The heating boiler is central device heating systems. To operate it at maximum performance and to avoid waste of energy, an accurate calculation of the power of the heating boiler is necessary. A properly designed heat generator will be able to maintain optimal functionality with much lower maintenance costs.
Basic calculation
The power of the heating device requires uniform heat transfer to the network. It is designed to supply heat to buildings of various sizes, be it multi-story building or a country house.
For optimal heating one-story cottage there is no need to purchase an overly powerful boiler, which is designed to heat a 3-4-story building.
The basis for the calculation is the area and dimensions of the building. How to calculate the boiler power taking into account other parameters?
What affects the calculation
The calculation method is specified in building codes and rules II-3-79 (SNiP). In this case, it is necessary to take into account the following characteristics:
- Average territorial temperature in winter;
- the level of thermal insulation of the building and the quality of the materials used for this;
- end location of the room, presence of windows, number of battery sections, thickness of external and interior walls, ceiling height;
- proportional correspondence of the size of openings and supporting structures;
- heating circuit layout form.
For the most accurate calculations, the presence of household equipment (computer, TV, electric oven, etc.) and indoor lighting that can generate heat is often taken into account. But this makes no practical sense.
Information that must be taken into account without fail
Every 10 m² of a private house with average thermal insulation, standard climatic conditions of the region and a typical ceiling height (approximately 2.5-3 m) will require about 1 kW for heating.
More than 20% must be added to the power of the heating boiler, which is designed for joint operation in the heating and water supply system.
Unstable pressure in the boiler and heating main will require equipment with a special device with reserve power, which exceeds the calculated values by approximately 15%.
Force heating boiler, which is connected to the heating system using a coolant (hot water), must also contain a reserve of more than 15%.
The number of possible heat energy losses in poorly insulated rooms
Insufficient quality thermal insulation leads to loss of heat energy in the following amounts:
- Badly insulated walls will transmit up to 35% of heat energy;
- regular ventilation of the room leads to losses of up to 15% of heat (temporary ventilation has practically no effect on losses);
- insufficiently sealed cracks in windows allow up to 10% of thermal energy to pass through;
- an uninsulated roof will draw 25%.
The simplest formula for calculating the required heat energy for heating
For an approximate calculation, there is an elementary formula: W = S × Wsp, where
W is the power of the unit;
S is the size of the building area in m², taking into account all rooms for heating;
Wsp is a standard indicator of specific power, which is used when calculating in a specific climatic region.
The standard power density value is based on experience with a variety of heating systems.
The average statistical information is obtained from a housing and communal services employee in your region. After this, multiply this value by the total area of the building, and you will get average required boiler power.
Calculation example
Gas is the most common type of fuel. How to calculate power gas boiler? Let's consider an example calculation for a building with an area of 150 m², which is presumably located in the Krasnoyarsk Territory. The calculation was made for a heating system with natural circulation without constant pressure from the pump. The specific power in the region under consideration is 0.90 kW/m².
150 m² / 10 m² = 15 is an intermediate calculation coefficient, which implies that 1 kW of the unit’s thermal power is required for an individual 10 m² of heated room area.
15 × 0.90 kW/m² = 13.5 kW.
As a result, the average value of thermal energy required for a specific building with average thermal insulation and climatic indicators was obtained.
Considering the use hot water for the bathroom and kitchen, you will need to add at least 20% to the power: 13.5 + 13.5 × 0.2 = 16.2 kW.
It is worth paying attention to the fact that the pressure in the boiler and the heating main may be unstable; for this it is necessary to add another 15% to the power: 16.2 + 13.5 × 0.15 = 18.225 kW.
Considering that a certain leakage of thermal energy cannot be avoided, it is necessary to round the result up. It turns out that to ensure heating of a particular building using a heating unit using gas fuel, you will need a boiler with a minimum power of 19 kW.
Power calculations for gas-fueled units are most often performed during building planning. The reason for this is the original design of the location heating devices, openings for air exchange, chimney, as well as a separate room for a heating installation.
If you need to think about heating in an existing building that does not have necessary conditions To place the unit on gas fuel, you will need to install an alternative heating system. Good for her role electrical installation, the power of which is calculated using similar calculations.
In addition to the above calculations, the thermal power of the boiler can be calculated using a calculator specially created for this purpose. It includes parameters such as the total area of the room, its height, type of windows, etc. To find out the thermal power, you need to enter the required indicators into the program, having previously found them out exact value.
Calculating the required power to heat a private house is not so difficult task, especially if you use a calculator program. Anyone who wants to save money and provide optimal heating without extra costs thermal energy.
One of the main components of comfortable housing is the presence of a well-thought-out heating system. At the same time, the choice of the type of heating and the required equipment is one of the main questions that must be answered at the stage of designing a house. An objective calculation of the heating boiler power by area will ultimately result in a completely efficient heating system.
We will now tell you about how to carry out this work correctly. At the same time, we will consider the features inherent different types heating. After all, they must be taken into account when carrying out calculations and subsequent decision-making on the installation of this or that type of heating.
Basic calculation rules
At the beginning of our story about how to calculate the power of a heating boiler, we will consider the quantities used in the calculations:
- room area (S);
- specific heater power per 10 m² of heated area – (W spec.). This value is determined adjusted for the climatic conditions of a particular region.
This value (W beat) is:
- for the Moscow region - from 1.2 kW to 1.5 kW;
- for the southern regions of the country - from 0.7 kW to 0.9 kW;
- for the northern regions of the country - from 1.5 kW to 2.0 kW.
Power calculation is carried out as follows:
W cat.=(S*Wsp.):10
Advice! For simplicity, you can use a simplified version of this calculation. In it Wsp.=1. Therefore, the heat output of the boiler is determined as 10 kW per 100 m² of heated area. But with such calculations, you must add at least 15% to the resulting value in order to get a more objective figure.
Calculation example
As you can see, the instructions for calculating the heat transfer intensity are simple. But, nevertheless, we will accompany it with a specific example.
The conditions will be as follows. The area of heated premises in the house is 100 m². The specific power for the Moscow region is 1.2 kW. Substituting the available values into the formula, we get the following:
W boiler = (100x1.2)/10 = 12 kilowatts.
Calculation for different types of heating boilers
The efficiency of a heating system depends primarily on the right choice her type. And of course, it depends on the accuracy of the calculation of the required performance of the heating boiler. If the calculation of the thermal power of the heating system was not carried out accurately enough, then negative consequences will inevitably arise.
If the boiler heat transfer is less than required, the rooms will be cold in winter. In case of excess productivity, there will be an overconsumption of energy and, accordingly, money spent on heating the building.
To avoid these and other problems, just knowing how to calculate the power of a heating boiler is not enough.
It is also necessary to take into account the features inherent in systems using different types heaters (you can see photos of each of them further in the text):
- solid fuel;
- electric;
- liquid fuel;
- gas.
The choice of one type or another largely depends on the region of residence and the level of infrastructure development. It is important to have the opportunity to purchase certain type fuel. And, of course, its cost.
Solid fuel boilers
Calculation of the power of a solid fuel boiler must be made taking into account the features characterized by the following features of such heaters:
- low popularity;
- relative accessibility;
- opportunity battery life- it is provided in a number of modern models these devices;
- efficiency during operation;
- the need for additional space for fuel storage.
Another characteristic feature that should be taken into account when calculating heating power solid fuel boiler, is the cyclicity of the resulting temperature. That is, in rooms heated with its help, the daily temperature will fluctuate within 5ºC.
Therefore, such a system is far from the best. And if possible, you should refuse it. But, if this is not possible, there are two ways to smooth out the existing shortcomings:
- Using a thermal balloon, which is needed to regulate the air supply. This will increase the burning time and reduce the number of fireboxes;
- Application of water heat accumulators, having a capacity from 2 to 10 m². They are included in the heating system, allowing you to reduce energy costs and, thereby, save fuel.
All this will reduce the required productivity. Therefore, the effect of these measures must be taken into account when calculating the power of the heating system.
Electric boilers
Characterized by the following features:
- high cost of fuel - electricity;
- possible problems due to network outages;
- environmental friendliness;
- ease of control;
- compactness.
All these parameters should be taken into account when calculating the power of an electric heating boiler. After all, it is not purchased for one year.
Liquid fuel boilers
They have the following characteristic features:
- not environmentally friendly;
- easy to use;
- require additional space for fuel storage;
- have an increased fire hazard;
- They use fuel, the price of which is quite high.
Gas boilers
In most cases are the most the best option organization of the heating system. have the following characteristic features that must be taken into account when calculating the power of the heating boiler:
- ease of operation;
- do not require space for fuel storage;
- safe to use;
- low cost of fuel;
- efficiency.
Calculation for heating radiators
Let's say you decide to install a heating radiator yourself. But first you need to purchase it. And choose exactly the one that is suitable in terms of power.
- First we determine the volume of the room. To do this, multiply the area of the room by its height. As a result, we get 42m³.
- Next, you should know that heating 1 m³ of room area in central Russia requires spending 41 watts. Therefore, to find out the required performance radiator, we multiply this figure (41 W) by the volume of the room. As a result, we get 1722W.
- Now let's calculate how many sections our radiator should have. It's easy to do. Each element has a bimetallic or aluminum radiator heat dissipation is 150W.
- Therefore, we divide the performance we received (1722W) by 150. We get 11.48. Round up to 11.
- Now you need to add another 15% to the resulting figure. This will help smooth out the increase in required heat transfer during the most severe winters. 15% of 11 is 1.68. Round up to 2.
- As a result, we add 2 more to the existing number (11). We get 13. So, to heat a room with an area of 14 m², we need a radiator with a power of 1722 W, having 13 sections.
Now you know how to calculate the required performance of the boiler, as well as the heating radiator. Use our tips and ensure yourself an efficient and at the same time not wasteful heating system. If you need more detailed information, then you can easily find it in the corresponding video on our website.
In the process of planning a heating system for a home, cottage or production premises A completely logical question arises: how to choose a boiler based on area? To do this correctly, you need to consider the following:
- If the house is insulated in accordance with all standards and requirements and has ceilings up to 3 m, then approximately the boiler power is determined at the rate of 1 kW per 10 m² of area that is supposed to be heated.
- If the house is poorly insulated, or the heated rooms are glazed verandas, uninsulated attics, etc., then the boiler power should be even greater.
- If the boiler is used not only for heating, but also for hot water supply, then the required power increases by 20-50%.
A layperson can determine the required power boiler only approximately, because in more complex formula several more different indicators are included (wall thickness, number, type and size of windows, etc.). Final payment should be done by a professional who can correctly select a boiler based on area. (See also: )
Formula for calculating boiler power
Why is the conversation primarily about the power of the heating boiler? Just because it's practically main parameter his works. Moreover, regardless of what type of fuel will be used (whether it is a gas boiler, liquid fuel, solid fuel or electric), it is the power that determines whether it is suitable for heating and hot water in your home. Will all rooms be comfortable? temperature regime in the winter season or in the spring-autumn cool period. If the power is too high, the boiler will not be able to reach its optimal operating mode and you will simply have to overpay for the excess fuel/energy for it.
Let's consider the formula that is used when selecting a boiler by area.
The parameters that determine thermal power are:
- area of the room that is planned to be heated (S);
- specific boiler power per 10 m² of heated room, already approximately established for different regions taking into account the climatic conditions of each (Wsp.). For Moscow and Moscow region Wud. = 1.5 kW. For areas of the North Wud. = from 1.5 to 2.0 kW. For areas of the South Wud. = from 0.7 to 0.9 kW.
This way you can solve the problem of how to choose a boiler based on area. This formula is considered simplified version, although, in principle, it shows the correct results. Its main advantage is simplicity. But it also has its downsides. It may not be suitable for calculating power over difficult cases(for example, as mentioned above, if something else is supposed to be heated along with the house, like a large glassed-in veranda).
Double-circuit boilers for houses up to 200 m²
Gas double-circuit boilers designed to provide both home heating and hot water supply. In the given example of calculating the boiler power for a house of 80 m², the obtained result of 9.6 kW is only an approximate figure. The table recommends purchasing equipment with a power of at least 25 kW for such an area (for example, such as Proterm Gepard boilers). Otherwise in winter, when it’s frosty outside - down to minus 25°C and heating system is fully loaded, one of your loved ones will not be able to receive warm shower, while you, for example, wash the dishes.
Therefore, if, according to your calculations, you need to purchase a boiler with, say, 14 kW of power, and in stores and on the market you only see boilers for which this indicator begins with the number 18, take a more powerful one (by an order of magnitude, you don’t need more), and don’t even think twice . Automation (after all, almost all brands of modern boilers are equipped with it) will itself adapt to the needs of the room. Just remember that the power reserve should not be more than 25%.
Designed for use in private residential buildings, apartments and cottages, Proterm Gepard boilers are very easy to maintain and are equipped with a display that displays all the information about the current operation of the boiler. Some models can be installed in rooms where there is no chimney at all. All this allows us to classify them as heating equipment of increased comfort.
Double-circuit boilers for houses up to 300 m²
It perfectly withstands not only temperature changes outside, but also power surges, which is also typical for Russia. He is also not afraid of a sudden drop in water or gas pressure. Such a boiler operates without breakdowns or failures for a very long time thanks to high quality all components. In addition, it has a very reasonable price, so the Navien mounted boiler is one of best options for country cottages.
Heating boilers for premises up to 1 thousand m²
For heating buildings large area Solid fuel boilers with mechanical fireboxes and a control cabinet are often used. They heat the room very quickly, which is important. If there is a sudden power failure or the water temperature and pressure deviate from acceptable standards, the automatic safety system, which is part of the fireboxes, is activated and the fuel supply is stopped. Such equipment includes the Bratsk M boiler. It operates on sorted brown and coal. The dimensions of the pieces should not exceed 100 mm. Cast iron sections The boiler must be installed on a brick base. One of the absolute advantages of its ease of maintenance is that during possible emergency situations, after the fuel supply is turned off, the alarm automatically turns on. All this makes the Bratsk M boiler convenient and safe to use.
Efficiency of heating boilers
What is boiler efficiency in general? This is the difference between the amount of heat in the fuel and the amount of heat that was transferred to the water (coolant). The formula with which you can calculate the boiler efficiency looks like this: efficiency = 100 - q2 - q3 - q4 -q5 - q6 (q values are heat losses).
Before calculating the efficiency, you need to measure the temperature of the flue gas with a special thermometer on the boiler flue. Divide the resulting value by 15, add 2, add 3, add 2. All these numbers are approximate and indicate the same heat losses.
Example: outlet gas temperature - 330°C
330/15 + 2 + 3 + 2 = 29 %
Total: boiler efficiency is 71%
Of course, to determine the operating efficiency of a heating device, the boiler efficiency is first calculated. But this coefficient is not considered decisive when assessing the performance of the entire system.
Autonomous heating is one of the most necessary and expensive components of any private home. The choice of the type of heating system and the calculations made determine how efficiently it will operate, its heat output, and what monetary costs will be required for maintenance during operation.
Electric boiler installation diagram.
To heat a private home, heating systems with boilers using various fuels are used.
But the calculation of the power of a heating boiler, no matter what type it belongs to, is made using a simple formula common to all systems:
Wcat= S x Wud/10
Designations:
- Wbot - boiler power in kilowatts;
- S is the total area of all heated rooms of the house in square meters;
- Wud - specific boiler power required to heat ten square meters room area. The calculation is made taking into account the climate zone in which the region is located.
Diagram of a wall-mounted gas boiler.
Calculations for Russian regions are made with the following power values:
- for regions of the Northern part of the country and Siberia Wud = 1.5-2 kW for every 10 m²;
- for the Middle Band, 1.2-1.5 kW is required;
- for the Southern regions, a boiler power of 0.7-0.9 kW is sufficient.
An important parameter when calculating the boiler power is the volume of liquid that fills the heating system. It is usually denoted as follows: Vsyst (system volume). The calculation is made using the ratio 15l/1kW. The formula looks like this:
Vsyst = Wcat x 15
Calculation of boiler power in the example
For example, the region is Central Russia, and the area of the premises is 100 m².
It is known that for this region the power density should be 1.2-1.5 kW. Let's take the maximum value of 1.5 kW.
Based on this, we obtain the exact value of the boiler power and system volume:
- Wcat = 100 x 1.5: 10 = 15 kW;
- Vsyst = 15 x 15 = 225 l.
The value of 15 kW obtained in this example is the boiler power with a system volume of 225 l, which guarantees in a room of 100 m² comfortable temperature at the most very coldy provided that the premises are located in the Central Zone of the country.
Types of heating systems
Regardless of which boiler is used for heating, if the coolant is water, then it belongs to the water heating systems for which the calculation was made. They, in turn, are divided into systems with natural and forced water circulation.
Heating system with natural water circulation
Diagram of a liquid fuel boiler.
The operating principle of the system is based on the difference physical characteristics hot and cold water. Exploiting these differences causes the water inside the pipes to move and transfer heat from the boiler to the radiators.
Hot water from the boiler rises upward through a vertical pipe (main riser). From it, pipes spread out along the highways. Also through risers (falling), but the movement goes down. From the falling risers, water disperses through the radiators and gives off heat. As it cools, it becomes heavier and, through reverse piping, enters the boiler again, heats up, and the process repeats.
When the boiler is operating, the water movement inside the system is continuous. The phenomenon of expansion of water when heated reduces its density, and therefore its mass, forming hydrostatic pressure in the system. At 40°C, the mass of water in one cubic meter is 992.24 kg, and when it is heated to 95°C, it becomes much lighter; one cubic meter will weigh 962 kg. This difference in density is what causes the water to circulate.
Heating system with forced water circulation
It is characterized by higher circulation pressure, which is created by a centrifugal pump. Typically, pumps are installed on a line through which the spent, cooled coolant returns back to the heating boiler. The pressure in the pipes created by a running pump is significantly higher than in a system with natural circulation. Therefore, water in the system can move in any direction along the horizontal and vertical axes.
Here special connection expansion tank. In systems with natural circulation, it is connected to the main riser. With forced circulation, the connection point is located in front of the pump. This point is connected through a special riser to expansion tank, which is brought up above the highest point of the heating system.
Comparative analysis of boilers for water heating systems
Solid fuel boiler diagram.
Water heating systems use boilers that run on different types of fuel with different heating outputs. The most common types of fuel for boilers:
- electricity;
- liquid: fuel oil, diesel fuel (diesel fuel);
- solid fuel: coal, firewood, pressed briquettes, pellets from wood waste and other combustible materials.
Some boilers are universal, can use various sources energy for your work. For example, liquid and solid fuels.
Electrical
With all the convenience electric boilers rarely used for full heating. They are used as auxiliary or for heating individual rooms. Commercially available electric boilers do not exceed 15 kW in power. Heating a home with electricity is too expensive. As the calculation of the power of the heating boiler given above showed, this is enough to heat the house with total area no more than 100 m².
Gas
Relatively cheap fuel makes it possible to install such boilers in houses with large living areas with a connected main gas supply pipeline. They are very convenient to use.
Liquid fuel
Although prices for liquid fuel are constantly rising, it is approximately 2 times cheaper than electricity. U liquid types fuel has good thermal performance. Heating a residential building of 300 m² will require about 3 tons of fuel per season. The use of such boilers is advisable, but they require special care.
Solid fuel
Requires constant supervision. The exception is boilers with automatic feeding from a granulated fuel bunker, with complex system monitoring parameters of power, burning rate, room temperature. Advantageous to use in areas with accessible, cheap solid fuel, in the coal regions of the country.
Combined
Boilers that can use different kinds fuel. Some models run on gas, liquid and solid fuel. When switching from gas fuel to liquid, a slight reconfiguration is usually required: replacing the burner.
Despite a large number of heating options for private homes, many people prefer the proven option - gas or solid fuel boilers. Such a unit is reliable and durable, does not require complex maintenance. In addition, the variety of models makes it possible to accurately select a device for a specific room. Power is the main characteristic of heating devices. The comfort of the home microclimate, efficiency, safety of the boiler, and its working life depend on how correctly the device is chosen. In this article, we will look at how to choose a boiler for heating a private house based on power, and what factors must also be taken into account.
Why is accurate power calculation necessary?
The choice of boiler is based on accurate calculations that allow you to have an idea of the real heat loss of a private house:
- Purchasing a device with an excessive resource leads to unnecessary fuel consumption.
- A low-power unit will not be able to efficiently heat a living space. In addition, working at the limit of its capabilities, it will quickly fail.
Important! How to choose a boiler according to the size of the house in a simple way? The simplest boiler calculation is 1 kW of power per 10 “squares” of housing plus a margin of 15-20%. For example, to heat a house of 100 m² you need a 12,000 W boiler. This calculation is very aggregated and approximate. It can only be used for buildings with good thermal insulation, with low ceilings and for regions with a mild climate. Naturally, not all private houses meet these requirements.
Initial data for calculation
For a house built according to a standard design, with ceilings 3.0 m high, calculate required power heating device is easy. Let's look at how to select a gas boiler for a private house by area. The calculation is based on 2 parameters:
- Total area of the house.
- Specific power of the boiler (UMK). This indicator varies for different climate zones.
The value of the UMC is:
- For southern regions - 0.7-0.9 kW.
- For middle zone- 1.0-1.2 kW.
- For northern regions - 1.5-2.0 kW.
The formula for calculation will look like this: M= S x UMK / 10, where
- M - boiler power, kW.
- S is the area of the house,
- UMK - specific power of the boiler.
Important! Eg:
- The value of the required indicator for a house with a square area of 100 m², located in southern region, is: M=100 x 0.9 / 10 = 9 kW.
- For the same building in the northern regions, a similar indicator for a heating boiler will be: M=100 x 2/10=20 kW.
As you can see, the difference is more than double. If you want to install a dual-circuit unit, increase the figure obtained in the calculation by 20%.
Heat loss accounting
Even the above calculation is not accurate. To correctly select a heating device, you need to have information about real heat loss. One house is well insulated, and the other has old frames made of dried out wood and walls one brick thick. Naturally, heat losses in these buildings will be different.
Important! According to experts:
- The largest heat leaks (about 35%) occur on insufficiently insulated walls.
- About a quarter of heat loss occurs on an uninsulated or poorly insulated roof.
- Insufficiently thought-out floor insulation is the cause of about 15% of heat leaks.
- Only 10-15% of heat loss occurs through ventilation and open windows.
As you can see, simplest formula It is clearly not enough for an accurate calculation. In each specific case, power calculation will be individual.
Taking into account the dispersion coefficient
This coefficient is one of the most important indicators heat exchange between the room and the external environment. The calculations are based on the following values of this coefficient:
- 3.0-4.0 - for buildings in which there is no thermal insulation. Most often these are temporary buildings made of wood and metal.
- 2.9-2.0 - for buildings with minimal thermal insulation. This refers to thin-walled houses with uninsulated walls, simplest design roofs and wooden frames.
- 1.9-1.0. This value of the dissipation coefficient corresponds to the average level of insulation ( brick house with insulated or double walls, with an insulated roof and attic space, with double glazed windows).
- 0.6-0.9. This coefficient applies to houses built using modern technologies and materials. They are characterized by well-thought-out ventilation system, the floor and roof are insulated, windows with good thermal insulation are installed.
Important! The most accurate formula for calculating possible heat loss: Qt = V*Pt*k/860, where
- Qt - possible heat loss;
- V is the volume of the room.
- Ht is the difference between the desired indoor temperature and the minimum external air temperature characteristic of these latitudes;
- k is the dissipation coefficient.
We calculate heat loss for a house of 100 “squares” with ceilings 3 m high and an average level of thermal insulation:
- The desired room temperature is +20 degrees.
- The minimum air temperature for this region is the same 20 degrees, but with a minus sign.
- Qt=300 x 40 x 1.9 /860 = 26.5 kW.
- Taking into account the reserve, we multiply the resulting figure by 20%: 26.5 x 1.2 = 31.8 kW.
- Rounding the resulting figure to the nearest whole number, we get a power of 32 kW.
This calculation allows you to select a boiler unit with fairly high accuracy, taking into account the climate in the region and the characteristics of the structure.
Special calculation programs
You can use various programs and online calculators for calculations. The advantage of such programs is that a large number of different factors are taken into account:
- Desired room temperature.
- Average temperature in the cold season.
- The need for hot water supply.
- Number of floors.
- The presence or absence of a forced ventilation system.
- Ceiling height.
- Wall thickness, floor characteristics.
- The number of windows, their sizes and characteristics (number of chambers, glass thickness).
By filling out the form fields, you receive the exact value of the initial power, and then select the device according to its characteristics.