Hot Water Tank: How Does It Work?


How does a hot water tank work?

Advantages of the hot water tank

Gas hot water tanks: chimney or suction cup outlet?

Electric hot water tanks: steatite or submerged resistance?

Price of the hot water tank: according to the energy used


For the production of domestic hot water, you have the choice between:

– a hot water tank or accumulation device (or cumulus): the heated water is stored in a confined tank;

– an instantaneous water heater: the water only heats on demand.

These two types of appliances exist for gas or electricity. These so-called storage appliances are independent of the central heating system in your home.

How does a hot water tank work?

Whatever the type of energy, gas, or electricity, a hot water tank works by accumulation, so it takes a certain amount of time to heat the water. The operating principle remains the same regardless of the type of energy:

The appliance consists of a tank with a thermostat; the heating element is:


– a resistor in the case of an electric cumulus;

– a burner in the case of a gas cumulus.

Hot water is stored at the top of the tank and cold water at the bottom. The hot water drawn is then replaced by cold water. The thermally insulated tank is protected against corrosion by an anode.

Advantages of the hot water tank

The advantage of electric hot water tanks is that they can benefit from the “off-peak” rate to heat water during these hours.

Gas-fired appliances have a higher heating rate and are capable of storing a large quantity of water. They are often chosen for large structures. More expensive to purchase, the gas hot water tank is more economical and more efficient in use than the electric hot water tank.

Gas hot water tanks: chimney or suction cup outlet?

You can choose between two models of gas hot water tank:

1. The suction cup outlets open directly to the outside. This makes the installation of such a tank easier, but it requires the hot water tank to be placed against an outside wall.

2. Balloons with chimney outlets are connected to the chimney flue of the house. They are equipped with a system that controls the evacuation of burnt gases.

Here is a table comparing the two types of gas hot water tanks:

Gas hot water tank


Chimney outlet appliances

Devices with suction cup outlet


Placed on the ground.

Placed against an outside wall.


Connection to a chimney flue.

Connection to the outside.


Large capacity.

Smaller capacity.


Total safety of the gas supply.

Safety cut-out in case of anomaly.

Total safety use.

Electric hot water tanks: steatite or immersed resistance?

The electric hot water tank integrates with its heating body a resistance that works by the Joule effect. There are two types of electric hot water tank depending on the type of resistance:

– with a soapstone heater;

– with an immersed or shielded resistance.

Here is a table comparing the two technologies:

Electric hot water tank

Steatite resistance

Immersion or shielded resistor

Protected in a sleeve away from water contact.

The tube retains the scale while the resistance remains protected.

Replacing the heating element does not require draining the unit.

More expensive, but longer service life.

It is in direct contact with water and therefore exposed to scale deposits.

The unit must be drained to replace the heating element.

The units are available in horizontal or vertical versions and it is advantageous to reduce the water exchange area between the two parts. Therefore, it is preferable to choose a vertical model: the hot water accumulates in the upper part of the unit. It is gradually replaced by the cold water coming from the lower part.

Good to know: the ACI system (integral anti-corrosion) and its hybrid anode protect the water heater from hard or aggressive water. The resistance and the tank are resistant to corrosion. In the end, the hot water tank increases its lifespan.

Price of the hot water tank: according to the energy used

As an indication, here are the indicative prices of gas and electric hot water tanks:

The hot water tank price




From $200 to $1 500.


From $400 to $3 000.

Hope the above helps you out. Next time the plumber talks about the hot water tank with you, you’ll better understnad what he is talking about.

Hot Water Tank: How Does It Work?

One thought on “Hot Water Tank: How Does It Work?

  • 11/09/2022 at 15:54

    Thanks for the reminder that it’s important to also look into the capacity of the tank when planning to get a hot water tank service. I plan to look for such services soon because I want to be able to more easily have hot water in my bathroom. That will surely be great for showering at night in the winter.


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