Calculation of the heating system of a private house: formulas, reference data, examples. Calculation of the heating system in a private house Calculate the heating of a private house calculator online

For the climate of the middle zone, warmth in the house is an urgent need. The issue of heating in apartments is solved by district boiler houses, thermal power plants or thermal power plants. But what about the owner of a private dwelling? There is only one answer - the installation of heating equipment necessary for a comfortable stay in the house, it is also an autonomous heating system. In order not to get a pile of scrap metal as a result of the installation of a vital autonomous station, the design and installation should be taken scrupulously and with great responsibility.

The first step in the calculation is to calculate heat loss of the room. The ceiling, the floor, the number of windows, the material from which the walls are made, the presence of an interior or front door - all these are sources of heat loss.

Let's look at an example corner room with a volume of 24.3 cubic meters. m.:

Surface area calculations:

• external walls minus windows: S1 = (6 + 3) x 2.7 - 2 × 1.1 × 1.6 = 20.78 sq. m.
• windows: S2 \u003d 2 × 1.1 × 1.6 \u003d 3.52 sq. m.
• floor: S3 = 6×3=18 sq. m.
• ceiling: S4 = 6×3= 18 sq. m.

Now, having all the calculations of heat-releasing areas, Let's estimate the heat loss of each:

• Q1 \u003d S1 x 62 \u003d 20.78 × 62 \u003d 1289 W
• Q2= S2 x 135 = 3x135 = 405W
• Q3=S3 x 35 = 18×35 = 630W
• Q4 = S4 x 27 = 18x27 = 486W
• Q5=Q+ Q2+Q3+Q4=2810W

Total: the total heat loss of the room on the coldest days is 2.81 kW. This number is written with a minus sign and now we know how much heat needs to be supplied to the room for comfortable temperature in her.

Hydraulic calculation

Let's move on to the most complex and important hydraulic calculation - guaranteeing the efficient and reliable operation of the OS.

Units of calculation of the hydraulic system are:

• diameter pipeline in areas of the heating system;
• quantities pressure networks at different points;
• losses coolant pressure;
• hydraulic linkage all points in the system.

Before calculating, you must first select system configuration, type of pipeline and control / stop valves. Then decide on the type of heating devices and their location in the house. Draw up a drawing of an individual heating system indicating the numbers, the length of the calculated sections and thermal loads. In conclusion, identify main circulation ring, including alternate sections of the pipeline directed to the riser (with a single-pipe system) or to the most distant heating device (with a two-pipe system) and back to the heat source.

In any mode of operation of CO, it is necessary to ensure noiseless operation. In the absence of fixed supports and compensators on the mains and risers, mechanical noise occurs due to thermal elongation. The use of copper or steel pipes contributes to noise propagation throughout the heating system.

Due to the significant turbulence of the flow, which occurs with increased movement of the coolant in the pipeline and increased throttling of the water flow by the control valve, hydraulic noise. Therefore, taking into account the possibility of noise, it is necessary at all stages of hydraulic calculation and design - selection of pumps and heat exchangers, balance and control valves, analysis of temperature expansion of the pipeline - to choose the appropriate ones for the given initial conditions optimal equipment and fittings.

It is possible to make heating in a private house on your own. Possible options are presented in this article:

Pressure drops in CO

Hydraulic calculation includes available pressure drops at the input of the heating system:

• diameters of CO sections
• control valves that are installed on branches, risers and piping of heating devices;
• dividing, bypass and mixing valves;
• balance valves and their hydraulic settings.

When starting the heating system, the balance valves are adjusted to the circuit settings.

On the heating scheme, each of the heating devices is indicated, which is equal to the thermal design load of the room, Q4. If there is more than one device, it is necessary to divide the load between them.

Next, you need to define the main circulation ring. In a one-pipe system, the number of rings is equal to the number of risers, and in a two-pipe system, the number of heating devices. Balance valves are provided for each circulation ring, so the number of valves in a one-pipe system is equal to the number of vertical risers, and in a two-pipe system - the number of heating devices. In a two-pipe CO, balance valves are located on the return connection of the heating device.

The calculation of the circulation ring includes:

It is necessary to choose one of the two directions for calculating the hydraulics of the main circulation ring.

In the first direction of calculation, the diameter of the pipeline and the pressure loss in the circulation ring are determined by according to the set speed of water movement on each section of the main ring with subsequent selection of the circulation pump. The pump head Pn, Pa is determined depending on the type of heating system:

• for vertical bifilar and one-pipe systems: Рн = Pс. about. - Re
• for horizontal bifilar and one-pipe, two-pipe systems: Рн = Pс. about. - 0.4Re

• Pc.o- pressure loss in the main circulation ring, Pa;
• Re- natural circulation pressure, which occurs due to a decrease in the temperature of the coolant in the pipes of the ring and heating devices, Pa.

In horizontal pipes, the coolant velocity is taken from 0.25 m/s, to remove air from them. The optimal calculated movement of the coolant in steel pipes up to 0.5 m/s, polymer and copper - up to 0.7 m/s.

After calculating the main circulation ring, calculation of the remaining rings by determining the known pressure in them and selecting the diameters according to the approximate value of specific losses Rav.

The direction is used in systems with a local heat generator, in CO with dependent (with insufficient pressure at the input of the thermal system) or independent connection to thermal CO.

The second direction of calculation is to select the pipe diameter in the calculated sections and determine the pressure loss in the circulation ring. Calculated according to the initially set value of the circulation pressure. The diameters of the pipeline sections are selected according to the approximate value of the specific pressure loss Rav. This principle is used in the calculations of heating systems with dependent connection to heating networks, with natural circulation.

For the initial calculation parameter, you need to determine the magnitude of the existing circulation differential pressure PP, where PP in a system with natural circulation is equal to Pe, and in pump systems - on the type of heating system:

• in vertical single-pipe and bifilar systems: PР \u003d Рn + Re
• in horizontal single-pipe, two-pipe and bifilar systems: PР \u003d Рn + 0.4.Re

Projects of heating systems implemented in their homes are presented in this material:

Calculation of CO pipelines

The next task of calculating hydraulics is determination of the pipeline diameter. The calculation is made taking into account the circulation pressure set for a given CO and the heat load. It should be noted that in two-pipe COs with a water coolant, the main circulation ring is located in the lower heating device, which is more loaded and remote from the center of the riser.

According to the formula Rav = β*?pp/∑L; Pa/m we determine the average value per 1 meter of the pipe of the specific pressure loss due to friction Rav, Pa / m, where:

• β - coefficient taking into account the part of the pressure loss due to local resistances from the total amount of the calculated circulation pressure (for CO with artificial circulation β=0.65);
• pp- available pressure in the adopted CO, Pa;
• ∑L- the sum of the entire length of the calculated circulation ring, m.

Calculation of the number of radiators for water heating

Calculation formula

In creating a cozy atmosphere in the house with a water heating system radiators are a necessary element. The calculation takes into account the total volume of the house, the structure of the building, the material of the walls, the type of batteries and other factors.

For example: one cubic meter of a brick house with high-quality double-glazed windows will require 0.034 kW; from the panel - 0.041 kW; built according to all modern requirements - 0.020 kW.

We calculate as follows:

• determine room type and choose the type of radiators;
• multiply house area to the specified heat flow;
• divide the resulting number by heat flow index of one element(section) of the radiator and round the result up.

For example: room 6x4x2.5 m of a panel house (house heat flow 0.041 kW), room volume V = 6x4x2.5 = 60 cubic meters. m. the optimal amount of heat energy Q \u003d 60 × 0.041 \u003d 2.46 kW3, the number of sections N \u003d 2.46 / 0.16 \u003d 15.375 \u003d 16 sections.

Characteristics of radiators

Radiator type

Radiator type	Section power	Corrosive effect of oxygen	Ph limits	Corrosive effect of stray currents	Operating/test pressure	Warranty period (years)
cast iron	110	-	6.5 - 9.0	-	6−9 /12−15	10
Aluminum	175−199	-	7- 8	+	10−20 / 15−30	3−10
Tubular Steel	85	+	6.5 - 9.0	+	6−12 / 9−18.27	1
Bimetallic	199	+	6.5 - 9.0	+	35 / 57	3−10

Having correctly carried out the calculation and installation of high-quality components, you will provide your home with a reliable, efficient and durable individual heating system.

Video of hydraulic calculation

Coziness and comfort of housing do not begin with the choice of furniture, finishes and appearance in general. They start with the heat that heating provides. And just buying an expensive heating boiler () and high-quality radiators for this is not enough - you first need to design a system that will maintain the optimum temperature in the house. But to get a good result, you need to understand what and how to do, what are the nuances and how they affect the process. In this article, you will get acquainted with the basic knowledge about this case - what are heating systems, how it is carried out and what factors affect it.

Why is thermal calculation necessary?

Some owners of private houses or those who are just going to build them are interested in whether there is any point in the thermal calculation of the heating system? After all, we are talking about a simple country cottage, and not about an apartment building or an industrial enterprise. It would seem that it would be enough just to buy a boiler, install radiators and run pipes to them. On the one hand, they are partially right - for private households, the calculation of the heating system is not such a critical issue as for industrial premises or multi-apartment residential complexes. On the other hand, there are three reasons why such an event is worth holding. , you can read in our article.

1. Thermal calculation greatly simplifies the bureaucratic processes associated with the gasification of a private house.
2. Determining the power required for home heating allows you to select a heating boiler with optimal performance. You will not overpay for excessive product features and will not experience inconvenience due to the fact that the boiler is not powerful enough for your home.
3. Thermal calculation allows you to more accurately select pipes, valves and other equipment for the heating system of a private house. And in the end, all these rather expensive products will work for as long as is laid down in their design and characteristics.

Initial data for the thermal calculation of the heating system

Before you start calculating and working with data, you need to get them. Here, for those owners of country houses who have not previously been involved in design activities, the first problem arises - what characteristics should you pay attention to. For your convenience, they are summarized in a small list below.

1. Building area, height to ceilings and internal volume.
2. The type of building, the presence of adjacent buildings.
3. The materials used in the construction of the building - what and how the floor, walls and roof are made of.
4. The number of windows and doors, how they are equipped, how well they are insulated.
5. For what purposes will certain parts of the building be used - where the kitchen, bathroom, living room, bedrooms will be located, and where - non-residential and technical premises.
6. The duration of the heating season, the average minimum temperature during this period.
7. "Wind rose", the presence of other buildings nearby.
8. The area where a house has already been built or is just about to be built.
9. Preferred room temperature for residents.
10. Location of points for connection to water, gas and electricity.

Calculation of the heating system power by housing area

One of the fastest and easiest to understand ways to determine the power of a heating system is to calculate the area of ​​​​the room. A similar method is widely used by sellers of heating boilers and radiators. The calculation of the power of the heating system by area takes place in a few simple steps.

Step 1. According to the plan or already erected building, the internal area of ​​\u200b\u200bthe building in square meters is determined.

Step 2 The resulting figure is multiplied by 100-150 - that is how many watts of the total power of the heating system are needed for each m 2 of housing.

Step 3 Then the result is multiplied by 1.2 or 1.25 - this is necessary to create a power reserve so that the heating system is able to maintain a comfortable temperature in the house even in the most severe frosts.

Step 4 The final figure is calculated and recorded - the power of the heating system in watts, necessary to heat a particular housing. As an example, to maintain a comfortable temperature in a private house with an area of ​​120 m 2, approximately 15,000 W will be required.

Advice! In some cases, cottage owners divide the internal area of ​​\u200b\u200bhousing into that part that needs serious heating, and that for which this is unnecessary. Accordingly, different coefficients are applied for them - for example, for living rooms it is 100, and for technical rooms - 50-75.

Step 5 According to the already determined calculated data, a specific model of the heating boiler and radiators is selected.

It should be understood that the only advantage of this method of thermal calculation of the heating system is speed and simplicity. However, the method has many disadvantages.

1. Lack of consideration of the climate in the area where housing is being built - for Krasnodar, a heating system with a power of 100 W per square meter will be clearly redundant. And for the Far North, it may not be enough.
2. The lack of consideration of the height of the premises, the type of walls and floors from which they are built - all these characteristics seriously affect the level of possible heat losses and, consequently, the required power of the heating system for the house.
3. The very method of calculating the heating system in terms of power was originally developed for large industrial premises and apartment buildings. Therefore, for a separate cottage it is not correct.
4. Lack of accounting for the number of windows and doors facing the street, and yet each of these objects is a kind of "cold bridge".

So does it make sense to apply the calculation of the heating system by area? Yes, but only as a preliminary estimate, allowing you to get at least some idea of ​​the issue. To achieve better and more accurate results, you should turn to more complex techniques.

Imagine the following method for calculating the power of a heating system - it is also quite simple and understandable, but at the same time it has a higher accuracy of the final result. In this case, the basis for the calculations is not the area of ​​\u200b\u200bthe room, but its volume. In addition, the calculation takes into account the number of windows and doors in the building, the average level of frost outside. Let's imagine a small example of the application of this method - there is a house with a total area of ​​​​80 m 2, the rooms in which have a height of 3 m. The building is located in the Moscow region. In total there are 6 windows and 2 doors facing the outside. The calculation of the power of the thermal system will look like this. "How to do , you can read in our article".

Step 1. The volume of the building is determined. This can be the sum of each individual room or the total figure. In this case, the volume is calculated as follows - 80 * 3 \u003d 240 m 3.

Step 2 The number of windows and the number of doors facing the street are counted. Let's take the data from the example - 6 and 2, respectively.

Step 3 A coefficient is determined depending on the area in which the house stands and how severe frosts are there.

Table. Values ​​of regional coefficients for calculating the heating power by volume.

Since in the example we are talking about a house built in the Moscow region, the regional coefficient will have a value of 1.2.

Step 4 For detached private cottages, the value of the volume of the building determined in the first operation is multiplied by 60. We make the calculation - 240 * 60 = 14,400.

Step 5 Then the result of the calculation of the previous step is multiplied by the regional coefficient: 14,400 * 1.2 = 17,280.

Step 6 The number of windows in the house is multiplied by 100, the number of doors facing the outside by 200. The results are summed up. The calculations in the example look like this - 6*100 + 2*200 = 1000.

Step 7 The numbers obtained as a result of the fifth and sixth steps are summed up: 17,280 + 1000 = 18,280 W. This is the capacity of the heating system required to maintain the optimum temperature in the building under the conditions indicated above.

It should be understood that the calculation of the heating system by volume is also not absolutely accurate - the calculations do not pay attention to the material of the walls and floor of the building and their thermal insulation properties. Also, no adjustment is made for natural ventilation, which is inherent in any home.

The problem of providing heat does not arise only among residents of areas with "eternal summer". In our conditions, such a problem needs to be solved. The quality and efficiency of the installed system in the future depends on how accurately and competently the calculation of heating will be performed.

At the stage of circuit design, all possible options are considered and the optimal one is selected. Calculation methods are different and they are carried out taking into account the features of the selected system type.

What heating system is preferable?

In each case, there are reasons for choosing one or another type, and they all have the right to exist.

There are many advantages in space heating from electric heaters, underfloor heating, infrared radiation - environmental friendliness, noiselessness and combinatoriality with other schemes. But this type is considered to be highly costly in terms of energy source, therefore, in heating calculations, it is usually considered as an additional option.

Air heating is a rarity. Heating by means of stoves and fireplaces is reasonable in places where there are no problems with the supply of firewood or other heat carrier. Both of these types are also meant only as auxiliary to the main scheme.

The radiator-type water heating system is currently considered the most common, and it should be discussed thoroughly.

Stages of heating design

Regardless of the purpose of the object - a private house, office or a large manufacturing enterprise, a detailed project is required. A complete calculation of the heating system includes energy consumption calculations based on the area of ​​​​all rooms and their location on the site, the choice of fuel type with its storage location, boiler and other equipment.

Preparatory

It is best if the designers have construction drawings - this will speed up the work and ensure the accuracy of the data. At this stage, the energy needs are calculated (power and type of boiler, radiators), possible heat losses are determined. The optimal heat distribution scheme, system equipment, level of automation and control are selected.

First stage

A preliminary design is submitted to the customer for approval, which reflects the methods of communication wiring and placement of heating equipment. On its basis, an estimate is formed, modeling, hydraulic calculation of the heating system is carried out, and work begins on the creation of working drawings.

Development of a complete package of documents

The designer completes and draws up the project in accordance with the requirements of SNiP, which later makes it easy to coordinate the documentation with the relevant authorities. The project includes:

• initial data and sketches;
• costings;
• main drawings - floor plans and boiler room, axonometric diagrams, sections with detailing of nodes;
• an explanatory note with the rationale for the decisions made and calculated indicators in conjunction with other engineering systems, technical and operational characteristics of the facility, information on security measures;
• specification of equipment and materials.

The finished project is considered the key to the efficiency and practicality of heating, its trouble-free operation.

General principles and features of heating calculation

The type of system directly depends on the dimensions of the heated object, therefore, the calculation of heating by area is necessary. In buildings over 100 sq.m. a forced circulation scheme is arranged, because in this case a system with natural movement of heat flows is not appropriate due to its inertia.

As part of such a scheme, circulation pumps are provided. In this case, one important nuance must be taken into account: pumping equipment must be connected to the return line (from appliances to the boiler) to prevent contact of parts of the units with hot water.

The calculation work is based on the features of each applied scheme.

• In a two-pipe system, the numbering of the calculated zones starts from the heat generator (or ITP) with the designation of the points of all nodes on the supply line, risers and branches of the sections. The calculation takes into account sections of a fixed diameter with a constant flow rate of the coolant, based on the heat balance of the room.
• A single-pipe wiring diagram implies a similar approach with the determination of the sections of pipelines and risers by pressure.
• In the vertical system version, the designation of the numbers of risers (instrument branches) is done clockwise from the place at the top left point of the house.

The calculation of the hydraulics for heating a private house is one of the complex elements of designing a water system. It is on its basis that the balance of heat in the premises is determined, a decision is made on the system configuration, the type of heating batteries, pipes and valves is selected.

Heating boiler calculation

There is a simplified method that is used for a water system with standard components and a single-circuit boiler. The required generator power for a cottage is determined by multiplying the total volume of the house by the required amount of thermal energy per 1 mᵌ (for the European part of Russia, this figure is 40 W).

The specific power of the boiler, depending on the climatic zone, is generally accepted and is: for the Southern regions - less than 1.0 kW, in the Central - up to 1.5 kW, the Northern - up to 2.0 kW.

Heating radiators

The construction market now presents 3 of their constructive types: tubular, sectional and panel radiators. According to the material they are divided:

• on obsolete cast iron;
• lightweight aluminum with the fastest heating;
• steel - the most popular;
• bimetallic, designed to work under high pressure.

How is the calculation of heating radiators applied to the water system?

Method 1

Here the calculation principle is involved, based on the area of ​​\u200b\u200ba specific room and the power of one section. There is a certain guideline: the power of 100 watts of one radiator for fast and sufficient heating of 1 mᵌ of the room. This indicator is established by building codes and is used in formulas.

The selection of heaters using this method is carried out by simple mathematical operations: multiplying the area of ​​\u200b\u200bthe room by 100, followed by dividing by the power of one section of the battery. The last characteristic is taken from the technical data of a particular radiator.

As a result, it is easy to determine the number of sections of the device and the required number of batteries for the room. When calculating, windows should be taken into account, adding another 10% to the number of sections for each window opening.

Method 2

Based on an average height of 2.5 m for a typical living space and heating 1.8 m² of its area with one section. As a result of simply dividing the total area by the last indicator, a radiator with the required number of sections is obtained (with the fractional number rounded up).

Method 3

This is a kind of standard method for calculating heating radiators, based on averages and room volume. Namely: 1 section with a power of 200 W is required for conditional heating of 5 m² of room volume.

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A modern alternative to sectional batteries is panel radiators. To calculate their number, a method without clear data is used. Its essence is as follows: the accepted indicator of 40 W for heating 1 mᵌ of a room is multiplied by its area and height. The received power serves as a criterion for determining the number of batteries, based on the power characteristics of a particular model.

What to pay attention to

When designing systems, many important factors, both general and individual, are taken into account. Everything matters here: the climatic conditions of the location of the object, the temperature regime in the heating season, the materials of the walls and roof.

If additional thermal insulation is made in the room or warm window structures are installed in it, then this definitely reduces heat loss. Therefore, the calculation of space heating in this case is carried out with other coefficients. And vice versa: each external wall or a wide protruding window sill above the radiator can significantly change the calculated picture.

It is considered wrong to choose a battery based on the size of the window. If in doubt - to install one long device, or two small ones, then it is better to stop at the latter option. They will heat up faster and are considered a more economical solution.

If the devices are planned to be covered with panels (with slots or gratings), then 15% is added to the required power. The heat dissipation of the battery is little affected by its width and height, although the larger the metal surface, the better. But for the final conclusions, you still need to familiarize yourself with the technical characteristics of the model.

Convenient form - heating calculation calculator

All the above methods are not always subject to the ordinary consumer, as they require certain skills and knowledge, the ability to operate with all the initial and received data. A convenient calculator for calculating heating in the "online" mode is an opportunity to carry out all the calculation manipulations in just seconds.

In order to use it, engineering and technical training is not required. You need to enter several parameters for the object into the program, after which the functionality will give the necessary indicators with the cost of installation work.

Use our simple heating system calculator at the bottom of this page.

Finally

There are no particular difficulties in calculating heating systems - there are only nuances and features that have already been described. But the work must be done carefully, with skill and proper use of available information. Do not neglect the recommendations and help of specialists.

Payment for district heating services has become a significant item of expenditure for the family budget of apartment residents. Accordingly, the number of users who want to understand the difficult method of calculating payments for heat consumption has increased. We will try to give a clear explanation of how the payment for heating in a private and multi-apartment building is calculated in accordance with the current regulations and rules.

Which payment method to choose for calculation

Calculating the cost of hot and cold water indicated on the receipt of the utility company is quite simple: the readings of the apartment meter are multiplied by the approved tariff. This is not the case with heat - the calculation procedure depends on a number of factors:

• the presence or absence of a house heat energy meter;
• whether the heating of all premises without exception is taken into account by individual heat meters;
• how you have to pay - during the winter period or all year round, including summer.

Note. The decision on payment for heating in the summer is made by the local authority. In the Russian Federation, a change in the accrual method is approved by the state governing body (according to Decree No. 603). In other countries of the former USSR, the issue can be resolved in other ways.

The legislation of the Russian Federation (Housing Code, Rules No. 354 and new Decree No. 603) allows you to calculate the amount of payment for heating in five different ways, depending on the factors listed above. To understand how the payment amount is calculated in a particular case, select your option from the options below:

1. The apartment building is not equipped with metering devices, payment for heat is charged during the period of the service.
2. The same, but heat supply is paid evenly throughout the year.
3. In a residential apartment building, a collective meter is installed at the input, the fee is charged during the heating period. Individual devices may be installed in apartments, but their readings are not taken into account until the heat meters register the heating of all rooms without exception.
4. The same, with the use of year-round payments.
5. All premises - residential and technical - are equipped with metering devices, plus there is a common house meter of consumed heat energy at the input. There are 2 payment methods - year-round and seasonal.

Comment. Residents of Ukraine and the Republic of Belarus will certainly find suitable options among them that comply with the laws of these countries.

The scheme reflects the existing charging options for the district heating service

The installation of apartment heat meters and the benefits of such accounting are described. Here we propose to consider each technique separately in order to clarify the solution of the problem as much as possible.

Option 1 - we pay without heat meters during the heating season

The essence of the methodology is simple: the amount of heat consumed and the amount of payment is calculated according to the total area of ​​​​the dwelling, taking into account the quadrature of all rooms and utility rooms. How much does heating an apartment cost in this case is determined by the formula:

• P is the amount to be paid;
• S - total area (indicated in the technical passport of the apartment or private house), m²;
• N - the rate of heat allocated for heating 1 square meter of area during a calendar month, Gcal / m²;

For reference. Tariffs for utility services for the population are set by government agencies. The heating price takes into account the cost of heat production and the maintenance of centralized systems (repair and maintenance of pipelines, pumps and other equipment). Specific norms of heat (N) are established by a special commission depending on the climate separately in each region.

To make the calculation correctly, ask the office of the service provider the value of the established tariff and the standard of heat per unit area. The above formula allows you to calculate the cost of 1 sq.m of heating an apartment or a private house connected to a centralized network (substitute the number 1 instead of S).

Calculation example. Heat is supplied to a one-room apartment of 36 m² by the supplier at a rate of 1,700 rubles/Gcal. The consumption rate is approved at 0.025 Gcal/m². The price of heating as part of the rent for 1 month is calculated as follows:

P \u003d 36 x 0.025 x 1700 \u003d 1530 rubles.

An important point. The above methodology is valid on the territory of the Russian Federation and is valid for buildings where it is impossible to install general house heat meters for technical reasons. If the meter can be supplied, but the installation and registration of the unit was not completed before 2017, then a multiplying factor of 1.5 is added to the formula:

The increase in the cost of heating by one and a half times, provided for by Decree No. 603, is also applied in the following cases:

• the house-wide heat energy metering unit put into operation failed and was not repaired within 2 months;
• the heat meter is stolen or damaged;
• the readings of the house appliance are not transferred to the heat supply organization;
• the admission of the organization's specialists to the house meter in order to check the technical condition of the equipment (2 visits or more) is not provided.

Option 2 - year-round accrual without metering devices

If you are obliged to pay for heat supply evenly throughout the year, and there is no metering unit installed at the entrance to the apartment building, then the formula for calculating heat energy takes the following form:

The decoding of the parameters involved in the formula is given in the previous section: S is the area of ​​the dwelling, N is the standard for heat consumption per 1 m², T is the price of 1 Gcal of energy. The coefficient K remains, showing the frequency of making payments during the calendar year. The value of the coefficient is calculated simply - the number of months of the heating period (including incomplete ones) is divided by the number of months in a year - 12.

As an example, consider the same one-room apartment with an area of ​​36 m². First, we determine the periodicity coefficient with a heating season duration of 7 months: K = 7 / 12 = 0.583. Then we substitute it into the formula along with other parameters: P \u003d 36 x (0.025 x 0.583) x 1700 \u003d 892 rubles. pay monthly for a calendar year.

If your house is not equipped with a heat meter without documented reasons, then the formula is supplemented with a multiplying factor of 1.5:

Then the payment for heating the apartment in question will be 892 x 1.5 = 1338 rubles.

Note. In case of switching to another method of payment for heating utility services (from year-round to seasonal and vice versa), the supplier organization makes an adjustment - recalculation of monthly payments.

Option 3 - payment for a common house meter during the cold period

This method is used to calculate the payment for central heating services in multi-apartment buildings where there is a common house meter, and only a part of the apartments are equipped with individual heat meters. Since thermal energy is supplied to heat the entire building, the calculation is still made through the area, and the readings of individual devices are not taken into account.

• P - amount payable per month;
• S is the area of ​​a particular apartment, m²;
• Stot is the area of ​​all heated premises of the building, m²;
• V is the total amount of heat consumed according to the readings of the collective meter during the calendar month, Gcal;
• T - tariff - the price of 1 Gcal of thermal energy.

If you want to independently determine the amount of payment in this way, you will have to find the values ​​​​of 3 parameters: the area of ​​\u200b\u200ball residential and non-residential rooms in an apartment building, the readings of the meter at the input of the heat main, and the value of the tariff established in your area.

This is how the heat consumption recorder for an apartment building looks like

Calculation example. Initial data:

• square footage of a particular apartment - 36 m²;
• square of all premises of the house - 5000 m²;
• the amount of thermal energy consumed in 1 month is 130 Gcal;
• the rate of 1 Gcal in the region of residence is 1700 rubles.

The amount of payment for the accounting month will be:

P \u003d 130 x 36 / 5000 x 1700 \u003d 1591 rubles.

What is the essence of the method: through the quadrature of the dwelling, your share of payment for the heat consumed by the building for the billing period (usually 1 month) is determined.

Option 4 - accruals by metering device, broken down for the whole year

This is the most difficult way for the user to calculate. The order of calculation looks like this:

Here Rgod and Rkv are the sums of last year's charges for the introductory heat meter for the entire building and a specific apartment, respectively, Rp is the amount of the adjustment.

Let's give an example of calculations for our one-room apartment, given that last year the common house heat meter counted 650 Gcal:

Vav = 650 Gcal / 12 calendar months / 5000 m² = 0.01 Gcal. Now we calculate the payment amount:

P \u003d 36 x 0.01 x 1700 \u003d 612 rubles.

Note. The main problem is not the complexity of the calculations, but the search for initial data. The owner of the apartment, who wants to check the correctness of the calculation of payment, must find out last year's readings of the common house meter or fix them in advance.

In addition, you need to perform an annual adjustment with reference to new meter readings. Suppose the annual heat consumption of the building has increased to 700 Gcal, then the increase in the heating payment should be determined as follows:

1. We consider the total amount of payment for the past year according to the tariff: Рyear \u003d 700 x 1700 \u003d 1,190,000 rubles.
2. The same for our apartment: Rkv = 612 rubles. x 12 months = 7344 rubles.
3. The amount of the surcharge will be: Rp \u003d 1190000 x 36 / 5000 - 7344 \u003d 1224 rubles. The specified amount will be credited to you next year, after recalculation.

If the consumption of thermal energy decreases, then the result of the adjustment calculation will turn out with a minus sign - the organization must reduce the amount of payment by this amount.

Option 5 - heat meters are installed in all rooms

When a collective meter is installed at the entrance to an apartment building, plus individual heat metering is organized in all rooms, payment during the heating season is determined according to the following algorithm:

Why such difficulties? The answer is simple: a priori, the readings of a good hundred individual devices cannot coincide with the data of a common meter due to errors and unaccounted for losses. Therefore, the difference is divided among all apartment owners in shares corresponding to the area of ​​dwellings.

Deciphering the parameters involved in the calculation formulas:

• P is the required payment amount;
• S - the square of your apartment, m²;
• Stot - the area of ​​​​all rooms, m²;
• V is the heat consumption recorded by the collective meter for the billing period, Gcal;
• Vpom - heat consumed during the same period, shown by your apartment meter;
• Vp - the difference between the costs shown by the house metering unit and a group of other devices located in non-residential and residential premises;
• T is the cost of 1 Gcal of heat (tariff).

As an example of calculation, let's take our apartment of 36 m² and assume that for a month an individual meter (or a group of individual meters) "twisted" 0.6, a brownie - 130, and a group of devices in all rooms of the building gave a total of 118 Gcal. The remaining indicators remain the same (see previous sections). How much does heating cost in this case:

1. Vp \u003d 130 - 118 \u003d 12 Gcal (the difference in readings was determined).
2. P \u003d (0.6 + 12 x 36 / 5000) x 1700 \u003d 1166.88 rubles.

When it is required to calculate the value of the year-round payment for heating, an identical formula is applied. Only indicators of thermal energy consumption are used monthly averages taken over the past year. Accordingly, the charge for consumed energy is adjusted annually.

Why do residents of neighboring houses pay different amounts for heat?

This problem arose along with the introduction of various payment methods - by quadrature (standard), by a common meter or by individual heat meters. If you've looked at the previous sections of the post, you've probably noticed the difference in monthly fees. The fact is explained quite simply: if there are measuring devices, residents pay for the resource actually used.

Now we list the reasons why apartment owners receive payments with different amounts, regardless of the heat meters installed in the houses:

1. Two neighboring buildings are heated by different heat supply organizations, for which different tariffs are approved.
2. The more apartments in the house, the less you can pay. Increased heat losses are observed in the corner rooms and dwellings of the last floor, the rest border on the street only through 1 outer wall. And such apartments are the vast majority.
3. One counter at the entrance to the house is not enough. A flow regulator is required - manual or automatic. The fittings allow you to limit the supply of too hot coolant, which is a sin for heat supply organizations. And then they charge a corresponding fee for the service.
4. An important role is played by the competence of the management chosen by the co-owners of the apartment building. A competent business executive will solve the issue of accounting and regulating the coolant in the first place.
5. Uneconomical use of hot water heated by a heat carrier from a centralized network.
6. Problems with metering devices from different manufacturers.

Final Conclusion

There are many reasons for high heating bills. Obvious: a building with thick brick walls loses less heat than reinforced concrete "nine-story buildings". Hence the increased energy consumption, recorded by the meter.

But before undertaking the modernization (insulation) of the building, it is important to establish control and accounting - to install heat meters in all rooms and on the supply line. The calculation method shows that such technical solutions give the best result.

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:

Purpose of the room	Air temperature, °С		Relative humidity, %		Air speed, m/s
	optimal	admissible	optimal	admissible, max	optimal, max	admissible, max
For the cold season
Living room	20÷22	18÷24 (20÷24)	45÷30	60	0.15	0.2
The same, but for living rooms in regions with minimum temperatures from -31 ° C and below	21÷23	20÷24 (22÷24)	45÷30	60	0.15	0.2
Kitchen	19:21	18:26	N/N	N/N	0.15	0.2
Toilet	19:21	18:26	N/N	N/N	0.15	0.2
Bathroom, combined bathroom	24÷26	18:26	N/N	N/N	0.15	0.2
Premises for rest and study	20÷22	18:24	45÷30	60	0.15	0.2
Inter-apartment corridor	18:20	16:22	45÷30	60	N/N	N/N
lobby, stairwell	16÷18	14:20	N/N	N/N	N/N	N/N
Storerooms	16÷18	12÷22	N/N	N/N	N/N	N/N
For the warm season (The standard is only for residential premises. For the rest - it is not standardized)
Living room	22÷25	20÷28	60÷30	65	0.2	0.3

• 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:

Building element	Approximate value of heat loss
Foundation, floors on the ground or over unheated basement (basement) premises	from 5 to 10%
"Cold bridges" through poorly insulated joints of building structures	from 5 to 10%
Engineering communications entry points (sewerage, water supply, gas pipes, electrical cables, etc.)	up to 5%
External walls, depending on the degree of insulation	from 20 to 30%
Poor quality windows and exterior doors	about 20÷25%, of which about 10% - through non-sealed joints between the boxes and the wall, and due to ventilation
Roof	up to 20%
Ventilation and chimney	up to 25 ÷30%

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 over 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 for each heated room is calculated, 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 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 is facing south receives some heating 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 side.

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 perfectly 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 opening of it 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 part, 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”:

Illustration	Features of installing radiators	The value of the coefficient "m"
	The radiator is located on the wall openly or is not covered from above by a window sill	m = 0.9
	The radiator is covered from above by a window sill or a shelf	m = 1.0
	The radiator is blocked from above by a protruding wall niche	m = 1.07
	The radiator is covered from above with a window sill (niche), and from the front - with a decorative screen	m = 1.12
	The radiator is completely enclosed in a decorative casing	m = 1.2

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:

The room, its area, ceiling height. Floor insulation and "neighborhood" from above and below	The number of external walls and their main location relative to the cardinal points and the "wind rose". Degree of wall insulation	Number, type and size of windows	Existence of entrance doors (to the street or to the balcony)	Required heat output (including 10% reserve)
Area 78.5 m²				10.87 kW ≈ 11 kW
1. Hallway. 3.18 m². Ceiling 2.8 m. Warmed floor on the ground. Above is an insulated attic.	One, South, the average degree of insulation. Leeward side	Not	One	0.52 kW
2. Hall. 6.2 m². Ceiling 2.9 m. Insulated floor on the ground. Above - insulated attic	Not	Not	Not	0.62 kW
3. Kitchen-dining room. 14.9 m². Ceiling 2.9 m. Well insulated floor on the ground. Svehu - insulated attic	Two. South, west. Average degree of insulation. Leeward side	Two, single-chamber double-glazed window, 1200 × 900 mm	Not	2.22 kW
4. Children's room. 18.3 m². Ceiling 2.8 m. Well insulated floor on the ground. Above - insulated attic	Two, North - West. High degree of insulation. windward	Two, double glazing, 1400 × 1000 mm	Not	2.6 kW
5. Bedroom. 13.8 m². Ceiling 2.8 m. Well insulated floor on the ground. Above - insulated attic	Two, North, East. High degree of insulation. windward side	One, double-glazed window, 1400 × 1000 mm	Not	1.73 kW
6. Living room. 18.0 m². Ceiling 2.8 m. Well insulated floor. Top - insulated attic	Two, East, South. High degree of insulation. Parallel to wind direction	Four, double glazing, 1500 × 1200 mm	Not	2.59 kW
7. Bathroom combined. 4.12 m². Ceiling 2.8 m. Well insulated floor. Above is an insulated attic.	One, North. High degree of insulation. windward side	One. Wooden frame with double glazing. 400 × 500 mm	Not	0.59 kW
TOTAL:

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 up the obtained values ​​​​for 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.