How does tankless water heater work?

A tankless water heater is a more efficient and space-saving alternative to a traditional water heater that stores and heats water in a tank. Instead of storing hot water, a tankless water heater heats water on demand as it flows through the unit. This means that there is no need for a large tank to store hot water, resulting in a more compact and energy-efficient system. In this blog post, we will discuss how does a tankless water heater work?

How does a tankless water heater work?

Installing a tankless water heater can greatly improve the convenience of your daily routine. These systems use either electricity or gas to provide instant hot water as needed, without the need for a storage tank. In this article, we will explore the inner workings of tankless water heaters and how they can benefit your home. So stick with me and let’s learn more about these efficient systems

As it does not have a tank, cold water comes directly from your water source or any other tank, when cold water passes through an aluminium heat exchanger, water heats up. As there is a burner inside the tankless instant water geyser that controls the system. So, you do not wait long for hot water as it works immediately.

Firstly, on the tap: 

Before turning on the tap make sure your water pressure is good so that hot water flows through the pipe easily. If you have dual knobs, it becomes easy to locate a warm water tap. So just on the tap for hot water, and within 15 seconds you get hot water. Moreover, you do not need to wait for hours for warm water.

A water flow sensor detects the water flow:

There is a sensor inside the tankless water heater that detects the water flow from the water reservoir. Along with this, it sends signals to an aluminium heat exchanger to ready for the process. The sensor works properly when water pressure is high.

Water enters the heater:

Inside the water heater system, cold water enters from one side of the pipe and goes to the aluminum heat exchanger. After cold water reaches the heat exchanger heat sensor triggers and the heating process started. The heat exchanger increases the temperature of the water up to 70 degrees. Moreover, a tankless water heater provides 2-5 gallons per minute of hot water.

Water circulates through the heat exchanger:

In the process, water circulates through a heat exchanger and the system takes only 12 to 15 seconds to work. As a result, you can get hot water for use in a short time period.

Automatically ignition of burner:

The automatic ignition of the burner is the most significant part of the tankless water heater. Whenever you need warm water, the water heater works automatically. The water heater system is sensing the user’s needs if the tap burner ignited, and if you off the tap burner also off spontaneously. So, there is no chance of wasting energy.

User Interface:

Modern tankless water heater system comes with a user panel that allows you to control temperature settings. You can easily adjust the desired temperature, and water flows, and manage fuel.

Tankless Electric water heater vs Tankless Gas water heater:

A tankless electric water heater uses electricity as its energy source to heat water on demand, while a tankless gas water heater uses burning fuel, such as natural gas, as its energy source.

Efficiency Difference:

One main difference between the two is their efficiency. Tankless gas water heaters tend to be less efficient than tankless electric water heaters because some heat is lost during the combustion process. Tankless electric water heaters, on the other hand, are able to convert nearly all of the electricity they use into heat, making them more energy efficient.


Another difference is the cost of operation. Gas is generally less expensive than electricity as an energy source, so a tankless gas water heater may have lower operating costs compared to a tankless electric water heater. However, the initial cost of purchasing and installing a tankless gas water heater may be higher due to the need for ventilation and the cost of installing a gas line.


In terms of maintenance, tankless electric water heaters tend to require less maintenance than tankless gas water heaters, as they don’t have any combustion components that can wear out or require cleaning.

In a nutshell, the choice between a tankless electric water heater and a tankless gas water heater will depend on factors such as the energy source availability and cost in your area, as well as your budget and preferences.

Things to consider before installing the tankless water heater :

There are several things to consider before installing a tankless water heater:

1. Size and capacity: It is important to choose a tankless water heater that is the right size and capacity for your home and your hot water needs. If the unit is too small, it may not be able to keep up with demand. In contrast to it,  a unit that is too large may be more expensive to operate and may not provide any additional benefits.
2. Energy efficiency: Tankless water heaters can be powered by electricity or gas. You should consider the energy efficiency of the unit, as well as the cost of the energy source in your area.
3. Location: Tankless water heaters need to be installed in a location with adequate space for ventilation. So, you have to make sure that you have a suitable location in your home for the unit.
4. Water quality: The quality of the water in your home can affect the performance and lifespan of a tankless water heater. Therefore, you have to keep in mind the pH and hardness of your water.
5. Cost: Tankless water heaters can be more expensive to purchase and install than traditional storage tank water heaters. Therefore, you have to evaluate the upfront cost as well as the long-term operating costs when deciding on a unit.


How long does it take to get hot water with a tankless water heater?

Tankless water heaters give hot water instantly. It takes at least 15 seconds to raise the water temperature.

What are the most common problems with tankless water heaters?

In tankless water heaters, some glitches happen that are following. Ignition failure. Mineral buildup. Low water pressure. Hard water. Low fuel pressure.

Do tankless water heaters need to be flushed every year?

After some time, minerals accumulate due to hard water, and the water heater needs to be flushed. For proper maintenance of a tankless water heater, you need to clean it at least once a year.


In summary, tankless water heaters offer many advantages over traditional tank water heaters. They are energy-efficient, provide an endless supply of hot water, and have a longer lifespan. Additionally, they take up less space in your home. If you are considering replacing your water heater, it may be worth considering a tankless system. In this article, we have discussed in detail how tankless water heaters work. We hope this has given you a better understanding of this innovative technology.

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