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Calculation options for high-power solid fuel boilers. How to calculate the power of a heating boiler based on the volume and area of ​​the apartment How to calculate the power of a heating boiler in kW

The heating boiler is the basis of the heating system; it is the main device, the performance of which will determine the ability of the communication network to provide the house with the amount of heat that is needed. And if you calculate the power of the heating boiler correctly and correctly, this will eliminate the occurrence of unnecessary costs associated with the purchase of devices and their operation. A boiler selected based on preliminary calculations will operate with the heat output that is included in it by the manufacturer - this will help maintain its technical parameters.

What is the calculation based on?

Calculating the power of a heating boiler is an important point. Power, as a rule, can be compared with the entire heat transfer of the heating system, which will provide a house with a certain size, with a given number of floors, and thermal properties.

To equip a one-story country or private house, you don’t need a very powerful heating boiler.

Thus, in calculating the performance of a boiler for an autonomous house, area is the main parameter if we consider the heating technology of the building in accordance with the climate of the region. So, the area of ​​the house is the most important parameter to calculate the boiler for heating.

Characteristics that will influence the calculation

Those who want to calculate a boiler for heating a house with maximum accuracy can use the methodology provided by SNiP II-3-79. In this case, professional calculations will take into account the following factors:

  • The average temperature of the region during the coldest time.
  • Insulating properties of materials that were used to build enclosing structures.
  • Type of heating circuit wiring.
  • The ratio of the area of ​​supporting structures and openings.
  • Separate information about each room.

How to calculate the power of a heating boiler? To perform the most accurate calculations, even information such as data on household appliances and digital appliances is used - after all, all of this also somehow releases heat into the premises.

However, we note that not every owner of a heating system requires professional calculations - it is usually customary to purchase autonomous heating circuits with devices with a power reserve.

Thus, the efficiency of heating boilers may be higher than the calculated values, especially since they are usually rounded.

What must be taken into account?

How to calculate the power of a heating boiler, what data must be present? One rule should be remembered: every 10 sq.m of a cottage with insulating characteristics, a standard ceiling height limit (up to 3 m) will require approximately 1 kW for heating. You will need to add at least 20% to the power of the boiler, which is designed to work together in heating and hot water supply.

An autonomous heating circuit that has unstable pressure in the heating boiler will need to be equipped with a device so that its power reserve is higher than the calculated value by at least 15 percent. To the power of the boiler, which provides heating and hot water supply, you need to add 15%.

We take into account heat loss

Let us note that regardless of whether the power of an electric boiler, a gas boiler, a diesel boiler or a wood boiler is calculated, in any case, the operation of the heating system will be accompanied by heat losses:

  • Ventilation of the premises is necessary, but if the windows are constantly open, the house will lose about 15% of energy.
  • If the walls are poorly insulated, then 35% of the heat will be lost.
  • 10% of the heat will escape through the window openings, and even more if the frames are old.
  • If the floor is not insulated, then 15% of the heat will be transferred to the basement or ground.
  • 25% of the heat will escape through the roof.

The simplest formula

Thermal calculations in any case will have to be rounded and also increased in order to provide a power reserve. That is why, in order to determine the power of a heating boiler, you can use a very simple formula:

W = S*Wsp.

Here S is the total area of ​​the heated building, which takes into account residential and household rooms in sq.m.

W is the power of the heating boiler, kW.

Wud. – this is the average specific power, this parameter is used for calculations taking into account a certain climatic zone, kW/sq.m. And it is worth noting that this characteristic is based on many years of experience in the operation of different heating systems in the regions. And when we multiply the area by this indicator, we get the average power value. It will need to be adjusted based on the features listed above.

Calculation example

Let's look at an example using a heating boiler power calculator. Natural gas is the most affordable fuel used in Russia. For this reason, it is so widespread and in demand. Therefore, we will calculate the power of a gas boiler. As an example, let’s take a private house with an area of ​​140 sq.m. Territory - Krasnodar region. In the example, we also take into account that our boiler will provide not only heating for the house, but also water for plumbing fixtures. We will do the calculations for a system with natural circulation; the pressure here will not be maintained by a circulation pump.

Specific power – 0.85 kW/sq.m.

So, 140 sq.m/10 sq.m = 14 is an intermediate calculation coefficient. It will provide for the condition that for every 10 square meters of heated premises, 1 kW of heat will be required, which will be provided by the boiler.

14 * 0.85 = 11.9 kW.

We receive thermal energy that the house will need, which has standard thermal properties. To ensure hot water supply for showers and sinks, we will add another 20%.

11.9 + 11.9 * 0.2 = 14.28 kW.

We are not using a circulation pump, so we have to remember that the pressure here may be unstable. Therefore, we must add another 15% to provide thermal energy reserves.

14.28 + 11.9 * 0.15 = 16.07 kW.

You should also remember that there will be some heat leakage. This is why we must round our result up. Thus, we will need a heating boiler with a power of at least 17 kW.

As a rule, the calculation of the heating boiler power is carried out at the building design stage. After all, in order for the heating system to work efficiently, specific conditions are required - arrangement of the combustion chamber, provision of the premises with a chimney and ventilation.

A boiler for autonomous heating is often chosen based on the same principle as your neighbor’s. Meanwhile, this is the most important device on which comfort in the home depends. Here it is important to choose the right power, since neither its excess, nor even its shortage will bring any benefit.

Boiler heat transfer - why calculations are needed

The heating system must completely compensate for all heat loss in the house, which is why the boiler power is calculated. The building constantly releases heat to the outside. Heat loss in a house varies and depends on the material of the structural parts and their insulation. This affects the calculated performance of the heat generator. If you take the calculations as seriously as possible, you should order them from specialists; based on the results, a boiler is selected and all parameters are calculated.

It is not very difficult to calculate heat loss yourself, but you need to take into account a lot of data about the house and its components, and their condition. An easier way is to use a special device for detecting heat leaks - a thermal imager. The screen of a small device displays not calculated, but actual losses. It clearly shows the locations of leaks, and measures can be taken to eliminate them.

Or maybe no calculations are needed, just take a powerful boiler and the house will be provided with heat. Not so simple. The house will really be warm and comfortable until it’s time to think about something. The neighbor has the same house, the house is warm, and he pays much less for gas. Why? He calculated the required boiler capacity, which is one third less. The understanding comes that a mistake has been made: you should not buy a boiler without calculating the power. Extra money is spent, some of the fuel is wasted and, what seems strange, an underloaded unit wears out faster.

A boiler that is too powerful can be reloaded for normal operation, for example, by using it to heat water or by connecting a previously unheated room.

A boiler with insufficient power will not heat the house and will constantly work with overload, which will lead to premature failure. And it will not only consume fuel, but eat it, and still there will not be good heat in the house. There is only one way out - install another boiler. Money went down the drain - buying a new boiler, dismantling the old one, installing another - everything is not free. And if we also take into account the moral suffering due to a mistake made, perhaps the heating season experienced in a cold house? The conclusion is clear - you cannot buy a boiler without preliminary calculations.

We calculate power by area - the basic formula

The simplest way to calculate the required power of a heat generation device is by the area of ​​the house. When analyzing calculations carried out over many years, a pattern was identified: 10 m 2 of area can be heated properly using 1 kilowatt of heat energy. This rule is valid for buildings with standard characteristics: ceiling height 2.5–2.7 m, average insulation.

If the housing fits into these parameters, we measure its total area and approximately determine the power of the heat generator. We always round up the calculation results and increase them a little in order to have some power in reserve. We use a very simple formula:

W=S×W beats /10:

  • here W is the required power of the thermal boiler;
  • S – total heated area of ​​the house, taking into account all residential and domestic premises;
  • W beat – specific power required to heat 10 square meters, adjusted for each climate zone.

For clarity and greater clarity, let’s calculate the power of a heat generator for a brick house. It has dimensions of 10 × 12 m, multiply and get S - the total area equal to 120 m 2. Specific power – Wsp is taken as 1.0. We make calculations using the formula: area 120 m2 multiplied by specific power 1.0 and we get 120, divide by 10 - the result is 12 kilowatts. A heating boiler with a capacity of 12 kilowatts is suitable for a home with average parameters. These are the initial data that we will adjust in the course of further calculations.

There are a lot of units on the market with similar characteristics, for example, solid fuel boilers from the “Kupper Expert” line from the Teplodar company, the power of which varies from 15 to 45 kilowatts. You can get acquainted with the other characteristics and find out the price on the official website of the manufacturer https://www.teplodar.ru/catalog/kotli/.

Correcting calculations - additional points

In practice, housing with average indicators is not very common, so additional parameters are taken into account when calculating the system. One determining factor - the climatic zone, the region where the boiler will be used, has already been discussed. We present the values ​​of the coefficient Wsp for all areas:

  • the middle band serves as a standard, power density is 1–1.1;
  • Moscow and Moscow region - multiply the result by 1.2–1.5;
  • for southern regions – from 0.7 to 0.9;
  • for the northern regions it rises to 1.5–2.0.

In each zone we observe a certain spread of values. We do it simply - the further south the area in the climate zone, the lower the coefficient; the further north, the higher.

Here is an example of adjustments by region. Let's assume that the house for which the calculations were carried out earlier is located in Siberia with frosts up to 35°. We take W beat equal to 1.8. Then we multiply the resulting number 12 by 1.8, we get 21.6. Rounding it off towards a higher value, it comes out to 22 kilowatts. The difference with the original result is almost double, but only one correction was taken into account. So it is necessary to adjust the calculations.

In addition to the climatic conditions of the regions, other corrections are taken into account for accurate calculations: ceiling height and heat loss of the building. The average ceiling height is 2.6 m. If the height differs significantly, we calculate the coefficient value - divide the actual height by the average. Let's assume that the ceiling height in the building from the previously considered example is 3.2 m. We calculate: 3.2/2.6 = 1.23, round up, it comes out to 1.3. It turns out that to heat a house in Siberia with an area of ​​120 m2 with ceilings of 3.2 m, a boiler of 22 kW × 1.3 = 28.6 is required, i.e. 29 kilowatts.

It is also very important to take into account the heat loss of the building for correct calculations. Heat is lost in any home, regardless of its design and type of fuel. 35% of warm air can escape through poorly insulated walls, and 10% or more through windows. An uninsulated floor will take 15%, and the roof will take all 25%. Even one of these factors, if present, should be taken into account. A special value is used by which the resulting power is multiplied. It has the following indicators:

  • for a brick, wooden or foam block house that is more than 15 years old, with good insulation, K = 1;
  • for other houses with non-insulated walls K=1.5;
  • if the house, in addition to uninsulated walls, does not have an insulated roof K = 1.8;
  • for a modern insulated house K=0.6.

Let's return to our example for calculations - a house in Siberia, for which, according to our calculations, a heating device with a capacity of 29 kilowatts will be needed. Let's assume that this is a modern house with insulation, then K = 0.6. Let's calculate: 29×0.6=17.4. We add 15–20% to have a reserve in case of extreme frosts.

So, we calculated the required power of the heat generator using the following algorithm:

  1. 1. Find out the total area of ​​the heated room and divide by 10. The specific power number is ignored; we need average initial data.
  2. 2. We take into account the climate zone where the house is located. We multiply the previously obtained result by the region coefficient.
  3. 3. If the ceiling height differs from 2.6 m, we also take this into account. We find out the coefficient number by dividing the actual height by the standard height. The boiler power obtained taking into account the climate zone is multiplied by this number.
  4. 4. We make allowances for heat loss. We multiply the previous result by the coefficient of heat loss.

Above we discussed exclusively boilers that are used exclusively for heating. If the device is used to heat water, the calculated power should be increased by 25%. Please note that the heating reserve is calculated after correction taking into account climatic conditions. The result obtained after all calculations is quite accurate, it can be used to select any boiler: gas , liquid fuel, solid fuel, electric.

We focus on the volume of housing - we use SNiP standards

When calculating heating equipment for apartments, you can focus on SNiP standards. Building codes and regulations determine how much thermal energy is needed to heat 1 m 3 of air in standard buildings. This method is called calculation by volume. SNiP provides the following standards for thermal energy consumption: for a panel house - 41 W, for a brick house - 34 W. The calculation is simple: we multiply the volume of the apartment by the rate of heat energy consumption.

Here's an example. An apartment in a brick house with an area of ​​96 sq.m., ceiling height - 2.7 m. Let's find out the volume - 96 × 2.7 = 259.2 m 3. Multiply by the norm - 259.2 × 34 = 8812.8 W. Converting to kilowatts, we get 8.8. For a panel house, we carry out the calculations in a similar way - 259.2×41 = 10672.2 W or 10.6 kilowatts. In heating engineering, rounding is carried out upward, but if you take into account energy-saving packages on windows, you can round down.

The obtained data on equipment power are initial. For a more accurate result, correction will be needed, but for apartments it is carried out according to different parameters. The first step is to take into account the presence of an unheated room or its absence:

  • if a heated apartment is located on the floor above or below, we apply an amendment of 0.7;
  • if such an apartment is not heated, we do not change anything;
  • if there is a basement under the apartment or an attic above it, the correction is 0.9.

We also take into account the number of external walls in the apartment. If one wall faces the street, we apply an amendment of 1.1, two – 1.2, three – 1.3. The method for calculating boiler power by volume can also be applied to private brick houses.

So, you can calculate the required power of a heating boiler in two ways: by total area and by volume. In principle, the data obtained can be used if the house is average, multiplying it by 1.5. But if there are significant deviations from the average parameters in the climate zone, ceiling height, insulation, it is better to correct the data, because the initial result may differ significantly from the final one.

How not to make a mistake and choose the device wisely so as not to freeze and not stretch your budget - read on. From the article you will learn which technique will be correct and necessary for you.

Calculation of heat losses at home

Let us say right away that there is no single method for calculating the coefficient. The setting varies depending on your climate. It is all the more important to pay more attention to this stage of preparation. Even a specialist cannot determine by eye, without calculations, information on the required boiler power. Even low-power ones, like , can heat an average apartment up to 65 m². But what exactly it should be will become known after filling out a special questionnaire - the document is freely available, anyone can fill it out on the Internet.

The experts took a responsible approach to compiling the questionnaire. By filling out the fields, you will not be able to make a mistake. The only exception is incorrect completion of the online form. All other boiler calculations for the house will be made by the program.

So, here are the questions you need to be prepared for - check:

1. Heat loss through walls

This parameter is influenced by the area of ​​the façade and the ventilated layer (walls may or may not have it). The first covering of the walls is the primary criterion, without which choosing a heating boiler will be too risky. Reinforced concrete or foam concrete, mineral wool, plasterboard, plywood or wood - the material influences the decision of what power to buy solid fuel equipment. The thickness of the first layer of the house is also important. For thin-walled houses, buy a medium-power boiler - for example.

2. Heat loss through windows

Important condition. It is logical that more heat will be lost with a single-chamber double-glazed window than with double-chamber ones. The area of ​​the windows is also important when calculating the power of the boiler. Measure it again before filling out the questionnaire.

3. Heat loss through the ceiling and floor

As you understand, in a room with an attic and an unheated basement you need to install powerful equipment - like. An incorrectly selected device power will ruin several winter months spent in a country house - the heating is clearly not enough for a comfortable life.

Useful for information:

If you do everything correctly, your efforts will be rewarded with a profitable investment in your purchase. Consider that you have completed the task - most likely, you will get the best result in terms of price and quality.

Why is it important to accurately determine the boiler power?

The first thing that comes to mind is saving money on purchases. This alone is worth spending a couple of hours on calculations. Considering the good performance and efficient operation of the boiler, calculating the power of the equipment becomes all the more necessary.

Here are some sad scenarios that will inevitably unfold if the above is not taken into account.

Remember: The regional adjustment for our climate is a factor of 1.2.

Incorrect calculation of the power of a less popular, but still available pellet device (for example) and a wood-burning boiler is the first choice parameter. To calculate the parameter, do not be lazy to spend time, otherwise you will not be able to avoid the above problems in lack of heat (if we are talking about weak appliances) or irrational excessive consumption of fuel (when you select an expensive and too powerful boiler, like).

Determining the boiler power is the most important stage of work

So you have become familiar with the theoretical part of the question, having received information about the importance of calculating the power of boilers. Now it's time to move on to the practical part - the most important. As an option, a specialist responsible for calculating parameters and installation. But you yourself can find out what equipment is really needed.

When calculating power, we start from the area of ​​the heated object - it is this that will help assess productivity. Keep in mind that with a room height of 2.7 m (and such ceilings in almost all houses), it takes 1 kW to heat 10 m².

This coefficient is approximate. It is influenced by the climate of the region and, again, the height of the ceilings, the presence of basements, etc.

Advice: to calculate the power of an ideal boiler for high ceilings, you need to identify a correction factor by dividing the parameter by the standard 2.7 m.

Example:

  • The ceilings are 3.1m.
  • Divide the parameter by 2.7 - we get 1.14.
  • So, for high-quality heating of a 200 m² house with 3.1 m ceilings, a boiler with a capacity of 200 kW * 1.14 = 22.8 kW is useful.
  • To ensure you don’t freeze, we recommend rounding the parameter up. Then you get 23kW. 24 kW will suit us.

Please note that this calculation is suitable for a single-circuit boiler. In the case of, you need to calculate what temperature of water you want to get in the cold, and choose equipment in accordance with the parameter (+25%, power, if you like your water hotter).

Step-by-step calculation of boiler power (double-circuit) for apartments

With apartments the situation is somewhat different. Here the coefficient is less than in a house - in apartments there is no heat loss through the roof (unless we are talking about the top floor) and losses through the floor (except on the first floor).

  • if the apartment above is “warmed” by another room, the coefficient will be 0.7
  • if there is an attic above you - 1

To calculate the parameter, we use the method indicated above, taking into account the coefficient.

Example: The area of ​​the apartment is 163 m². Its ceilings are 2.9 m, the apartment is located in our strip.

We determine the power in five steps:

  1. We divide the area by the coefficient: 163m²/10m²= 16.3 kW.
  2. Do not forget about the adjustment for the region: 16.3 kW * 1.2 = 19.56 kW.
  3. Since the double-circuit boiler is designed for hot water, we add 25% 7.56 kW * 1.25 = 9.45 kW.
  4. And now don’t forget about the cold (experts advise adding another 10%): 9.45 kW * 1.1 = 24.45 kW.
  5. We round it up and it comes out to 25 kW. It turns out that a device that runs on natural gas and interacts with solar collectors will suit us.

Please note that in this way the power of boilers is calculated, no matter what fuel they use - be it gas, electricity, or solid fuel. .

Step-by-step calculation of boiler power (single-circuit) for an apartment

But what if you don’t need a double-circuit boiler, and with tasks? Let's make calculations, taking into account one more factor - the material the house is made of. The heating standard established at the legislative level looks like this:

  • Heating 1m³ in a panel house will require 41 W.
  • Heating 1m³ in a brick house will require 34 W.

We invite you to familiarize yourself with:

We remember the area of ​​the apartment, multiply it by the height of the ceilings, and get the volume. This indicator must be multiplied by the norm - we get the boiler power.

Example:

  1. You live in an apartment with an area of ​​120 m², and its ceilings are 2.6 m.
  2. The volume will be: 120m²*2.6m=192.4m³
  3. We multiply by the coefficient and calculate the heat requirement 192.4 m³ * 34 W = 106081 W.
  4. Converting to kilowatts and rounding, we get 11 kW. This is the power a single-circuit thermal unit should have. A good option is the model. A little "with reserve", the power of this equipment is more than enough for a comfortable microclimate in your home.

As you can see, the task of selecting a boiler will not take more than an hour. By choosing the right heating device, you will be protected from uncomfortable cold throughout the winter, saving money on the purchase of a boiler and utilities. Correctly calculating the parameter is equally important for all types of heaters: coal, TT,

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;
  • Wsp is the specific power of the boiler required to heat ten square meters of 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.

Related article: Methods for heating outdoor areas

The value of 15 kW obtained in this example is the boiler power with a system volume of 225 liters, which guarantees a comfortable temperature in a room of 100 m² in the most severe frosts, provided that the room is 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 principle of operation of the system is based on the difference in the physical characteristics of hot and cold water. Using 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.

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There is a special connection for the 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 an expansion tank, which is placed 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 and can use various energy sources for their operation. For example, liquid and solid fuels.

Electrical
Despite all their convenience, electric boilers are 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 a house with a total area of ​​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. Liquid fuels have 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 supply of granular fuel from a bunker, with a complex system for monitoring the parameters of power, burning rate, and room temperature. It is beneficial to use in areas with accessible, cheap solid fuel, in coal-bearing regions of the country.

The main question that arises when it is necessary to install autonomous heating at home is how to calculate the power of a gas boiler so that living quarters are comfortable in winter, and at the same time avoid unnecessary costs. It would be a mistake to think that you can select a boiler without calculations, simply by installing a unit with a large power reserve, since all modern heat generators are equipped with automatic systems that allow you to regulate fuel consumption. However, the installation of a boiler unit, the power of which will exceed the actual heat requirements, will lead, firstly, to additional costs for the purchase of the boiler itself and the corresponding components, and secondly, to its inefficient operation, which can cause automation failures and increased wear and tear of the equipment.

For large facilities, boiler units are selected by designers based on complex calculations, but for low-rise private houses this can be done independently, using simplified methods.

Boiler power calculation

Wall-mounted boiler with piping

Calculating the power of a gas boiler using simplified methods can be done both for an apartment or house built according to a standard design, and for a private house built according to an individual project.

Calculation for a typical house

To simplify the calculation of boiler power for a typical house, we proceed from the standard required specific thermal power of the boiler Um = 1 kW/10 m2, which means that to maintain a comfortable temperature in a room of 10 m2, 1 kW of thermal energy is required. The calculation does not take into account the volume of premises, since in all houses built according to standard designs, the height of the premises does not exceed 3 meters.

The formula for calculating the power of a boiler unit is as follows:

Rm = Mind x P x Kr

  • P – the sum of all areas of heated premises;
  • Kr is a coefficient that takes into account the climatic characteristics of the regions.

Since in Russia the climate in the regions is significantly different, a correction factor Kp is introduced, the value of which is accepted:

  • for regions of southern Russia – 0.9;
  • for middle zone regions – 1.2;
  • for the Moscow region – 1.5;
  • for northern regions – 2.0.

For example, for an apartment or house with a total area of ​​120 m2 located in the Moscow region, the required boiler power will be equal to:

Рм = 120 x 1.5/ 10 = 18 kW

The example shows a calculation for a boiler used only for heating purposes. In the case when it is necessary to calculate the power of a double-circuit unit intended, in addition to heating, for hot water supply, the power obtained from the formula should be increased by approximately 30%. In this case, the optimal boiler power will be equal to: 18 x 1.3 = 23.4 kW. Since the boiler capacities offered by manufacturers are given in whole numbers, you should choose a unit with the power closest to the design indicator - 25 kW.

Calculation of boiler power for an individual house

Heating system of a private house

Calculating the power of a gas boiler for a house built according to an individual project is more accurate, since it takes into account the height of the premises and some other parameters. The calculation is made using the formula:

Рм = Тп x Кз

  • Рм – required design power of the boiler unit;
  • Тп – possible heat losses of the building;
  • Kz – safety factor, accepted within the range of 1.15-1.2.

In turn, the amount of possible heat loss from the building is calculated using the following formula:

Tp = Oz x RT x Kr

  • Oz - the total volume of heated premises of the house;
  • RT – temperature difference between outdoor air and indoor air;
  • Kr is a coefficient that takes into account the dissipation of thermal energy and depends on the type of building envelope, the type of filling of window openings, and the degree of insulation of the building.

The dispersion coefficient value is taken for:

  • buildings with a low degree of thermal protection, the walls of which, for example, are made of brick without a layer of insulation with standard wooden windows equal to 2.0-2.9;
  • for buildings with an average degree of thermal protection, double walls with insulation, a small number of windows equal to 1.0-1.9;
  • for houses with a high degree of thermal protection - insulated floors, double-glazed windows, wooden frames, timber or rounded logs, etc., equal to 0.6-0.9.

For example, for a house with an average degree of thermal protection, a total volume of heated premises of 630 m3 (two-story, with an area of ​​one floor of 100 m2, but the height of the premises on the 1st floor is 3.3 m, on the 2nd floor - 3.0 m), the temperature difference between the outside air and indoor air 45 (calculated as the difference between the standard temperature in residential premises, taken to be 20 degrees, and the temperature of the coldest period of the year according to SNiP data for a given region, for example, 25 degrees below zero), the amount of heat loss will be equal to:

Tp = 630 x 45 x 1.0 = 28350 W.

The design power of the boiler will then be:

Рм = 28.35 x 1.2 = 34 kW

Calculation of boiler power using a calculator on the manufacturer’s website

Online calculator

Many manufacturers or companies selling heating equipment offer online calculators on their websites. Typically, for such a calculation you simply need to enter the following parameters into the calculator program:

  • the temperature that needs to be maintained in the house;
  • outside air temperature during the coldest period of the year;
  • need for hot water supply;
  • presence of a forced ventilation system;
  • number of storeys of the house;
  • height of premises;
  • the nature of the floor structure;
  • parameters of external walls - what material they are made of, whether there is insulation or not;
  • information about the length of each external wall;
  • information about the number and size of window openings and the nature of their filling;

It’s not difficult to determine all this data yourself, and then all you have to do is insert it into the appropriate sections of the program and get a ready-made calculation of the boiler power.

Detailed video lesson on calculation:

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