Electricity Saving Tips For Homes And Offices

Gas Water Heaters/geyser better than Electric Geysers in saving energy

By on April 22, 2016

We at Bijli Bachao have always mentioned that instant water heaters are the best for electricity saving, however they increase the load on your electricity distribution. In fact we wrote about in detail in our article: Instant water heater/geyser: may be good for individual but bad for system. If you do not go for instant water heater then the next best choice is to go for smallest sized water heater (read more at: Choose the right sized water heater/geyser for electricity saving). However most small storage water heaters do not provide sufficient hot water in most conditions and in fact in colder cities the instant water heaters do not work effectively as the rate at which they heat water is very low. But if you are someone who is looking for small storage capacity heater and also want fast, energy saving water heater that can give continuous supply of hot water for a long time, then you should go for a gas based water heater. In this article we will give you some numbers to compare.

Comparison of heating rate

Most regular water heaters have 2 kW or 3 kW heating element. An instant electric water heater has a 4 kW heating element. The following table shows how they compare in terms of rate of heating:

Heating Element Wattage
2 kW3 kW4 kW
Time taken to raise temperature of 6 lts of water by 25 degrees5.25 mins3.5 mins2.63 mins

Which means even with the instant electric water heater it will take about 30 seconds to heat 1 litre water by 25 degrees. And if you are in a place with very cold winters and extremely cold water during this period, then the temperature rise needed would be more and thus it would take more than 30 seconds to heat just 1 litre of water to the temperature good for bathing.

In comparison gas water heaters are available with equivalent of 12 kW so it will heat water 3 times faster than an instant electric water heater and thus it would take just 10 seconds to heat 1 litre water by 25 degrees. This means that you will get hot water much faster.

Comparison of cost of heating

Gas water heaters are as high as 85% energy efficient. Which means 15% of heat is lost but still 85% is used for heating water. Electric instant water heater are close to 100% efficient because all the heat is used up to heat water (assuming standing losses are negligible as there is no storage in instant water heater). If we compare the cost of raising temperature of 6 lts of water by 25 degrees, the cost comparison is shown in the table below:

LPGPNGElectric
Unit Definition1 Cylinder (14.2 kgs LPG)1 SCM1 kWH
Energy (in Joules) per unit654620000418680003600000
Energy (in Joules) per unit factoring efficiency556427000355878003600000
Units Required to heat 6 lts of water by 25 degrees0.0011322240.0177026960.175
Cost per Unit (in Rs)Rs 423 (Subsidised),Rs 23Rs 5
Rs 750 (Un-Subsidised)
Cost of heating 6 lts water (in Rs)Rs 0.48 (Subsidised),Rs 0.41Rs 0.875
Rs 0.85 (Un-Subsidised)

This shows that gas water heating is at least 50% cost saving as compared to electric water heater if you have subsidised gas or PNG.

Gas water heater has 85% efficiency, how is it energy efficient?

Gas is a primary source of energy i.e. it is extracted and used as is and the only losses are during transportation and those are minimal. Where as electricity is an secondary source of energy. It is generated using coal or other forms of fossil fuel. There are inefficiencies in generation, transmission and distribution of electricity. In general it is said that there are 15-30% losses in India. So using electricity in itself is not as good as using the fuel directly and thus using gas for heating water is energy efficient.

How does Gas Water Heater work?

The technology behind a gas water heater is a very simple one. The water moves through a pipeline which passes through a heat exchanger. The heat exchanger has water pipe covered with fins and there is a gas burner below it. The gas burner is ignited using an electric impulse created using the inbuilt batteries. The flames heat up the fins which in turn heat the water. And the hot water is obtained from hot water outlet. The system starts up the moment you switch on a tap and switches off immediately after you close the tap.

Diagram Source: http://www.waterheatingsystemsale.com/tanklessone.jpg

Diagram Source: http://www.waterheatingsystemsale.com/tanklessone.jpg

Are these water heaters safe?

In general these water heaters are quite safe to use as long as you follow basic safety precautions. Certain things that you should take care of are:

  • Never install it in a closed space (like bathroom). Make sure that there is good ventilation.
  • Avoid keeping it close to inflammables, explosives or corrosives. Also avoid any electric wiring close to the water heater.
  • Make sure that connecting pipes are leak proof, anti corrosive and clean.
  • Keep it at a height at which you can easily see the pilot flame.
  • Never leave the gas water heater on (or the tap on) for long time.

Are there any specific buying tips?

  • First and Foremost, BIS or Bureau of Indian Standards have specific safety and performance standards for gas water heaters. So always buy a gas water heater with ISI mark. Do not buy unbranded gas water heaters.
  • You should make sure that you have space to install the water heater. As mentioned above make sure that you have a space with good ventilation.
  • Some good brands as per Consumer Voice Report (link) are: Kenstar, Crompton Greaves, Marc, Venus, Racold and Bajaj.

Conclusion

Choosing the smallest possible water heater is the best way to minimize your electricity consumption and also costs. However smaller water heaters may not give you sufficient amount of hot water at the right time and longer duration. If you have an option to install a gas water heater, then that is the best to save both energy and costs.

References

http://consumeraffairs.nic.in/consumer/writereaddata/Gas Water Heater-13.pdf

http://www.iocl.com/products/indanegas.aspx

http://www.mahanagargas.com/


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36 comments

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1

Hello,
Following Bijapur BBachao very closely since more than year.
After your articles, exchanged our 13 year old refrigerator with 4 star Inverter Refrigerator.

Now my question is
We are using 15 liter 5 star (2011) storage Gyeser title 5 family members around 6-7 bucket of hot water.

We are getting PNG connection in our home in Pune. So shall we move to png gas geyser with initial cost of around 9.5 k ( 5 K heater cost+ 2.3 K MNGL cost + rest plumbing cost)??

Is this 10k investment is worth & how much time it will take to recover thiscist as gas price is 23 here in Pune.

Any other comments on this will be very helpful.

Thanks.

Piyush

2
Abhishek Jain (Mod)

We have done detailed analysis on this on this page: https://www.bijlibachao.com/water-heaters/gas-water-heatersgeyser-better-than-electric-geysers-in-saving-energy.html

7 buckets would be about 70 lts of water. And in pune your tariff would be about Rs 8-9 per unit (if you are in middle slab). With gas water heater you can save up to Rs 10-12 per day or Rs 300-350 per month. Which means your payback will happen in 2-3 years (assuming that you junk your old water heater and there is no salvage cost). If there is salvage cost (you sell it in 2nd hand market) then it will be much less.

3

Hi Abhishek, I'm from Kolkata and want to have a multipoint Water Heater. There are 4 Bathrooms in my apartment (All in the same floor) and 2 Kitchen Taps. Are there any Multipoint Water Heaters available in India, to suffice all of them? If yes, kindly guide me to their websites/ details. Also can you suggest whether to go for Gas or Electric (P.S I given up the Gas subsidy) for Economic reasons as we don't generally have an extremely chilly weather here in Kolkata? Thanks!

4
Abhishek Jain (Mod)

Hi Arijit,

I am not aware of multipoint water heaters, however I do not think it is difficult to create considering the fact that you can play with design of piping.

There won't be much of a difference in energy costs if you have given up subsidy on gas. You can choose anyone of them.

5

Hi abhishek , We are 2 people and one child 2 years old , i am going for bajaj 150710 model Majesty Duetto Gas Water Heater (PNG)
Please advice is this sufficiant for us ?
We are from ahmedabad .

6
Abhishek Jain (Mod)

Hi Nirav,

Gas water heaters are pretty quick in heating water as their heating capacity is much more than regular instant water heaters. So I think this should be good. However, I am still doubtful about their performance when used with shower. They should be good for bucket bath.

7

we are going to use shower instead of bucket bath so please suggest gas geysar or ele geysar

8
Abhishek Jain (Mod)

For shower bath, it is better to go for a 15 lts electric storage geyser.

9

could you please recommend specialist who could convert LPG gas geyser to PNG gas geyser in Delhi/NCR region Faridabad.

10

Hi, nice post. and I have a doubt! can gas geysers be used with 'gober gas' or 'biogas'? Any modifications needed for that? If needed, how to do them?

11
Abhishek Jain (Mod)

Hi Shiva,

It should work with gobar gas or bio gas as well. I do not think it should need any modification. In a gas water heater the gas is just used to burn a flame and so any gas that burns should work.

12
Srinivasa Kamath

I want to purchase gas water heater. Is it OK to apply domestic cylinder or I have to purchase commercial cylinder. Please guide me

13
Abhishek Jain (Mod)

Hello Mr Srinivasa,

I am not sure about it. You will have to check it with your gas company.

14

Dear Abhishek need your valuable guidance. I want to buy a gas geyser. But in my case, the distance between gas cylinder and the gas geyser is approximately 30 feets. Will this distance of 30 feets cause any problem with regard to gas pressure getting reduced till arrives near the geyser or elsewise. Secondly, how are these brands 1) Surya & 2) Suraksha.

15
Abhishek Jain (Mod)

By increasing length of the gas pipe you are increasing the risk of the system. The biggest challenge with gas geysers is the safety, as gas leakage, etc can cause accidents. I would rather suggest you to have a longer pipe from the geyser to the destination, than having a long pipe for gas between geyser and cylinder. Try to have a short pipe from cylinder to geyser.

16

Today I have install the gas gyser but it is not working .water is not getting heated up .our water storage tank is nearer to ( at about 5 feet height)
The gyser .Does gas water gyser will depend on height ??

17

It needs pressure to startup and ignite the flames. Geyser must be pressure sensitive. In that case Racold is best. Even I had one with 5 feet of tank and worked just fine.

18

We are 4 people small family -2 adults +2 children. I wanna purchase Geyser but not sure which one to purchase, whether Electrical or Gas Geyser. We are leaving in 1 bhk flat. So just need your kind advice regarding same which one will be suited best & if possible just tell why. Also guide about the appropiate god brand please.-Rajesh Rana

19
Abhishek Jain (Mod)

Hi Rajesh,

If you can ensure that the geyser in a safe place, then going for a gas geyser would be most economical. I am not sure about the best brand, but a lot of these regular water heater manufacturers (like Bajaj, Havells, Racold, AO Smith, etc) have gas models.

20

Hi,Abhishek ji......Thks for ur article.I have bought a SURAHSHA brand gas water heater which is ISI certified. It is working very well and also saves my money and energy.thanks a lot.

21
Abhishek Jain (Mod)

Great. Thanks for the feedback.

22

I need hot/warm shower which electric geaser provides, but gas geaser output pressure is slow as it is instant and no tank... I am thinking to lead outlet of gasgeaser to another electric geyser( may not switch it on).. will the pressue be ok for it?

23
Abhishek Jain (Mod)

Will depend on how much pressure you are getting out of gas geyser. However I do not see any benefit that you would get by putting electric geyser in front of it. Gas geyser will still heat at a slow rate and that is why will drive the ultimate pressure.

24

We are 7 peoplein family 5Adult & 2children.Using Electric geyser.planning to switch to gas gyser please give comparison

25
Abhishek Jain (Mod)

Hi,

Gas geysers are instant water heaters and there is no storage options available in them. So in case you are going for gas geysers, you will have to put one wherever hot water is required (i.e. if there are two bathrooms you will need two of them). Many brands like Bajaj, Vguard, AO Smith, Racold have gas geysers. However safety is the prime most important in gas water heaters and I have seen AO Smith model to be good at it (http://www.aosmithindia.com/HIG-VNS.html). I do not have detailed comparison right now, but this one model from AO Smith looks good (as compared to other models that I have seen).

26

We have installed instant water heaters after reading your earlier article. There is an opinion, that instant water heaters should not be installed where shower is used. How does it matter? Can you comment on this?

27
Abhishek Jain (Mod)

Well it depends on location where it is installed and the heating element wattage. Instant water heaters have 3 kW or 4 kW heating element which signify the rate at which it can heat water. 4 kW will heat faster than 3 kW. If one lives in a very cold climate instant water heater may not be able to supply sufficiently hot water because even with a 4 kW heating element the temperature of water would be so low that 4 kW heating element will need a few minutes to heat water which may work with bucket (as one can wait) but not with shower.

28

Hi, thanks for this article. I wish to use geyser for getting hot water from shower. which will be best and comfortable along with being economical ? thanks for reply.

29
Abhishek Jain (Mod)

You should go for storage water heater for that. Size of the storage will depend on the climate of the city you live in.

30

We read about fatal accidents due to leakage of current in a pond or puddle of water.My question: How come water in a pond or a puddle can give fatal shock as same is already earthed due to wet earth !

31
Abhishek Jain (Mod)

Hi Avinash,

Where did you read about it? Ideally just a pond and puddle should not cause fatal accidents unless someone touches a metallic item carrying current.

32

It's common to read in newspaper that someone or animal entered a pond and got electrocuted because live wire fell into it.My doubt when water is a good conducter of electricity then the current from live wire should go to earth and break the circuit.

33
Abhishek Jain (Mod)

Hi Avinash,

Found this on reading more. May be this can help:

http://www.brl.uiuc.edu/Publications/2009/Fish_Geddes_Eplasty_2009.pdf

34

Use solar water Heater

Just for 13500/- per 100 lpd.

systems capacity are 100, 200, 300, 500, 1000...

5 yrs warranty.

No electricity \, no gas required

One time investment.

within three year its repayable.

Temp. rise up-to 65-70 deg. celc.

For sales and distribution contact

Tulsi Energies 09319415806

35

hi, would like to buy AC for a 10*10 SqFeet room in Navi Mumbai. daily requirement might be around 8 hours. Can I buy inverter AC for long term savings. If yes. Which inverter AC should I buy. Kindly advice.

36
Abhishek Jain (Mod)

Hi Kartikey,

You should go for 0.75 ton inverter AC for your room. You can look at these models:

0.75 ton inverter AC:
Mitsubishi MSY-GE10VA
Daikin FTKM25PRV16
Sharp AH-XP10LV
OGeneral ASGA09JGCA
Daikin FTKP25PRV16
O General ASGG09JLCA
Panasonic CS-YS9PKY

The sequence above is in decreasing order of energy efficiency.

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