Electricity Saving Tips For Homes And Offices

Instant water heater/geyser: may be good for individual but bad for system

By on April 22, 2016
Hindi Translation: तत्काल पानी हीटर/गीजर: व्यक्तिगत जरुरत के लिए तो ठीक हैं लेकिन संपूर्ण व्यवस्था के लिए बहुत अच्छे नहीं हो सकते हैं

We recently got an email from a reader of Bijli Bachao saying that he purchased an instant water heater after reading our articles. This made us think: did we ever recommend using instant water heater to people? The answer was NO. Were the articles written in such a way that it came out that instant water heaters were better? May be! So we thought of writing this article that can give our understanding and take on instant water heaters. There is nothing like buying instant water heaters/geysers is right or wrong, but with this article we will provide our take on instant water heaters and the impact of using the same.

Water Heater/Geyser electricity consumption

As we presented in our previous article: Choose the right sized water heater/geyser for electricity saving, it is important to choose the right sized water heater because the amount of electricity used by water heater depends a lot on the usage of hot water. The lesser the hot water used, the lesser is the electricity consumed. Also lesser the water you heat, lesser is the electricity consumption. Thus it is important to choose the optimum sized water heater that suffices your needs. The smaller the size better it is. Although smaller the size, higher will be the rating of the water heater. Also it is better to switch on the water heater before the use and switch it off immediately after.

Instant water heaters

Looking at the suggestions above, instant water heaters come across as the most ideal solution as they do not have any storage (so no chance of heating extra water or wasting hot water) also they have to be switched on before use and switched off immediately after. The electricity unit consumption is apt and there is very less wastage. From an individual’s perspective it sounds great.

Drawbacks of Instant Water Heaters

Because the instant water heaters have to provide water at the desired temperature, the rate at which it draws electricity at any moment is very high. So a storage water heater may be rated at 2 kW, an instant water heater is rated at 3 to 4.5 kW. So if 15 liters of water is heated in both, although the units consumed may be the same, but because instant water heater heats it immediately, it draws more power from the system i.e. it puts more load on the system.

Imagine a city where most people use water heaters between 7 AM and 10 AM in the morning and most water heaters are switched on during this time. If most of them are of 4.5 kW then the infrastructure required to handle the same will be huge and if the infrastructure is not there then grid failures (similar to the one happened in North India in 2012) can happen again. There will be sudden need of a lot of power. Instead if most systems are 2 kW systems, it may take time to heat water, but the system will not be strained.

Personally for an individual, the connected load of the house will increase by 2.5 kW (4.5 – 2) and may cost additional money in terms of fixed cost. So the savings in energy cost may get transferred to fixed costs.

Our recommendations

We always recommend saving water and using lesser water for all purposes. More water is required if you take bath in shower or tub (about 25-30 lts), bathing using a bucket uses lesser water (about 15 lts). A 6, 10 or a 15 lts storage water heater is mostly sufficient for such use. In places that are cold or extremely cold during winters, a 15 lts water heater may be sufficient, whereas in places where the room water temperature is not too cold, a 10 or even a 6 lts water heater may suffice.

If water heater is to be used in kitchen and usage of water is less, a 6 or 10 lts storage water heater may be good enough. The intent should always be to heat optimum water to save electricity.  Smaller water heaters also have smaller energy losses and thus provide ideal water heating. Please note that there are few models of 6 or 10 ltrs storage water heaters are also rated at 3 kW (and not 2 kW). These are again not recommended from power system point of view.

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  • dinesh joshi

    Finally decided to get Instant Water heater instead of Storage living in Mumbai

    Which Instant heater should i go for Shower Bath electrician guy was telling me to go for 4KW but what storage and brand and model ?

  • shawn

    Hi, I want to know if buying an instant water heater of 3 ltr for 2 people who use a bucket and require 6-10 ltrs of hot water (total 15 ltrs warm water) having 3kw will be good enough to give out that quantity of hot water. Will 4 or 4.5K be better in such cases. As i live in mumbai the weather is usually hot and tap water is usually room temperature. I am confused between havells, crompton greaves and bajaj models of 3 ltrs. I have also heard remson is a excellent choice but it usually has 25 lts storage which is too big for me and i am not sure if remson has safety features as my parents are both aged and may forget to switch off the power sometimes. I am also unable to find BEE ratings for instant water heaters. does the govt not give BEE ratings to instant water geysers?? Thank you bijlibajao team just for taking time out to help out the average indian.

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

      BEE star rating is not available for Instant Water Heaters. It is only there for storage water heaters. I think an instant water heater can work great if you live in Mumbai and prefer buckets. Even a 3 KW heater should also work. Havells and Bajaj are good brands. You can choose anyone of them. Instant water heater can be great energy saver for you and I would not recommend you to go for 25 lts model.

  • Athiraj Dhayalan

    Hello !!
    I am planning to buy a Instant water heater (Racold 3Ltr) for my home use.
    I have a big confusion weather instant water heaters will cause any health problems for new born baby’s..
    Can some on help me on this..

    Thanks in Advance !!

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

      There is not much difference between storage and instant water heater. Instant just heats faster. As long as water is not too hot, I do not think instant water heater should cause any health problems. Make sure that you collect water in a bucket and mix it with right amount of cold water so that temperature is just right for your baby.

  • Karthik

    We take some hot (boiling) water , mix it with cold water and use for bathing purposes. Also, while during bathing, we may even take additional hot water and mix it with cold water and use. Storage or instant water heater should be used ?

  • raman

    hi plz tell the difference between 1 ltr instant geyser and 3 ltr instant geyser?

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

      The main difference as the name says is in storage. 1 lts one will have storage capacity of 1 ltr and 3 lts one will have storage capacity of 3 lts. The other difference that comes is that 3 lts one will come with a 3 kW heater while 1 ltr models have 3 or 4.5 kW heaters. The 4.5 kW heater will heat faster as compared to 3 kW heater. You can read more on instant water heaters on this page: https://www.bijlibachao.com/water-heaters/should-you-buy-instant-water-heater-for-your-bathroom.html

  • sandeep

    hi my self sandeep. I want to buy a water heater . I am living in join family with separate bedroom attached with bath. I am confused whether to buy instant water heater or storage one. please guide.

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

      Hi Sandeep,

      Instant water heaters are good when you use them for taps for washing hands or washing utensils or usage where the water use is less. If you plan to buy a geyser for bathing, then it is better to go for storage water heater.

  • Ankur

    Also i want to ask when its an instant geyser n nt storage geyser then what difference does it make, i mean b/w 3 or 1 ltr ?

  • Ankur

    Hii, we are a family of 4 people 3 adult n 1 chil in Delhi. Should i go for a 3 ltr instant geyser or 1 ltr? Consumption is just bucket bath on morning.

  • Sunny

    Hi, I am from Bangalore and use Solar Water Heater. However, 60 – 75 days (not continuous) in a year Solar will not work due to weather conditions. I would be requiring water heater during this time. We are family of 4 (3 adults + 1 Kid). Usually it would be bucket bath. Please suggest whether instant would be suitable or storage. If storage what capacity should I opt. Also please advise few geysers.

    Thanks in advance.

  • KK Joshi

    I want to buy 10 Leter Geyser not preferably instant but it must be more reliable and energy efficient. Please suggest which will be the best option Morphy Richards or AO Smith or anyone else??

  • Ajay

    I am Ajay from New Delhi. I need to buy water heater & need your guidance for the same.
    Our usage of water heater is restricted to Bathing only [Shower & bucket use] We are two members.
    What should I choose ?

    Instant or Storage geyser and with what capacity?

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

      Hi Ajay,

      A storage water heater with 15-25 lts capacity would be better in Delhi especially if you use shower. If both of you will use it immediately one after another then a 25 lts would be better. Climate is quite cold in Delhi in winters.

    • Ajay

      Thanks Abhishek

  • Rajiv Jaithlia

    can you guide me… its an confusion electric heater is good enough or investment in solar water heater is good option. as we consume hot water for maximum 4 months as belongs to Ajmer Rajasthan

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

      Hi Rajiv,

      If you consume hot water only for 4 months then I assume that those are the coldest 4 months of a year. A solar water heater may not be very effective in winters and you would need additional electric heater. And thus I would suggest that you go for electric heater.

    • Rajiv Jaithlia

      And what is good.. Instant heating system or storage type of system… One more thing can we make assumption of electricity uses for 5 star rating 15 ltr storage and 5 star rating 3 ltr instant heater for a bucket…

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

      Well it depends on usage. Instant heating system can be more efficient as it does not have much storage and thus heat loss will be less. Storage ones will have more heat loss. But instant water heater will not work well if you use it for bathing in Rajasthan. Because it has less storage and it does take some time to heat water, it may not work as you may expect. For extreme cold in Rajasthan a 15 lts water heater would be good in Winters.

  • s. natarajan

    the tap water in bangalore is very cold especially in winter. what geizer can we buy with temperature control from say, 30 degrees to say 50 degrees centigrade so that we can wash our hand straight on the taps

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

      Hello Mr Natarajan,

      If you are looking for something for tap water (and not for bathing) then an instant water heater of 1 lt would be great for you (if you keep tap open for long then you may go for 3 lts one).

    • s. natarajan

      as a senior citizen i face the problem of washing my hands in cold water. by tapwater i meant water say at 20 /25 degrees. what i want is water at say 32 degress for directly washing hands instead of mixing hot and cold water etc. and 36 degrees for washing my plates,mugs etc. is there any geizer with adjustments at such low heat. thanks for such immediate response

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

      Hello Mr Natarajan,

      If you go for a geyzer with temperature control (thermostat) then you can adjust the settings as per your comforts. Some of these might be good for you: http://www.havells.com/Product.aspx?s=122

  • Varun

    We are 2 adults and 1 child and uses shower. My son likes to stay in water for little long. Should I got for instant water heater or storage type? I currently have 35 litres storage type and want to change it now.

    Please advise.

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

      Hi Varun,

      Instant water heater would not give hot water for long unless you are in a place that does not get too cold in winters. Instant water heater may not work well with Shower. You would need storage. A 15 lts water heater is usually good enough for shower. But if you like long bath then max 25 lts should be good enough.

  • Balaji

    This is Balaji from Bangalore. Since our solar water heater went down, we started using the 3L instant water heater. Since then, the electricity bill has doubled.
    Meanwhile, we have a newborn baby in our house and we require lot of hot water for both mother and baby throughout the day.
    In this scenario, I’m wondering if it would be better if I replace my instant heater with a storage type.

    Thanks for the advises.
    Best Regards,

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

      Hi Balaji,

      Instant water heater should not cause increase in electricity bill as electricity bill depends on amount of hot water you use. If your hot water usage has increased then certainly your electricity bill will go higher. But a storage type water heater would not help in reducing electricity bills if your hot water usage has increased.

  • Sandeep M.

    Hi Bijli Bachao Team
    First of all thanks for such an gr8 initiative. Energy conservation / going green is need of the hour. Its quite useful for many ppl. Thanks again.

    Myself Sandeep M. from Mumbai’s Western Suburbs. I need to change our old 1 litre 3kw Instant water heater & need your guidance for the same.
    Our usage of water heater is restricted to Bathing only [bucket use] We are 5 elders & 1 four yrs old kid & our usage is around approx. 100-130 litres of hot water daily maximum would be 150 litres.
    Instant water heaters is preferred as there is hardly any space to fit large storage heaters. Gas heaters skipped due to space issue as it requires proper ventilation.

    What should I choose ?
    3 liter Instant or 1 liter instant Heater?

    Suggest me some energy saving Instant Water Heaters asap as need to fix it by next 2-3 days.

    Thanks & Regards
    Sandeep M.

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

      For bucket bath in Mumbai, 3 lts instant water heater should be good enough.

    • Sandeep M.

      What will be energy consumption?
      Will 3 litres instant water heater save some energy compare to 1 litre while heating faster or its otherwise please elaborate.


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

      Hi Sandeep,

      Electricity consumption of water heater depends on volume of hot water you use. As the volume of hot water will be same in both the cases (as with small volume water heaters, it is less likely that you will leave hot water lying in the water heater), electricity consumption will almost be the same in both. Also as both are small water heaters, standing loss (loss of heat due to hot water lying in the water heater) will be very less.

    • Sandeep M

      I installed 1 litre 3kw racold prono neo.
      Due to poor rainfall there is water shortage in Mumbai so had to choose this as the water will also come from storage tank over loft.

      Thanks for your help.

  • Saurabh

    Hello BB Team,

    This is Saurabh from Mumbai, we are a family of 5 adults n water usage 70 ltrs approx. n looking for small size gyeser…pls suggest me which type.. instant or storage..which brand…n size of gyeser to buy…

    Thanks in advance..

  • Angad

    Does it mean that a higher wattage instant geyser will give more hot water ? Comparing a 3KW instant geyser with a 4.5KW geyser. Will the 4.5kw one give hot water for a longer duration ?

    • Bijli Bachao Team

      Higher wattage geyser will heat faster. It will not give more hot water. Heating rate will also depend on the rate at which you draw water from instant geyser. If flow rate is high, then you need a higher wattage geyser so that it can heat faster. If flow rate is low, then low wattage will also be fine. Finally as far as electricity units consumption is concerned, it will depend on the volume of hot water you use. If you use 20 lts, then the unit consumption will be same for both 3 kW and 4.5 kW, however 4.5 kW will heat it faster.

  • Iresh

    Good comparison. Good Suggestion.
    I also read your reply of Srinivas G question. Still i want your suggestion.
    We are 5 (2+3kids). Am using solar heater system. But in extreme winter at my city Baroda, after 3 person am not getting hot water so want to connect with solar system in master bedroom for bucket bath. Which one is good for me Instant or Storage ? if storage then capacity ? Can you pls suggest me 2 brands with usage style ?

  • Css

    Your review on instant electric water heaters shows Morphy Richards Lavo EM 6 model on the top however I am not able to trace this model to buy online even on the Company’s web site. Can you please help me locate the product for Purchase decisions ? I am located in Ahmedabad Gujarat and even a address of Company’s authorised both for sales and service outlet may help if the same is not available on web shopping. Please guide.

  • Guest

    Please suggest on what to select so that power consumption is less and the choice to be economical and serve are need :). Confused on what to choose between Geyser or Solar water heater connection for our new house in Bangalore.Thanks in advance.

    • Bijli Bachao Team

      Solar Water Heater is a great choice in B’lore.

  • krishna rao

    hi iam krishna rao from vizag, i want to use two water storage geysers for master bedroom (two adult)and children(two child) bed room for shower and bucket bath. please adivce me which brand and capacity of heater is better to us.

    • Bijli Bachao Team

      Hello Mr Rao,

      If you use shower bath then the water usage would be high (25-30 lts). In that case a 15 lts water heater would be better. You can look at these water heaters for your bathrooms:

      AO SMITH HSE-VAS-015
      Ferroli Caldo.15V
      USHA Aquagenie 15L

  • Vishal

    In Kolkata which water heater will be the best for 6time*10ltr hot water in a day?and how much amount will come for this usage?

    • Bijli Bachao Team

      Hi Vishal,

      Any 6 lts water heater can give you 10 lts hot water suitable for bath. For 6 lts you can look at these models:

      BAJAJ Majesty 6 GPU
      Ferroli Mito.6
      AO Smith HSE-SBS-006
      AO Smith HSE-SDS-006
      AO Smith HSE-SAS-006

      If you use it 6 times then you will heat 36-40 lts of water in a day. For the same you would end up using 1-1.2 units of electricity per day.

  • Rahul

    I have a 10 year old storage type electric geyser. Nameplate says 15 Litres & 3 kW. It does not have any BEE stars on it probably because it ages from before the rules came in.

    What I want to estimate is how much savings could I potentially get by replacing this old heater with a new heater that is rated, say, 5 stars? What’s the best way to calculate this? Currently load cycle on this geyser is approx. 45 minutes everyday. Unit cost is Rs 7 / kWh approx.

    But even current unit does not always stay on for 45 minutes every day because internal thermostat will cycle it on & off.

    I see online that a 5 star A O Smith Unit for 15 Litres shows a 2 kW power. But will the on-off duty cycle be identical to the existing unit to compare power consumption? I want to estimate payback period since this new unit costs approx Rs. 11,000

    • Bijli Bachao Team

      Hi Rahul,

      Electricity consumption of water heaters depend on the amount of water heated. The time for which it is switched on is less important. The insulation of water heater defines the standing loss (or heat loss) and BEE rating is done on standing loss. If standing loss is more star rating will be less. However standing loss in general is less than 1 unit of electricity. You may read more about all this on our article: https://www.bijlibachao.com/water-heaters/choose-the-right-sized-water-heater-geyser-for-electricity-saving.html

      So if the amount of hot water used remains the same then the savings will only be on standing loss difference. And it will be difficult to tell the standing loss value of your existing water heater.

      As far as power rating of water heater is concerned, a 3 kW heats faster than a 2 kW. Otherwise electricity consumption is not dependent on that.

    • Rahul

      Thank you. To illustrate this better, can you show a calculation of payback on geysers? Say replacing a 2 star with a 5 star. With typical usage values. What’s the payback? I wanted to get a general idea.

    • Bijli Bachao Team

      Hi Rahul,

      Electricity consumption of water heater = Amount of electricity used to heat up water + Standing Losses.

      Now assuming you heat the same amount of water using both 5 star and 2 star. The electricity used by both to heat up water will be the same.

      Again let us assume that you leave hot water standing (stored) in both the water heaters for the whole day. Then the only difference would be the difference in standing losses.

      The standing loss of most efficient BEE 5 star rated water heater of 15 lts is 0.426 units (or KWH) per day. That of most inefficient water heater is 0.681 units per day. The difference between the two is 0.255 units per day. So in a month the total savings would be 0.255 x 30 = 7.65 units. If you are in Mumbai where the tariff is highest (about Rs 10 a unit), then in a month you save 7.65 x 10 = Rs 76.5 per month.

      If your water heater is not start rated and the standing loss is much higher (say 0.826 units) then the difference would be of 0.4 and monthly it would amount to 12 units (or Rs 120 if in Mumbai).

  • Sushama


    We are a family of 5 including small baby, placed in hyderabad, for our apartment with 3 bathrooms we are thinking of putting 2 water heaters , one in the master bedroom 15lts storage heater ( for 3 people bucket bath 2 times per day ) we prefer Racold Eterno dg/ Havells quantro 15 lts based on your other answers , for the other bathroom we like to go for 3Kw 1ltr instant water heater , can you suggest a good brand for that

    • Bijli Bachao Team

      You may go for Racold Pronto I or Havells Opal 1 L.

    • Sushama

      thank you for the suggestion and do you plan any articles on electric chimney ? i found your articles very useful good work

    • Bijli Bachao Team

      We are glad that you found the articles useful. We will surely try to do some research on electric chimney.

  • Amish

    At Kolkata, where Pipe Gas is not served, which Electronic Instrument will be Best in Saving Electricity & Give us Best of the Services.
    My Mobile No.is 8017404525. Amish.M.Doshi

    • Abhishek Jain

      Hi Amish,
      Are you looking for a storage or instant water heater?

  • Shital Kanitkar

    Sorry I don’t buy your argument about the storage heater. The heater has to keep that water at a certain temperature. Every time some amount of water is consumed, and the water is topped up, the heater turns on to heat it up again. every time the water cools down, the heater turns on. unnecessarily .. in an instant geyser u heat only a small amount of water which we cool as per our need by topping it up with room temperature water.

    • Nitin

      “So the savings in energy cost may get transferred to fixed costs.”
      What fixed costs ?
      Are they actually equal to the savings in energy ?

    • Abhishek Jain

      Hi Nitin,

      In an electricity bill there is fixed cost component that is dependent on connected load (the total kW load that your house has which is sum of wattage of all appliances in your house) and then there is energy cost which is the actual electricity consumption. Instant water heater has high wattage. So it can increase fixed costs but can certainly save on energy costs as it consumes less energy. On the whole it will depend on daily usage, but in general there certainly are overall savings (if the usage is daily).

    • Abhishek Jain


      Which argument did you not buy? The article mentions that instant water heaters are the most energy saving heaters. It is just that the load or wattage of the instant water heaters is high and so it takes more instantaneous energy (not total energy) from the grid. It is just like having a higher CC engine in a car to run fast (not to cover more distance).

  • Senthil

    It would be bucket bath

    • Abhishek Jain

      I would suggest that you go for 6 lts water heater. You can look at these:

      Havells BUENO 6
      Havells QUATRO 6
      Bajaj Majesty 6GPU
      A O Smith HSE-SBS-006 or HSE-SAS-006

  • Senthil

    Hi Amit,

    I live in Chennai and we are a family of three(2 adult+1 child). Which one (instant vs storage) would you suggest for use in Winter @Chennai and the capactity (6 or 10). Also can you list 5 brand which are cost effective

    • AJS

      If I am Chennai, I would not buy any water heater as I wouldn’t need to. I was in Chennai, Pallavaram to be precise, it was intolerably warm even in Jan, 81. Therefore, there does not appear to be any need. However, if Chennai ever gets colder during some other months, which, I might not know?

      Another joke, once in Trivandrum, I heard a comment that the grass has gone dry due to winters, I could stop laughing, winter in Trivandrum?

    • Abhishek Jain

      Would you use it for bucket bath or shower bath?

  • Premkumar

    Hi Amit

    Since new BEE 5 star rated storage water heaters has very minimal insulation/standby losses, we can switch it on before 6 AM ( during off peak hours 12 am to 6 am) to reduce the peak load of grid. I think if we practice this in national level, MWs of peak load can be reduced. DISCOM should start promoting TOD tariff in domestic as well to reduce house hold peak loads like washing machine, geysers, etc.,


    • Abhishek Jain

      well said sir :). As it is hot water is needed only in morning.

  • George Abraham

    I stay in Delhi and am considering an instant water heater. My family has three members, including an eight-year old. Could you advise if it is a good idea to go for an instant water heater, like Racold 3-litre Pronto?

    • Abhishek Jain

      Hi George,

      Delhi is extremely cold in winters, instant water heater will not be able to provide you sufficiently hot water in winters. In Delhi weather it will take roughly 2-3 mins for 3 lts water to get hot enough for bathing. If you use bucket bath then you would need about 15 lts water. At rate of 2-3 mins for 3 lts, you would get full 15 lts in 10-15 mins. In that case as well buy a storage water heater and start it 15-20 mins before use.

  • vidit


    That was a very nice and short article on instant water heaters. I have a family of 4 and I still feel Instant water heater will be a better fit for my house. Can you please recommend what size and make would be a good choice inetrms of reliability and performance.

    • Abhishek Jain


      Which city are you in? Also do people in the house prefer bucket bath or shower bath?

  • Srinivas G

    which water heater do you think will be good for connecting to solar water heater? Instant or storage. I am asking because solar water heater doesn’t sufficiently heat in winters.. It will be warm.. So thinking we can connect instant water heater to the output of solar water heater.. what’s your opinion?

    • Abhishek Jain

      Hello Mr Srinivas,

      Technically any of the electric water heater can act as a backup for solar water heater. There is no restriction or preference for the same. Although from an energy saving perspective Instant Water Heater sounds good, but the whole premise of this article is that an instant water heater can add to the load to the grid. So if you ask for our opinion, we would suggest a storage water heater with lesser wattage.

      Hope this helps.


    • anikethan

      Hi Abhishek, Usually the water in the solar pipeline will be cold, so to heat this water shouldn’t geyser be switched on? Also what temperature should we set in the geyser so that, if solar water is hot enough we need not use geyser at all ( storage type)

    • Abhishek Jain

      Yes the geyser should be switched on if you connect it with solar water heater. But it is better to switch it on only when you need hot water and switch it off when you do not need hot water. For regular bathing, you need water at about 38-39 degrees (or max 40). If you have a adjustable thermostat in your electric geyser, you can keep it at around 40-42 and it will be more than enough (unless you mix cold water with it in which case you can keep it till 50).

  • Faisal Lohani

    Nice Short Article !!!