Water Heater Size Calculator | Geyser | 6, 10,15,25,50 liters – What size do I need?

What should be the ideal water heater size? It depends on the number of people using the geyser. You can use the Geyser size calculator below to easily find the right size for your family.

Water Heater Size Calculator

Water Heater Size Calculator
Select Geyser Type

How to use Geyser size calculator

1. Use the slider to select Number of Members in Family

2. Select the Manner of Intended Use

  • Bathing Bucket
  • Bathing Shower
  • Washing Utensils

3. Select Geyser Type Instant or Storage

The ideal Geyser Size will be Displayed

If people use the bathroom one after the other and consume say 15 to 25 liters of water, a 15 liter or 25-liter geyser should be the ideal one, especially if you belong to the southern part of India where the input water temperature is not very low.

If you go north, the temperature of input water goes down drastically. Hence, you will need nothing less than a 25-liter geyser.

You might be having two bathrooms. Under such circumstances, you would require double the capacity as two people might use the bathroom simultaneously.

Does this rule out the 6 liters and 10-liter geysers? No, it does not. You can still use the smaller geysers, except that they take a longer time for heating up the required water.

What, then, is the ideal size of a geyser?

An ideal size is one that can generate enough hot water for maximum instant use. You know your family better.

Note the following points when you wish to know the ideal size of water heaters for your house.

  • A smaller water heater tank entails that you get less hot water that you need.
  • A bigger tank can result in wasting water and electricity due to standing loss.
  • For the ideal size, you can refer to the size calculator shown below.
Size of FamilyManner of intended useGeyser TypeIdeal Geyser capacity
2 to 3 membersBathing – bucketInstant6 litres
2 to 3 membersBathing – bucketStorage10 to 15 litres
2 to 3 membersBathing – ShowerStorage15 to 25 litres
2 to 3 membersWashing utensilsInstant1 to 3 litres
4 to 8 membersBathing – bucketStorage25 litres
4 to 8 membersBathing – ShowerStorage25 litres
4 to 8 membersWashing utensilsInstant1 to 3 litres

Space is important

The average bathroom is small. In this age of attached bathrooms, there is far less space. Hence, the instant geyser is best suited for such bathrooms. The storage geyser has use only when you have more space.

Longevity of geyser

It depends on the type of water available. Many places in India have a high percentage of salt. Hence, you can expect scaling to occur. This can reduce the life of the coils.

In the normal course, instant water heaters last longer than storage ones. The principal reason is that storage geyser water heaters can decompose. However, with the easy availability of spare parts, you have geysers lasting for more than 10 years.

Advantages of choosing the right size of geyser

Choosing the right size should not be a problem for anyone after going through this article. The advantages of choosing the optimum size are many. Let us look at some of them in brief.

  • You save energy in the form of electricity consumed.
  • You save time because the water will be at optimum temperature at all times.
  • As you run your geyser for the right amount of time, you increase the longevity of the appliance.
What is the Ideal Water heater Size For a Family of 4?
For a family of 4 members, 25 Litre Storage Geyser is the right size for Bucket bathing and shower. If you want Instant Geyser, you can go with the 6-liter model but it is not suitable for a shower bath.
What is the Ideal Water heater Size For 5 Person Family?
Instant Water heaters are not suitable for 5 Person families, 25 Liter water heater is required for a Bucket bath. 1 x 25 liters, 1 x 15 Liters Geysers Required for shower bathing.
Water Heater Size for 3 Bedroom House and 4 Bedroom House
For an Apartment with 3 or 4 Bedrooms and attached bathrooms, you can install 15 Liter or 25 Liter storage water heaters in each bathroom. The size of the Geyser depends on the size of the family.

You have just seen the Water heater buying guide as well as the optimum size of the geyser for your family. You can use the above water heater size calculator to easily find the right size.

We shall now proceed further and compare the instant geyser with the storage geyser as far as power consumption is concerned. This will give you the right idea about the type of geyser to install in your house. You had seen the comparison with regard to space in this particular article. Let us move ahead with the comparison in the next article.

Chaithanya Vanjari
Chaithanya Vanjari
I'm Chaithanya Vanjari, the Creator and Editor-in-Chief at KitchenArena. With a decade of experience in evaluating large appliances like air conditioners, washing machines, refrigerators, and various small home devices, I possess the technical expertise needed to thoroughly review and understand the operational complexities of these appliances.


  1. We are 3 members in the family and my bathroom space is limited and I also have a shower,which geyser size(litres) and brand should I prefer ??

    • Since your bathroom space is limited, you can install an instant water heater which is good for 3 members. If you want to take showers, it is better to install a storage model. 6 liters capacity is enough. checkout the top models below.

      Racold Pronto 6 Litres Instant 5 Star

      Havells Instanio 6-Litre Instant Geyser

      AO Smith SGS-PLUS-006 Storage 6 Litre

      Crompton Arno Neo ASWH-3006 6-litres

    • There are 3 people in my family, typically 2 will use bucket bath and one will use shower bath. There may be another person added only once per week (bucket bath), can I stick with 15 litre or should I opt for a 25L one?

      Also when referring to the number of people and the storage size, does it mean in heating of one cycle a total of x number of people can bath by y method? Or is it like a different full cycle of heating for each of the x amount of people?

      • 25 Litre model is required for 4 people. If a person can wait a few minutes and there is no hurry for bathing, then 15L model will also suffice.

  2. I have 5 family members. But our bathing time is different. What type of geyser should I buy? And how much litters?


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