Calculate the heating power. Thermal calculation of the heating system. Calculation algorithm taking into account the characteristics of the house and its individual premises

A competent choice of the boiler will allow you to maintain a comfortable indoor air temperature in the winter season. A large selection of devices allows you to most accurately select the right model, depending on the required parameters. But in order to provide heat in the house and at the same time prevent unnecessary expenditure of resources, you need to know how to calculate the power of a gas boiler for heating a private house.

The floor-mounted gas boiler has more power Source termoresurs.ru

The main characteristics affecting the power of the boiler

The boiler power indicator is the main characteristic, however, the calculation can be carried out using different formulas, depending on the configuration of the device and other parameters. For example, in a detailed calculation, they can take into account the height of the building, its energy efficiency.

Varieties of boiler models

Boilers can be divided into two types depending on the purpose of the application:

single circuit– are used only for heating;

Dual circuit- are used for heating, as well as in hot water systems.

Units with a single circuit have a simple structure, consist of a burner and a single heat exchanger.

In dual-circuit systems, the water heating function is primarily provided. When hot water is used, the heating is automatically turned off for the duration of hot water use so that the system is not overloaded. The advantage of a two-circuit system is its compactness. Such a heating complex takes up much less space than if the hot water and heating systems were used separately.

Boiler models are often divided according to the method of placement.

Boilers can be installed in different ways depending on their type. You can choose a model with a wall mount or installed on the floor. It all depends on the preferences of the owner of the house, the capacity and functionality of the room in which the boiler will be located. The way the boiler is installed is also affected by its power. For example, floor boilers have more power compared to wall-mounted models.

In addition to fundamental differences in terms of application and placement methods, gas boilers also differ in control methods. There are models with electronic and mechanical control. Electronic systems can only work in homes with constant access to the mains.

On our website you can find contacts of construction companies that offer home insulation services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Typical device power calculations

There is no single algorithm for calculating both single and double-circuit boilers - each of the systems must be selected separately.

Formula for a typical project

When calculating the required power for heating a house built according to a standard project, that is, with a room height of not more than 3 meters, the volume of the rooms is not taken into account, and the power indicator is calculated as follows:

Determine the specific thermal power: Um = 1 kW / 10 m 2;

Rm \u003d Um * P * Kr, where

P - a value equal to the sum of the areas of heated premises,

Kr is a correction factor, which is taken in accordance with the climatic zone in which the building is located.

Some coefficient values ​​for different regions of Russia:

Southern - 0.9;

Located in the middle lane - 1.2;

Northern - 2.0.

For the Moscow region take the value of the coefficient equal to 1.5.

This technique does not reflect the main factors affecting the microclimate in the house, and only approximately shows how to calculate the power of a gas boiler for a private house.

Some manufacturers issue memos-recommendations, but for accurate calculations they still recommend contacting specialists. Source parki48.ru

Calculation example for a single-circuit device installed in a room with an area of ​​100 m 2, located on the territory of the Moscow region:

Pm \u003d 1/10 * 100 * 1.5 \u003d 15 (kW)

Calculations for double-circuit devices

Double-circuit devices have the following principle of operation. For heating, water is heated and flows through the heating system to radiators, which give off heat to the environment, thus heating the premises and cooling. When cooled, the water flows back for heating. Thus, the water circulates around the circuit of the heating system, and goes through the cycles of heating and transfer to the radiators. At the moment when the ambient temperature becomes equal to the set one, the boiler goes into standby mode for a while, i.e. temporarily stops heating water, then starts heating again.

For domestic needs, the boiler heats water and supplies it to the taps, and not to the heating system.

When calculating the power of a device with two circuits, another 20% of the calculated value is usually added to the received power.

Calculation example for a two-circuit device, which is installed in a room with an area of ​​100m 2; the coefficient is taken for the Moscow region:

R m \u003d 1/10 * 100 * 1.5 \u003d 15 (kW)

R final \u003d 15 + 15 * 20% \u003d 18 (kW)

Additional factors to consider when installing the boiler

In construction, there is also the concept of energy efficiency of a building, that is, how much heat a building gives off to the environment.

One of the indicators of heat transfer is the coefficient of dissipation (Kp). This value is a constant, i.e. constant and does not change when calculating the level of heat transfer of structures made of the same materials.

It is necessary to take into account not only the power of the boiler, but also the possible heat loss of the building itself. Source pechiudachi.ru

For calculations, a coefficient is taken, which, depending on the building, can be equal to different values ​​​​and the use of which will help to understand how to calculate the power of a gas boiler for a house more accurately:

The lowest level of heat transfer, corresponding to the value of K p from 0.6 to 0.9, is assigned to buildings made of modern materials, with insulated floors, walls and roofs;

K p is from 1.0 to 1.9, if the outer walls of the building are insulated, the roof is insulated;

K p is from 2.0 to 2.9 in houses without insulation, for example, brick with single masonry;

K p is from 3.0 to 4.0 in non-insulated rooms, in which there is a low level of thermal insulation.

Heat loss level Qt calculated according to the formula:

Q t = V * P t * k / 860, where

V – is the volume of the room

Pt- R temperature difference calculated by subtracting the minimum possible air temperature in the region from the desired room temperature,

k is the safety factor.

The power of the boiler, taking into account the dissipation factor, is calculated by multiplying the calculated level of heat loss by the safety factor (usually from 15% to 20%, then it is necessary to multiply by 1.15 and 1.20, respectively)

This technique allows you to more accurately determine the performance and, therefore, approach the issue of choosing a boiler with the highest quality.

What happens if you calculate the required power incorrectly

It is still worth choosing a boiler so that it matches the power required to heat the building. This will be the best option, since, first of all, buying a boiler that does not match the power level can lead to two types of problems:

A low-power boiler will always work to the limit, trying to heat the room to the set temperature, and can quickly fail;

An appliance with an excessively high power level costs more and even in economy mode consumes more gas than a less powerful device.

Boiler power calculator

For those who do not like to do calculations, even if not very complicated, a special calculator will help to calculate a boiler for heating a house, a special calculator is a free online application.

Interface of the online calculator for calculating the power of the boiler Source idn37.ru

As a rule, the calculation service requires you to fill in all the fields, which will help you make the most accurate calculations, including the power of the device and the thermal insulation of the house.

To get the final result, you will also need to enter the total area that will require heating.

Next, you should fill in information about the type of glazing, the level of thermal insulation of walls, floors and ceilings. As additional parameters, the height at which the ceiling is located in the room is also taken into account, information is entered on the number of walls interacting with the street. Take into account the number of storeys of the building, the presence of structures on top of the house.

After entering the required fields, the button for performing calculations becomes “active” and you can get the calculation by clicking on the corresponding button with the mouse. To check the information received, you can use the calculation formulas.

Video description

Visually about the calculation of the power of a gas boiler, see the video:

Benefits of using gas boilers

Gas equipment has a number of advantages and disadvantages. The advantages include:

the possibility of partial automation of the boiler operation process;

unlike other energy sources, natural gas has a low cost;

devices do not require frequent maintenance.

The disadvantages of gas systems include high explosiveness of gas, however, with proper storage of gas cylinders, timely maintenance, this risk is minimal.

On our website you can find construction companies that offer services for connecting electrical and gas equipment. You can talk directly with representatives at the exhibition of houses "Low-Rise Country".

Conclusion

Despite the apparent simplicity of the calculations, we must remember that gas equipment must be selected and installed by professionals. In this case, you will receive a trouble-free device that will work properly for many years.

Creating a heating system in your own home or even in a city apartment is an extremely responsible task. At the same time, it would be completely unreasonable to purchase boiler equipment, as they say, “by eye”, that is, without taking into account all the features of housing. In this, it is quite possible to fall into two extremes: either the power of the boiler will not be enough - the equipment will work “to its fullest”, without pauses, but will not give the expected result, or, conversely, an overly expensive device will be purchased, the capabilities of which will remain completely unclaimed.

But that's not all. It is not enough to purchase the necessary heating boiler correctly - it is very important to optimally select and correctly place heat exchange devices in the premises - radiators, convectors or "warm floors". And again, relying only on your intuition or the "good advice" of your neighbors is not the most reasonable option. In a word, certain calculations are indispensable.

Of course, ideally, such heat engineering calculations should be carried out by appropriate specialists, but this often costs a lot of money. Isn't it interesting to try to do it yourself? This publication will show in detail how heating is calculated by the area of ​​\u200b\u200bthe room, taking into account many important nuances. By analogy, it will be possible to perform, built into this page, will help you perform the necessary calculations. The technique cannot be called completely “sinless”, however, it still allows you to get a result with a completely acceptable degree of accuracy.

The simplest methods of calculation

In order for the heating system to create comfortable living conditions during the cold season, it must cope with two main tasks. These functions are closely related, and their separation is very conditional.

• The first is maintaining an optimal level of air temperature in the entire volume of the heated room. Of course, the temperature level may vary slightly with altitude, but this difference should not be significant. Quite comfortable conditions are considered to be an average of +20 ° C - it is this temperature that, as a rule, is taken as the initial temperature in thermal calculations.

In other words, the heating system must be able to heat a certain volume of air.

If we approach with complete accuracy, then for individual rooms in residential buildings the standards for the necessary microclimate are established - they are defined by GOST 30494-96. An excerpt from this document is in the table below:

• The second is the compensation of heat losses through the structural elements of the building.

The main "enemy" of the heating system is heat loss through building structures.

Alas, heat loss is the most serious "rival" of any heating system. They can be reduced to a certain minimum, but even with the highest quality thermal insulation, it is not yet possible to completely get rid of them. Thermal energy leaks go in all directions - their approximate distribution is shown in the table:

Naturally, in order to cope with such tasks, the heating system must have a certain thermal power, and this potential must not only meet the general needs of the building (apartment), but also be correctly distributed among the premises, in accordance with their area and a number of other important factors.

Usually the calculation is carried out in the direction "from small to large". Simply put, the required amount of thermal energy is calculated for each heated room, the obtained values ​​​​are summed up, approximately 10% of the reserve is added (so that the equipment does not work at the limit of its capabilities) - and the result will show how much power the heating boiler needs. And the values ​​​​for each room will be the starting point for calculating the required number of radiators.

The most simplified and most commonly used method in a non-professional environment is to accept the norm of 100 W of thermal energy per square meter of area:

The most primitive way of counting is the ratio of 100 W / m²

Q = S× 100

Q- the required thermal power for the room;

S– area of ​​the room (m²);

100 — specific power per unit area (W/m²).

For example, room 3.2 × 5.5 m

S= 3.2 × 5.5 = 17.6 m²

Q= 17.6 × 100 = 1760 W ≈ 1.8 kW

The method is obviously very simple, but very imperfect. It is worth mentioning right away that it is conditionally applicable only with a standard ceiling height - approximately 2.7 m (permissible - in the range from 2.5 to 3.0 m). From this point of view, the calculation will be more accurate not from the area, but from the volume of the room.

It is clear that in this case the value of specific power is calculated per cubic meter. It is taken equal to 41 W / m³ for a reinforced concrete panel house, or 34 W / m³ - in brick or made of other materials.

Q = S × h× 41 (or 34)

h- ceiling height (m);

41 or 34 - specific power per unit volume (W / m³).

For example, the same room, in a panel house, with a ceiling height of 3.2 m:

Q= 17.6 × 3.2 × 41 = 2309 W ≈ 2.3 kW

The result is more accurate, since it already takes into account not only all the linear dimensions of the room, but even, to a certain extent, the features of the walls.

But still, it is still far from real accuracy - many nuances are “outside the brackets”. How to perform calculations closer to real conditions - in the next section of the publication.

You may be interested in information about what they are

Carrying out calculations of the required thermal power, taking into account the characteristics of the premises

The calculation algorithms discussed above are useful for the initial “estimate”, but you should still rely on them completely with very great care. Even to a person who does not understand anything in building heat engineering, the indicated average values ​​\u200b\u200bmay certainly seem doubtful - they cannot be equal, say, for the Krasnodar Territory and for the Arkhangelsk Region. In addition, the room - the room is different: one is located on the corner of the house, that is, it has two external walls, and the other is protected from heat loss by other rooms on three sides. In addition, the room may have one or more windows, both small and very large, sometimes even panoramic. And the windows themselves may differ in the material of manufacture and other design features. And this is not a complete list - just such features are visible even to the "naked eye".

In a word, there are a lot of nuances that affect the heat loss of each particular room, and it is better not to be too lazy, but to carry out a more thorough calculation. Believe me, according to the method proposed in the article, this will not be so difficult to do.

General principles and calculation formula

The calculations will be based on the same ratio: 100 W per 1 square meter. But that's just the formula itself "overgrown" with a considerable number of various correction factors.

Q = (S × 100) × a × b × c × d × e × f × g × h × i × j × k × l × m

The Latin letters denoting the coefficients are taken quite arbitrarily, in alphabetical order, and are not related to any standard quantities accepted in physics. The meaning of each coefficient will be discussed separately.

• "a" - a coefficient that takes into account the number of external walls in a particular room.

Obviously, the more external walls in the room, the larger the area through which heat loss occurs. In addition, the presence of two or more external walls also means corners - extremely vulnerable places in terms of the formation of "cold bridges". The coefficient "a" will correct for this specific feature of the room.

The coefficient is taken equal to:

- external walls No(indoor): a = 0.8;

- outer wall one: a = 1.0;

- external walls two: a = 1.2;

- external walls three: a = 1.4.

• "b" - coefficient taking into account the location of the external walls of the room relative to the cardinal points.

You may be interested in information about what are

Even on the coldest winter days, solar energy still has an effect on the temperature balance in the building. It is quite natural that the side of the house that faces south receives a certain amount of heat from the sun's rays, and heat loss through it is lower.

But the walls and windows facing north never “see” the Sun. The eastern part of the house, although it "grabs" the morning sun's rays, still does not receive any effective heating from them.

Based on this, we introduce the coefficient "b":

- the outer walls of the room look at North or East: b = 1.1;

- the outer walls of the room are oriented towards South or West: b = 1.0.

• "c" - coefficient taking into account the location of the room relative to the winter "wind rose"

Perhaps this amendment is not so necessary for houses located in areas protected from the winds. But sometimes the prevailing winter winds can make their own “hard adjustments” to the thermal balance of the building. Naturally, the windward side, that is, "substituted" to the wind, will lose much more body, compared to the leeward, opposite.

Based on the results of long-term meteorological observations in any region, the so-called "wind rose" is compiled - a graphic diagram showing the prevailing wind directions in winter and summer. This information can be obtained from the local hydrometeorological service. However, many residents themselves, without meteorologists, know very well where the winds mainly blow from in winter, and from which side of the house the deepest snowdrifts usually sweep.

If there is a desire to carry out calculations with higher accuracy, then the correction factor “c” can also be included in the formula, taking it equal to:

- windward side of the house: c = 1.2;

- leeward walls of the house: c = 1.0;

- wall located parallel to the direction of the wind: c = 1.1.

• "d" - a correction factor that takes into account the peculiarities of the climatic conditions of the region where the house was built

Naturally, the amount of heat loss through all the building structures of the building will greatly depend on the level of winter temperatures. It is quite clear that during the winter the thermometer indicators “dance” in a certain range, but for each region there is an average indicator of the lowest temperatures characteristic of the coldest five-day period of the year (usually this is characteristic of January). For example, below is a map-scheme of the territory of Russia, on which approximate values ​​​​are shown in colors.

Usually this value is easy to check with the regional meteorological service, but you can, in principle, rely on your own observations.

So, the coefficient "d", taking into account the peculiarities of the climate of the region, for our calculations in we take equal to:

— from – 35 °С and below: d=1.5;

— from – 30 °С to – 34 °С: d=1.3;

— from – 25 °С to – 29 °С: d=1.2;

— from – 20 °С to – 24 °С: d=1.1;

— from – 15 °С to – 19 °С: d=1.0;

— from – 10 °С to – 14 °С: d=0.9;

- not colder - 10 ° С: d=0.7.

• "e" - coefficient taking into account the degree of insulation of external walls.

The total value of the heat loss of the building is directly related to the degree of insulation of all building structures. One of the "leaders" in terms of heat loss are walls. Therefore, the value of the thermal power required to maintain comfortable living conditions in the room depends on the quality of their thermal insulation.

The value of the coefficient for our calculations can be taken as follows:

- external walls are not insulated: e = 1.27;

- medium degree of insulation - walls in two bricks or their surface thermal insulation with other heaters is provided: e = 1.0;

– insulation was carried out qualitatively, on the basis of heat engineering calculations: e = 0.85.

Later in the course of this publication, recommendations will be given on how to determine the degree of insulation of walls and other building structures.

• coefficient "f" - correction for ceiling height

Ceilings, especially in private homes, can have different heights. Therefore, the thermal power for heating one or another room of the same area will also differ in this parameter.

It will not be a big mistake to accept the following values ​​​​of the correction factor "f":

– ceiling height up to 2.7 m: f = 1.0;

— flow height from 2.8 to 3.0 m: f = 1.05;

– ceiling height from 3.1 to 3.5 m: f = 1.1;

– ceiling height from 3.6 to 4.0 m: f = 1.15;

– ceiling height over 4.1 m: f = 1.2.

• « g "- coefficient taking into account the type of floor or room located under the ceiling.

As shown above, the floor is one of the significant sources of heat loss. So, it is necessary to make some adjustments in the calculation of this feature of a particular room. The correction factor "g" can be taken equal to:

- cold floor on the ground or over an unheated room (for example, basement or basement): g= 1,4 ;

- insulated floor on the ground or over an unheated room: g= 1,2 ;

- a heated room is located below: g= 1,0 .

• « h "- coefficient taking into account the type of room located above.

The air heated by the heating system always rises, and if the ceiling in the room is cold, then increased heat losses are inevitable, which will require an increase in the required heat output. We introduce the coefficient "h", which takes into account this feature of the calculated room:

- a "cold" attic is located on top: h = 1,0 ;

- an insulated attic or other insulated room is located on top: h = 0,9 ;

- any heated room is located above: h = 0,8 .

• « i "- coefficient taking into account the design features of windows

Windows are one of the "main routes" of heat leaks. Naturally, much in this matter depends on the quality of the window structure itself. Old wooden frames, which were previously installed everywhere in all houses, are significantly inferior to modern multi-chamber systems with double-glazed windows in terms of their thermal insulation.

Without words, it is clear that the thermal insulation qualities of these windows are significantly different.

But even between PVC-windows there is no complete uniformity. For example, a two-chamber double-glazed window (with three glasses) will be much warmer than a single-chamber one.

This means that it is necessary to enter a certain coefficient "i", taking into account the type of windows installed in the room:

- standard wooden windows with conventional double glazing: i = 1,27 ;

– modern window systems with single-chamber double-glazed windows: i = 1,0 ;

– modern window systems with two-chamber or three-chamber double-glazed windows, including those with argon filling: i = 0,85 .

• « j" - correction factor for the total glazing area of ​​the room

No matter how high-quality the windows are, it will still not be possible to completely avoid heat loss through them. But it is quite clear that it is impossible to compare a small window with panoramic glazing almost on the entire wall.

First you need to find the ratio of the areas of all the windows in the room and the room itself:

x = ∑SOK /SP

∑ SOK- the total area of ​​windows in the room;

SP- area of ​​the room.

Depending on the value obtained and the correction factor "j" is determined:

- x \u003d 0 ÷ 0.1 →j = 0,8 ;

- x \u003d 0.11 ÷ 0.2 →j = 0,9 ;

- x \u003d 0.21 ÷ 0.3 →j = 1,0 ;

- x \u003d 0.31 ÷ 0.4 →j = 1,1 ;

- x \u003d 0.41 ÷ 0.5 →j = 1,2 ;

• « k" - coefficient that corrects for the presence of an entrance door

The door to the street or to an unheated balcony is always an additional "loophole" for the cold

The door to the street or to an open balcony is able to make its own adjustments to the heat balance of the room - each of its opening is accompanied by the penetration of a considerable amount of cold air into the room. Therefore, it makes sense to take into account its presence - for this we introduce the coefficient "k", which we take equal to:

- no door k = 1,0 ;

- one door to the street or balcony: k = 1,3 ;

- two doors to the street or to the balcony: k = 1,7 .

• « l "- possible amendments to the connection diagram of heating radiators

Perhaps this will seem like an insignificant trifle to some, but still - why not immediately take into account the planned scheme for connecting heating radiators. The fact is that their heat transfer, and hence their participation in maintaining a certain temperature balance in the room, changes quite noticeably with different types of insertion of supply and return pipes.

Illustration	Radiator insert type	The value of the coefficient "l"
	Diagonal connection: supply from above, "return" from below	l = 1.0
	Connection on one side: supply from above, "return" from below	l = 1.03
	Two-way connection: both supply and return from the bottom	l = 1.13
	Diagonal connection: supply from below, "return" from above	l = 1.25
	Connection on one side: supply from below, "return" from above	l = 1.28
	One-way connection, both supply and return from below	l = 1.28

• « m "- correction factor for the features of the installation site of heating radiators

And finally, the last coefficient, which is also associated with the features of connecting heating radiators. It is probably clear that if the battery is installed openly, is not obstructed by anything from above and from the front, then it will give maximum heat transfer. However, such an installation is far from always possible - more often, radiators are partially hidden by window sills. Other options are also possible. In addition, some owners, trying to fit heating priors into the created interior ensemble, hide them completely or partially with decorative screens - this also significantly affects the heat output.

If there are certain “baskets” on how and where the radiators will be mounted, this can also be taken into account when making calculations by entering a special coefficient “m”:

So, there is clarity with the calculation formula. Surely, some of the readers will immediately take up their heads - they say, it's too complicated and cumbersome. However, if the matter is approached systematically, in an orderly manner, then there is no difficulty at all.

Any good homeowner must have a detailed graphical plan of their "possessions" with dimensions, and usually oriented to the cardinal points. It is not difficult to specify the climatic features of the region. It remains only to walk through all the rooms with a tape measure, to clarify some of the nuances for each room. Features of housing - "vertical neighborhood" from above and below, the location of the entrance doors, the proposed or existing scheme for installing heating radiators - no one except the owners knows better.

It is recommended to immediately draw up a worksheet, where you enter all the necessary data for each room. The result of the calculations will also be entered into it. Well, the calculations themselves will help to carry out the built-in calculator, in which all the coefficients and ratios mentioned above are already “laid”.

If some data could not be obtained, then, of course, they can not be taken into account, but in this case, the “default” calculator will calculate the result, taking into account the least favorable conditions.

It can be seen with an example. We have a house plan (taken completely arbitrary).

The region with the level of minimum temperatures in the range of -20 ÷ 25 °С. Predominance of winter winds = northeasterly. The house is one-story, with an insulated attic. Insulated floors on the ground. The optimal diagonal connection of radiators, which will be installed under the window sills, has been selected.

Let's create a table like this:

Then, using the calculator below, we make a calculation for each room (already taking into account a 10% reserve). With the recommended app, it won't take long. After that, it remains to sum the obtained values ​​\u200b\u200bfor each room - this will be the required total power of the heating system.

The result for each room, by the way, will help you choose the right number of heating radiators - it remains only to divide by the specific heat output of one section and round up.

In any heating system using a liquid heat carrier, its “heart” is the boiler. It is here that the energy potential of the fuel (solid, gaseous, liquid) or electricity is converted into heat, which is transferred to the coolant, and is already distributed to all heated rooms of the house or apartment. Naturally, the possibilities of any boiler are not unlimited, that is, they are limited by its technical and operational characteristics indicated in the product passport.

One of the key characteristics is the thermal power of the unit. Simply put, it must be able to produce in a unit of time such an amount of heat that would be sufficient to fully heat all the premises of a house or apartment. The selection of a suitable model "by eye" or according to some overly generalized concepts can lead to an error in one direction or another. Therefore, in this publication we will try to offer the reader, although not professional, but still with a sufficiently high degree of accuracy, an algorithm on how to calculate the boiler power for heating a house.

A banal question - why know the required boiler power

Despite the fact that the question does seem rhetorical, it still seems necessary to give a couple of explanations. The fact is that some owners of houses or apartments still manage to make mistakes, falling into one or another extreme. That is, purchasing equipment of either obviously insufficient thermal performance, in the hope of saving money, or greatly overestimated, so that, in their opinion, it is guaranteed, with a large margin, to provide themselves with heat in any situation.

Both of these are completely wrong, and negatively affect both the provision of comfortable living conditions and the durability of the equipment itself.

• Well, with the lack of calorific value, everything is more or less clear. With the onset of winter cold weather, the boiler will operate at its full capacity, and it is not a fact that there will be a comfortable microclimate in the rooms. This means that you will have to “catch up with heat” with the help of electric heaters, which will entail considerable extra costs. And the boiler itself, functioning at the limit of its capabilities, is unlikely to last long. In any case, after a year or two, homeowners clearly realize the need to replace the unit with a more powerful one. One way or another, the cost of a mistake is quite impressive.

• Well, why not buy a boiler with a large margin, what can prevent it? Yes, of course, high-quality space heating will be provided. But now we list the "cons" of this approach:

Firstly, a boiler of greater power can cost much more in itself, and it is difficult to call such a purchase rational.

Secondly, with increasing power, the dimensions and weight of the unit almost always increase. These are unnecessary installation difficulties, "stolen" space, which is especially important if the boiler is planned to be placed, for example, in the kitchen or in another room in the living area of ​​​​the house.

Thirdly, you may encounter uneconomical operation of the heating system - part of the energy spent will be spent, in fact, wasted.

Fourthly, excess power is regular long shutdowns of the boiler, which, in addition, are accompanied by cooling of the chimney and, accordingly, abundant formation of condensate.

Fifth, if powerful equipment is never properly loaded, it does not benefit him. Such a statement may seem paradoxical, but it is true - wear becomes higher, the duration of trouble-free operation is significantly reduced.

Prices for popular heating boilers

An excess of boiler power will be appropriate only if it is planned to connect a water heating system for household needs to it - an indirect heating boiler. Well, or when it is planned to expand the heating system in the future. For example, in the plans of the owners - the construction of a residential extension to the house.

Methods for calculating the required boiler power

In truth, it is always better to entrust the conduct of heat engineering calculations to specialists - there are too many nuances to take into account. But, it is clear that such services are not provided free of charge, so many owners prefer to take responsibility for choosing the parameters of boiler equipment.

Let's see what methods of calculating thermal power are most often offered on the Internet. But first, let's clarify the question of what exactly should affect this parameter. So it will be easier to understand the advantages and disadvantages of each of the proposed calculation methods.

What principles are key in making calculations

So, the heating system faces two main tasks. Let us immediately clarify that there is no clear division between them - on the contrary, there is a very close relationship.

• The first is the creation and maintenance of a comfortable temperature for living in the premises. Moreover, this level of heating should apply to the entire volume of the room. Of course, due to physical laws, temperature gradation in height is still inevitable, but it should not affect the feeling of comfort in the room. It turns out that it should be able to warm up a certain volume of air.

The degree of temperature comfort is, of course, a subjective value, that is, different people can evaluate it in their own way. But still, it is generally accepted that this indicator is in the region of +20 ÷ 22 ° С. Usually, it is precisely this temperature that is used during thermal engineering calculations.

This is also indicated by the standards established by the current GOST, SNiP and SanPiN. For example, the table below shows the requirements of GOST 30494-96:

• The second task is the constant compensation of possible heat losses. To create an “ideal” house in which there would be no heat leakage is a problem of problems, practically unsolvable. You can only reduce them to the ultimate minimum. And almost all elements of the building structure become leakage paths to one degree or another.

Why were all these rather lengthy explanations given? And only in order for the reader to have complete clarity that in the calculations, willy-nilly, it is necessary to take into account both directions. That is, the "geometry" of the heated premises of the house, and the approximate level of heat loss from them. And the amount of these heat leaks, in turn, depends on a number of factors. This is the temperature difference in the street and in the house, and the quality of thermal insulation, and the features of the whole house as a whole and the location of each of its premises, and other evaluation criteria.

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Now, armed with this preliminary knowledge, we turn to the consideration of various methods for calculating the required thermal power.

Calculation of power by the area of ​​heated premises

It is proposed to proceed from their conditional ratio, that for high-quality heating of one square meter of the area of ​​​​the room it is necessary to spend 100 W of thermal energy. Thus, it will help to calculate which:

Q=Stotal / 10

Q- the required thermal power of the heating system, expressed in kilowatts.

Stot- the total area of ​​the heated premises of the house, square meters.

However, there are caveats:

• The first - the ceiling height of the room should be on average 2.7 meters, a range of 2.5 to 3 meters is allowed.
• The second - you can make an adjustment for the region of residence, that is, take not a rigid norm of 100 W / m², but a “floating” one:

That is, the formula will take a slightly different form:

Q=Stot ×Qud / 1000

Qud - the value of the specific heat output per square meter taken from the table shown above.

• Third - the calculation is valid for houses or apartments with an average degree of insulation of enclosing structures.

However, despite the above reservations, such a calculation cannot be called accurate. Agree that it is largely based on the "geometry" of the house and its premises. But heat losses are practically not taken into account, except for the rather “blurred” ranges of specific thermal power by region (which are also with very vague boundaries), and remarks that the walls should have an average degree of insulation.

But be that as it may, this method is still popular, precisely for its simplicity.

It is clear that it is necessary to add the operating power reserve of the boiler to the calculated value obtained. It should not be excessively overestimated - experts advise stopping at a range of 10 to 20%. This, by the way, applies to all methods for calculating the power of heating equipment, which will be discussed below.

Calculation of the required heat output by the volume of the premises

By and large, this method of calculation largely repeats the previous one. True, the initial value here is no longer the area, but the volume - in fact, the same area, but multiplied by the height of the ceilings.

And the norms of specific thermal power here are accepted as follows:

• for brick houses - 34 W / m³;
• for panel houses - 41 W / m³.

Even based on the proposed values ​​(from their wording), it becomes clear that these norms were established for apartment buildings, and are mainly used to calculate the heat demand for premises connected to a central separation system or to an autonomous boiler station.

It is quite obvious that "geometry" is again put at the forefront. And the whole system for accounting for heat losses comes down only to differences in the thermal conductivity of brick and panel walls.

In a word, this approach to calculating thermal power also does not differ in accuracy.

Calculation algorithm taking into account the characteristics of the house and its individual premises

Description of the calculation method

So, the methods proposed above give only a general idea of ​​the required amount of thermal energy for heating a house or apartment. They have a common vulnerability - the almost complete disregard for possible heat losses, which are recommended to be considered "average".

But it is quite possible to carry out more precise calculations. This will help the proposed calculation algorithm, which is embodied, in addition, in the form of an online calculator, which will be proposed below. Just before starting the calculations, it makes sense to consider step by step the very principle of their implementation.

First of all, an important note. The proposed methodology involves the assessment not of the entire house or apartment in terms of total area or volume, but of each heated room separately. Agree that rooms of equal area, but differing, say, in the number of external walls, will require a different amount of heat. It is impossible to put an equal sign between rooms that have a significant difference in the number and area of ​​​​windows. And there are many such criteria for evaluating each of the rooms.

So it would be more correct to calculate the required power for each of the premises separately. Well, then a simple summation of the obtained values ​​\u200b\u200bwill lead us to the desired indicator of the total heat output for the entire heating system. That is, in fact, for its "heart" - the boiler.

One more note. The proposed algorithm does not claim to be "scientific", that is, it is not directly based on any specific formulas established by SNiP or other governing documents. However, it has been field tested and shows results with a high degree of accuracy. Differences with the results of professionally carried out heat engineering calculations are minimal, and do not affect the correct choice of equipment in terms of its rated thermal power.

The "architecture" of the calculation is as follows - the base value of the specific thermal power mentioned above is taken, equal to 100 W / m², and then a whole series of correction factors is introduced, to one degree or another reflecting the amount of heat loss in a particular room.

If this is expressed by a mathematical formula, then it will turn out something like this:

Qk= 0.1 × Sk× k1 × k2 × k3 × k4 × k5 × k6 × k7 × k8 × k9× k10 × k11

Qk- the desired thermal power required for the full heating of a particular room

0.1 - translation of 100 W into 0.1 kW, just for the convenience of obtaining the result in kilowatts.

Sk- area of ​​the room.

k1 hk11- correction factors for adjusting the result, taking into account the characteristics of the room.

With the determination of the area of ​​\u200b\u200bthe room, presumably, there should be no problems. So let's move on to a detailed discussion of the correction factors.

• k1 is a coefficient that takes into account the height of the ceilings in the room.

It is clear that the height of the ceilings directly affects the amount of air that the heating system must warm up. For the calculation, it is proposed to accept the following values ​​of the correction factor:

• k2 is a coefficient that takes into account the number of walls in the room that are in contact with the street.

The larger the area of ​​contact with the external environment, the higher the level of heat loss. Everyone knows that it is always much cooler in a corner room than in a room with only one outer wall. And some rooms of a house or apartment may even be internal, not having contact with the street.

According to the mind, of course, one should take not only the number of external walls, but also their area. But our calculation is still simplified, so we restrict ourselves only to the introduction of a correction factor.

The coefficients for various cases are shown in the table below:

The case when all four walls are external is not considered. This is no longer a residential building, but just some kind of barn.

• k3 is a coefficient that takes into account the position of the outer walls relative to the cardinal points.

Even in winter, you should not discount the possible impact of the energy of the sun's rays. On a clear day, they penetrate through the windows into the premises, thereby being included in the overall heat supply. In addition, the walls receive a charge of solar energy, which leads to a decrease in the total amount of heat loss through them. But all this is true only for those walls that "see" the Sun. There is no such influence on the north and northeast side of the house, which can also be corrected.

The values ​​​​of the correction factor for the cardinal points are in the table below:

• k4 is a coefficient that takes into account the direction of winter winds.

Perhaps this amendment is not mandatory, but for houses located in open areas, it makes sense to take it into account.

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In almost any area there is a predominance of winter winds - this is also called the "wind rose". Local meteorologists must have such a scheme - it is compiled based on the results of many years of weather observations. Quite often, the locals themselves are well aware of which winds most often disturb them in winter.

And if the wall of the room is located on the windward side, and is not protected by any natural or artificial barriers from the wind, then it will cool much more. That is, the heat loss of the room increases. To a lesser extent, this will be expressed near the wall located parallel to the direction of the wind, and to a minimum - located on the leeward side.

If there is no desire to "bother" with this factor, or there is no reliable information about the winter wind rose, then you can leave the coefficient equal to one. Or, on the contrary, take it to the maximum, just in case, that is, for the most unfavorable conditions.

The values ​​of this correction factor are in the table:

• k5 is a coefficient that takes into account the level of winter temperatures in the region of residence.

If heat engineering calculations are carried out in accordance with all the rules, then the assessment of heat losses is carried out taking into account the temperature difference in the room and on the street. It is clear that the colder the climatic conditions of the region, the more heat is required to be supplied to the heating system.

In our algorithm, this will also be taken into account to a certain extent, but with an acceptable simplification. Depending on the level of minimum winter temperatures falling on the coldest decade, a correction factor k5 is selected .

Here it would be appropriate to make one remark. The calculation will be correct if temperatures are taken into account, which are considered normal for a given region. There is no need to recall the anomalous frosts that happened, say, a few years ago (and that's why, by the way, they are remembered). That is, the lowest, but normal temperature for the area should be selected.

• k6 is a coefficient that takes into account the quality of the thermal insulation of the walls.

It is quite clear that the more efficient the wall insulation system, the lower the level of heat loss. Ideally, to which one should strive, thermal insulation in general should be complete, carried out on the basis of heat engineering calculations performed, taking into account the climatic conditions of the region and the design features of the house.

When calculating the required heat output of the heating system, the existing thermal insulation of the walls should also be taken into account. The following gradation of correction factors is proposed:

An insufficient degree of thermal insulation or its complete absence, in theory, should not be observed at all in a residential building. Otherwise, the heating system will be very expensive, and even without a guarantee of creating really comfortable living conditions.

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If the reader wishes to independently assess the level of thermal insulation of his home, he can use the information and calculator that are located in the last section of this publication.

• k7 andk8 - coefficients that take into account heat loss through the floor and ceiling.

The following two coefficients are similar - their introduction into the calculation takes into account the approximate level of heat loss through the floors and ceilings of the premises. There is no need to describe in detail here - both the possible options and the corresponding values ​​of these coefficients are shown in the tables:

To begin with, the coefficient k7, which corrects the result depending on the characteristics of the floor:

Now - the coefficient k8, which corrects for the neighborhood from above:

• k9 is a coefficient that takes into account the quality of the windows in the room.

Here, too, everything is simple - the better the windows, the less heat loss through them. Old wooden frames usually do not have good thermal insulation properties. This is better with modern window systems equipped with double-glazed windows. But they can also have a certain gradation - according to the number of cameras in a double-glazed window and according to other design features.

For our simplified calculation, the following values ​​of the coefficient k9 can be applied:

• k10 is a coefficient that corrects for the room's glazing area.

The quality of windows does not yet fully reveal all the volumes of possible heat loss through them. Glazing area is very important. Agree, it is difficult to compare a small window and a huge panoramic window almost the entire wall.

To make an adjustment for this parameter, first you need to calculate the so-called room glazing coefficient. It's easy - just find the ratio of the glazing area to the total area of ​​​​the room.

kw =sw/S

kw- coefficient of glazing of the room;

sw- total area of ​​glazed surfaces, m²;

S- room area, m².

Anyone can measure and sum the area of ​​windows. And then it is easy to find the desired glazing coefficient by simple division. And he, in turn, makes it possible to enter the table and determine the value of the correction factor k10 :

• k11 - coefficient taking into account the presence of doors to the street.

The last of the considered coefficients. The room may have a door leading directly to the street, to a cold balcony, to an unheated corridor or entrance, etc. Not only is the door itself often a very serious “cold bridge” - if it is opened regularly, a fair amount of cold air will enter the room each time. Therefore, this factor should also be corrected: such heat losses, of course, require additional compensation.

The values ​​of the coefficient k11 are given in the table:

This coefficient should be taken into account if the doors are regularly used in winter.

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* * * * * * *

So, all correction factors are considered. As you can see, there is nothing super complicated here, and you can safely proceed to the calculations.

One more tip before starting calculations. Everything will be much easier if you first draw up a table, in the first column of which you sequentially indicate all the rooms of the house or apartment to be soldered. Next, in columns, place the data that is required for calculations. For example, in the second column - the area of ​​\u200b\u200bthe room, in the third - the height of the ceilings, in the fourth - orientation to the cardinal points - and so on. It is not difficult to make such a plate, having in front of you a plan of your residential properties. It is clear that the calculated values ​​​​of the required heat output for each room will be entered in the last column.

The table can be compiled in an office application, or even simply drawn on a piece of paper. And do not rush to part with it after making the calculations - the obtained indicators of thermal power will still be useful, for example, when purchasing heating radiators or electric heaters used as a backup heat source.

To make it as easy as possible for the reader to carry out such calculations, a special online calculator is placed below. With it, with the initial data previously collected in a table, the calculation will take literally a few minutes.

Calculator for calculating the required heat output for the premises of a house or apartment.

Autonomous heating for a private house is affordable, comfortable and varied. You can install a gas boiler and not depend on the vagaries of nature or failures in the central heating system. The main thing is to choose the right equipment and calculate the heat output of the boiler. If the power exceeds the heat needs of the room, then the money for installing the unit will be thrown to the wind. In order for the heat supply system to be comfortable and financially profitable, at the design stage it is necessary to calculate the power of the gas heating boiler.

The main values ​​\u200b\u200bof calculating the heating power

The easiest way to get data on the heat output of the boiler by area of ​​​​the house: taken 1 kW of power for every 10 sq. m. However, this formula has serious errors, because it does not take into account modern building technologies, the type of terrain, climatic temperature changes, the level of thermal insulation, the use of double-glazed windows, and the like.

To make a more accurate calculation of the heating power of the boiler, you need to take into account a number of important factors that affect the final result:

• dimensions of the dwelling;
• the degree of insulation of the house;
• the presence of double-glazed windows;
• thermal insulation of walls;
• building type;
• air temperature outside the window during the coldest time of the year;
• type of wiring of the heating circuit;
• the ratio of the area of ​​\u200b\u200bbearing structures and openings;
• building heat loss.

In houses with forced ventilation, the calculation of the heating capacity of the boiler must take into account the amount of energy needed to heat the air. Experts advise making a gap of 20% when using the obtained result of the thermal power of the boiler in case of unforeseen situations, severe cooling or a decrease in gas pressure in the system.

With an unreasonable increase in thermal power, it is possible to reduce the efficiency of the heating unit, increase the cost of purchasing system elements, and lead to rapid wear of components. That is why it is so important to correctly calculate the power of the heating boiler and apply it to the specified dwelling. You can get data using a simple formula W=S*Wsp, where S is the area of ​​the house, W is the factory power of the boiler, Wsp is the specific power for calculations in a certain climatic zone, it can be adjusted according to the characteristics of the user's region. The result must be rounded up to a large value in terms of heat leakage in the house.

For those who do not want to waste time on mathematical calculations, you can use the gas boiler power calculator online. Just keep the individual data on the features of the room and get a ready answer.

The formula for obtaining the power of the heating system

The online heating boiler power calculator makes it possible in a matter of seconds to obtain the necessary result, taking into account all of the above characteristics that affect the final result of the data obtained. In order to use such a program correctly, it is necessary to enter the prepared data into the table: the type of window glazing, the level of thermal insulation of the walls, the ratio of floor and window opening areas, the average temperature outside the house, the number of side walls, the type and area of ​​​​the room. And then press the "Calculate" button and get the result of the heat loss and heat output of the boiler.

To ensure a comfortable temperature throughout the winter, the heating boiler must produce such an amount of heat energy that is necessary to replenish all the heat losses of the building / room. Plus, it is also necessary to have a small power reserve in case of abnormal cold weather or expansion of areas. We will talk about how to calculate the required power in this article.

To determine the performance of heating equipment, it is first necessary to determine the heat loss of the building / room. Such a calculation is called thermal engineering. This is one of the most complex calculations in the industry as there are many factors to consider.

Of course, the amount of heat loss is affected by the materials that were used in the construction of the house. Therefore, the building materials from which the foundation is made, walls, floor, ceiling, floors, attic, roof, window and door openings are taken into account. The type of system wiring and the presence of underfloor heating are taken into account. In some cases, even the presence of household appliances that generate heat during operation is considered. But such precision is not always required. There are techniques that allow you to quickly estimate the required performance of a heating boiler without plunging into the wilds of heat engineering.

Calculation of the heating boiler power by area

For an approximate assessment of the required performance of a thermal unit, the area of ​​\u200b\u200bthe premises is sufficient. In the simplest version for central Russia, it is believed that 1 kW of power can heat 10 m 2 of area. If you have a house with an area of ​​160m2, the boiler power for heating it is 16kW.

These calculations are approximate, because neither the height of the ceilings nor the climate are taken into account. For this, there are coefficients derived empirically, with the help of which appropriate adjustments are made.

The indicated rate - 1 kW per 10 m 2 is suitable for ceilings 2.5-2.7 m. If you have higher ceilings in the room, you need to calculate the coefficients and recalculate. To do this, divide the height of your premises by the standard 2.7 m and get a correction factor.

Calculating the power of a heating boiler by area - the easiest way

For example, the ceiling height is 3.2m. We consider the coefficient: 3.2m / 2.7m \u003d 1.18 rounded up, we get 1.2. It turns out that for heating a room of 160m 2 with a ceiling height of 3.2m, a heating boiler with a capacity of 16kW * 1.2 = 19.2kW is required. They usually round up, so 20kW.

To take into account climatic features, there are ready-made coefficients. For Russia they are:

• 1.5-2.0 for northern regions;
• 1.2-1.5 for regions near Moscow;
• 1.0-1.2 for the middle band;
• 0.7-0.9 for the southern regions.

If the house is located in the middle lane, just south of Moscow, a coefficient of 1.2 is applied (20kW * 1.2 \u003d 24kW), if in the south of Russia in the Krasnodar Territory, for example, a coefficient of 0.8, that is, less power is required (20kW * 0 ,8=16kW).

Calculation of heating and selection of a boiler is an important stage. Find the wrong power and you can get this result ...

These are the main factors to be considered. But the values ​​found are valid if the boiler will only work for heating. If you also need to heat water, you need to add 20-25% of the calculated figure. Then you need to add a "margin" for peak winter temperatures. That's another 10%. In total we get:

• For home heating and hot water in the middle lane 24kW + 20% = 28.8kW. Then the reserve for cold weather is 28.8 kW + 10% = 31.68 kW. We round up and get 32kW. When compared with the original figure of 16kW, the difference is two times.
• House in the Krasnodar Territory. We add power for heating hot water: 16kW + 20% = 19.2kW. Now the "reserve" for the cold is 19.2 + 10% \u003d 21.12 kW. Rounding up: 22kW. The difference is not so striking, but also quite decent.

It can be seen from the examples that it is necessary to take into account at least these values. But it is obvious that in calculating the power of the boiler for a house and an apartment, there should be a difference. You can go the same way and use coefficients for each factor. But there is an easier way that allows you to make corrections in one go.

When calculating a heating boiler for a house, a coefficient of 1.5 is applied. It takes into account the presence of heat loss through the roof, floor, foundation. It is valid with an average (normal) degree of wall insulation - laying in two bricks or building materials similar in characteristics.

For apartments, different rates apply. If there is a heated room (another apartment) on top, the coefficient is 0.7, if a heated attic is 0.9, if an unheated attic is 1.0. It is necessary to multiply the boiler power found by the method described above by one of these coefficients and get a fairly reliable value.

To demonstrate the progress of calculations, we will calculate the power of a gas heating boiler for an apartment of 65m 2 with 3m ceilings, which is located in central Russia.

1. We determine the required power by area: 65m 2 / 10m 2 \u003d 6.5 kW.
2. We make a correction for the region: 6.5 kW * 1.2 = 7.8 kW.
3. The boiler will heat the water, so we add 25% (we like it hotter) 7.8 kW * 1.25 = 9.75 kW.
4. We add 10% for cold: 7.95 kW * 1.1 = 10.725 kW.

Now we round the result and get: 11 kW.

The specified algorithm is valid for the selection of heating boilers for any type of fuel. The calculation of the power of an electric heating boiler will not differ in any way from the calculation of a solid fuel, gas or liquid fuel boiler. The main thing is the performance and efficiency of the boiler, and heat losses do not change depending on the type of boiler. The whole question is how to spend less energy. And this is the area of ​​\u200b\u200bwarming.

Boiler power for apartments

When calculating heating equipment for apartments, you can use the norms of SNiPa. The use of these standards is also called the calculation of boiler power by volume. SNiP sets the required amount of heat for heating one cubic meter of air in standard buildings:

• heating 1m 3 in a panel house requires 41W;
• in a brick house on m 3 there is 34W.

Knowing the area of ​​\u200b\u200bthe apartment and the height of the ceilings, you will find the volume, then, multiplying by the norm, you will find out the power of the boiler.

For example, let's calculate the required boiler power for rooms in a brick house with an area of ​​​​74m 2 with ceilings of 2.7m.

1. We calculate the volume: 74m 2 * 2.7m = 199.8m 3
2. We consider according to the norm how much heat will be needed: 199.8 * 34W = 6793W. Rounding up and converting to kilowatts, we get 7kW. This will be the required power that the thermal unit should produce.

It is easy to calculate the power for the same room, but already in a panel house: 199.8 * 41W = 8191W. In principle, in heating engineering they always round up, but you can take into account the glazing of your windows. If the windows have energy-saving double-glazed windows, you can round down. We believe that double-glazed windows are good and we get 8kW.

The choice of boiler power depends on the type of building - brick heating requires less heat than panel

Next, you need, as well as in the calculation for the house, to take into account the region and the need to prepare hot water. The correction for abnormal cold is also relevant. But in apartments, the location of the rooms and the number of storeys play a big role. You need to take into account the walls facing the street:

• One outer wall - 1.1
• Two - 1.2
• Three - 1.3

After you take into account all the coefficients, you will get a fairly accurate value that you can rely on when choosing equipment for heating. If you want to get an accurate heat engineering calculation, you need to order it from a specialized organization.

There is another method: to determine the real losses with the help of a thermal imager - a modern device that will also show the places through which heat leaks are more intense. At the same time, you can eliminate these problems and improve thermal insulation. And the third option is to use a calculator program that will calculate everything for you. You just need to select and / or enter the required data. At the output, get the estimated power of the boiler. True, there is a certain amount of risk here: it is not clear how correct the algorithms are at the heart of such a program. So you still have to at least roughly calculate to compare the results.

We hope you now have an idea of ​​​​how to calculate the power of the boiler. And it doesn’t confuse you that it is, and not solid fuel, or vice versa.

You may be interested in articles about and. In order to have a general idea of ​​​​the mistakes that are often encountered when planning a heating system, watch the video.