TOP 11 best indirect heating boilers: rating of models + recommendations on how to choose a boiler

We have compiled a rating of indirect heating boilers and noted the pros and cons of each model to make your final choice easier.

Rating of indirect heating boilers

Our list of the best includes the most interesting models in terms of design and performance, which easily fit the definition of “price-quality”.

We decided to divide all models into 4 groups, the main criterion being volume.

Rating of the best boiler models

Photo	Name	Rating	Price
The best boilers up to 100 l
#1	Read also: Rating of the TOP 13 video nannies: characteristics and review of the best models in terms of price-quality ratio	Gorenje GV 100	⭐ 4.9 / 5 2 - votes	Find out the price
#2		Protherm WH B100Z	⭐ 4.8 / 5	Find out the price
#3		Baxi Premier plus 100	⭐ 4.65 / 5	Find out the price
The best boilers up to 150 l
#1		Vaillant VIH R 150	⭐ 4.85 / 5 2 - votes	Find out the price
#2		De Dietrich BP 150	⭐ 4.75 / 5	Find out the price
#3		Baxi Premier plus 150	⭐ 4.6 / 5	Find out the price
The best boilers up to 200 l
#1		Drazice OKC 200 NTRR	⭐ 4.85 / 5 2 - votes	Find out the price
#2		Baxi Premier plus 200	⭐ 4.75 / 5 2 - votes	Find out the price
#3		Protherm FE 200 VM	⭐ 4.65 / 5	Find out the price
The best boilers up to 300 l
#1		Protherm FS B300S	⭐ 4.85 / 5	Find out the price
#2		Gorenje VLG300B1-1G3	⭐ 4.7 / 5 1 - voice	Find out the price

Which indirect heating boiler will you choose?

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The best boilers up to 100 l

No. 3. Baxi Premier plus 100

This Italian model is a high-quality assembled boiler, the heat accumulator of which is made of stainless steel. It has a built-in thermostat, space for installing a tubular electric heater and a spare coil.

Let's look at its technical characteristics:

power – 3000 W;
volume – 100 l;
pressure (inlet) – 7 atm.;
Max. water temperature – +65 °C;
time for heating water to +45 °C is 10 minutes.

The installation diagram is quite universal. This water heater can be installed both on the wall and on the floor.

pros

thermal insulation is made of high-quality material;
not afraid of corrosion;
water heats up quickly and evenly;
light weight;
installation versatility.

Minuses

the lowest maximum water temperature.

Baxi Premier plus 100

Reviews of the indirect heating boiler Baxi Premier plus 100

No. 2. Protherm WH B100Z

Czech wall model, the container of which is made of steel and covered with enamel. This water heater comes with the following components:

steel coil;
titanium electrode;
three-way valve;
three-pin thermostat;
thermal insulation made of polyurethane material, the thickness of which is 3.5 cm.

Let's look at its technical characteristics:

power – 1920 W;
volume – 95 l;
pressure (inlet) – 6 atm.;
Max. water temperature – +80 °C;
time for heating water to +60 °C is 18 minutes.

Two things are noted about this boiler. The first is that by installing a boiler from the same company, the boiler works more efficiently. The second is that after a long time with irregular maintenance, the technical characteristics do not undergo qualitative and quantitative changes.

Installation can be done on the wall.

pros

wall mounting will save space;
the set temperature lasts a long time;
two types of protection – against corrosion and bacteria;
nice design;
high quality insulation.

Minuses

it is not possible to install a tubular electric heater;
low power;
high price.

Protherm WH B100Z

No. 1. Gorenje GV 100

This model from a well-known Slovenian company has mechanical control. Its design is quite simple:

steel tank with enamel coating;
heat exchanger made of stainless steel;
dial thermometer;
two indicators - power and heating.

In order for the boiler to work properly, two valves were added to the design - a non-return valve and a safety valve. In addition, there is overheat protection. Also available is a magnesium anode which serves the same purpose as the valves.

Vertical position is the standard installation scheme using floor mounting. You can connect a gas boiler to it. An alternative option is to connect the central heating system to it.

Let's look at its technical characteristics:

power – 3000 W;
volume – 100 l;
pressure (inlet) – 6 atm.;
Max. water temperature – +85 °C;
time for heating water to +45 °C is 15 minutes.

pros

stainless steel as the basis of the structure;
external insulation is made of high quality material;
short heating time to the optimal temperature;
build quality;
small dimensions;
affordable price.

Minuses

Replacing the anode yourself is a rather difficult procedure.

Gorenje GV 100

The best indirect heating boilers up to 100

Indirect heating boilers with a volume of up to 100 liters combine two qualities - compactness and good performance. They are more affordable, excellent for domestic use and can fully replace centralized hot water supply. Conventionally, models up to 100 liters are classified as small, but this does not reduce their functionality. Many models provide several water collection points, all protective functions and the installation of a heating element. At the same time, they are easier to install - the dimensions of the tank allow it to be installed in small rooms, such as an apartment or the bathroom of a country house.

Nibe-Biawar Mega W-E100.81

An excellent boiler with an enameled tank and one heat exchanger is connected to the water supply system and is compatible with any type of heating boiler. For convenience, the model is equipped with several water supply points, so hot water can be supplied to the kitchen and bathroom at the same time. You can install a heating element into the device, turning the boiler into a regular heater. A large 100 liter tank is enough to provide hot water to a family of 2-3 people. The maximum heating temperature is 95 degrees; the water heater also has a thermometer, a heating limiter, and a power indicator. Thermal insulation is made of extruded polystyrene foam, which retains heat for a long time.

Advantages:

optional installation of heating elements;
heating temperature limitation;
several water points;
removable protective cover;
metal thickness;
cost of consumables;
Retains heat for a long time.

Flaws:

floor installation only.

Kospel Termo Hit WW 80

The heater from the Polish manufacturer stands out among competitors due to careful control at every stage of production. The steel container is high-quality enamel coated with Kospel’s own powder coating system. The equipment is connected to the boiler, and it is also possible to install an electric heating element. The capacity is small - 80 liters, but heating is quite fast - up to 25 degrees - in 6 minutes, up to 55 - in just 29. Due to the small tank, this compact boiler in the list of the best indirect heating boilers has become very popular for installation in apartments and country houses. In reviews, buyers noted thermal insulation and durability. Kospel paid a lot of attention to the design - the steel tank fits into any interior.

Advantages:

high-quality thermal insulation;
fast water heating;
magnesium anode;
possibility of installing an electric heating element;
clear instructions.

Flaws:

average heating temperature.

Hajdu ID 25A

Water heater Hajdu ID 25A is a new product for 2021 in the line of budget boilers from the Hungarian manufacturer. The equipment is connected to heating boilers of any type and heats water up to 95 degrees. You can connect a heating element up to 2.4 kW with a thermostat, a sensor or various third-party automation to the device. High-temperature glass enamel protects the inner surface of the tank, and there is a magnesium anode. Despite the budget, the manufacturer took care of effective thermal insulation; pentane foamed polyurethane foam was used here. The declared service life is 10 years.

Advantages:

European production;
excellent, durable glass enamel;
possibility of installing various automation and heating elements;
accelerated heating;
modern design;
spiral heating element;
6 bar combination pressure relief valve included;
low price.

Flaws:

Low-functionality in the factory configuration.

Drazice OKC 100 NTR

A stationary indirectly heated floor water heater is an excellent choice for domestic use all year round. The 100 liter model is equipped with a power indicator, overheat protection, thermostat, safety valve, and a recirculation line inlet. In addition to the above, a temperature sensor is installed here that controls the operation of a three-way valve and circulation pump. It is possible to install an alternative source of heat energy. Modern electronic control and the ability to distribute water to several points make the model convenient for daily use.

Advantages:

high-quality spiral heater;
presence of temperature sensors;
electronic control;
European production.

Flaws:

useful volume – 87 l.

The best boilers up to 150 l

No. 3. Baxi Premier plus 150

Baxi Premier plus 150
This model has two installation methods - on the floor and on the wall. Let's look at its technical characteristics:

pressure (inlet) – 7 atm.;
power – 3000 W;
volume – 150 l;
Max. water temperature – +65 °C;
time for heating water to +65 °C is 15 minutes.

The design includes the ability to install a tubular electric heater, which can heat up to +45 °C in two and a half hours. There is a recirculation circuit through which water can enter the coolant in a short time.

pros

two built-in thermostats – for safety and temperature maintenance;
short water heating time;
high efficiency of the heat exchanger due to its design;
strength is at a high level;
light weight.

Minuses

incomplete compatibility of the temperature sensor with the boiler;
quite high price.

Baxi Premier plus 150

No. 2. De Dietrich BP 150

De Dietrich BP 150
This model of a cylindrical water heater has a rather interesting design. In addition, the water heater of this company is known for its high-quality assembly.

The design includes the following components:

tank – steel outside, glass ceramics inside;
dial thermometer;
side flange;
magnesium anode;
thermal insulation made of polyurethane, the thickness of which is 5 cm.

Let's look at its technical characteristics:

power – 3300 W;
volume – 150 l;
pressure (inlet) – 6 atm.;
Max. water temperature – +90 °C;
time for heating water to +50 °C is 17 minutes.

The height of this boiler is one meter and its weight is slightly less than 90 kg. Mount it vertically.

pros

high resistance to corrosion;
you can turn it on and not configure it – the device will start working immediately;
easy installation and dismantling;
high-quality assembly;
reliability at the European level;
nice design.

Minuses

heavy in weight.

De Dietrich BP 150

No. 1. Vaillant VIH R 150

Vaillant VIH R 150
This German-made model is made of stainless steel. The inside of the tank is covered with enamel. Its design includes the following elements:

spiral heat exchanger made of stainless steel;
check valve;
dial thermometer;
magnesium anode;
drain valve;
thermal insulation material.

Let's move on to consider its technical characteristics:

pressure (inlet) – 10 atm.;
power – 2600 W;
volume – 144 l;
Max. water temperature – +85 °C;
time for heating water to +65°C is 23 minutes.

You can install this water heater on the floor. You can connect in two ways: through boilers (atmoVIT and iroVIT have the greatest compatibility) or through a central water supply.

pros

height adjustment of legs;
high-quality heating element;
good build quality;
compatibility with gas-type boilers;
nice design.

Minuses

Installation is a little difficult.

Vaillant VIH R 150

The best indirect heating boilers up to 150 l

Indirect heating boilers with a capacity of up to 150 liters solve several problems at once. In domestic conditions, this volume is enough to effectively provide hot water to a large family of 4-6 people. Several water supply points allow you to supply it to the bathroom and kitchen at the same time, and a large supply eliminates any interruptions. For commercial purposes, boilers will find use in small hotels, hostels, hotels as an additional or backup source of hot water. Despite their capacity, water heaters are economical, and heating water to a given temperature occurs relatively quickly. The time depends on the model; the best boilers will heat up the full volume in 20-30 minutes.

BAXI Premier Plus 150

BAXI makes some of the best water heaters on the market for reliability and durability. The Premier Plus 150 model is made of stainless steel, resistant to corrosion, and is equipped with a modern coil-in-coil heater. The useful volume is 150 l, of course, the installation of an additional heating element is provided, and there is protection against overheating. The indirect heating boiler is not multifunctional, but it has simple controls and a long service life of 10 years.

Advantages:

high quality workmanship;
durability and reliability;
universal mount;
efficient and economical;
excellent thermal insulation.

Flaws:

high price.

Hajdu ID 40A

The new 2021 ID 40A from Hajdu entered the rating of indirect heating boilers due to its affordable price and good quality. Among the main features are effective thermal insulation made of polyurethane foam, high-quality and durable glass enamel and a magnesium anode, providing high protection against corrosion and leaks. The standard supply has been reduced as much as possible to reduce the price; additionally, you can install a heating element, thermostat, thermometer and automatic start system. According to user reviews, devices from the Hungarian manufacturer serve reliably for a long time.

Advantages:

affordable price;
possibility of upgrade - installation of automation, heating elements;
good anti-corrosion protection;
excellent performance (610 l/h);
effective protection against heat loss;
recirculation line input;
fast heating up to 95 degrees.

Gorenje GV 150

A professional and inexpensive indirect heating boiler with a capacity of 150 liters will provide a full supply of hot water to a large family, and is also suitable for commercial use. The full volume warms up to 75 degrees in just 18 minutes, which becomes a record among models in this class. The thickness of the thermal insulation layer of 4 cm provides an effective barrier to heat loss. Ease of use consists of several water collection points and simple installation on the floor. The water heater is distinguished by its equipment, in addition to the standard overheating protection and magnesium anode, there is a thermometer, heating and switching indicator, as well as a check valve.

Advantages:

connection to an additional heat source;
high quality insulation;
there is a possibility of installation under a gas boiler;
large area of the tubular heat exchanger;
convenient mechanical control.

Flaws:

some models with erroneous markings of cold and hot water inlet.

Ariston BCH CD1 120

A high-quality boiler of a classic cylindrical shape with floor mounting and top supply is distinguished by good assembly. Useful volume – 120 l, water heating – up to 90 degrees. The functionality is modest - only a power-on indication. But it can be connected to any boiler or heating system, and it is compatible with mixed type equipment. The internal coating is enamel applied in accordance with DIN 4753 standard at a temperature of 850 degrees. A reliable boiler with a magnesium anode and a spiral heat exchanger is quite efficient and reliable, there are absolutely no complaints. Additionally, you can purchase an electric heating element, a second titanium or magnesium anode, and other components for the upgrade.

Advantages:

high quality enamel coating;
universal installation type;
fast heating in 21 minutes;
country of origin: Italy.

Flaws:

lack of a thermometer and automation, additional sensors.

The best boilers up to 200 l

No. 3. Protherm FE 200 VM

Protherm FE 200 VM
Another Czech model from Protherm, but with a capacity of 200 liters, was included in our rating. Its controls are mechanical; the body is made of stainless steel coated with enamel.

The design of the water heater includes the following elements:

heating temperature limiter;
dial thermometer;
thermal insulation made of polyurethane;
magnesium anode.

Let's look at its technical characteristics:

pressure (inlet) – 6 atm.;
power – 1920 W;
volume – 184 l;
Max. water temperature – +80 °C;
time for heating water to +55 °C is 30 minutes.

Installation is carried out in a vertical position on the floor, since all the water supply is located on top.

pros

twin type heat exchanger;
protection against bacteria and corrosion;
long-term maintenance of the set temperature;
high-quality thermal insulation;
nice design.

Minuses

possible incompatibility with boilers - more information needed.

Protherm FE 200 VM

No. 2. Baxi Premier plus 200

Baxi Premier plus 200
The Italian company Baxi has released a water heater in its series of Premier Plus boilers with a volume of 200 liters. There are three water heating modes known for this model:

boiler;
heating element;
recirculation circuit.

Let's look at its technical characteristics:

inlet pressure – 7 atm;
power – 3000 W;
volume – 200 l;
Max. water temperature – +65 °C;
time for heating water to +45 °C is 20 minutes.

Important! Use the thermostat reading if you want to keep your boiler running longer.

Floor mounting possible. As an alternative, you can hang it on the wall.

pros

two types of installation;
not afraid of corrosion;
the design is extremely durable;
ease of installation and dismantling;

Minuses

mediocre design.

Baxi Premier plus 200

Reviews of the indirect heating boiler Baxi Premier plus 200

No. 1. Drazice OKC 200 NTRR

Drazice OKC 200 NTRR
Czech model, but from another company – Drazice. The body is made of enameled steel. It contains the following elements:

heat exchanger (quantity – 2 pcs.);
power indicator;
overheat protection;
dial thermometer;
magnesium anode;
safety valve;
6.5 cm thick polyurethane insulation.

Let's look at its technical characteristics:

pressure (inlet) – 6 atm.;
power – 4800 W;
volume – 208 l;
Max. water temperature – +90 °C;
time for heating water to +60 °C is 28 minutes.

Due to the non-standard number of heat exchangers, the boiler can be connected to two boilers at the same time - the person who prefers it will simply use it.

Important! Since the eyeliner is at the top, it can only be installed in a vertical position.

pros

connection to two boilers at a time;
high-quality thermal insulation;
the second heat exchanger is practically free;
frost protection;
easy installation and dismantling.

Minuses

It will be difficult to install due to the location of the liner at the back.

Drazice OKC 200 NTRR

Types of indirect heating boilers

Classic models

An indirect heating boiler is a cylindrical, cubic or rectangular-parallelepiped storage device, with the help of which hot water is produced and supplied to the faucets of plumbing fixtures. Installed in canteens, bars, restaurants, as well as in houses with autonomous and/or centralized heating to create a hot water supply system.

The design and configuration of the unit includes: a housing consisting of an external casing, insulation and an internal tank; heat exchanger coil, magnesium anode and recirculation pipe; inlet/outlet for cold/hot water and inlet/outlet for circulating coolant; pump, thermometer, thermostat, drain valve, water filter and three-way valve; security group and control unit. The device is mounted vertically in close proximity to the boiler in a specially designed room: volume ≤ 200 l to the main wall, capacity ˃ 200 l to the floor.

A distinctive feature of the storage device in question is the absence of a standard power source, which is replaced by a boiler that generates energy for the heating system. In order for hot water to flow to the sink, sink, bathtub and shower, the unit is “tied” by one closed circuit to the SGVS, and the other to the CO.

Part of the coolant intended for radiators is sent to the tank, passes through the coil from top to bottom, and returns to the boiler; cold water is supplied to the container, heated from the bottom up from the heat exchanger, moves under pressure to the mixers, and is recirculated back through a ring pipeline.

Since a portion of the thermal energy intended for heating is consumed by the boiler, a single-circuit boiler is selected with a 30% power reserve; in addition, a 3-way valve is installed at the entrance to the tank, which regulates the balance between the systems using a relay. No less useful is the insulation, thanks to the presence of which the water cools down by only 2...4 °C per day.

Advantages of classic indirect heating boilers:

high productivity – simultaneous supply to several parsing points;
possibility of recirculation - after opening the tap, hot water instantly flows;
the presence of thermal insulation - the liquid cools down by no more than 4 ° C per day;
indirect heating factor – low cost of produced water;
simplicity of design - ease of use.

Flaws:

heating duration for large tank dimensions;
periodic extraction of heat from the heating system;
low efficiency in the spring-autumn season.

As you can see, the biggest advantage of classic models is the lack of consumption of electricity, gas or other fuel. A significant disadvantage is that at the end of the heating season this advantage loses its effect.

The best boilers up to 300 l

No. 2. Gorenje VLG300B1-1G3

Gorenje VLG300B1-1G3
Another model from Gorenje made it into our rating. With a volume of 285 liters and a nicely designed enamelled steel body, the KGV 300-1 is a fairly powerful water heater. It includes the following elements:

dial thermometer;
safety valve;
overheat protection;
magnesium anode.

Let's look at its technical characteristics:

pressure (inlet) – 6 atm.;
power – 5540 W;
volume – 275.5 l;
Max. water temperature – +85 °C;
time for heating water to +50 °C is 22 minutes.

The large weight of the structure (140 kg) forces the boiler to be installed only vertically. What’s more interesting is that there is support for solar collectors to the water heater itself, which is an additional advantage.

pros

support for solar collectors, allowing them as an alternative heating source;
thick layer of insulation (5.7 cm);
environmental friendliness of the thermal insulation layer;
efficiency due to the solar collector;
nice design.

Minuses

The summer season is the time for problems in the operation of the boiler. The main thing is to make sure it works correctly.

Gorenje VLG300B1-1G3

No. 1. Protherm FS B300S

Protherm FS B300S
Czech boiler in the shape of a cylinder with a steel tank and an enamel coating inside. Has mechanical switches. A double heating element heats the water. Equipped with the following components:

double heating element;
titanium anode;
temperature limiter;
protection against bacteria;
recirculation circuit;
drain fitting;
thermal insulation made of polyurethane.

Let's look at its technical characteristics:

inlet pressure – 10 atm;
power – 4600 W;
volume – 295 l;
Max. water temperature – +85 °C;
Warm-up time to +45 °C – 16 minutes.

Can only be installed on the floor.

pros

double heating element quickly and easily heats water;
easy connection of the water heater;
long-term maintenance of water at a certain temperature;
high-quality thermal insulation;
The presence of a recirculation circuit will allow you to quickly heat the water.

Minuses

There are no significant shortcomings.

Protherm FS B300S

Which indirect heating boiler is better to buy?

Having studied all possible modifications of water heaters with indirect heating, the question arises, which one is better to take for home or commercial use. Any model from the rating is suitable for household use; it is enough to decide on the main characteristics and layout. If the equipment is needed for business or the consumption of hot water is high, you should not skimp on productivity. Otherwise the device will be ineffective. The rating of the best indirect water heaters from our editorial experts reveals not only the technical characteristics, but also the pros and cons of various models. Based on them, it is easy to get a complete picture and make the right choice of a good heater for any purpose.

About the selection criteria

Before choosing the best option for this type of boiler, you need to understand what to look for.

We decided to briefly talk about the most significant criteria of all. Their knowledge and understanding will help you choose the most suitable option for you.

Storage tank volume

Its quantity is determined by daily needs and the boiler to which the water heater will be connected. If it is calculated incorrectly, there will be a problem with the appearance of hot water in several places at once. To prevent this from happening, you need to calculate the required volume in your boiler. As a rule, one person uses, on average, up to eighty liters of water per month. So much is spent not only on hygiene, but also on washing dishes.

Conclusion: you need to take a boiler with a reserve volume so that there is enough for everyone.

Volume is an important criterion when selecting a high-quality water heater

Storage tank material

Today tanks are made from three materials:

steel with enamel;
"stainless steel";
titanium coating.

Titanium is rarely used, but its strength is much higher, as is its price.

Conclusion: the tank must be made of a material that is resistant to corrosion. In addition, you need to pay attention to the presence of a magnesium anode.

Heat exchanger structure

There are two options for its structure.

"Matryoshka" With this structure, one tank is located in another. The one inside is filled with water. The one on the outside is where the coolant circulates.
Heat exchanger with coil. Typically one coil is used, although more than one can be used.

Important! If there are two coils, the boiler can be connected to a second heat source.

How does an indirect heating boiler work?

heating element

If you have a tubular electric heater, the boiler can be used all year round. If it is impossible to connect an alternative heating element, the water heater will heat from the mains.

Inlet pressure

This indicator is one of the determining criteria when installing it in an apartment, since central heating often fluctuates.

Conclusion: you need to take durable boiler models.

It is important to consider what water pressure will be at the inlet

Find out more about the correct connection of an indirect heating boiler with your own hands - in the article you will find detailed step-by-step instructions.

Criteria for choosing an indirect heating boiler

Using a volumetric tank that produces heating thanks to an already installed heating system or additionally connected equipment, you can significantly increase the hot water resources in the house.

More often, the BKN is installed near the boiler that provides heating of water for heating the house, and the DHW circuit is connected. Thus, it becomes part of the general house water supply system

The advantages of the boiler include efficiency, durability, and the possibility of being integrated into a DHW system with recirculation. Let's look at what criteria need to be taken into account when choosing a household water heater.

Criterion #1 – tank volume

Useful volume is one of the important parameters, directly dependent on the number of residents and the frequency of hot water consumption.

With a properly selected boiler, there will never be a shortage of hot water, and family members will always be able to simultaneously use the shower, bathtub and all installed taps.

For a large water heater, especially a floor-standing one, it is necessary to provide a special room. Usually this is a boiler room in which the rest of the equipment is installed

When buying a boiler, you can rely on general recommendations for volume:

1-2 consumers and 1-2 water points - 50-80 l;
2-3 consumers and 2-3 water points - 100-150 l;
4-5 consumers and from 4 water points – 200-250 l.

It must be remembered that water in small tanks heats up faster, in large tanks it takes longer, and regardless of the size of the tank, the heating rate also depends on the temperature of the coolant, if the heating element is not connected.

Criterion #2 – heating temperature

The water in the BKN never reaches 100°C, since it most often takes heat from the liquid from the heating circuit - and there the temperature usually does not exceed 90°C.

To control the temperature, a temperature sensor connected to a thermometer is installed inside the tank. Using it, you can monitor the parameters, and if adjustment is provided, then set the desired temperature

On average, the temperature inside the container heats up to 65-85°C. But keep in mind that some of the heat is still lost if the pipeline is long and passes through uninsulated areas, so water may enter the tap with a temperature lowered by 5-10 ° C.

Criterion #3 – installation method

Based on the position of the body, boilers are divided into vertical and horizontal. The first ones are more popular, the second ones can be found much less often - these are either small household “indirect” ones or huge production models.

According to the place of installation, all water heaters are divided into floor-mounted and wall-mounted. Wall mounting is only possible for tanks of limited capacity. Before purchasing, be sure to check whether your wall can withstand the installation of equipment, taking into account the weight with water.

The vertical shape of the water heater is more convenient for floor installation - the base takes up much less space, and connection and maintenance are much easier

In general, among BKN there are most vertical models with floor-mounted installation, less often with universal installation. From a safety point of view, floor-mounted options are more reliable.

Criterion #4 – material of manufacture

The material from which the outer and inner tanks are made affects wear resistance and service life.

To protect the internal surface from corrosion, various types of coatings are used, including:

stainless steel;
glass ceramics;
enamel.

The first option is the most preferable; high-quality food-grade steel is used to protect expensive models. Enamel cracks over time due to constant temperature changes, and glass ceramics applied using the dry method are not inferior to a steel surface.

The outer casing is made of stainless steel, cheaper metal or heat-resistant plastic.

The metal of the outer tank is coated with heat-resistant paint, which lasts throughout its entire service life. If the paint is peeling off and the metal underneath is rusting, it is better to replace the boiler in a timely manner with a better one.

One of the best options for floor installation is a water heater made entirely of stainless steel. They are heavier and more expensive, but they are maximally protected from corrosion and leaks.

Criterion #5 – connecting the heating element

The introduction of an additional energy source is necessary in some cases:

if the heating system, centralized or autonomous, is turned off for the warm season, maintenance or repair;
if the coolant temperature is unstable and requires support;
if the temperature from the heating circuit is not enough.

Before purchasing, be sure to check whether it is possible to connect a heating element: some models do not have it, others are designed to install 1-2 heating elements. Special pipes or inspection holes are provided for them.

You can read more about how to choose a boiler for heating water in this material.

About manufacturers

Boilers are a fairly narrow-profile product, known in detail only to professionals in their field. We offer you a table with a brief description of well-known companies whose products deserve attention due to their high quality.

Table No. 1. Manufacturers

Manufacturer	Description
Gorenje	A world-famous company from Slovenia. Founded in 1950. Specialization – household appliances. Almost all of its products are export-oriented.
Protherm	A company whose main office is in the Czech Republic. Founded in 1992. Since the same year, it has been producing water heating and heating equipment.
De Dietrich	French group of companies. Founded in 1864. Mainly produces equipment for heating systems and more.
Vaillant	It is Germany's leading manufacturer of heating equipment. Formed in 1874. The company is known for the fact that today people assemble robots and instruments.
Drazice	A company from the Czech Republic, which is known for its reliable water heaters. Founded in 1956. Its products meet all the standards and requirements of EU countries.
Baxi	An Italian company that has been making high-quality heating and water heating equipment for more than half a century. The company was formed in 1866.

The best manufacturers offer only high-quality devices

Which indirect heating boiler is worth purchasing?

As mentioned earlier, choosing a boiler requires taking into account a large number of criteria. Among them, several important ones stand out.

Number of people.
Water consumption rate.
Number of water points.
Storage tank volume.
Power.
Inlet pressure.
Water heating speed.

Taking into account all the above criteria, we decided to help you choose water heater models that are suitable in most cases.

If you have a small living space and you live alone or with someone, then a boiler model like the Gorenje GV 100 will be more than enough.
If you have a larger living space and your family consists of 2-3 members, then you should take the Baxi Premier plus 150.
A two-story house in which four people live? Then you need to pay attention to the Drazice OKC 200 NTRR model.
If your life is at the “luxury” level, then there is only one option for you - Protherm FS B300S.

How to choose an indirect heating boiler

When choosing a suitable indirect water heater, experts recommend considering several factors:

Volume of the tank. On average, a family of 3-4 people needs a tank of 100 to 150 liters to ensure an uninterrupted supply of hot water. For low consumption, models with a smaller useful volume are suitable, but if the consumption is high, you should pay attention to larger and more productive versions.
The ability to install a heating element will turn the device into a regular electric water heater. This is relevant in the absence of centralized heating in the summer.
Internal coating - it comes in three types: stainless steel, enamel or titanium. Versions with the first two types are more common, and a minimum of 1 magnesium anode is required, which provides anti-corrosion properties.
Heat exchanger design. One coil in the standard configuration, two in models with connection to an alternative coolant source. “Coil in coil” is a more expensive but effective option.
Additional functionality. It is convenient when the model is equipped with sensors, automation, thermometers, power-on indicators at the factory or optionally. There are also important safety functions - protection against overheating, switching on without water.
Number of water points. Most often, there are models with two outlets for supplying hot water, which allows it to be supplied to several separate rooms at once, for example, a bathroom and a toilet or a kitchen.

In addition to the above, indirect heating boilers differ in the method of connection and installation. It is better when the model can be connected to a boiler or heating system of any type. Installation is divided into two types: wall and floor, divided into vertical and horizontal. There is also a difference in the coolant supply side. All this should be taken into account when planning.