The 9 Best Watertight Heaters of 2022

Sealed Heater – Buying Guide, Opinions and Analysis

Having a watertight heater at home is one of the best options during the winter season. Their designs usually have distinctive characteristics in terms of aesthetics and additional functions, so it will be enough to be careful in the selection, to get a model that adapts to the specific needs of each user. A good example of this is the Junkers Hydronext 5700 S, a sealed heater with a compact casing, grade-by-grade adjustable thermostat and evacuation tube, which allow greater safety and energy savings. Likewise, there are those who opt for the Centro Confort Butane Gas watertight heater, whose minimalist design offers an intuitive method of use, through a small digital screen.

The 9 Best Watertight Heaters – Opinions 2022

Sealed heaters are equipment specially designed to save energy and avoid toxic emissions inside the home. The models are usually varied and their operation depends on the applied technology. Here are nine watertight heaters recommended among the best of the year.

Junkers watertight heater

1. Junkers Watertight Gas Heater Hydronext 5700 S WTD12-4

This is a model valued in the main purchase portals as the best watertight heater, since its structure offers a simple design and greater energy efficiency.

The casing of the product has dimensions of 18 x 33.5 x 57.5 centimeters corresponding to its depth, width, height, so it is a sealed Junkers heater with a compact format and easy to handle when it is assembled.. In addition, a convenient tube kit is included in the purchase package, necessary for carrying out a correct smoke evacuation.

We can also mention the low energy consumption of the device, which has been marked with a type A classification label. Likewise, it admits the incorporation of a module for Wi-Fi accessories, which will allow you to control the device remotely, while the thermostat with a mechanism grade-by-grade adjustment makes energy-conscious consumption possible.

This model could be the best watertight heater of the moment. Get to know its most significant details, below.


Thermostat: The thermostat allows a degree-by-degree adjustment of the temperature, for conscious energy savings.

Evacuation kit: With the attached evacuation kit, you won’t have to spend time or money buying accessories separately.

Format: Its compact format will not take up much space in the mounting area.

Efficiency: This is an A energy class device, so you will enjoy low consumption that takes care of the environment.


Wifi: You must purchase the Wifi connection module separately, because it is not included with the purchase.

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Sealed butane gas heater

2. Comfort Center Gas Watertight Heater with Kit

This is a model valued among the best sealed heaters of 2022, designed to offer low energy consumption and efficient operation. In addition, the rectangular structure in white has a minimalist aesthetic that will not break the decoration codes of the room.

This sealed butane gas heater has a height, width, depth corresponding to 57 x 34.5 x 15.3 centimeters. On the lower front part, there is an easy-to-handle digital screen and large numbers for quick reading. It also incorporates a small control panel, so you can adjust the temperature and fan speed.

On the other hand, it is important to mention that the equipment belongs to a type A energy classification, to achieve a consumption that does not increase the monthly billing too much. In addition, the noise generated after its start-up is only 61 decibels. On the other hand, in the package, a smoke extractor set is attached.

Centro Confort is recommended as the best brand of watertight heaters and, below, we present the pros and cons of its model.


Efficiency: You will obtain low consumption, thanks to its type A energy classification.

Display: The large digits on the display allow quick reading with just a glance.

Format: Its compact format is easy to handle and takes up little space when assembled.

Noise: You will not have problems due to the level of noise generated, since it is moderate.


Instruction manual: The information in the instruction manual could be imprecise, but you can consult the official website of the brand.

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11 liter Cointra watertight heater

3. Cointra S0421534 Gas Heater CPA11b

This is a model that could clarify your doubts about which is the best watertight heater, since it has positioned itself in the market due to the quality of its rectangular structure. In addition, it has a completely intuitive operation, through a small control panel made up of two buttons and a screen. In this way, you will only have to press these controls to adjust the temperature as desired and monitor it on the display.

Among other details to highlight, of this 11-liter Cointra watertight heater, we have the incorporation of butane gas for its start-up and a maximum work force of 19.2 kilowatts, which corresponds to a low electrical consumption of classification A. Thus, you will not have to worry about the rise in the costs of the monthly electricity bill. Also, it should be mentioned that this equipment has been provided with special technology to work with solar energy.

If you don’t know which watertight heater to buy, you might be interested in this model with the Cointra quality seal.


Screen: Through its small screen, you can quickly view the temperature.

Format: The structure of this heater has height, width, and length dimensions of 77 x 37 x 47 cm, which take up little space in the assembly site.

Energy efficiency: This is an A energy class equipment, for this reason, it has low consumption.

Temperature: You can easily regulate the temperature, according to your convenience, from its small front control panel.


Turning on: To turn on the equipment it is necessary to open the tap to the maximum, which for some people could be uncomfortable.

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Butane gas sealed heater

4. Forcali Butane gas water heater

Forcali is a brand that is used to bringing to the market quality products that are resistant, safe, easy to handle and with a pleasant aesthetic. This is the case of this model, recommended as the best price-quality sealed heater.

The equipment has a rectangular format in white, the valve is made of aluminum, anticorrosive, to provide long life, while the ignition by means of batteries avoids the use of the pilot, for greater energy savings.

On the other hand, this sealed butane gas heater has a front control panel with a couple of buttons, to quickly adjust the temperature level and the water flow, according to your needs of use.

In addition, the equipment incorporates a prevention system against overheating, antifreeze and a gas control mechanism. A hydraulic kit with the keys, and their respective hoses and batteries is also attached.

Among the cheapest watertight heaters, this model stands out. Here, more of its details.


Kit: You will not have to invest time and money acquiring the hydraulic kit, since it is included, along with some hoses.

Batteries: This equipment requires batteries to turn it on, which represents significant energy savings.

Control: You have a couple of buttons to control the temperature level and the water flow.

Valve: Its aluminum valve has been treated against corrosion, for greater durability.


Assembly: The manufacturer recommends that the installation be carried out by a professional, so you will have to make an extra investment when hiring their services.

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Sealed natural gas heater

5. Ariston Instantaneous Natural Gas Heater Next Evo

Ariston is a manufacturer of Italian origin, with a long history in the market, which presents this time a sealed natural gas heater, made with high quality raw material. Its structure has an elegant rectangular design, quality finishes and a small HMI-type screen with large digits for quick viewing. 

Likewise, a couple of soft touch controls are incorporated, which achieves an intuitive manipulation of the device at all times. On the other hand, this sealed heater works directly with natural gas, has an automated ignition and is connected to a power source. 

In addition, the equipment has been provided with an internal fan that facilitates the correct evacuation of smoke; a convenient regulating thermostat, in charge of keeping the temperature of the device stable; and a system of sensors with advanced technology, which are activated immediately when detecting flames, water and smoke. In this way, you can avoid the deterioration of the heater.

This is a sealed heater with an elegant design and safe operation, which has a series of advantages and disadvantages that might interest you.


Evacuation: You will enjoy a correct smoke evacuation, due to the built-in internal fan.

Ignition: This heater offers an automated ignition for quick use.

Thermostat: Thanks to the integrated thermostat, you will achieve adequate temperature stability.

Security: The incorporation of sensors helps prevent any accident, by detecting flames, smoke and water.


Power cord: The power cord might not be very long, so if the plug is too far away, you’ll need to use an extension cord.

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Vaillant watertight heater

6. Vaillant Atmomag Water Heater 10022573

If you are looking for a Vaillant watertight heater with a compact format and attractive aesthetics, capable of adding an elegant touch to your kitchen or bathroom, then this model might interest you. Its gray structure has dimensions of 50 x 30 x 30 centimeters, corresponding to its height, width, depth. 

In addition, it incorporates a small control panel on the front, with a pressure button and another pair with a rotary mechanism. In this way, you will be able to adjust the operation of the equipment quickly.

This heater uses butane gas, which is a fuel with a low level of toxic emissions. Likewise, it has an automatic flame control system; and the ignition of the electric burner is by means of batteries, which save energy, added to the fact that it is an A-class energy equipment. Likewise, the low noise level generated by the device stands out, at 63 decibels.

Find out below the positive and negative aspects of this watertight heater.


Noise: You will not have problems due to the noise level generated by this sealed heater, because it is quite low.

Flame: The flame of this watertight heater has mechanical regulation, so you can control gas consumption.

Burner: A stainless steel burner is incorporated, which offers great resistance to wear.

Energy classification: This is equipment with a type A label, which suggests low energy consumption.


Batteries: The batteries necessary to perform the automated start-up are not included with the purchase.

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Other products

7. Forcali LPG Butane Propane gas water heater

A model that has been valued among the cheapest in this list is the current sealed heater from Forcali, which has a rectangular and modern design in white. Its structure has been made of moisture resistant material; the water valve in brass and the gas valve in aluminium.

The device incorporates a black screen with easy-to-read red digits on the front and soft touch controls for intuitive programming. The nominal power of the equipment corresponds to 24 kilowatts and offers a low energy consumption of type A classification. 

In addition, it incorporates an exchanger, so you can easily install a solar energy module. In this way, you will achieve significant energy savings and take care of the environment. Also, it should be mentioned that the heater has been provided with a thermostat that stabilizes the temperature, automated ignition mechanisms and controllers to adjust the level of the flame.

To make a successful purchase, you should review the good and bad of this 12-liter watertight heater.


Thermostat: The thermostat built into the structure allows the water temperature to be stabilized.

Mounting: This is a watertight heater suitable for mounting indoors or outdoors, without any inconvenience.

Exchanger: Thanks to the integrated copper exchanger, you can install a solar energy module for greater energy savings.

Gas: You can use the heater with propane or butane gas, as you wish.


Accessories: The necessary tube for gas extraction is not included with the purchase, so you must purchase it separately.

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8. Bosch T5600s12d31 Watertight Butane Gas Heater

Bosch is a manufacturer with a long history in the world of electrical appliances, whose main objective is to offer its followers products with high quality standards, for a better user experience in carrying out each of the tasks.

A good example of this is this watertight heater, belonging to the collection of said brand, which has a rectangular casing with rounded edges and a convenient soft touch control system in the lower front part of the structure. Together, these features give the design a minimalist appearance, but with great elegance, so you can easily incorporate it into any bathroom or kitchen.

This 12-litre watertight heater is easy to assemble and handle, since it only weighs 30 kilograms. In addition, the method of lighting the device is electrical and, therefore, incorporates a power cable for alternating current.

If you want to buy a watertight heater with intuitive operation and that adds an elegant touch to the room, you will have to review the details of this model.


Ignition: Its electric ignition generates low energy consumption.

Weight: You will be able to manipulate the structure with ease when assembling, due to its moderate weight of 30 kilos.

Design: The structure has an elegant and minimalist design, which will aesthetically adapt to any space.

Control: You will enjoy rapid temperature control, thanks to the soft touch technology on the front panel.


Power cable: The length of the power cable could be short, but you can add an extension.

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9. Giatsu 12 Liter Rhombus Sealed Gas Heater

It is a sealed heater that offers a hot water production of up to 12 liters per minute. In addition, it incorporates a DC fan capable of adjusting electrical consumption according to power demand, which helps to achieve maximum efficiency.

Also, it offers a low level of NOx, which means that it produces few emissions of nitrogen oxides in order to minimize damage to the environment. For greater practicality, it comes with a kit with everything necessary for installation, including the gas outlets, so it is not necessary to incur additional costs for its assembly.

On the other hand, it has a Super Slim design, with measurements of 57 cm in height, 34.5 cm in width and only 15 cm in depth, making it a compact device that does not take up much space wherever you decide to install it.

A watertight heater must provide efficiency and high technology, such as the Rombo model of the Giatsu brand. Let’s get to know its pros and cons in detail.


Adjustment: It offers an automatic temperature regulation mode, as well as a control panel to adjust it according to need.

Design: It has a 15 cm deep Super Slim design so as not to take up too much space.

Compatibility: Provides compatibility with solar energy systems, which can promote energy savings.


Electric: Although it works with gas, it must be connected to the electric current to turn on the control panel, so it is necessary to install it near a socket.

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Shopping guide

Acquiring a watertight heater is not a complex task, which only requires reviewing the main quality identifiers present in the products that have caught your attention. In any case, below you will find a small guide to buying the best watertight heater, which we hope will help you.

Display and drivers

The screen and the controllers are a couple of aspects that cannot be forgotten in any comparison of sealed heaters, since the practicality offered will depend on them, when programming the device.

In this sense, most of the models of sealed heaters incorporate an HMI-type screen, which, although it is small in size, usually offers a quick visualization, due to its large black, red or white digits, depending on the background. of said display.

On the other hand, there are the controllers that are next to the screen, whose design can be of the button type and with a twist mechanism. It is also common to find soft touch controls on higher-end models. In this way, it will be enough to lightly press that area with your fingers.

It is important to keep in mind that, whatever the system implemented for the selected sealed heater, these parts must be properly identified, so that the programming experience is as intuitive as possible.


It does not matter how cheap the watertight heater you are going to buy is; If it does not incorporate its respective thermostat, it could be an inconvenient purchase. Remember that this component is responsible for stabilizing the temperature of the water in this type of device, which will allow you to save energy from the first day you put the heater into use.

When reviewing the proposals for sealed heaters on the market, we will find designs provided with intelligent thermostats, through which a degree-by-degree adjustment of the temperature can be made. In this way, it is possible to make a conscious consumption of electrical energy, since you can start the equipment only when you need hot water.

Mounting and safety set

When thinking about purchasing a watertight heater, there are many factors to check, highlighting among them the mounting method and the safety offered by the device.

In the first case, it is usually a task to be carried out carefully, to avoid any type of accident due to a gas leak. Likewise, it is necessary that said equipment has been provided with its respective assembly kit, that is, a special tube for evacuating smoke, with its respective hoses and key. Thus, you will be able to start using the device from the first day, without having to invest time and money buying these elements separately.

As a second aspect of interest to verify in the watertight heater, there is the issue of safety. In this sense, more and more manufacturers are incorporating special sensors into their models, in order to detect overheating of the equipment’s electrical system. Likewise, this technology is applied in case of smoke, flame and water, to prevent unexpected incidents after the heater starts up.

Additional components

The watertight heaters are equipment capable of offering a basic operation of heating water for the home, which allows you to adjust the level of heat and water flow, just by pressing the buttons on the small control panel of the structure. However, there are some models that put within your reach the possibility of enjoying special functions, which may influence how much the product costs, but in the long term, they manage to improve the user experience with the heater.

It is a kind of bays for you to place, for example, a special solar component. Thus, you will avoid the use of batteries or electric current to carry out the ignition process and, therefore, you will achieve significant energy savings, which will benefit the environment and your economy, by paying the monthly electricity bill. Likewise, there are the areas assigned for the Wi-Fi components, which are convenient for those who wish to enjoy remote operation, through their smartphone, during the switching on and adjustment of the working modes offered by the device.

Frequently asked questions

Q1: How to install a sealed heater?

To assemble a watertight heater, the first thing you should do is read the instruction manual. In this way, you will be able to familiarize yourself with the pieces of equipment and know which is the most suitable area for placing the device, depending on the model. In addition, you should check that a hydraulic kit, keys, hoses and gas expulsion tube have been included in the purchase package. Otherwise, you will have to purchase these items separately.

Then, proceed to fix the heater on the wall, but remember that the evacuation tube must be directed outside the house. Also, it is necessary that there is a power source near the structure, in case you have to connect the heater to the power of the built-in ignition system.

Q2: How does a sealed heater work?

The sealed heaters have a completely hermetic air chamber, which works together with a dual tube system, in charge of evacuating smoke and absorbing oxygen, for a correct ignition of the equipment.

The sealed heater is directly connected to said combustion chamber, which allows it to generate the flame, without presenting any type of leak that could contaminate the interior environment. In addition, a fan is attached to enhance a better and safer exit of the smoke. In any case, the system of these heaters absorbs external oxygen, to ignite and expel the gas, product of the combustion process.

Q3: How to place the gas outlet tube in a sealed heater?

To place the gas outlet tube in a sealed heater, you need to check the diameter of the piece and contrast this measurement with that of the upper mouth of the appliance. Both parts must coincide to achieve a correct fit. In addition, it confirms that, if there is any curved area in the tube, it is no less than 20 centimeters away from the gas outlet. In this way, you can get rid of all the carbon dioxide generated after the combustion process.

Then, proceed to place the evacuation tube in the respective outlet of the heater and carefully seal the connection, with the help of a special aluminum adhesive tape. Remember to turn on the equipment, to check that there has been no leak.

Q4: Which is better, a sealed or atmospheric heater?

If you are wondering which heater is better to buy between a sealed model and an atmospheric one, you will be interested to know that both equipment offer quite efficient operation when heating the water. In addition, they are characterized by having a pleasant aesthetic and having an intuitive programming method.

However, sealed heaters offer greater energy savings, due to their hermetic tank and dual fan tube system, for rapid smoke evacuation to the outside of the home. On the other hand, the atmospheric models carry out said evacuation, by means of the variation in the ambient air pressure. In this way, the electricity consumption reflected in your monthly electricity bill could be higher.

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