Tank vs Tankless Water Heater


Both tank and tankless water heaters can be reliable options for your home. However, it is important to figure out which one would suit you and your requirements best.

There are several considerations that you must keep in mind here that can also denote the differences between these two heaters.

Through this guide, we will take you through these differences so that you can make an informed choice.

What Is a Tank Water Heater?

Tank water heaters come with a storage tank or reservoir that heats up the water and holds it in until it is needed around the house. Whenever you turn on a tap or shower, the hot water will make its way to it through a pipe attached to the tank water heater.

Once the water level starts reducing in the heater, cold water replaces it which the heater heats up all over again.

Tank water heaters are quite popular in households. They tend to come in a range of sizes and capacities, most commonly around 30-60 gallons. They can run on electricity, gas, or oil depending on your household power supply.

What Is a Tankless Water Heater?

A tankless water heater does not use a reservoir to store water. Instead, it heats water up only when you require it.

For this, cold water travels to the heater and runs through a burner or heat exchanger where it is heated up. This hot water then directly flows to your taps or shower when you turn them on.

Tankless water heaters also run on gas or electricity. They differ in terms of their size but can usually easily be mounted on the walls of your house due to the absence of a tank.

These heaters can heat up to five gallons of water in a minute.

What’s the Difference?

There are a few other ways in which both these heaters differ that we can look into below, based on which you can then make a choice.


Tank water heaters are more affordable than tankless water heaters in terms of both purchasing and installation costs. Since tankless waters usually require structural changes when it comes to venting, piping, fuel, and power supply.

Beyond these initial costs, however, tankless water heaters can be more cost-effective in the long run. This is because they use less power than tank heaters to heat up the water. This saves energy and ends up reducing your energy bills.

This leads to savings that can total over $100 every year as compared to tank water heaters.

Energy Efficiency

Tankless water heaters are more energy-efficient as compared to tank water heaters. This is because they only heat up water on demand instead of maintaining a constant supply and storage of hot water.

In fact, tankless heaters are up to 34% more energy efficient. Since there are fewer losses of heat and energy since the water is directly supplied to taps instead of being stored, the efficiency improves.

In either case, gas heaters tend to consume less energy even though electric ones are more efficient. This is because electricity is more expensive to use.


Tank water heaters are generally much easier to install, especially if your previous heater was a similar one too. It is possible to do this on your own or by calling a professional.

With tankless water heaters, you need to change the piping, alter the supply system, add venting and more, particularly if you previously used a tank water heater. This can increase costs significantly.

However, you have the option of installing tankless water heaters wherever you require them since they do not take up too much space.


Since tank water heaters come with a storage reservoir, you need to account for that when you figure out a space for installation. Since they tend to have a large capacity of around 50 gallons, they are quite big in size.

However, this does ensure a good and equal flow of water across your taps until the water runs out.

Tankless water heaters don’t have a tank at all, which is why they can save up plenty of space in your house.


Tank water heaters hold a certain amount of hot water in their tank. This means that they can steadily supply sufficient hot water to all taps and devices across the house.

When this water runs out, however, it takes some time for it to refill and reheat.

On the other hand, tankless water heaters need to heat water on demand, which is why the hot water output might vary if two or more devices or taps require hot water simultaneously.

Thus, if you have a greater demand for hot water, you might need to install more than one tankless heater.

The waiting period is practically minimized with tankless heaters as there is no need for refilling.

Maintenance and Durability

Tankless water heaters are estimated to have a lifespan of over 20 years whereas tank water heaters only last for 10-15 years.

Further, tank heaters require more frequent maintenance in order to prevent rusting in the tanks. You will also need to take protective measures to prevent functioning failures that tend to take place due to substantial water amounts.

These failures could cause leakages that can lead to mold and dampness inside your house, thus requiring more immediate repairs to prevent health and structural damage.

Parting Thoughts—Which One Should I Choose?

We have now seen most of the ways in which tank and tankless water heaters differ from each other. Based on these considerations, you can then make your choice.

Overall, it might be better to opt for a tankless water heater since it tends to save a lot of energy and money in the long run. However, you might need to install more than one of these heaters if you have a higher demand for water at home.

Ultimately, it depends on your own requirements. You can opt for alternative power supply options to make your water heating system even more efficient and cost-effective.

1 thought on “Tank vs Tankless Water Heater”

  1. Tankless space heaters use a counter-current heating element that does not store heat but instead discharges it into the air surrounding the unit. This means the unit is always running, and it allows you to avoid storage costs.


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