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How to calculate the power of a heating boiler. We make the correct calculation of the power of the gas heating boiler Power of the heating boiler room area

To provide comfortable living in the house in winter, the boiler must produce enough heat energy to fully compensate for the heat loss of the building. In addition, it is necessary to provide a certain power reserve in case of severe cold or an increase in the area of ​​\u200b\u200bthe building. To calculate the power of the boiler, you need to take into account quite a few factors. In heat engineering, such a calculation is one of the most difficult.

There are many calculations of the heating system, namely the power of the boiler - one of the most difficult

The need to calculate the heat transfer of the boiler

Whatever materials a building is made of, it constantly releases heat to the outside. The heat loss of the house for each room may differ and depend on the materials of construction and the degree of insulation. If you take the calculations seriously, then it is better to entrust such work to specialists. Then, in accordance with the results obtained, a boiler is selected.

It is not very difficult to independently calculate the heat loss of a building, but many factors must be taken into account. The easiest way to solve the problem is with the help of a special device - a thermal imager. This device small sizes, which displays the actual heat loss of the building. At the same time, you can clearly see those places where the maximum leakage of thermal energy is observed, and take measures to correct the situation.

You can immediately install a powerful boiler without calculations

Of course, you can just take a powerful boiler and not carry out any calculations. However, in such a situation, gas costs can be very high. In addition, if the boiler is underloaded, then its service life is reduced. However, the heat generator can be loaded, for example, by using it to heat previously unheated rooms. However, not a single owner of a private house wants to overpay for wasted fuel.

If the power of the heat generator turned out to be insufficient, then it will not be possible to create comfortable living conditions in the building, and the boiler itself will operate in constant overload mode. As a result, expensive equipment will fail prematurely. Thus, only one conclusion can be drawn - you need to calculate the power of the boiler for the house, thereby making a competent selection heating equipment.

The easiest way is to independently calculate the power of the heating boiler for the area of ​​\u200b\u200bthe house. After that, it will be possible to say exactly which heating unit is needed to heat all the premises of the building.

Basic Formula

If we analyze the results of calculations carried out over several years, then one regularity is observed - for heating every 10 m 2 of an area, 1 kW of thermal energy must be spent. This statement is true for buildings with medium insulation, and the height of the ceilings in them is in the range from 2.5 to 2.7 m.

If the building meets these standards, then it will be quite simple to determine the capacity of the heating boilers, just use a simple formula:

Latest indicator for different regions of the country has the following meanings:

  1. Moscow region - from 1.2 to 1.5 kW.
  2. The middle band is from 1 to 1.2 kW.
  3. South of the country - from 0.7 to 0.9 kW.
  4. Northern territories - from 1.5 to 2 kW.

As an example, you can calculate the power of a heat generator for a 12 × 14 m house built of brick in the Moscow region. The total area of ​​the building is 168 m 2 . The value of specific power Wsp is taken equal to 1. As a result, W = (168 × 1) / 10 = 16.8 kW. The resulting design power of the heat generator should be rounded up. However, this is not yet a complete calculation of a gas boiler for a house by area, since it is necessary to adjust the obtained indicator.

Additional Calculations

Residential buildings with average characteristics are quite rare in practice. In order for the calculation of the power of the boiler house to be as accurate as possible, additional indicators have to be taken into account. One of them has already been considered in the main formula - the specific power spent on heating 10 m 2.

As a reference, it is necessary to use the indicator for the middle band. At the same time, in each zone, one can see a rather serious scatter of specific capacitance values. The way out of this situation is simple - the further north the area is located in the climatic zone, the higher the coefficient should be, and vice versa. For example, for Siberia with frosts of about 35 degrees, it is customary to use Wsp = 1.8.

Another factor affecting the calculation of the boiler power is the height of the ceilings. If this parameter differs significantly from the average (2.6 m), then a correction factor must be calculated. To do this, the real value must be divided by the average.

It is equally important to take into account in the calculations heat loss buildings. The process of heat leakage is observed in every building. For example, if the walls are poorly insulated, then losses can reach up to 35%. Thus, during the calculations a special coefficient should be used:

  1. A structure made of wood, foam blocks or bricks, the age of which exceeds 15 years with high-quality insulation - K = 1.
  2. Buildings of other materials with poorly insulated walls - K = 1.5.
  3. If the roof was not insulated in the building, and not just the walls - K = 1.8.
  4. Modern high-quality insulated houses - K = 0.6.

Do not forget to take into account the coefficient of wood blocks

This is how the required power of the heat generator is calculated in order to make the right choice of equipment. However, if the boiler is also planned to be used for heating water, the obtained value of its power will have to be increased by 25%. Thus, to determine the required power of the heat generator you need to use the following algorithm:

  1. The total area of ​​\u200b\u200bthe building is calculated and divided by 10. In this case, the indicator Wud does not need to be taken into account.
  2. The calculated value is adjusted depending on the climatic zone in which the building was erected. The indicator determined at the first stage is multiplied by the coefficient of the region.
  3. If the actual value of the ceiling height differs significantly from the average, this must be taken into account in the calculation. First you need to divide the actual figure by the average. The resulting coefficient is multiplied by the power of the heat generator, determined taking into account the correction for the climatic features of the area.
  4. The heat losses of the building are taken into account. The result obtained at the previous stage must be multiplied by the heat loss coefficient.
  5. If the boiler is also used for heating water, its capacity is increased by 25%.

The result obtained using this algorithm is different high precision, and it is suitable for choosing a boiler that runs on any type of fuel.

In accordance with the norms of SNiP

Calculate the equipment power for heating system houses can be based on building codes and regulations (SNiP). This document defines the required amount of thermal energy to heat 1 m 3 of air. The volume calculation is fairly easy to do. It is enough to determine the volume interior spaces buildings and multiply it by the rate of consumption of thermal energy.

According to SNiP, in a panel building, 41 W of heat energy must be spent to heat 1 m 3 of air.

For brick house the norm is 34 watts. After performing the calculation, the resulting power value must be converted to kilowatts. It should also be recalled that in heat engineering, calculated indicators are rounded up.

If you want to get the most accurate results, then correction factor must be taken into account:

  1. If a heated room is located above or below the apartment, the correction is 0.7.
  2. If it is unheated, the coefficient will be 1.
  3. If the apartment is located above the basement or under the attic - the amendment will be 0.9.


You also need to take into account the number of external walls in the room. When only one wall goes out, the coefficient will be 1.1, with two - 1.2, three - 1.3. Thus, the calculation of a boiler for heating a house can be calculated by the total volume of the building or its area. Whichever method is chosen, the process is not very complex. All necessary calculations can be carried out by anyone who does not have special knowledge.

Despite the abundance modern options heating for private houses, most consumers stop at a traditional and proven gas boiler over the years. They are durable and reliable, do not require frequent and complex maintenance, and latitude model range allows you to choose the unit for any room.

Main characteristic gas boiler- it is his power, for the correct determination of which one should take into account a large number of factors. It is from right choice power depends on the comfort of the climate in the house, and the efficiency of the boiler, and its service life.

Why is an accurate calculation of the boiler power necessary?

A competent approach should be based on clear measurements that will allow you to see a complete picture of the heat loss of a private house. Buying a unit with excess capacity will lead to unreasonably high gas consumption, and, consequently, to unnecessary expenses. At the same time, the lack of boiler power can cause it to fail quickly, because in order to heat the house, it will have to work at high speeds all the time.

The easiest way to calculate the power of a gas boiler, which has been used for quite a long time, is 1 kW for every 10 square meters housing plus 15-20%. That is, from this simple formula it follows that for a private house with an area of ​​​​100 m², a boiler with a capacity of about 12 kW is required.

This calculation is very rough and is only suitable for houses with good thermal insulation and windows, low ceilings and in a fairly mild climate. Practice shows that not all private houses meet these criteria.

What data is needed to calculate the power of a gas boiler

For private houses built according to a standard project, with a ceiling height of about 3 meters, the calculation formula looks quite simple. In this case, it is necessary to take into account the building area (S) and the boiler specific power index (UMK), which varies depending on the climatic zone. He hesitates:

  • From 0.7 to 0.9 kW in the southern regions of the country
  • From 1 to 1.2 kW in the regions of the middle lane
  • From 1.2 to 1.5 kW in the Moscow region
  • 1.5 to 2 in the north of the country

Thus, the formula for calculating the power of a gas boiler for a typical private house will look like this:

M=S*UMK/10

80*2/10 = 16 kW

If the consumer, whose task, in addition to heating the home, will also be heating water, experts recommend adding another 20% to the figure obtained using the formula.

What other heat losses should be taken into account?

Even taking into account the climate zone cannot give a complete picture of the heat loss of a private house. Someone has double plastic windows installed, and someone else has not bothered to change the old wooden frames, someone, and someone has only one layer of brick between the street and the room.

According to averaged data, based on experts' calculations, the largest heat losses occur on non-insulated walls and amount to about 35%. A little less, 25% of the heat is lost due to a poorly insulated roof. Ideally, above the house should be warm attic. The bad one can take up to 15% of the heat generated by the boiler, like the old ones. wooden windows. We should also not forget about ventilation and open windows, which account for 10 to 15% of heat loss.

Thus, it turns out that the generally accepted formula is far from suitable for every residential building. For such cases, there are their own counting systems.

The concept of dissipation factor

The dissipation coefficient is one of the important indicators of heat exchange between a living space and environment. Depending on how well, there are such indicators that are used in the most accurate calculation formula:

  • 3.0 - 4.0 is the dissipation factor for structures in which there is no thermal insulation at all. Most often in such cases we are talking about makeshift houses made of corrugated iron or wood.
  • A coefficient from 2.9 to 2.0 is typical for buildings with a low level of thermal insulation. This refers to houses with thin walls (for example, one brick) without insulation, with ordinary wooden frames and simple roof.
  • The average level of thermal insulation and a coefficient from 1.9 to 1.0 are assigned to houses with double plastic windows, insulation of external walls or double masonry, as well as with an insulated roof or attic.
  • The lowest dispersion coefficient from 0.6 to 0.9 is typical for houses built using modern materials and technologies. In such houses, the walls, roof and floor are insulated, good windows and a well thought out ventilation system.

Table for calculating the cost of heating in a private house

The formula in which the value of the dissipation coefficient is used is one of the most accurate and allows you to calculate the heat loss of a particular building. It looks like this:

Qt \u003d V * Pt * k / 860

In the formula Qt – is the level of heat loss, V – is the volume of the room (the product of length, width and height), Pt – this is the temperature difference (to calculate it is necessary to subtract from the desired temperature in the room the minimum air temperature that can be in this latitude), k – is the scattering coefficient.

Let's substitute the numbers into our formula and try to find out the heat loss of a house with a volume of 300 m³ (10 m * 10 m * 3 m) with an average level of thermal insulation at a desired air temperature of + 20 ° C and a minimum winter temperature of - 20 ° C.

300*48*1,9/860 ≈31,81

Having this figure, we can find out what power the boiler needs for such a house. To do this, the obtained value of heat loss should be multiplied by a safety factor, which is usually from 1.15 to 1.2 (the same 15-20%). We get that:

31, 81* 1,2 = 38,172

Rounding the resulting number down, we find the desired number. To heat a house with the conditions we set, a boiler of 38 kW is required.

Such a formula will allow you to very accurately determine the power of the gas boiler required for a particular house. Also, to date, a wide variety of calculators and programs have been developed that allow you to take into account the data of each individual building.

The article was prepared with the information support of Teplodar engineers https://www.teplodar.ru/catalog/kotli/ – heating boilers at manufacturer's prices.

The main characteristic that is taken into account when buying heating boilers, both gas and electric or solid fuel, is their power. Therefore, many consumers who are going to purchase a heat generator for a space heating system are concerned about the question of how to calculate the boiler power based on the area of ​​\u200b\u200bthe premises and other data. This is discussed in the following lines.

Calculation parameters. What to Consider

But first, let's figure out what this such an important value is in general, and most importantly, why it is so important.

In essence, the described characteristic of a heat generator operating on any type of fuel shows its performance - that is, what area of ​​\u200b\u200bthe room it can heat together with the heating circuit.

For example, heating apparatus with a power value of 3 - 5 kW, as a rule, it is able to “cover” with heat a one-room or even two-room apartment, as well as a house up to 50 sq. m. An installation with a value of 7 - 10 kW will "pull" on a three-room housing with an area of ​​​​up to 100 square meters. m.

In other words, they usually take a power equal to about a tenth of the entire heated area (in kW). But this is only in the most general case. To obtain a specific value, a calculation is needed. Various factors must be taken into account in the calculations. Let's list them:

  • total heated area.
  • The region where the calculated heating operates.
  • The walls of the house, their thermal insulation.
  • Roof heat loss.
  • Type of boiler fuel.

And now let's talk directly about the calculation of power in relation to different types boilers: gas, electric and solid fuel.

gas boilers

Based on the foregoing, the power of boiler equipment for heating is calculated using one fairly simple formula:

N boiler \u003d S x N sp. / ten.

Here the values ​​are deciphered as follows:

  • Boiler N - the power of this particular unit;
  • S is the total sum of the areas of all rooms heated by the system;
  • N beats - the specific value of the heat generator required to warm up 10 square meters. m. area of ​​the premises.

One of the main determining factors for the calculation is the climatic zone, the region where this equipment is used. That is, the calculation of the power of a solid fuel boiler is carried out with reference to specific climatic conditions.

What is typical, if once, during the existence of Soviet standards for the appointment of the power of a heating installation, 1 kW was considered. always equal to 10 sq. meters, today it is extremely necessary to make an accurate calculation for real conditions.

In this case, you need to take the following values ​​of N beats.

For example, we will calculate the power of a solid fuel heating boiler relative to the Siberian region, where winter frosts sometimes reach -35 degrees Celsius. Let's take N beats. = 1.8 kW. Then for heating the house with total area 100 sq. m. you will need an installation with a characteristic of the following calculated value:

Boiler N = 100 sq. m x 1.8 / 10 = 18 kW.

As you can see, the approximate ratio of the number of kilowatts to the area as one to ten is not valid here.

It's important to know! If you know how many kilowatts a particular installation has on solid fuel, you can calculate the volume of coolant, in other words, the volume of water that is needed to fill the system. To do this, simply multiply the obtained N of the heat generator by 15.

In our case, the volume of water in the heating system is 18 x 15 = 270 liters.

However, taking into account the climatic component for calculating the power characteristics of the heat generator in some cases is not enough. It must be remembered that heat losses may occur due to the particular design of the premises. First of all, you need to consider what the walls of the living space are. How insulated the house is - this factor has great importance. It is also important to consider the structure of the roof.

In general, you can use a special coefficient by which you need to multiply the power obtained by our formula.

This coefficient has the following approximate values:

  • K = 1, if the house is more than 15 years old, and the walls are made of brick, foam blocks or wood, and the walls are insulated;
  • K = 1.5 if the walls are not insulated;
  • K \u003d 1.8, if, in addition to non-insulated walls, the house has a bad roof that lets heat through;
  • K = 0.6 y modern home with insulation.

Suppose, in our case, the house is 20 years old, it is built of brick and well insulated. Then the power calculated in our example remains the same:

Boiler N = 18x1 = 18 kW.

If the boiler is installed in an apartment, then a similar coefficient must be taken into account here. But for ordinary apartment, if it is not on the first or last floor, K will be equal to 0.7. If the apartment is on the first or last floor, then K = 1.1 should be taken.

How to calculate power for electric boilers

Electric boilers are used for heating infrequently. The main reason is that electricity is too expensive today, and the maximum capacity of such installations is low. In addition, failures and long-term power outages in the network are possible.

The calculation here can be made using the same formula:

N boiler \u003d S x N sp. / ten,

after which the resulting indicator should be multiplied by the necessary coefficients, we have already written about them.

However, there is another, more accurate in this case, method. Let's point it out.

This method is based on the fact that the value of 40 watts is taken initially. This value means that so much power, without taking into account additional factors, is necessary to warm up 1 m3. Further, the calculation is carried out as follows. Since windows and doors are sources of heat loss, you need to add 100 W to each window, and 200 W to the door.

On the last step take into account the same coefficients that have already been mentioned above.

For example, we calculate in this way the power of an electric boiler installed in a house of 80 m2 with a ceiling height of 3 m, with five windows and one door.

Boiler N \u003d 40x80x3 + 500 + 200 \u003d 10300 W, or approximately 10 kW.

If the calculation is carried out for an apartment on the third floor, it is necessary to multiply the resulting value, as already mentioned, by a reduction factor. Then N boiler = 10x0.7=7 kW.

Now let's talk about solid fuel boilers.

For solid fuel

This type of equipment, as the name implies, is used for heating solid fuel. The advantages of such units are obvious for the most part in remote villages and suburban communities where there are no gas pipelines. As a solid fuel, firewood or pellets are usually used - pressed chips.

The method for calculating the power of solid fuel boilers is identical to the above method, which is typical for gas heating boilers. In other words, the calculation is carried out according to the formula:

N boiler \u003d S x N sp. / ten.

After calculating the strength indicator according to this formula, it is also multiplied by the above coefficients.

However, in this case, it is necessary to take into account the fact that the solid fuel boiler has a low efficiency. Therefore, after the calculation by the described method, a power margin of approximately 20% should be added. However, if it is planned to use a heat accumulator in the form of a container for the accumulation of coolant in the heating system, then the calculated value can be left.

Drawing of a solid fuel boiler of rated power

Overshoot and Undershoot

Finally, we note that installing a boiler for heating without preliminary calculation of its power can lead to two undesirable situations:

  1. The boiler output is lower than required for heating the existing premises.
  2. The boiler output is more than necessary to heat the existing premises.

In the first case, in addition to the fact that it will be constantly cold at home, the unit itself may fail due to constant overloads. And the fuel consumption will be unreasonably large. Reinstalling the boiler to a new one is associated with high material costs and difficulties in dismantling, is it worth talking about moral costs? That is why it is so important to correctly calculate the power of the unit!

In the second case, not everything is so deplorable. Excessive boiler power is basically just an inconvenience. Firstly, this feeling of unnecessarily spent money on an expensive unit. Secondly, oddly enough, a too powerful unit that constantly works at half strength reduces its efficiency and wears out quickly. In addition, a lot of fuel will be wasted.

As you can see, in the second case, there are also significant disadvantages. However, here the situation can be corrected if, say, the function of heating hot water supply is added to the boiler. In any case, the final decision is up to the consumer.

So, we have considered methods for calculating the power of a heating boiler. These recommendations should help consumers during complex process selection and purchase of a heating unit.

From the author: welcome, dear readers! in private houses with independent heating it is important to maintain a stable temperature in living quarters. To solve this problem, the heating boiler must produce a certain amount of thermal energy, which will be enough to make up for the loss of heat through doors and windows.

In addition, it is worth considering a power reserve in case of abnormal low temperatures or the proposed increase in the area of ​​a private house. How to calculate the power of a heating boiler? You will learn about this in this material.

The first step to determine the performance of a boiler is to calculate the heat loss of the building as a whole or of an individual room. This calculation, called thermal engineering, is considered one of the most time-consuming in the industry, because many different indicators must be taken into account to carry it out.

You will learn more about this by watching a video on the calculation of heat loss.

What factors affect the "leakage" of heat? First of all, these are the materials that were used in the construction of the building. It is important to consider everything: the foundation, walls, floor, attic, ceilings, doorways and windows. In addition, the type of system wiring, the presence of underfloor heating in the house is considered.

Often taken into account Appliances which generates heat during operation. However, such a detailed approach is not always necessary. There are many methods that allow you to calculate the required performance of a gas boiler without deep immersion in the topic.

Calculation taking into account the area of ​​\u200b\u200bthe room

To understand the approximate performance of a thermal unit, it is important to take into account such an indicator as the area of ​​\u200b\u200bthe room. Of course, this data will not be entirely accurate, since you do not consider the height of the ceilings. For example, for central Russia, 1 kW can heat 10 square meters. meters of area. That is, if your housing has an area of ​​​​160 square meters. meters, then the power of the heating boiler must be at least 16 kW.

How do you include ceiling height or climate information in this formula? This has already been taken care of by specialists who have empirically derived coefficients that allow certain adjustments to be made to the calculations.

So, the above rate is 1 kW per 10 square meters. meters - implies a ceiling height of 2.7 meters. For higher ceilings, a correction factor will need to be calculated and recalculated. To do this, the ceiling height must be divided by the standard 2.7 meters.

We propose to consider a specific example: the ceiling height is 3.2 meters. The calculation of the coefficient looks like this: 3.2 / 2.7 \u003d 1.18. This figure can be rounded up to 1.2. How to use the received number? Recall that for heating a room of 160 square meters. meters need 16 kW of power. This figure must be multiplied by a factor of 1.2. The result is 19.2 kW (round up to 20 kW).

  • in the northern regions 1.5–2.0;
  • in the Moscow region 1.2–1.5;
  • in the middle lane 1.0–1.2;
  • in the south 0.7–0.9.

How it works? If your house is located south of Moscow (in the middle lane), then you need to use a factor of 1.2 (20 kW * 1.2 \u003d 24 kW). For residents of the southern regions - for example, the Stavropol Territory - a coefficient of 0.8 is taken. Thus, heat costs for heating become more modest (20 kW * 0.8 = 16 kW).

However, that's not all. The above values ​​\u200b\u200bcan be considered correct if the factory one or will work exclusively for heating. Suppose you want to entrust it with the functions of heating water. Then add another 20% to the final figure. Take care of the power reserves for peak temperatures in severe frosts, and this is another 10%.

You will be surprised by the results of these calculations. Let's give concrete examples.

A house in central Russia with heating and hot water will require 28.8 kW (24 kW + 20%). For cold weather, another 10% of the power is added 28.8 kW + 10% \u003d 31.68 kW (round up to 32 kW). As you can see, this last figure is 2 times higher than the original one.

Calculations for a house in the Stavropol Territory will be slightly different. If we add to the above indicators the power for heating water, then you will get 19.2 kW (16 kW + 20%). And another 10% of the “reserve” for cold will give you the figure of 21.12 kW (19.2 + 10%). We round up to 22 kW. The difference is not so great, but, nevertheless, these indicators must be taken into account.

As you can see, when calculating the power of a heating boiler, it is very important to take into account at least one additional indicator. Please note that the formula for heating for an apartment and for a private house are different from each other. In principle, when calculating this indicator for an apartment, you can follow the same path, taking into account the coefficients that display each factor. However, there is a simpler and fast way, which will allow you to make adjustments at a time.

The calculation of the heating boiler power for a private house and apartment will look a little different. The coefficient for houses is 1.5. It allows you to take into account heat loss through the floor, foundation and roof. This number can be used for average wall insulation: 2-brick masonry, or walls made of similar materials.

For apartments, this figure will be different. If there is a heated room above your apartment, then the coefficient is 0.7, if you live on the top floor, but with a heated attic - 0.9, with an unheated attic - 1.0. How to apply this information? The power of the boiler, which you calculated according to the above formula, must be corrected using these coefficients. Thus, you will receive reliable information.

Before us are the parameters of an apartment, which is located in a city in central Russia. To calculate the volume of the boiler, we need to know the area of ​​​​the apartment (65 square meters) and the height of the ceilings (3 meters).

The first step: determining the power by area - 65 m2 / 10 m2 = 6.5 kW.

The second step: correction for the region - 6.5 kW * 1.2 = 7.8 kW.

Third step: the gas boiler will be used for water heating (add 25%) 7.8 kW*1.25=9.75 kW.

Fourth step: correction for extreme cold (add 10%) - 7.95 kW * 1.1 \u003d 10.725 kW.

The result must be rounded up, and you get 11 kW.

Summing up, we note that these calculations will be equally true for any heating boilers, regardless of what type of fuel you use. Exactly the same data is relevant for an electric heater, and for a gas boiler, and for one that runs on a liquid energy carrier. The most important thing is the efficiency and performance indicators of the device. Heat loss does not depend on its type.

If you are interested in how to spend a smaller amount of coolants, then you should pay attention to the insulation of the living space.

Capacities according to SNiPs

When calculating the power of a heating boiler for an apartment, be guided by the norms of SNiP. This method is also called "calculation of power by volume". SNiP shows the amount of heat needed to heat one cubic meter of air in typical buildings, namely: to warm up 1 cubic meter. meter in panel house, it will take 41 watts, and in a brick house - 34 watts.

If you know the height of the ceiling and the area of ​​​​the apartment, you can calculate the volume. And then this figure is multiplied by the above rate and the required boiler power is obtained, regardless of the type of fuel - this rule also works for heating in an apartment.

We propose to carry out calculations and find out the power of the boiler for an apartment of 74 sq. meters with ceilings 2.7 meters high, which is located in a brick house.

First step: calculate the volume - 74 m 2 * 2.7 m = 199.8 cubic meters. meters.

Suppose that you need to calculate the same indicator for an apartment located in. Then the formula will look like this: 199.8 * 41 W = 8191 W. As you have already noticed, all indicators for heat engineering are rounded up, but in this case, if we take into account the presence of good metal-plastic windows, then the power can be calculated as 8 kW.

This is not the final number. Next, you need to take into account such indicators as the region of residence and the need to heat water using a boiler. A 10% correction for abnormal cold in winter will be no less relevant. However, in apartments, unlike houses, such indicators as the localization of rooms and the number of storeys are very important. It is important to take into account how many walls in the apartment are external. If a outer wall only one, then the coefficient is 1.1, if two - 1.2, if three - 1.3.

Thanks to the calculations, you will get the final value of the power of the heater when you take into account all the above indicators. If you want to get a reliable heat engineering calculation, experienced specialists recommend contacting specialized organizations that specialize in this.

Application of modern technologies

In conclusion, let's talk about innovative methods for calculating the power of the boiler, which take into account not only the heating area, but also other important data. It's about on the use of a thermal imager. It will show in which places in the apartment heat loss occurs most intensively. This method has the added benefit of improving the thermal insulation of your home.

It is no less efficient and convenient to make calculations using a specialized calculator program. She will calculate the indicator instead of you - the user is only required to enter the numbers for the apartment or house. True, it is not entirely clear how accurate the algorithm underlying the program is. In any case, experts recommend recalculating the indicators manually according to the formulas discussed in this article.

All the best and see you soon!

In terms of power, the comfort of living in the house depends. This also affects the depreciation of boiler equipment, the duration of its operation and fuel consumption, that is, the monthly cost of operating the cottage.

Autonomous home heating is a complex system that requires detailed calculation. One of the important variables is heating boiler power. This article is about how to calculate it correctly, what parameters you should pay attention to and why do it at all - calculate the boiler power. Let's start with the "why" question.

If the capacity of the boiler exceeds the needs, then, of course, it will perform its function of heating the building and preparing hot water. But, firstly, the cost of boiler equipment depends on the power. Therefore, making a purchase without preliminary calculations, you will certainly spend more money in vain.





Secondly, excess power that exceeds the building's heat loss requirements results in increased stress on the entire hydraulic system. Excessive load leads to unbalanced operation of the system, failures in automation and, ultimately, to a rapid failure of equipment.

Partially, this problem can be overcome if the boiler is equipped with a multi-stage modulating burner, when the flame burning intensity is regulated depending on the requested power. Another option is to install a hydraulic switch in the system, perhaps in addition to a multi-stage burner.


But in this way the issue is only partially solved: if the difference between the required and generated power is significant, then the modulating burner will not work in a multi-stage mode. Consequently, the operation of the boiler will be pulsed, as in equipment with single stage burner.

Thirdly, the burner of a powerful boiler, heating the coolant, turns off too quickly, does not have time to completely burn out, but warms up. As a result, we get increased soot deposition in the chimney and on the heat exchanger (the need for frequent cleaning), as well as the formation of excessive condensate. And all the same possible failures in the heating system.

What parameters affect the choice of the boiler

In addition to the financial issue and the type of fuel available, the main parameter when choosing a heating boiler is its power. That is, how much heat does it generate, and is this heat enough for heating and hot water preparation, if hot water supply (hot water supply) is also assigned to this boiler.

What affects the ability of heating equipment to heat a house?

Heat loss

Most main parameter, which determines whether the house will have comfortable temperature, this is heat loss building. No matter how powerful the boiler is and has high efficiency if the house is not, then do not expect comfort in it.

Most of the heat escapes through the roof and the ventilation system, including chimneys: approximately 25-30% each. Through the outer walls and windows, 10-15% is lost, the junction of the foundation to the ground also takes about 15%, another 10-15% falls on the floor of the first floor and unheated. Therefore, the task of insulating a building is closely related to the choice of heating equipment: it is better to insulate - a boiler will be required for less power.


Simplified boiler power calculation scheme

In practice, a simplified scheme of heat engineering calculations based on the building area is often used. If the building has standard insulation of walls and other enclosing structures, that is, it has calculated heat loss, then it is assumed that 1 kW of power is required for heating every 10 m² of space.

To correct calculations for different regional climatic conditions, the following coefficients are used:

  • for central Russia - 1-1.5;
  • for the northern regions - 1.5-2;
  • for the southern regions - 0.7-0.9.
In addition to the region, in simplified calculations, you can take into account the volume of heated air, that is, the height of the ceilings. If the ceilings in your house are higher than the standard 2700 mm, then the correction factor is calculated by dividing the actual ceiling height by the standard one.

In case of severe abnormal frosts, when calculating, we add a power reserve of 10%, and if the boiler is also hot water warms, then we add an additional 25%.

Let's count on specific examples

To make it easier to understand the methodology for calculating the required power of the boiler, consider a specific example. Let's say we have brick house with walls 2 bricks thick, located in the Kaluga region.

House area - 160 m². The height of the ceilings in the rooms is higher than the standard - 3500 mm. And the boiler, in addition to the heating system, is also supposed to be used for hot water supply.





So, let's start the calculations. Our house is with brick walls 500 mm thick (2 bricks). According to building codes, these walls have standard heat loss. We assume that other building envelopes are also made in accordance with standard requirements. We divide the area of ​​\u200b\u200bthe house by ten (160/10 \u003d 16) and we get that a boiler with a capacity of 16 kW is required for heating. Now we use all the coefficients and corrections.

Since the Kaluga region is the middle zone of Russia, we will use a coefficient of 1. Our ceilings are higher than the standard ones, so we calculate the correction factor: 3500/2700 = 1.29. Rounding up to the first digit after the decimal point, we get 1.3. We apply the coefficients: 16 kW * 1 * 1.3 \u003d 20.8 kW. We round up to 21 kW.

Since the boiler will, in addition to heating, also heat hot water, let's add another 25%: 21 + 5.3 = 26.3 kW. For abnormal winter temperatures, we add another 10%: 26.3 + 2.1 = 28.4 kW. We round up and look at which model of boilers the power value most closely matches the calculated one.

To finally understand, consider another example.


Log house in the Pskov region. House area - 72 m², ceiling height - 2500 mm. The house is built from a thickness of at least 220 mm. The boiler is not supposed to be used to heat water.

If non-brick is used as the material for the walls, then we correlate the thermal conductivity of the existing structures with the same parameter of a brick wall 500 mm thick. The walls of our house correspond to the standard thermal conductivity of a brick wall of 2 bricks. A log house, given the thickness of the log, is even warmer than a brick house (wood has a lower thermal conductivity than brick). But since the house is old, we will consider that in terms of heat loss, they are the same.

Although the Pskov region belongs to the middle lane, it is still its north, so we will use a regional coefficient of 1.5. So, 72/10=7.2 kW, 7.2*1.5=10.8 kW. Since the ceilings in the house are below standard, we will not use the correction factor, as well as add 25% for hot water supply. Consider only possible very coldy: 10% is 1.08 kW. This means that we need to purchase a boiler with a capacity of at least 12 kW.



The above simplified power calculation scheme justifies itself in the selection of heating equipment only for standard projects detached houses. If your house is blocked, part of a townhouse or an apartment, then the calculations will be different, because the neighbors on the side, below or above reduce the heat loss of the premises. Separate heat engineering calculations will also be required if the house is built according to an individual project.