How Do Water Heaters Work?

Water heaters are very popular in the Indian market, and we all know how useful they are in the winter season. If you have the best geyser at home, then you can enjoy a relaxing bath every morning. But have you ever thought about how do water heaters work?

If you are thinking of investing in a new water heater, then knowing the working process of water heaters will be helpful for you. Once you know how a water heater works, you can know it better and decide which water heater will be suitable for your use. So, let’s now understand how do water heaters work?

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How Do Water Heaters Work?

Before you understand the working process, you need to first know about the components of a water heater. Usually, a water heater has three main components, and those are the heating element, storage tank, and thermostat. Here are the tasks of these three components in a water heater.

Heating Element

The heating element of a water tank is the most important part because it helps heat water. When buying a water heater, it is crucial to consider the quality of the heating element. If the heating element of the water heater is of good quality, then it can last for a long time.

In general, very hard and soft water can damage the heating element. To prevent this, heating elements of water heaters are coated with a glass lining. This keeps the heating element from scaling.

The heating element is fixed in the middle of the water tank, which passes current through it. It is further connected to a 220V circuit. When the current passes through the heating element, it heats the water.

Havells Adonia Spin 15-Litre Vertical Storage Water Heater (Geyser)

havells water heater
Havells Adonia Spin 15-Litre Vertical Storage Water Heater (Geyser)

Water Tank

The next major component of a water heater is a water tank. The main purpose of a water tank is to store the hot water. Therefore, the water tank should be strong and offer resistance to corrosion. Mainly, two types of water tanks are used in water heaters.

The first type of water tank used in water heaters is a stainless-steel water tank. These are the old models of water tanks and are rarely used nowadays. These water tanks can cause hard water scaling and corrosion. Therefore, the use of these water tanks is not recommended.

Another type of water tank used in water heaters is a vitreous enamel glass-coated water tank. These water tanks are usually made with stainless steel water tanks, which are coated with advanced polymers. This makes the stainless-steel tank corrosion-resistant. These water tanks are also capable of preventing hard water scaling.

Vitreous enamel water tanks usually come with 5 years to 7 years of warranty. These water tanks are similar to glass-lined coating. When buying a water heater, you should consider buying this type of water tank.


The thermostat is another prominent component of a water heater. This helps the water heater in deciding when to start or stop the water heater. So, we can say that the thermostat acts as an operating system in a water heater. It uses a bimetallic strip to regulate the water temperature and operate the water heater.

The bimetallic strip is made of copper and steel, which is attached to the thermostat. Depending on the response of the bimetallic strip, the thermostat takes any action. If the thermostat of the water heater is in good condition, it will keep the water from overheating.

The thermostat in water heaters also helps in reducing power consumption. But it can’t do it all alone. So, you shouldn’t keep the water heater on for a long time, depending on the thermostat. The functions of a thermostat in a water heater are as follows.

AO Smith SDS-GREEN SERIES-025 Storage 25 Litre Vertical Water Heater (Geyser)

how do water heaters work
AO Smith SDS-GREEN SERIES-025 Storage 25 Litre Vertical Water Heater (Geyser)

Functions Of a Thermostat in A Water Heater

  • Suppose you have switched on the water heater when the water temperature is 25 degrees Celsius. In this step, the thermostat gives a signal to the heating element to start heating the water.
  • The thermostat waits until the water reaches 60 degrees Celsius. Once the water temperature is 60 degrees Celsius, the thermostat sends a signal to the heating element to stop heating the water.
  • In this context, if you forget to switch off the geyser, the water temperature reduces slowly and reaches 29 degrees Celsius.
  • When the thermostat notices that the water temperature is below 30 degrees Celsius, it sends a signal to the heating element to start heating water. This way, the loop continues if you don’t switch off the heater. Therefore, it is recommended to switch off the geyser once the water reaches your desired temperature.

How do water heaters work?

So now you know how do water heaters work. Also, you know the major parts of a water heater and how they help in the water purification process. Therefore, you can now pick the best water heater for your use and maintain it appropriately.

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