Top 10 Best 300l Water Heater 2021

Difficult to make a choice for your new 300l water heater? We wrote this special buying guide 300l water heater to help you, with the TOP10 of the best sales of the moment, tests, opinions… As in all our buying guides, we did our best to help you choose the best 300l water heater!

Our selection of 300l water heaters

300L water heater buying guide

Hot water is undoubtedly the essential element to guarantee the comfort of everyone on a daily basis. Manufacturers compete in imagination and creativity to provide consumers with water heaters with optimized heating times and a perfectly elaborate design. With the multitude of models available on the market, choosing the device to quickly obtain domestic hot water can quickly become a real obstacle course. Browse this file to learn about the criteria to consider in order to set up a credible comparison that will help you define the best water heater.

About the water heater

This is equipment designed to produceDHW (Hot water) through an energy source (fuel oil, gas, electricity or solar energy). The water heater comes in two categories:

  • The instantaneous water heater whose main advantage lies in its ability to heat water when it is drawn off.
  • The storage water heater which has a more or less important hot water reserve. The type of device that interests us in this article concerns the 300-liter model.

Water heater, hot water tank and boiler are 3 terms that are often confusing. The hot water tank is commonly used to designate the storage water heater. The boiler is a device that heats all heaters and radiators, but also sanitary water.

Zoom on the 300 liter hot water tank

This device is ideal for a household of 5 or 6 people. As hot water consumption concerns approximately 20% of the budget of a French household, it is important to know the advantages offered by each technology to choose the right 300-liter hot water tank.

The electric water heater

The electric hot water tank (or electric cumulus) is present in most households in France. Simple to install and with increased performance, this type of storage water heater stores and heats the water contained in its 300-liter tank to meet your hot water needs at all times. The price of such a domestic hot water production system varies depending on the type of resistance it incorporates: soapstone or thermo-immersion.

The thermodynamic water heater

This device equipped with a storage tank and a heat pump is a real innovation.Indeed, it collects ambient air, water or heat from the earth to transform it into gas intended to heat the water contained in the tank.However, this type of device has some drawbacks.First of all, it is necessary to combine it with a back-up system if you live in an area where it is particularly cold or if you have a high consumption of hot water.Then, although a thermodynamic water heater allows for considerable energy savings, the initial investment remains significant.In fact, it takes about ten years to make the purchase price profitable.The good news is that by purchasing it you get a tax benefit: CITE (energy transition tax credit).

If you choose this type of device, you must seek the services of a professional to install it. Indeed, its installation must comply with certain very specific rules. For example, it should be placed in a heated room to optimize its performance.

The gas water heater

This device represents a good medium-term alternative, because it makes it possible to reduce your energy bill. Admittedly, its price is higher compared to the electric water heater, but this drawback is largely rewarded by the excellent efficiency it offers as well as its high heating speed. In addition, most gas devices are rugged to reliable.

Its main drawback is its maintenance. To avoid risk of carbon monoxide poisoning which is a very dangerous combustion gas, we must not forget the maintenance that must be done every year. In addition, it is important that the room where the water heater is installed is well ventilated for safety reasons. If you use an instant device, you must install it in a kitchen incorporating a double-opening CMV.

The solar water heater

This type of device is appreciated for its highly ecological character. Indeed, the solar water heater contributes to a better environment, because, as its name suggests, it uses solar energy. In addition, it does not produce any hazardous waste and does not cause polluting emissions.

However, be aware that the solar water heater collectors have a limited heat storage capacity.In other words, it may not cover all of your hot water needs.If you live in an area with little sun or have a high consumption, it is advisable to combine the use of a solar water heater with an electric water heater or a gas water heater.It should also be noted that this type of equipment needs regular maintenance to remain efficient throughout the year.Its condition must also be checked during the winter.Also, it's worth noting that this type of device costs more to buy. RGE (Recognized as a guarantor of the environment), you can benefit from a tax credit of 30% as well as the energy premium.

If you live in a very sunny area, you can easily use a monobloc water heater consisting of a tank and 2m² panels. In this case, it is advisable to turn to a thermosiphon water heater which is more efficient in terms of efficiency. However, your home must have an attic where you will place the ball.

A condensing water heater

This type of equipment works on the same principle of the condensing boiler. To save energy, it is advisable to combine its use with a gas water heater. The latter recovers some of the energy released during combustion. In other words, it improves the efficiency of the water heater.

Selection criteria

To determine the best water heater for your needs, consider the following.

The type of water heater

So you have a choice of different types of water heater models that you can choose according to your needs and budget. On the one hand, you have the traditional solutions like the electric water heater and the gas water heater. On the other side, you have the innovative equipment like the solar water heater, the thermodynamic water heater or the condensing water heater.

The installation configuration

As the 300-liter tank has considerable dimensions, it is not easy to integrate it into your interior. Therefore, the ideal model depends on the configuration of the room in which it will be installed.

  • The vertical wall-mounted water heater is the most common
  • The horizontal water heater can be fixed to the floor, wall or ceiling

As the 300 liter hot water tanks are very heavy, anchors are required. However, make sure the walls are load-bearing. If not, place your water heater on the ground, on a plinth or tripod.

The type of resistance

Resistances fall into two main categories:

  • Soapstone resistance is valued for its optimal lifespan and for its ability to withstand medium to very hard water.
  • Armored resistance (or thermo-diving) is recommended if you live in an area with medium hard water.

The type of anode

When choosing your water heater, you must also take into account the quality of the water it will contain. Indeed, the tank can deteriorate very quickly if the water is very soft. Likewise, a too hard water may damage the resistance. Also, make sure that the equipment you wish to acquire has an anode intended to protect the tank. Favor themagnesium anode, a hybrid anti-corrosion device called ACI (Imposed Electric Current Anode). It is perfect for protecting the interior of your water heater, especially when you live in an area where the water is particularly rich in lime.

The water heater model

You will find two models of water heaters on the market:

  • The water heater with tank which has hot water at all times. This type of water heater generally has a large storage capacity and remains economical. It therefore allows a home to be quickly supplied with hot water while consuming as little power as possible.
  • The instantaneous water heater or tankless water heater which provides energy savings of around 30%. Also, it is more expensive to buy. In addition, it is less bulky compared to the water heater with tank. On the other hand, an instantaneous water heater is not suitable for a home that uses several devices at the same time.


In case you have chosen a water heater that works with fuel, it is important to make sure that the device is well secured. In this case, it is advisable to provide a monoxide detector that you will install near your water heater.

The durability of the water heater

Thanks to technological developments, you will easily find several devices combining energy saving and sustainability. This type of equipment is designed to last twice as long as a conventional device, even if the water supplying your home is particularly aggressive in nature. Apart from saving energy, this type of water heater therefore provides better protection against corrosion and reduces the frequency of maintenance.


Depending on your daily habits and the different technical constraints of your home, it may be that a single boiler can cover your domestic hot water needs. In this case, a backup water heater will be more suitable. Indeed, the needs of a house located in the countryside and a housing located in the city will not be the same if only in terms of the configuration of the housing such as the length of the water network for example.

The different options

Do you want to benefit from optimal comfort without losing all your savings? Choose the connected water heaters. They incorporate a soapstone resistor, a protective anode and a programmer. You can thus adjust the water production of your device according to your needs. These types of water heaters also have an "absence" mode which allows you to stop the production of water when you are not at home. Thanks to the advanced technologies with which they are equipped, these devices are able to automatically trigger the heating cycles during off-peak hours.

These models are remote programmable. Also, you can for example switch your water heater to absence mode from your bedroom, your kitchen or the sofa in your living room. Likewise, you can trigger the different heating options remotely with its nomadic digital control or from your phone.

Get help from a professional

A professional specializing in the installation of water heaters will know how to estimate your consumption by taking into account only the number of tenants and their habits. It will also be able to determine whether or not the configuration of your home conforms to the type of water heater you plan to purchase.

The intervention of a professional is all the more necessary if you have chosen a water heater powered by renewable energy. In this case, your heating engineer must be qualified RGE or recognized as guarantor of the environment. He will not only take care of the installation of your water heater, but will also provide the necessary materials for the installation.

Remember that calling in a professional gives you the assurance of a perfectly done and secure installation, especially if you have chosen a gas-powered device. You will also avoid breakdowns and other malfunctions caused by improper installation. In addition, seeking professional help will allow you to benefit from an intermediate VAT rate of 10% for the cost of supplies as well as the cost of installation. This benefit applies to homes that have been built for more than two years, whether it is your primary residence or your second home.

The final word

When installing your storage water heater, it is recommended to connect to a day-night contactor. This device allows you to save energy in the long term.

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Dernière mise à jour : 2021-04-10 02:39:28