ensures that the water is hot irrespective of solar water heater being able to heat it or not. If the solar water heater is able to heat the water then electric geyser does not have to work (it has a thermostat that detects the water temperature and switches it on only if the water is not hot). If solar water heater is not effective on any day, then the geyser takes care. Having a geyser in the bathroom will also ensure that you get hot water when you switch on the tap. But the most likely culprit in your case looks to be the piping. You may want to check the length as well as insulation of the pipes connecting solar water heater and the bathroom.

  • Prerak Mehta

    i want to installed the solar water heater for my home (Navsari-Gujarat, 396436). i need guidance for how to take the subsidizer water heater and what procedure i should have to do?

    • Prakash H K

      Prerak: There are 2 types of subsidy. (1) Manufacturing subsidy to manufacturer benefits him and not you. He may give you SWH at cheaper price! (2) Subsidy from elec board is given monthly to you, on submission of cert given by SWH supplier (Ktaka gives Rs 50 monthly subsidy)

  • saniconenergy

    The solar water heater comprises of two parts viz., solar collector (which absorbs sun radiations & transfer the heat to water) and a storage tank, which stores the water heated by the solar collector. The most commonly used collectors are of two types, Flat Plate Collector also referred as FPC, which is usually a flat insulated box covered with the glass and a bunch of tubes , usually of copper. This tube is covered & welded to the wide fins,usually of Aluminium painted with high absorption coatings such as TINOX.

    The other type of collector is the evacuated tube collector also know as ETC. This comprises of hollow glass tubes with anti reflective coating inside. This tube contains a metal pipe usually of Copper placed in the center. The metal tube is hermetically sealed with glass tube and the air inside is sucked to create sort of vacuum.

    The collectors are placed on the rooftop facing the south in northern hemisphere and north in southern hemisphere.The solar collector turns the sun’s radiation into heat which is then transferred on the the water inside these tubes.

    The heated water is transferred to the storage tank either through the pumps, which is controlled by the solar controller or if the tank is placed on the top of the collectors then through thermosiphon (hot is lighter thus rises, cold is denser, heavier thus settles down).

    In case of non sunny days or fluctuation in hot water demand, The solar water heater is backed up by auxiliary heating which could either be of gas, electric, heat pump etc. It is always recommended to install a thermostatic mixture in the solar water heater so as to prevent scalding if the temperature of the water rises exceptionally.

  • jappen

    Videocon Ltd has come out with its products of Solar water heaters with a 10 year Guarantee, free insitallation and direct fast service.It is a very good option also!!
    https://www.facebook.com/pages/Videocon-Solar-Water-Heaters-Maharashtra/1634478383358668?ref=aymt_homepage_panel. you can also visit its facebook page .

  • matri neer aanath ashram

    We are looking for solar water geysers for our orphanage at haridwar. To be used by 120 inmates, at a time, for bathing and other activities. Please depute your representative with catalogue for detailed discussion and order placement

    • संजय sharmaशर्मा

      क्या आप सोलर वॉटर हीटर लगवा चुके हैं या अभी लगवाने हैं ?

    • Abhishek Jain

      Hello Mr Bajpai,

      Bijli Bachao is just an information portal. We do not sell solar water heaters.

  • Sanjay mittal

    What is the subsidy given by govt in delhi &which company system is latest and best with low mantinance and good service

  • gagan deep singh

    Hi. I need to install best solar water heater system and solar power back system for my home, need very latest and trouble free system in ludhiana,punjab. capacity

    for water heater required around 200 ltr / day.

    kindly contact us directly. 09815996464 .

  • ashraf

    does the government gives discount in the electrical bill if your are having a solar geyser, if yes what is the percentage.

    • Abhishek Jain

      In some states yes. Which state are you in?

  • Suvendu Baral

    Good information. I am going to have one and use the existing electric one as stand by. Please share some info on solar AC, if they are available. This will be of great use for the summer.

    • Rakesh Pandey

      Solar Hybrid ac is available which can save your bill by 50%

      for detail contact me:08527021151 or mail:[email protected]

    • Abhishek Jain

      Hello Mr Pandey,

      How much is the EER of your AC?

  • Pannaga

    I’m trying to get the people of my area in Bangalore to buy swh. So want to show them a cost benefit analysis. How do I calculate the savings made without knowing the actual power consumption of the electric water heaters? There are many different models and I’m unable to find an average value of the number of units.

  • Ruchika

    Do you have updated numbers for the cost estimate for setting up a solar water heater for both technologies? Thanks!

    • Abhishek Jain

      HI Ruchika,

      We are trying to get the latest numbers from the market and will update them soon.

      Regards,
      Abhishek

  • Ruchika

    Why have you assumed 300 days of usage in South India? Are these some specific cities you are looking at?

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