How to calculate the number of heating radiators?

How to calculate radiator sections by room volume

With this calculation, not only the area is taken into account, but also the height of the ceilings, because all the air in the room needs to be heated. So this approach is justified. And in this case, the technique is similar. We determine the volume of the room, and then, according to the norms, we find out how much heat is needed to heat it:

• in a panel house, 41W is required to heat a cubic meter of air;
• in a brick house for m 3 - 34W.

You need to heat the entire volume of air in the room, therefore it is more correct to count the number of radiators by volume

Let's calculate everything for the same room with an area of ​​16m 2 and compare the results. Let the ceiling height be 2.7m. Volume: 16 * 2.7 = 43.2m 3.

Next, let's calculate for options in a panel and brick house:

• In a panel house. Heat required for heating 43.2m 3 * 41V = 1771.2W. If we take all the same sections with a power of 170W, we get: 1771W / 170W = 10.418 pieces (11 pieces).
• In a brick house. Heat is needed 43.2m 3 * 34W = 1468.8W. We count radiators: 1468.8W / 170W = 8.64pcs (9pcs).

As you can see, the difference turns out to be quite large: 11 pieces and 9 pieces. Moreover, when calculating by area, an average value was obtained (if rounded in the same direction) - 10 pcs.

Additional conditions taken into account in the calculations

There are a large number of additional indicators that are taken into account when making calculations. We have already considered some of them above, and we will consider another, implying additional conditions, below. These include the following:

1. If the room is equipped with a balcony, 20% is added to the result.
2. If there are two window openings in the room, the result is increased by 30%.
3. High quality and well installed insulating glass units reduce the value by 10-15%.
4. If you plan to install a grill or some kind of decor, the indicator increases by 10-15%.
5. To obtain a certain margin of power, which can be useful when the temperature of the region drops below the average, a certain margin is provided. Accordingly, the obtained value must be increased by 15%.
6. The heat carrier does not always have the temperature specified by the standard. Sometimes it is 10-15 degrees cooler. Therefore, the power of the radiator must be increased by 18-23%.

Bimetallic radiator with diagonal connection

As you already understood, calculating the required number of radiators is quite a responsible and serious issue that requires a serious approach. Based on this, it is recommended to make an accurate calculation taking into account all the above components and some correction factors.

How to take effective power into account

When determining the parameters of the heating system or its individual circuit, one of the most important parameters, namely the thermal head, should not be discounted. It often happens that the calculations are performed correctly, and the boiler heats well, but somehow it does not work out with the heat in the house. One of the reasons for the decrease in thermal efficiency may be the temperature regime of the coolant. The thing is that most manufacturers indicate the power value for a head of 60 ° C, which takes place in high-temperature systems with a coolant temperature of 80-90 ° C. In practice, it often turns out that the temperature in the heating circuits is in the range of 40-70 ° C, which means that the value of the temperature head does not rise above 30-50 ° C. For this reason, the heat transfer values ​​obtained in the previous sections should be multiplied by the real head, and then the resulting number should be divided by the value indicated by the manufacturer in the data sheet. Of course, the figure obtained as a result of these calculations will be lower than that which was obtained when calculating according to the above formulas.

It remains to calculate the real temperature head. It can be found in tables in the vastness of the Network, or calculated independently using the formula ΔT = ½ x (Tn + Tk) - Tvn). In it, Тн is the initial temperature of the water at the inlet to the battery, Тк is the final temperature of the water at the outlet from the radiator, Тн is the temperature of the external environment.If we substitute in this formula the values ​​of Тн = 90 ° С (high-temperature heating system, which was mentioned above), Тк = 70 ° С and Тн = 20 ° С (room temperature), then it is easy to understand why the manufacturer focuses on this value of the thermal pressure ... Substituting these numbers in the formula for ΔT, we just get the "standard" value of 60 ° C.

Taking into account not the passport, but the real power of the heating equipment, it is possible to calculate the parameters of the system with an acceptable error. All that remains to be done is to make an amendment of 10-15% in case of abnormally low temperatures and to provide for the possibility of manual or automatic adjustment in the design of the heating system. In the first case, experts recommend putting ball valves on the bypass and the coolant supply line to the radiator, and in the second, installing thermostatic heads on the radiators. They will allow you to set the most comfortable temperature in each room, without letting heat out into the street.

Calculation of different types of radiators

If you are going to install sectional radiators of a standard size (with an axial distance of 50 cm in height) and have already chosen the material, model and the required size, there should be no difficulty in calculating their number. Most reputable companies supplying good heating equipment have technical data for all modifications on their website, including heat output. If not the power is indicated, but the flow rate of the coolant, then it is simple to translate into power: the flow rate of the coolant in 1l / min is approximately equal to the power of 1 kW (1000W).

The axial distance of the radiator is determined by the height between the centers of the holes for supplying / removing the coolant

To make life easier for buyers, a specially designed calculator program is installed on many sites. Then the calculation of heating radiator sections is reduced to entering data on your room in the appropriate fields. And at the output you have the finished result: the number of sections of this model in pieces.

The axial distance is determined between the centers of the holes for the coolant

But if you are just thinking about possible options, then it is worth considering that radiators of the same size from different materials have different thermal power. Methodology for calculating the number of sections bimetallic radiators from the calculation of aluminum, steel or cast iron is no different. Only the heat output of one section can be different.

To make it easier to read, there is averaged data by which you can navigate. For one section of a radiator with an axial distance of 50 cm, the following power values ​​are adopted:

• aluminum - 190W
• bimetallic - 185W
• cast iron - 145W.

If you are just wondering which of the materials to choose, you can use this data. For clarity, we present the simplest calculation of sections of bimetallic heating radiators, which takes into account only the area of ​​the room.

When determining the number of heating devices made of bimetal of standard size (center distance 50cm), it is assumed that one section can heat 1.8m 2 of area. Then for a room of 16m 2 you need: 16m 2 / 1.8m 2 = 8.88 pcs. Rounding up - we need 9 sections.

We consider the same for cast iron or steel barriers. We only need norms:

• bimetallic radiator - 1.8m 2
• aluminum - 1.9-2.0m 2
• cast iron - 1.4-1.5m 2.

This data is for sections with a center distance of 50cm. Today, there are models on sale with very different heights: from 60cm to 20cm and even lower. Models 20cm and below are called curbs. Naturally, their capacity differs from the specified standard, and if you plan to use a "non-standard", you will have to make adjustments. Either look for passport data, or count yourself. We proceed from the fact that the heat transfer of a thermal device directly depends on its area. With decreasing height, the area of ​​the device decreases, and, therefore, the power decreases proportionally.That is, you need to find the ratio of the heights of the selected radiator to the standard, and then use this coefficient to correct the result.

Calculation of cast iron heating radiators. Can count by area or volume of the room

For clarity, we will calculate the area of ​​aluminum radiators. The room is the same: 16m 2. We count the number of sections of a standard size: 16m 2 / 2m 2 = 8pcs. But we want to use small sections with a height of 40cm. We find the ratio of radiators of the selected size to the standard ones: 50cm / 40cm = 1.25. And now we adjust the quantity: 8pcs * 1.25 = 10pcs.

Calculation of high-precision sections for household and administrative facilities

Speaking for the installation of heating on the territory of household and administrative facilities, there is a more accurate formula than the basic calculation of sections.

The formula for the exact calculation of sections is: 100 * S * ((K1 + K2 + K3 + K4 + K5 + K6 + K7) / 7) / P, where 100 is the optimal heat output for one meter of the square area of ​​the room, K1 is the correction factor for glazing:

• For ordinary double glass - 1.27
• For double glazing - 1.0
• For triple glazing - 0.85

K2 - correction factor for thermal insulation of walls:

• Standard thermal insulation - 1.27
• Improved thermal insulation - 1.0
• Good thermal insulation - 0.85

K3 - coefficient of correction for the ratio of window area to floor area:
50% – 1,2

• 40% – 1,1
• 30% – 1,0
• 20% – 0,9
• 10% – 0,8

K4 - coefficient of correction for temperature in the coldest part of the year:

• -35 ⁰С - 1.5
• -25 ⁰С - 1.3
• -20 ⁰С - 1.1
• -15 ⁰С - 0.9
• -10 ⁰С - 0.7

K5 - correction factor for the number of external walls:

• one wall - 1.1
• two walls - 1.2
• three walls - 1.3
• four walls - 1.4

K6 - the correction factor for the type of room is higher:

• cold attic - 1.0
• heated attic - 0.9
• heated living quarters - 0.8

K7 - correction factor for ceiling height:

• 2.5 (m) - 1.0
• 3.0 (m) - 1.05
• 3.5 (m) - 1.1
• 4.0 (m) - 1.15
• 4.5 (m) - 1.2

7 - the number of correction factors.

P - thermal power of each section (W).

Let's make a calculation using a more accurate formula. Recall that using the basic calculation formula, we got a value of 14 sections. This is provided that the area of ​​the room is 25 (m2), and the power of one section of the bimetallic radiator is 175 (W).

An example of an exact calculation: 100 * 25 * ((1 + 1 + 1.2 + 1.3 + 1.2 + 1 + 1.05) / 7) / 175 = 15.81 (pcs). Round up to 16 sections.

Please note that in this case it is advisable to use 2 radiators with 8 sections each. If there is 1 window opening in the room, then one of the batteries must be located under the window

The radiator located under the window acts as a stationary heat curtain. If there are 2 windows in the room, then both radiators are mounted under the window openings.

The required value of the heat output of the radiator

When calculating a heating battery, it is imperative to know the required thermal power so that it is comfortable to live in the house. How to calculate the power of a heating radiator or other heating devices for heating an apartment or house is of interest to many consumers.

1. The method according to SNiP assumes that 100 watts are required per "square" of area.

But in this case, a number of nuances should be taken into account: - heat loss depends on the quality of thermal insulation. For example, heating an energy efficient house equipped with a heat recovery system with walls made of vulture panels will require less than 2 times heat output; - the creators of sanitary norms and rules, when developing them, were guided by the standard ceiling height of 2.5-2.7 meters, and this parameter can be equal to 3 or 3.5 meters; - this option, which allows you to calculate the power of the heating radiator and heat transfer, is correct only under the condition of an approximate temperature of 20 ° C in the apartment and on the street - 20 ° C. A similar picture is typical for settlements located in the European part of Russia. If the house is located in Yakutia, much more heat will be required.

The calculation method based on volume is not considered difficult. For each cubic meter of the room, 40 watts of thermal power is required. If the dimensions of the room are 3x5 meters, and the ceiling height is 3 meters, then 3x5x3x40 = 1800 watts of heat will be required. And although the errors associated with the height of the premises have been eliminated in this version of the calculation, it is still not accurate.
The refined method of calculating by volume, taking into account more variables, gives a more realistic result. The base value remains the same 40 watts per cubic meter of volume.

When an updated calculation of the heat output of the radiator and the required amount of heat transfer is made, it should be borne in mind that: - one door to the outside takes 200 watts, and each window - 100 watts; - if the apartment is corner or end, a correction factor of 1.1 - 1.3 is applied, depending on the type of wall material and their thickness; - for private households, the coefficient is 1.5; - for the southern regions, a coefficient of 0.7 - 0.9 is taken, and for Yakutia and Chukotka, an amendment from 1.5 to 2 is applied.

As an example, a corner room with one window and a door in a private brick house measuring 3x5 meters with a three-meter ceiling in the north of Russia was taken for the calculation. The average temperature outside the window in winter in January is - 30.4 ° C.

The calculation order is as follows:

• determine the volume of the room and the required power - 3x5x3x40 = 1800 watts;
• a window and a door increase the result by 300 watts, for a total of 2100 watts;
• taking into account the angular location and the fact that the house is private will be 2100x1.3x1.5 = 4095 watts;
• the previous total is multiplied by the regional coefficient of 4095x1.7 and 6962 watts are obtained.

Video on the choice of heating radiators with power calculation:

Thermal power of 1 section

As a rule, manufacturers indicate average heat transfer rates in the technical characteristics of heaters. So for heaters made of aluminum, it is 1.9-2.0 m2. To calculate how many sections are required, you need to divide the area of ​​the room by this coefficient.

For example, for the same room with an area of ​​16 m2, 8 sections will be required, since 16/2 = 8.

These calculations are approximate and it is impossible to use them without taking into account the heat loss and the real conditions for placing the battery, since you can get a cold room after installing the structure.

To get the most accurate indicators, you will have to calculate the amount of heat that is needed to heat a specific living area. To do this, you will have to take into account many correction factors. This approach is especially important when the calculation of aluminum heating radiators for a private house is required.

The formula required for this is as follows:

KT = 100W / m2 x S x K1 x K2 x K3 x K4 x K5 x K6 x K7

1. CT is the amount of heat that a given room needs.
2. S - area.
3. K1 - designation of the coefficient for a glazed window. It is 1.27 for standard double glazing, 1.0 for double glazing and 0.85 for triple glazing.
4. K2 is the coefficient of the wall insulation level. For a non-insulated panel, it = 1.27, for a brick wall with masonry in one layer = 1.0, and in two bricks = 0.85.
5. K3 is the ratio of the area occupied by the window and the floor. When between them:
   • 50% - the coefficient is 1.2;
   • 40% — 1.1;
   • 30% — 1.0;
   • 20% — 0.9;
   • 10% — 0.8.
6. K4 is a coefficient that takes into account the air temperature according to SNiP on the coldest days of the year:
   • +35 = 1.5;
   • +25 = 1.2;
   • +20 = 1.1;
   • +15 = 0.9;
   • +10 = 0.7.
7. K5 indicates a correction when there are exterior walls. For example:
   • when she is alone, the indicator is 1.1;
   • two outer walls - 1.2;
   • 3 walls - 1.3;
   • all four walls - 1.4.
8. K6 takes into account the presence of a room above the room for which calculations are made.
   • unheated attic - coefficient 1.0;
   • heated attic - 0.9;
   • living room - 0.8.
9. K7 is a coefficient that indicates the height of the ceiling in the room:
   • 2.5 m = 1.0;
   • 3.0 m = 1.05;
   • 3.5 m = 1.1;
   • 4.0 m = 1.15;
   • 4.5 m = 1.2.

If you apply this formula, you can foresee and take into account almost all the nuances that can affect the heating of the living space. Having made a calculation on it, you can be sure that the result obtained indicates the optimal number of aluminum radiator sections for a particular room.

If you decide to install aluminum radiators, it is important to know the following:

Whatever calculation principle is undertaken, it is important to make it as a whole, since correctly selected batteries allow you not only to enjoy the heat, but also significantly save on energy costs. The latter is especially important in the context of constantly growing tariffs.

Premises with a ceiling height of more than 3 meters

The calculation of the number of sections of heating devices for rooms with a ceiling height of more than three meters is based on the volume of the room. Volume is the area multiplied by the height of the ceilings. To heat 1 cubic meter of a room, 40 W of the heating power of the heater is required, and its total power is calculated by multiplying the volume of the room by 40 W. To determine the number of sections, this value must be divided by the capacity of one section according to the passport.

Calculation example:

A room with a width of 3.5 meters and a length of 4 meters, with a ceiling height of 3.5 meters. The power of one radiator section is 160 watts. It is necessary to find the number of heating radiator sections.

1. We find the area of ​​the room by multiplying its length by its width: 3.5 4 = 14 m2.
2. We find the volume of the room by multiplying the area by the height of the ceilings: 14 3.5 = 49 m3.
3. We find the total power of the heating radiator: 49 40 = 1960 W.
4. Find the number of sections: 1960/160 = 12.25. Round up and get 13 sections.

You can also use the table:

As in the previous case, for a corner room, this indicator must be multiplied by 1.2. It is also necessary to increase the number of sections if the room has one of the following factors:

• Located in a panel or poorly insulated house;
• Located on the first or last floor;
• Has more than one window;
• Located next to unheated premises.

In this case, the resulting value must be multiplied by a factor of 1.1 for each of the factors.

Calculation example:

A corner room with a width of 3.5 meters and a length of 4 meters, with a ceiling height of 3.5 meters. Located in a panel house, on the ground floor, it has two windows. The power of one radiator section is 160 W. It is necessary to find the number of heating radiator sections.

1. We find the area of ​​the room by multiplying its length by its width: 3.5 4 = 14 m2.
2. We find the volume of the room by multiplying the area by the height of the ceilings: 14 3.5 = 49 m3.
3. We find the total power of the heating radiator: 49 40 = 1960 W.
4. Find the number of sections: 1960/160 = 12.25. Round up and get 13 sections.
5. We multiply the resulting amount by the coefficients:

Corner room - coefficient 1.2;

Panel house - coefficient 1.1;

Two windows - coefficient 1.1;

First floor - coefficient 1.1.

Thus, we get: 13 · 1.2 · 1.1 · 1.1 · 1.1 = 20.76 sections. We round them up to a larger whole number - 21 sections of heating radiators.

When calculating, it should be borne in mind that different types of heating radiators have different heat outputs. When choosing the number of heating radiator sections, it is necessary to use exactly those values ​​that correspond to the selected type of batteries.

Radiator

In order for the heat transfer from the radiators to be maximized, it is necessary to install them in accordance with the manufacturer's recommendations, observing all the distances specified in the passport. This contributes to a better distribution of convective currents and reduces heat loss.

Bimetallic radiators: features

Bimetallic radiators are becoming more and more popular today. This is a worthy replacement for the hopelessly outdated "cast iron". The prefix "bi" means "two", i.e. two metals are used in the manufacture of radiators - steel and aluminum. They are made of an aluminum frame with a steel pipe inside. This combination is optimal in itself. Aluminum guarantees high thermal conductivity, and steel - a long service life and the ability to easily withstand pressure drops in the heating network.

Prices for popular bimetallic heating radiators

Combining the seemingly incompatible became possible thanks to a special production technology. Bimetallic radiators are made by spot welding or injection molding.

• long term "life". High build quality and reliable "union" of two metals make radiators "long-livers". They are capable of regularly serving up to 50 years;
• strength. The steel core is not afraid of pressure surges inherent in our heating systems;
• high heat transfer. Thanks to the aluminum housing, the bimetallic radiator quickly heats up the room. In some models, this figure reaches 190 W;
• resistance to rust formation. Only steel is in contact with the coolant, which means that corrosion is not terrible for a bimetallic radiator. This quality becomes especially valuable when carrying out seasonal cleanings and water discharge;
• pleasant appearance". The bimetallic radiator is visually much more attractive than its cast-iron predecessor. There is no need to hide it from prying eyes with curtains or special screens. In addition, the radiators differ in color and design. You can choose what you like best;
• light weight. Significantly simplifies the installation process. Now the installation of the battery does not require a lot of effort and time;
• compact size. Bimetallic radiators are prized for their small size. They are compact enough and easily fit into any interior.

How to calculate the number of radiator sections

There are several methods for calculating the number of radiators, but their essence is the same: find out the maximum heat loss in a room, and then calculate the number of heating devices required to compensate them.

There are different calculation methods. The simplest ones give approximate results. Nevertheless, they can be used if the premises are standard or apply coefficients that allow taking into account the existing "non-standard" conditions of each particular room (corner room, exit to the balcony, full-wall window, etc.). There is a more complex calculation using the formulas. But in fact, these are the same coefficients, only collected in one formula.

There is one more method. It determines the actual losses. A special device - a thermal imager - determines the real heat loss. And on the basis of these data, they calculate how many radiators are needed to compensate them. What's more good about this method is that the thermal imager clearly shows where the heat is most actively removed. This can be a defect in work or building materials, a crack, etc. So at the same time you can straighten things out.

The calculation of radiators depends on the heat loss in the room and the rated heat output of the sections.

What if you need a very accurate calculation?

Unfortunately, not every apartment can be considered standard. This applies even more to private residential buildings. The question arises: how to calculate the number of heating radiators, taking into account the individual conditions of their operation? To do this, you will need to take into account many different factors.

When calculating the number of heating sections, you need to take into account the height of the ceiling, the number and size of windows, the presence of wall insulation, etc.

The peculiarity of this method is that when calculating the required amount of heat, a number of coefficients are used that take into account the characteristics of a particular room, which can affect its ability to store or give off thermal energy. The calculation formula looks like this:

CT = 100W / sq.m. * P * K1 * K2 * K3 * K4 * K5 * K6 * K7. where

CT - the amount of heat required for a particular room; P is the area of ​​the room, sq. M .; K1 - coefficient taking into account the glazing of window openings:

• for windows with conventional double glazing - 1.27;
• for windows with double glazing - 1.0;
• for windows with triple glazing - 0.85.

K2 - coefficient of thermal insulation of walls:

• low degree of thermal insulation - 1.27;
• good thermal insulation (laying in two bricks or a layer of insulation) - 1.0;
• high degree of thermal insulation - 0.85.

K3 - the ratio of the area of ​​windows and floor in the room:

K4 is a coefficient that allows you to take into account the average air temperature in the coldest week of the year:

• for -35 degrees - 1.5;
• for -25 degrees - 1.3;
• for -20 degrees - 1.1;
• for -15 degrees - 0.9;
• for -10 degrees - 0.7.

K5 - adjusts the heat demand taking into account the number of external walls:

K6 - accounting for the type of premises that is located above:

• cold attic - 1.0;
• heated attic - 0.9;
• heated living quarters - 0.8

K7 - coefficient taking into account the height of the ceilings:

Such a calculation of the number of heating radiators includes almost all the nuances and is based on a fairly accurate determination of the room's need for thermal energy.

It remains to divide the obtained result by the value of the heat transfer of one section of the radiator and round the result to an integer.

Some manufacturers offer an easier way to get the answer. On their websites you can find a handy calculator specially designed to do these calculations. To use the program, you need to enter the required values ​​in the appropriate fields, after which the exact result will be given. Or you can use special software.

When we received an apartment, we did not think about what kind of radiators we have and whether they are suitable for our house. But over time, a replacement was required and here they began to approach it from a scientific point of view. Since the power of the old radiators was clearly not enough. After all the calculations, we came to the conclusion that 12 is enough. But you also need to take into account this point - if the TEC does its job poorly and the batteries are slightly warm, then no amount will save you.

I liked the last formula for a more accurate calculation, but the K2 coefficient is not clear. How to determine the degree of wall insulation? For example, a 375mm thick wall made of GRAS foam block, is it low or medium? And if you add 100mm thick building foam to the outside of the wall, is it high, or is it still medium?

Ok, the last formula seems to be of good quality, the windows are taken into account, but what if the room also has an outer door? And if this is a garage with 3 windows 800 * 600 + door 205 * 85 + sectional garage doors 45mm thick with dimensions 3000 * 2400?

If I do it for myself, I would increase the number of sections and put a regulator. And voila - we are already much less dependent on the whims of thermal power plants.

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