Instant Geyser Vs Storage Geyser

When you go to the market to buy a water heater, you will see that there will be two different types of water heater available. One is the Instant Water Heater and the other one is the Storage Water Heater.

It is very important to know the differences between Instant Geyser Vs Storage Geyser as both come with their own advantages and disadvantages and we should know which one is the best based on our requirements.

So, this article will be all about discussing Instant Water Heaters vs. storage Water Heaters based on different parameters, and at the end we will conclude which one has an edge.

What Is An Instant Water Heater / Geyser?

Instant Water Heaters do not have a tank to store hot water. That is why it is also called a Tankless water heater.

Water gets heated when it passes through the heat exchanger. You will get instant hot water as it does not have to heat the complete volume of water before delivering it.

Instant Geyser Vs Storage Geyser

Instant water heaters are available in the range of 3-6 liters capacity. Please don’t get confused by the term capacity when there is no tank. Here the 3-5 liters capacity denotes the flow rate per minute. This means a 3-liter instant water heater will deliver 3 liters of hot water per minute.

Instant water heaters are energy efficient, occupy less space, and are cheap too. However, for heavy usage, instant water heaters are not a good option.

What Is A Storage Water Heater / Geyser?

Storage water heaters have a water tank generally between 10 liters to 35 liters capacity for storing hot water.

The heating element will heat the water to the desired temperature and store it in the tank. As long as the water temperature does not go down, the heating element will be idle.

Once the water temperature goes below the desired range, the thermostat will activate the heating coil and heat the water again. The cycle flows like that until you turn off the power.

Instant Geyser Vs Storage Geyser

Storage water heaters are for big families and heavy usage. It occupies more space and often requires professional installation. It also consumes and wastes more power than instant water heaters.

Instant Geyser Vs Storage Geyser: Which One Is Better

We will find out the differences between an Instant Geyser and a storage Geyser based on the following parameters.

Hot Water Availability

You will get instant hot water in Instant Geysers but the amount of hot water you will get is limited to the flow rate. For example, if you buy a 3-liter instant water heater, you will get 3 liters of hot water instantly. However, if you need more water, you need to wait.

Storage water takes about 5-10 minutes before it can deliver hot water. Once it starts delivering, you will get a continuous flow of water until it exhausts its capacity.

You also need to consider the input water temperature. For example, if the input water temperature is 5°C and you want the output water temperature to be 40°C, you may get hot water instantly. However, if you want the output water temperature to be 60°C, then it may take some time to get hot water.

The time taken by water heaters to deliver hot water directly depends on the temperature difference. For example, the water heater that provides hot water instantly in Hyderabad may not deliver hot water instantly in Delhi due to the temperature difference.

Energy Efficiency

Instant water heaters use powerful heating elements to deliver hot water instantly. So it consumes more power. However, there is no power loss as it does not heat the water, store it, and heat up again. That is why, for regular use, instant water heaters are more energy efficient.

Storage water heaters have to heat water, store it, and heat it up again when required. The cycle continues until you turn off the power. So it consumes more power as it runs for more time than an instant water heater.

You also need to consider the energy loss in storage water heaters. For example, even if you need a bucket of water for a bath, the storage water heater will heat up the full capacity of water in the water heater although you don’t need that much water.

Considering all these use case scenarios, instant water heaters are always more energy efficient than storage water heaters.

Flow Rate

The flow rate is a very important aspect to compare the differences between instant water heaters and storage water heaters.

Generally, the tap in the kitchen has a flow rate of around 3 liters/minute whereas showers have a flow rate of around 8 liters/minute.

Now consider if you have a 3-liter instant water heater, you will get hot water instantly in the kitchen tap as the tap water flow rate and the water heater flow rate is the same.

Now if you use the same water heater for the shower, you may not get hot water as the shower flow rate is more than the water heater flow rate. You may get a mix of cold and hot water.

Storage water heaters have a different story. They come in the size 10-35 liters capacity which is good for even showers. This means if you use storage water heaters, you won’t get a mix of hot and cold water during showers or similar heavy usage.


Many Indian households have cramped bathroom space. Fitting a storage water heater could be a challenge due to its huge size. You may also need special brackets to hold the heater in place.

On the other hand, instant water heaters are so small in size that you can hang them anywhere you want. Be it in a cramped bathroom or on top of your kitchen tap.

So, if space is a concern for you, you have no option except to choose an instant water heater.


Instant water heaters are available in the range of 3-6 liters capacity whereas storage water heaters come in the range of 10-35 liters capacity. Commercial heaters have more than 100 liters capacity too.

Please note that instant water heaters do not have a tank. The capacity of instant water heaters means the flow rate.

So, for casual day-to-day usage, instant water heaters are good but for heavy usage, storage water heaters are better as you will have more volume of hot water at any given point in time.

Multi Point Usage

Storage water heaters can be used for multi-point usage. For example, you can use the same water heater to supply hot water to the kitchen as well as in the bathroom. All you need to do is to get your piping done properly.

Since Storage water heaters store hot water, it is very easy to supply hot water to different outlets without any issues.

In the case of an instant water heater, it is good for single-point use only as the water volume per minute is very limited and there is no storage tank. Even if you use it for multi-point usage, you may not get hot water from every outlet.


Instant water heaters do not need regular maintenance. Since there is no tank, no issues related to corrosion or any mineral deposits. The only concern is the heating element. But the technology is advanced enough to serve you for at least 5-7 years before the heating element fails.

In the storage water heater, the lifespan depends on how frequently you do servicing and how good is the water. If it is hard water, you will see issues popping up within 2-3 years in the tank. Although different technologies like Blue Diamond glass-lined technology and other corrosion-resistant technologies are in place, still the tank will give you trouble in no time.


No compromises on safety in both an instant water heater and the storage water heater. Features like pressure release valves, thermostats, PUF insulation (storage), and circuit breakers are available in both types of water heaters.


Instant water heaters are only good for casual single-point usage. If you are a heavy user, you may choose to install multiple instant water heaters or buy a storage water heater and implement multi-point usage.

The benefits are different in both these types of water heaters, however, for heavy usage, storage water heaters are the only option


Storage water heaters are costly as it has a water tank and other features to safeguard the tank. The initial setup cost is also high as you may need professional installation and regular servicing. If you use gas for powering the storage water heater, then the setup cost is huge.

Instant water heaters are cheap to own and operate. But you need to compromise on the usage.

Conclusion: Instant Geyser Vs Storage Geyser

There is no clear conclusion to decide which one is better as it all depends on your family size and usage. If your usage is more, choose a storage water heater. Otherwise, instant water heaters are more than sufficient.

If your budget is low, choose an instant water heater and compromise on the usage. So, ultimately it’s your requirement that decides which one is the best for you.

I would recommend you go through this Water Heater Size Chart that will give a fair idea about how to choose a water heater based on different common-case scenarios.

Rajib Is The Founder And The Key Brain Behind RiansDeal. A NIT 2004 Graduate In Mechanical Engineering With Close To Two Decades Of Experience In Designing Large Appliances And Consumer Electronics Products.


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