Today, one of the most common types of heating boilers are devices of small dimensions and low power. This is due to the fact that small buildings are common in Russia - private cottages, dachas and small houses, for which high-power boilers are not required.
Excessive power of boiler equipment leads not only to discomfort for the residents of the house, but also to failure of the heating equipment itself. Therefore, it is important to approach the choice of a boiler installation, and especially its power, responsibly. This article will discuss the main features and characteristics of small low-power boilers, as well as the parameters that should be taken into account when choosing.
Where are small boilers used?
Boilers with a capacity of 5 to 7 kW are considered small. They are actively used in small buildings with an area of up to about 50 - 100 square meters, moreover, for a wide variety of purposes:
- in small city apartments
- in small dachas, in houses and cottages with several rooms
- in utility rooms
- in small shops
- in the foresters' houses
- in workshops, garages, sheds
- other small premises up to 50 - 100 square meters
Attention!
It is important to consider that when choosing power, it is necessary to take into account possible heat loss. For example, for a well-insulated house, built according to modern standards of heat and energy saving, with an area of 50 square meters, a boiler power of 5 kW is suitable. But if the house or cottage is poorly insulated, then this level of power will be insufficient. In general, heat loss can range from 10 to even about 30%.
By the way, high heat losses are by no means beneficial for the user, because it turns out that the boiler installation will waste some of the fuel, and the heat will simply “go through the cracks.” Therefore, industry experts recommend insulating the building to the maximum - eliminating cracks and drafts, updating windows, doors, etc.
Gas low-power boilers
The first place in terms of optimal parameters among low-power boilers for small rooms is occupied by gas boilers from 5 to 7 kW. Firstly, gas fuel is the cheapest and most accessible in Russia. Secondly, such a unit does not require a full-fledged smoke removal system - a regular coaxial pipe, which is often provided in a ready-made kit with equipment, will do.
Important!
When purchasing a 5-7 kW gas boiler, you should understand that the manufacturer in the technical data sheet for the equipment indicates the maximum maximum power that the boiler is capable of, but which cannot be used at this limit constantly, as it can quickly wear out. Thus, if a building has a poor level of insulation, then it is necessary to take into account possible heat loss and choose a model with a power higher by 10-30% of the originally expected one.
Pros and cons of small gas installations
Small single-circuit gas boilers, as a rule, do not have a display, complex monitoring and control systems and the ability to connect various engineering systems of the house to the unit - for example, batteries or heated floors. However, such devices are equipped with all the necessary options for high-quality and uninterrupted operation.
To summarize, we can highlight the following advantages of small gas units:
- extremely economical operation, low maintenance bills
- easy assembly and installation
- small dimensions: do not take up much space
- fuel availability
- unpretentious at work
- easy to use
- do not require a chimney
- low cost of equipment
The disadvantages include:
- limited feature set
- lack of control and automation systems
- do not cope well with heating tasks with a low level of building insulation and incorrectly selected power
TOP 5 single-circuit boilers with an open chamber
The rating of devices with an open combustion chamber includes the TOP 5 best gas boilers, which include both devices of the highest price category and budget heating devices.
1. Vaillant atmoTEC plus VU 240/5-5 24 kW - a 24 kW wall-mounted boiler is suitable for heating private houses or apartments up to 240 m². Developed automation and safety systems protect the boiler room from emergency operating conditions, and the reliability and quality of the installed components have been tested over the long-term operation of already installed heating devices.
Models in the line:
Vaillant (Vailant) atmoTEC plus VU 200/5-5 20 kWkW
Vaillant atmoTEC plus VU 240/5-5 24 kW
Vaillant (Vailant) atmoTEC plus VU 280/5-5 art 28 kW
Among the distinctive features of this model, it is worth noting the flame modulation mode of the burner made of chromium-nickel steel, as well as the automatic switching of operating modes of the circulation pump.
Advantages:
- the heating circuit heat exchanger is made of high-quality copper alloy, which eliminates its corrosion even at low-temperature operating conditions;
- intelligent control over the pressure level in the heating circuit increases the safety of the entire system;
- automatic search and detection of errors reduces the time for troubleshooting;
- Programmable partial power mode allows you to save fuel in houses with an area of less than 240 m².
Flaws:
- A rather complex and developed control and diagnostic system, the proper use of which requires a certain amount of knowledge.
Expert opinion: perhaps the best model in its class from a well-known and time-tested manufacturer, the only drawback of which is its price.
2. Baxi ECO Four 1.24 is a single-circuit wall-mounted economy class model with a power of 24 kW from a popular Italian manufacturer, the main advantages of which include excellent price-quality ratio.
An important feature of this model is its high-quality adaptation to Russian gas supply conditions, which maintains the operation of the heating device even when the pressure in the supply line drops to 5 mbar.
Other features of the ECO Four 1.24 include a draft presence sensor at the combustion chamber exit, ionization flame control and built-in weather-compensating automation.
Models in the line:
Baxi (Baxi) ECO Four 1.14 14 kW
Baxi (Baxi) ECO Four 1.14 24 kW
Advantages:
- additional special coating of the copper heat exchanger reliably protects it from corrosion;
- a group for connecting an external indirect heating boiler simplifies the implementation of a hot water preparation circuit;
- high-quality modulation of the burner flame is a serious factor in fuel economy;
- the ability to reconfigure modes to operate on liquefied gas significantly expands the operational capabilities of the product.
Flaws:
- Customer complaints about poor build quality require increased attention from installers during initial installation and commissioning of the product.
Expert opinion: a good model for heating a private home, the minor shortcomings of which are compensated by an excellent price-quality ratio, as well as a wide network of regional service centers.
3. Protherm Panther 25 KOO - an easy-to-use and reliable Slovak-made model that has proven itself well in Russian conditions. Manufactured at the plant of the German Vaillant group, the Panther 25 KOO gas single-circuit boiler with a power of 25 kW is distinguished by the quality of the installed components and high safety standards of the heating device.
Models in the line:
Protherm (Proterm) Panther 25 KOO 25 kW
Protherm Panther 30 KTV 30 kW
The new generation hydraulic block made of composite materials is developed based on the experience of previous operation, which increases its reliability many times over. Also, the automatic air vent installed on the circulation pump meets high standards of reliability and safety.
Advantages:
- the copper heat exchanger of the heating circuit is highly resistant to corrosion and prevents scale deposits on its walls;
- built-in control microprocessor analyzes all operating parameters of the heating device and simplifies fault diagnosis.;
- The display of increased brightness increases the comfort of controlling the operation of the heating system.
Flaws:
- Many customers complain that the sensitivity level of the flue gas sensor is too high, but this fact may also indicate an insufficient level of ventilation in the boiler room.
Expert opinion: there are practically no complaints about the quality and reliability of the Protherm Panther 25 KOO, however, the inflated price tag and expensive after-sales service switch the attention of customers either to products from the Baxi group (good service) or to wall-mounted Vaillant models, which are slightly higher in price.
4. Ariston CLAS X SYSTEM 24 CF NG - a wall-mounted single-circuit boiler with a capacity of 24 kW from a well-known manufacturer from Italy is characterized by extremely low requirements for gas pressure in the supply line, which ensures its operation even at a pressure of 5 mbar.
Models in the line:
Ariston (Ariston) CLAS X SYSTEM 24 CF NG 24 kW
A large and convenient control panel makes it easy to set and adjust the operating parameters of the heating system, and the purchase of an additional set of jets makes it possible to switch the operation of the device to liquefied gas.
Other features of the Ariston CLAS X SYSTEM 24 CF NG include an aluminum alloy heat exchanger and a two-speed circulation pump with automatic speed switching.
Advantages:
- built-in frost protection and circulation pump blocking systems reliably protect the heating system from emergency situations;
- a developed switching system makes it easy to connect external control and automation devices;
- The innovative stainless steel burner increases the durability of the heating device, and the modulation of the burner flame significantly reduces fuel consumption.
Flaws:
- heat exchangers made of aluminum alloy place increased demands on the quality of water for the heating circuit.
Expert opinion: a good and reliable model in the mid-price category, but before purchasing it is worth checking the availability of service organizations in the region of installation.
5. Bosch Gaz 4000 W ZSA 24-2 K - a German Turkish-assembled boiler with a power of 24 kW belongs to the lower price range, however, the single-circuit design of the heating device eliminates the known shortcomings of this company’s bithermal heat exchangers.
Models in the line:
Gas boiler Bosch (Bosch) Gaz 4000 W ZSA 24-2 K art. 7736901490
Built-in draft control in the chimney and ionization flame sensor of the burner significantly increase the safety of the gas group and the overall safety of the heating system. Also, the quality of operation of the heating circuit is well affected by the copper heat exchanger, the main advantages of which include high resistance to corrosion.
Among other features of this model, it is worth noting a three-stage circulation pump, which allows you to adapt the operation of the pump group to the volume of coolant in the heating circuit.
Advantages:
- electronic ignition optimizes the initial period of switching on the heating device;
- built-in protection against overheating and freezing of the heating circuit reliably protects the heating system from emergency operating conditions;
- a convenient and clear LCD display displays the current operating parameters of the device, and also includes an automatic self-diagnosis system.
Flaws:
- Among the shortcomings, some owners note difficulties in connecting this model to utility networks.
Expert opinion: a good boiler in the lower price segment with simple controls and a well-thought-out design for easy replacement of failed components.
Dual circuit systems
A more common heating option for small buildings is a system consisting of a double-circuit boiler. Such equipment allows you to organize the work of two utility networks at once:
- Heating
- Hot water supply
At its core, such a device is a combination of a boiler for heating water and the boiler itself, which operates on the principle of a closed internal loop. The boiler itself performs the function of a water tank to which other systems are connected - for example, batteries and boilers.
Advice
. Experts recommend choosing gas turbocharged models as a double-circuit unit, which represent a full-fledged boiler installation, only of small dimensions.
Turbocharged gas unit
But why a turbine? The answer is quite simple. Large boiler installations require large amounts of oxygen in order for the fuel to burn well and generate the required amount of heat for the boiler power. This requires a large combustion chamber and air ducts. But in the case of small-sized gas installations, there is no talk of any enlarged combustion chamber. What is the mystery? And the fact is that the turbine with which the equipment is equipped pumps large volumes of oxygen forcibly under pressure, increasing the combustion force and efficiency of the boiler even with its small size.
Attention!
When using a boiler with a turbine (fan), it is necessary to exclude the possibility of interaction of the equipment with the wind, since such strong and uncontrolled air flows can change the required oxygen circulation in the combustion chamber.
A turbocharged boiler with two circuits has a closed fuel combustion chamber, therefore it is extremely safe, and due to its small dimensions it can be installed both on the floor and on the wall, and even built into furniture, for example, in kitchen cabinets or bathroom units.
Floor models
The Premium 7.5 unit, developed by Lemax, belongs to the category of single-circuit non-volatile equipment. The boiler is connected to centralized gas supply lines, and the possibility of using liquefied fuel is provided. The design includes brackets for installing an indirect boiler that supplies heated water to the mixers. The standard heat exchanger is made of steel sheet 2 mm thick, connected by resistance welding. The surface is covered with heat-resistant enamel, which prevents corrosion of elements.
The gas is atomized by a small-sized burner from the Italian manufacturer Polidoro; the line is equipped with a SIT safety valve, which allows pressure drops in the pipeline. The design does not contain electrically controlled elements; the boiler can be used in places with unstable power supply.
To ignite the fuel, a piezoelectric element is used, which is activated when the button is pressed. At the bottom of the housing there are ventilation windows that supply heated air into the room.
The Lemax plant offers a 6-kilowatt AOGV unit of the Gazovik series, used for organizing heating in residential buildings. Under the heat exchanger there is an open combustion chamber, air is supplied from the room. Hot gases pass through the radiator and are then released into the atmosphere through a channel with a diameter of 112 mm. The temperature of the combustion products does not fall below 110°C, the manufacturer claims an efficiency of 87%. The installation has a height of 680 mm, weight is 35 kg, the design does not provide for connecting an additional boiler.
Another representative is the Russian-made 8 kW floor-standing gas boiler HotSpot ECO KSts-G-8S. To heat the coolant, a steel heat exchanger is used, equipped with protection against temperature rise. The manufacturer claims an efficiency of 92% and a service life without major repairs. The cylindrical radiator has increased strength; the heater can be used in a closed heating system with forced circulation (the pump must be purchased separately).
Optimal type of small boilers
The smallest and most remote are wall-mounted gas boilers - that is, those that require installation on the wall. If such a boiler is double-circuit, and even turbocharged, then this is the most optimal option, which will cover absolutely all issues of heating and hot water supply in houses with an area of up to about 50 - 100 square meters.
What can be done to ensure that a small boiler heats the premises well?
Often the choice of boiler equipment up to 5 - 7 kW is associated with the desire to save money while at the same time understanding that the power should be enough to heat the existing footage. In such cases, the main thing is not to make a mistake and provide the equipment with optimal operating conditions. We list these conditions:
- the walls, floor and ceiling of the house, cottage, cottage or other premises where the equipment is installed must be well insulated;
- It is not permissible to have gaps between doors, windows and frames;
- the height of the ceilings in the room should be no more than 2.7 meters;
- The climatic zone in which the house is located should not be characterized by long frosts of -15 degrees Celsius.
Low power application
Heating equipment with reduced performance, running on natural or liquefied gas, is designed to maintain comfortable air temperature in apartments up to 100 m². Due to possible heat losses (for example, through the walls of a house or window openings), it is recommended to take into account a correction factor that reduces the size of the serviced room by 15-20%. Since the design does not include electronics, the heaters can be used in buildings not connected to AC power.
When using a 5 kW gas boiler, the following conditions must be met:
- high-quality insulation of walls, flooring and ceilings;
- no gaps between window frames, door frames and load-bearing surfaces;
- the height of the premises should not exceed 2.7 m;
- the house should not be located in a climate zone with prolonged frosts below -15°C.
Small-sized gas-type heating systems are easy to operate and configure.
The small size of the heat exchanger has a positive effect on fuel consumption and efficiency. Disadvantages of the equipment include a limited selection of models and the lack of additional functions. Boilers produced by small Chinese companies are equipped with original design elements, which makes repairing the equipment difficult.
Small-sized alternative to low-power gas units
Despite the almost universal prevalence of gas fuel in Russia, not all buildings have the ability to connect to the gas main. In such cases, owners of small dachas and country houses with an area of up to 50 - 100 square meters may consider an alternative in the form of low-power electric boilers. These installations can also be one or two circuit, ensuring the operation of only the heating system, or two at once - heating and hot water.
Electrical units are also easy to operate, install and install, and are equipped with modern options. But they have a significant drawback - high maintenance costs, since electricity tariffs in Russia, as well as in the rest of the world, are quite high. But the prices for electric boilers are the lowest on the market.
Another alternative is to install two boilers at once, for example, electric and solid fuel, the operation of which can alternate. For example, a wood-burning boiler can operate during the day, and an electric unit can operate at night when electricity tariffs are low.
Rating of single-circuit gas boilers with a closed chamber
The TOP 5 rating of single-circuit models with a closed combustion chamber includes the most popular models from well-known manufacturers, the main requirement for whose products is increased reliability of heating devices.
1. Viessmann Vitopend 100-W A1HB 24 - a single-circuit gas boiler with a capacity of 24 kW from a well-known German manufacturer has no competitors today in terms of the best price-quality ratio. The reliability of this manufacturer’s equipment belongs to the highest price category, while the price is set at the level of the lower price segment.
Models in the line:
Gas boiler Viessmann (Visman) Vitopend 100-W A1HB 24 kW
Gas boiler Viessmann (Visman) Vitopend 100-W A1HB 34 kW
Vitopend 100-W A1HB 24 is equipped with all the necessary safety systems, such as frost protection and pump blocking, auto-ignition and overheating protection. To this it is worth adding a comprehensive auto-diagnosis function and a convenient control system.
A high-quality copper alloy heat exchanger operates reliably even at low coolant temperatures, which is especially convenient in heating systems with heated floors.
Advantages:
- a digital controller with a comprehensive diagnostic system is combined with a built-in time relay, which allows you to set weekly and daily operating modes;
- reliable protection against fluctuations in gas pressure in the supply line and 220 V power supply voltage;
- weather-compensated automation qualitatively regulates the parameters of the heating circuit depending on fluctuations in outside temperature.
Flaws:
- the high price of spare parts is partially offset by the reliability of the device itself.
Expert opinion: an excellent German-assembled model with the best price-quality ratio.
2. Vaillant turboTEC plus VU 242/5-5 24 kW - a high-quality and expensive model from Germany with an installed power of 24 kW. The manufacturer's specialization in wall-mounted heating devices guarantees the reliability and durability of all components, and mandatory inspection of all heating equipment after its assembly implies the complete absence of manufacturing defects.
Models in the line:
Vaillant turboTEC plus VU 242/5-5 24 kW
Vaillant turboTEC plus VU 282/5-5 32 kW
Vaillant turboTEC plus VU 362/5-5 36 kW
Vaillant turboTEC plus VU has an integrated indirect boiler control circuit, which simplifies the preparation of hot water with an external water heater. The volume of the boiler is calculated based on the practical needs of the owner, which distinguishes single-circuit boilers from double-circuit boilers.
Among the technical features of the boiler, it is worth noting the electronic method of controlling pressure in the heating circuit and the safety valve with an electric drive.
Advantages:
- the ability to configure Vaillant turboTEC plus VU to partial power is well suited for small private houses or apartments;
- the primary heat exchanger made of high-quality copper operates reliably even at low coolant temperatures;
- a processor with a liquid crystal display monitors operating parameters, helps configure many functions and conducts automatic troubleshooting.
Flaws:
- high price for spare parts and service
Expert opinion: an excellent model of a single-circuit heating device with a closed combustion chamber from one of the best manufacturers, the widespread use of which is limited only by its high price.
3. Baxi LUNA-3 COMFORT 1.240 Fi is a third-generation gas single-circuit boiler with a capacity of 24 kW from an Italian manufacturer, which takes into account extensive experience in operating wall-mounted heating equipment in Russian conditions.
Models in the line:
Baxi LUNA-3 COMFORT 1.240 Fi 24 kW
Baxi (Baxi) LUNA-3 COMFORT 1.310 Fi art 31 kW
The main distinguishing feature of this boiler is the electronic control module, which can simultaneously serve as a remote thermostat with room temperature control. The purchase of just one outside temperature sensor for this option turns the Baxi LUNA-3 COMFORT into a fully automated boiler room, which itself monitors all heating parameters.
Another feature of this model is the low level of gas pressure (5 mbar), at which Baxi LUNA-3 remains fully operational.
Advantages:
- the copper heat exchanger is additionally coated with a special compound, which further increases its resistance to corrosion;
- the operating algorithm of this model includes operation at low coolant temperatures, which optimizes the operation of the Baxi LUNA-3 COMFORT with heated floors;
- built-in weather-compensated automation saves the owner money on purchasing external control devices.
Flaws:
- To install an external boiler, it is necessary to purchase an electric three-way valve actuator.
Expert opinion: a built-in room temperature control system with a remote panel and low gas consumption distinguishes this model from the best products of competing manufacturers.
4. Buderus Logamax U072 24 - a single-circuit 24 kW model from a well-known German manufacturer, specially designed for Russian conditions and adapted to power surges and natural gas pressure drops in the supply pipeline. The Buderus Logamax U072 is assembled at a newly built plant in the city of Engels, Saratov region.
Models in the line:
Buderus (Buderus) Logamax U072 24KW
Buderus (Buderus) Logamax U072 28Kw
Among the distinctive features of this device, it is worth noting the wide range of modulation of the burner flame, which allows you to optimize gas consumption when the outside temperature fluctuates. The boiler design also includes basic safety systems: protection against freezing and pump blocking, a maximum pressure safety valve, a flame sensor and a temperature limiter in the heating circuit.
Advantages:
- a simple and intuitive boiler control interface allows you to control its operation even by an untrained user;
- electronic ignition and ionization flame sensor increase the safety of gas equipment;
- extended voltage range of the electrical network (165 - 240 V) does not require additional installation of a voltage stabilizer.
Flaws:
- Many users note spontaneous reset of user settings, which leads to the need to re-configure operating modes.
Expert opinion: a fairly reliable boiler of Russian assembly, the quality of which is controlled by German standards.
5. Bosch Gaz 6000 W WBN 6000-24 N - the main difference between the single-circuit model with a closed combustion chamber from the German manufacturer is the high resistance of the device to natural gas pressure drops in the supply line and to voltage surges in the 220 volt electrical network. The power of the device is 24 kW, which is usually enough to heat apartments or private houses with an area of up to 240 m².
Models in the line:
Bosch (Bosch) Gaz 6000 W WBN 6000-18 N
Bosch (Bosch) Gaz 6000 W WBN 6000-24 N
Bosch (Bosch) Gaz 6000 W WBN 6000-35 N
An important feature of the Gaz 6000 W WBN 6000-24 N is the built-in three-way valve, which facilitates the connection of an external indirect heating boiler for preparing hot water.
Another difference between the 6000 W series units with a closed combustion chamber is a modulated fan with automatic speed control. This feature optimizes the operation of the gas burner at different power values.
Advantages:
- a gas fitting leak sensor and ionization flame control qualitatively increase the safety parameters of gas equipment;
- built-in protection against overheating of the heating circuit protects the heating system from emergency situations;
- The service life of a copper heat exchanger is approximately 15 years, which is a very high indicator for wall-mounted models of heating equipment.
Flaws:
- • some owners complain about the quality and reliability of circulation pumps.
Expert opinion: A good and inexpensive domestically assembled boiler, the main advantage of which, as its owners note, is the low noise level and the availability of spare parts.
