Battery capacity for 1 square meter. Calculation of heating radiators: options and methods

It is very important to buy modern high quality and efficient batteries. But it is much more important to correctly calculate the number of radiator sections so that in a cold season it properly warms up the room and does not have to think about installing additional portable heating devices that will increase the consumption of funds for heating.

SNiP and basic regulations

Today we can name a huge number of SNiPs, which describe the rules for the design and operation of heating systems in various rooms. But the most clear and simple is the document "Heating, ventilation and air conditioning" under the number 2.04.05.

It details the following sections:

General provisions for the design of heating systems
Building heating systems design rules
Features of the heating system

It is also necessary to install heating radiators in accordance with SNiP under the number 3.05.01... He prescribes the following installation rules, without which the calculations of the number of sections will be ineffective:

The maximum width of the radiator should not exceed 70% of the same characteristic of the window opening under which it is installed
The radiator must be mounted in the center of the window opening (a slight error is allowed - no more than 2 cm)
Recommended space between radiators and wall - 2-5 cm
Height above the floor should not be more than 12 cm
The distance to the windowsill from the top point of the battery is at least 5 cm
In other cases, to improve heat transfer, the surface of the walls is covered with a reflective material.

It is necessary to follow such rules so that air masses can freely circulate and replace each other.

Read also, different types of heating radiators

Volume calculation

In order to accurately calculate the number of heating radiator sections required for efficient and comfortable heating of a dwelling, its volume should be taken into account. The principle is quite simple:

We determine the need for heat
Find out the number of sections capable of giving it away

SNiP prescribes to take into account the need for heat for any room - 41 W per 1 cubic meter. However, this indicator is very relative. If the walls and floor are poorly insulated, it is recommended to increase this value to 47-50 W, because some of the heat will be lost. In situations where a high-quality heat insulator has already been laid on the surfaces, high-quality PVC windows have been installed and drafts have been eliminated - this indicator can be taken equal to 30-34 W.

If the room has heating, the heat demand must be increased up to 20%. Part of the heat heated air masses will not be passed by the screen, circulating inside and quickly cooling down.

Formulas for calculating the number of sections by the volume of the room, with an example

Having decided on the need for one cube, you can start calculating (an example with specific numbers):

At the first step, we calculate the volume of the room using a simple formula: [height length Width] (3x4x5 = 60 cubic meters)
The next step is to determine the heat demand for a particular room under consideration using the formula: [volume] * [demand per cubic meter] (60x41 = 2460 W)
You can determine the desired number of ribs using the formula: (2460/170=14.5)
It is recommended to round up - we get 15 sections

Many manufacturers do not take into account that the coolant circulating through the pipes is far from the maximum temperature. Consequently, the power of the ribs will be lower than the specified limit value (it is it that is prescribed in the passport). If there is no minimum power indicator, then the existing one is underestimated by 15-25% to simplify the calculations.

Area calculation

The previous calculation method is an excellent solution for rooms with a height of more than 2.7 m. In rooms with lower ceilings (up to 2.6 m), you can use another method, taking the area as a basis.

In this case, calculating the total amount of heat energy, the need for one square meter. m take equal to 100 watts. As long as it is not required to make any adjustments to it.

Formulas for calculating the number of sections by area of the room, with an example

At the first stage, the total area of the room is determined: [length Width] (5x4 = 20 sq. M.)
The next step is to determine the heat required to heat the entire room: [area] * [need per sq. m.] (100x20 = 2000 W)
In the passport attached to the heating radiator, you need to find out the power of one section - the average indicator of modern models is 170 W
To determine the required number of sections, use the formula: [total heat demand] / [capacity of one section] (2000/170=11.7)
We introduce correction factors ( considered further)
It is recommended to round up - we get 12 sections

The above methods for calculating the number of radiator sections are perfect for rooms whose height reaches 3 meters. If this indicator is higher, it is necessary to increase the heat output in direct proportion to the increase in height.

If the whole house is equipped with modern plastic windows, in which the heat loss coefficient is as low as possible, it becomes possible to save money and reduce the result obtained by up to 20%.

It is believed that the standard temperature of the coolant circulating through the heating system is 70 degrees. If it is below this value, it is necessary to increase the result by 15% for every 10 degrees. If it is higher, on the contrary, decrease it.

Premises with an area of more than 25 sq. m. to heat with one radiator, even consisting of two dozen sections, will be extremely problematic. To solve this problem, it is necessary to divide the calculated number of sections into two equal parts and install two batteries. Heat in this case will spread more evenly throughout the room.

If there are two window openings in the room, heating radiators must be placed under each of them. They should be 1.7 times more than the rated power, determined in the calculations.

Having bought stamped radiators, which cannot be divided into sections, it is necessary to take into account the total power of the product. If it is not enough, you should think about buying a second battery of the same or slightly less heat capacity.

Correction factors

Many factors can influence the final result. Let's consider in what situations it is necessary to introduce correction factors:

Windows with conventional glazing - magnification factor 1.27
Insufficient thermal insulation of the walls - increasing factor 1.27
More than two window openings per room - increasing factor 1.75
Headers with bottom wiring - multiplying factor 1.2
Reserve in case of unforeseen situations - increasing coefficient 1.2
The use of improved thermal insulation materials - reduction factor 0.85
Installation of high-quality insulating glass units - reduction factor 0.85

The number of corrections made to the calculation can be enormous and depends on each specific situation. However, it should be remembered that it is much easier to reduce the heat transfer of a heating radiator than to increase it. Therefore, all rounding is done upwards.

Summing up

If you need to make the most accurate calculation of the number of radiator sections in a complex room, do not be afraid to contact a specialist. The most accurate methods, which are described in special literature, take into account not only the volume or area of the room, but also the temperature outside and inside, the thermal conductivity of various materials from which the box of the house is built, and many other factors.

Of course, you can not be afraid and sketch out a few edges to the result. But an excessive increase in all indicators can lead to unjustified expenses, which are not immediately, sometimes not always possible to recoup.

Calculation of the number of heating radiator sections

Heating radiators are the most common heating device that is installed in residential, public and industrial premises. It consists of elements that are hollow inside and filled with a coolant. Through them, thermal energy enters the room to heat it. When choosing radiators, you must first of all pay attention to two technical indicators. This is the power of the device and the pressure of the coolant withstand it. But in order to finally determine the temperature regime of the room, it is necessary to carry out an accurate calculation of heating radiators.

This includes not only the number of devices themselves and their sections, but also the material from which they are made. The modern market for heating equipment offers a huge range of batteries with different technical characteristics. The main thing to know is the capabilities of one section of the battery, namely, its ability to release the maximum amount of thermal energy. This indicator will form the basis of the calculation for the entire heating system.

Let's make a calculation

Knowing that 100 watts of heat is needed per 1 square meter of room area, you can easily calculate the number of required radiators. Therefore, first you need to accurately determine the area of the room where the batteries will be installed.

The height of the ceilings, as well as the number of doors and windows, must be taken into account - after all, these are openings through which heat evaporates most quickly. Therefore, the material from which the doors and windows are made is also taken into account.

The lowest temperature in your area and the temperature of the heating medium at the same time are now determined. All nuances are calculated using the coefficients that are entered in the SNiP. Taking these factors into account, the heating power can also be calculated.

A quick calculation is done by simply multiplying the area of the room by 100 watts. But this will not be accurate. Coefficients are used for correction and.

Power correction factors

There are two of them: decreasing and increasing.

Derating factors are applied as follows:

If plastic multi-chamber double-glazed windows are installed on the windows, then the indicator is multiplied by 0.2.
If the ceiling height is less than the standard (3 m), then a reduction factor is applied. It is defined as the ratio of the actual height to the standard height. Example - the ceiling height is 2.7 m. This means that the coefficient is calculated using the formula: 2.7 / 3 = 0.9.
If the heating boiler operates with increased power, then every 10 degrees of the heat energy it generates, the power of the heating radiators is reduced by 15%.

Power increase factors are taken into account in the following situations:

If the ceiling height is higher than the standard size, then the coefficient is calculated using the same formula.
If the apartment is corner, then a factor of 1.8 is applied to increase the power of heating devices.
If the radiators have a bottom connection, then add 8% to the calculated value.
If the heating boiler lowers the temperature of the coolant on the coldest days, then for every 10 degrees of decrease, an increase in the power of the batteries by 17% is necessary.
If sometimes the temperature outside reaches critical levels, then you will have to double the heating power.

Determine the number of sections of one radiator

Equipment sections

Experts offer several options for calculating the number of heating radiators and their sections.

The first is the so-called ordinary way. It is the simplest one. Usually, technical parameters are set in the passport or quality certificate, which is issued as an accompanying document for each product. Here you can find information on what power one section of heating radiators has.

For example, it is equal to 200 watts. The power required to heat the room is calculated, taking into account the decreasing and increasing coefficients. Let's assume that it is equal to 2400 watts.

Now purely mathematical calculations are made: 2400/200 = 12. This is the number of sections that need to be installed in a given room. You can use one 12-cell battery or two 6-cell batteries.

The second option - a calculation is made taking into account the heating capacity of one section for a certain volume of space. For this, the total volume of the room is calculated and divided by the volumetric heating indicator of the section.

Heating equipment coloring

The third is an approximate calculation that masters use based on their personal experience. All radiators are practically the same size. There are differences, but minor ones. So it was noticed that with a ceiling height of 2.7 meters, one section can heat an area equal to 1.8 square meters.

There are no problems with the choice of heating radiators today. Here you have cast iron, and aluminum, and bimetallic - choose what you want. However, the very fact of buying expensive radiators of a special design is not a guarantee that your home will be warm. In this case, both quality and quantity play a role. Let's figure out how to correctly calculate heating radiators.

Calculation of the whole head - starting from the area

An incorrect calculation of the number of radiators can lead not only to a lack of heat in the room, but also to excessively high heating bills and too high temperatures in the rooms. The calculation should be made both during the very first installation of the radiators and when replacing the old system, where, it would seem, everything has been clear for a long time, since the heat transfer of radiators can differ significantly.

Different rooms - different calculations. For example, for an apartment in a multi-storey building, you can get by with the simplest formulas or ask your neighbors about their heating experience. In a large private house, simple formulas will not help - you will need to take into account many factors that are simply absent in city apartments, for example, the degree of house insulation.

The most important thing is not to trust the numbers voiced at random by all kinds of "consultants" who by eye (even without seeing the room!) Tell you the number of sections for heating. As a rule, it is significantly overestimated, which is why you will constantly overpay for excess heat, which will literally go through the open window. We recommend using several methods for calculating the number of radiators.

Simple formulas - for an apartment

Residents of multi-storey buildings can use fairly simple calculation methods that are completely inappropriate for a private house. The simplest calculation does not shine with high accuracy, but it is suitable for apartments with standard ceilings no higher than 2.6 m. Please note that a separate calculation of the number of sections is carried out for each room.

It is based on the statement that heating a square meter of a room requires 100 W of the radiator's thermal power. Accordingly, in order to calculate the amount of heat required for a room, we multiply its area by 100 W. So, for a room with an area of 25 m 2, it is necessary to purchase sections with a total power of 2500 W or 2.5 kW. Manufacturers always indicate the heat dissipation of the sections on the packaging, for example, 150 W. Surely you already figured out what to do next: 2500/150 = 16.6 sections

The result is rounded up, however, for the kitchen, you can round it down - in addition to batteries, there will also be a stove and a kettle to heat the air.

You should also take into account the possible heat loss depending on the location of the room. For example, if this is a room located at the corner of a building, then the thermal power of the batteries can be safely increased by 20% (17 * 1.2 = 20.4 sections), the same number of sections will be needed for a room with a balcony. Please note that if you intend to hide radiators in a niche or hide them behind a beautiful screen, then you will automatically lose up to 20% of the thermal power, which will have to be compensated for by the number of sections.

Calculations based on volume - what does SNiP say?

A more accurate number of sections can be calculated taking into account the height of the ceilings - this method is especially relevant for apartments with non-standard room heights, as well as for a private house as a preliminary calculation. In this case, we will determine the heat output based on the volume of the room. According to SNiP, 41 W of thermal energy is required to heat one cubic meter of living space in a standard multi-storey building. This standard value must be multiplied by the total volume that can be obtained, we multiply the height of the room by its area.

For example, the volume of a 25 m 2 room with 2.8 m ceilings is 70 m 3. We multiply this figure by the standard 41 W and get 2870 W. Then we act as in the previous example - we divide the total number of watts by the heat transfer of one section. So, if the heat transfer is 150 W, then the number of sections is approximately 19 (2870/150 = 19.1). By the way, be guided by the minimum heat transfer rates of radiators, because the temperature of the carrier in the pipes rarely meets the requirements of SNiP in our realities. That is, if the radiator data sheet indicates frames from 150 to 250 W, then by default we take the lower figure. If you yourself are responsible for heating a private house, then take the average.

Exact numbers for private houses - we take into account all the nuances

Private houses and large modern apartments do not fall under the standard calculations in any way - there are too many nuances to consider. In these cases, you can apply the most accurate calculation method, in which these nuances are taken into account. Actually, the formula itself is very simple - a student will cope with this, the main thing is to choose the right coefficients that take into account the characteristics of a house or apartment that affect the ability to save or lose thermal energy. So here's our exact formula:

CT = N * S * K 1 * K 2 * K 3 * K 4 * K 5 * K 6 * K 7
CT is the amount of thermal power in W that we need to heat a particular room;
N - 100 W / m2, the standard amount of heat per square meter, to which we will apply decreasing or increasing coefficients;
S is the area of the room for which we will calculate the number of sections.

The following coefficients have both the property of increasing the amount of thermal energy and decreasing, depending on the conditions of the room.

K 1 - we take into account the nature of the glazing of windows. If these are windows with ordinary double glazing, the coefficient is 1.27. Windows with double glazing - 1.0, with triple glazing - 0.85.
K 2 - we take into account the quality of wall insulation. For cold, non-insulated walls, this coefficient is 1.27 by default, for normal thermal insulation (laying in two bricks) - 1.0, for well-insulated walls - 0.85.
K 3 - we take into account the average air temperature at the peak of winter cold. So, for -10 ° C, the coefficient is 0.7. For every -5 ° C, add 0.2 to the coefficient. So, for -25 ° C, the coefficient will be 1.3.
K 4 - we take into account the ratio of the floor and the area of the windows. Starting from 10% (the coefficient is 0.8) for each next 10%, add 0.1 to the coefficient. So, for a ratio of 40%, the coefficient will be 1.1 (0.8 (10%) + 0.1 (20%) + 0.1 (30%) + 0.1 (40%)).
K 5 is a reduction factor that corrects the amount of heat energy taking into account the type of room located above. We take a cold attic per unit, if the attic is heated - 0.9, if the heated living space above the room is 0.8.
K 6 - adjust the result upward, taking into account the number of walls in contact with the surrounding atmosphere. If there is 1 wall - the coefficient is 1.1, if two - 1.2 and so on up to 1.4.
K 7 - and the last factor that corrects the calculations relative to the height of the ceilings. The height of 2.5 is taken as a unit, and for every half meter of height, 0.05 is added to the coefficient.Thus, for 3 meters, the coefficient is 1.05, for 4 - 1.15.

Thanks to this calculation, you will receive the amount of thermal energy that is necessary to maintain a comfortable living environment in a private house or non-standard apartment. It remains only to divide the finished result by the heat transfer value of your chosen radiators to determine the number of sections.

At first glance, it is easy to calculate how many radiator sections to install in a given room. The larger the room, the more sections the radiator should consist of. But in practice, how warm it will be in a particular room depends on more than a dozen factors. Taking them into account, it is possible to calculate the required amount of heat from radiators much more accurately.

General information

The heat transfer of one section of the radiator is indicated in the technical characteristics of products from any manufacturer. The number of radiators in a room usually corresponds to the number of windows. Most often, radiators are located under the windows. Their dimensions depend on the area of the free wall between the window and the floor. It should be borne in mind that the radiator must be lowered at least 10 cm from the window sill. And the distance between the floor and the lower line of the radiator must be at least 6 cm. These parameters determine the height of the device.

Heat transfer of one section of a cast-iron radiator is 140 watts, more modern metal ones - from 170 and above.

You can calculate the number of heating radiator sections , leaving the area of the room or its volume.

According to the norms, it is believed that heating one square meter of a room requires 100 watts of thermal energy. If we proceed from the volume, then the amount of heat per 1 cubic meter will be at least 41 watts.

But none of these methods will be accurate if you do not take into account the characteristics of a particular room, the number and size of windows, the material of the walls, and much more. Therefore, calculating the radiator sections using the standard formula, we will add the coefficients created by this or that condition.

Room area - calculation of the number of heating radiator sections

This calculation is usually applied to premises located in standard panel residential buildings with a ceiling height of up to 2.6 meters.

The area of the room is multiplied by 100 (the amount of heat for 1m2) and is divided by the heat transfer of one section of the radiator indicated by the manufacturer. For example: the area of the room is 22 m2, the heat transfer of one section of the radiator is 170 watts.

22X100 / 170 = 12.9

This room needs 13 radiator sections.

If one section of the radiator has 190 watts of heat transfer, then we get 22X100 / 180 = 11.57, that is, you can limit yourself to 12 sections.

You need to add 20% to the calculations if the room has a balcony or is located at the end of the house. A battery installed in a niche will reduce heat transfer by another 15%. But the kitchen will be 10-15% warmer.

We make calculations on the volume of the room

For a panel house with a standard ceiling height, as already mentioned above, the heat is calculated from the need for 41 watts per 1m3. But if the house is new, brick, double-glazed windows are installed in it, and the outer walls are insulated, then you need 34 watts per 1m3.

The formula for calculating the number of radiator sections looks like this: the volume (area multiplied by the ceiling height) is multiplied by 41 or 34 (depending on the type of house) and divided by the heat transfer of one radiator section specified in the manufacturer's passport.

For instance:

Room area 18 m2, ceiling height 2, 6 m. The house is a typical panel building. Heat transfer of one section of the radiator - 170 watts.

18X2.6X41 / 170 = 11.2. So, we need 11 radiator sections. This is provided that the room is not angular and does not have a balcony, otherwise it is better to install 12 sections.

We will calculate as accurately as possible

And here is the formula by which you can calculate the number of radiator sections as accurately as possible :

The area of the room is multiplied by 100 watts and by the coefficients q1, q2, q3, q4, q5, q6, q7 and divided by the heat transfer of one section of the radiator.

More about these ratios:

q1 - type of glazing : with a triple-glazed unit, the coefficient will be 0.85, with a double-glazed unit - 1 and with ordinary glazing - 1.27.

Correctly calculating the required number of sections is not difficult on the one hand, but nevertheless a very important task for any homeowner. It is on the correctness of the calculation that the comfort of staying in a home will depend, even in the most severe frosts. At the same time, an excessive number of mounted sections will lead to the need to artificially limit the supply of coolant to the heater during the entire winter period or, much worse, to open windows and heat the street, which is fraught with additional costs.

Standard calculation method for a heating radiator

The simplest calculation, often recommended by the sellers of this equipment, is based on generally accepted norms, according to which about 100 W of heating device power should be used to heat one square meter of the area of the room. This roughly corresponds, according to their own estimates, to one battery section per two square meters of the room.

This approach is overly simplistic. The choice of the number of radiator sections or its area is influenced by a number of different factors. First of all, it should be understood that heating batteries are selected not depending on the area in the room, but depending on its heat loss, which is determined by the presence of one or more windows, doors, the location of the room, incl. angular, as well as a number of other factors.

The thermal power of the section is the most important parameter

In addition, different types of heating devices have different heat outputs. For aluminum radiators, it can reach 185-200 W per section, while for cast-iron radiators it rarely exceeds 130 W. But in addition to the material of the sections, the parameter (DT), which takes into account the temperature of the coolant entering and leaving the battery, also strongly affects the thermal power. So, the high thermal power of the aluminum battery, corresponding to the passport of 180 W, is achieved at DT = 90/70, that is, the temperature of the incoming water should be 90 degrees, and the temperature of the outgoing water should be 70 degrees.

However, you need to understand that the operation of almost any boiler under such conditions is very rare. Wall-mounted boilers have a maximum temperature of 85 degrees, and while the coolant reaches the battery, the temperature value will drop even more. Therefore, even when buying aluminum batteries, one must proceed from the fact that the thermal power of the section will not exceed the value corresponding to DT = 70/55, i.e. about 120 watts.

What determines the heat loss of the room

So, the selection of the thermal power of heating devices is based on the magnitude of heat losses in order to be able to fully compensate them.

Factors affecting heat loss:

The place in which the room is located. This is either the south, or the north, or the central part of the country, for which the values of the minimum annual temperature are quite different.
How the room is located relative to the cardinal points. The presence of windows located both on the north and south sides greatly affects the heat loss of the room.
Ceiling height. In the case when the height in the building differs from the standard 2.5 meters, certain adjustments must also be made to the calculation.
Required temperature. Not all rooms need the same temperature. In the hall, for example, the temperature values may be slightly lower than in the bedroom, which is reflected in the calculation of the required power of heating devices.
The thickness of walls, ceilings, as well as their composition, the presence of thermal insulation, since the coefficient of thermal conductivity for different materials can vary greatly. For concrete, for example, the coefficient is maximum, and for heat-insulating foam - the minimum.
The presence of window openings, doors and their number. It is clear that the larger the area in the room, the stronger the heat loss will be in it, since it is through these openings that the main heat losses occur.
The presence of ventilation. This parameter cannot be ignored, even if it is absent in the room. The so-called infiltration is always present - from time to time windows open, visitors enter the room through the doors, etc.

Determine the required thermal power

However, it is possible to fully take into account all possible factors that increase or decrease heat losses using only rather complex calculation methods and professional software. In general, such calculations confirm that for a room in which no special work has been carried out aimed at improving energy efficiency, an indicator of 100 watts of radiator power per square meter is correct. This is true for the middle lane. For northern regions, the parameter should be increased to 150 or even 200 watts.

However, if during construction or repairs, floors were also carried out, there are energy-saving double-glazed windows in the window openings, then even in a harsh winter, the power of heating devices even at 70 W will be quite enough. This issue, of course, is not so important for the owners of apartments with central heating, but for the owners of private houses, reducing the required heat output will help save money during the year.

We calculate the number of battery sections

So, let's carry out a simple calculation of the number of sections of an aluminum battery required to heat a small room with an area of 15 square meters and a normal ceiling height. Let's take a value of 100 W per 1 sq. m as the required power of heating devices, and the rated power of one battery section is 120 W. Then the required number of sections can be determined by the formula:

N = S * Qп / Qн, where

N is the number of sections,
S is the area of the room,
Qп - the required heat output depending on the type of room,
Qн - rated thermal power of one section of the battery.

In our case, N = 15 * 100/120 = 12.5

Table: example of the number of radiator sections depending on the area of the room

However, it should be borne in mind that the thermal power of modern batteries, be it not only aluminum, but also bimetallic, depending on the design and manufacturer, can vary greatly, being in the range from 120 to 200 W. Accordingly, the number of sections will also be quite different.