Calculation of the power of a gas boiler for a private house - for single and double circuit circuits

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

A floor-standing gas boiler has greater power Source termoresurs.ru

Varieties of boiler models

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

• Single-circuit – used only for heating;
• Double-circuit – used for heating, as well as in hot water supply systems.

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

Single-circuit wall-mounted gas boiler Source ideahome.pp.ua

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

Boiler models are often divided by placement method.

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

In addition to fundamental differences in purpose of use and placement methods, gas boilers also differ in control methods. There are models with electronic and mechanical control. Electronic systems can only operate in homes with constant access to the power grid.

Double-circuit gas boiler with indirect heating boiler Source norogum.am

See also: Catalog of companies that specialize in home insulation services.

We calculate power by area - the basic formula

The simplest way to calculate the required power of a heat generation device is by the area of ​​the house. When analyzing calculations carried out over many years, a pattern was identified: 10 m2 of area can be heated properly using 1 kilowatt of thermal energy. This rule is valid for buildings with standard characteristics: ceiling height 2.5–2.7 m, average insulation.

If the housing fits into these parameters, we measure its total area and approximately determine the power of the heat generator. We always round up the calculation results and increase them a little in order to have some power in reserve. We use a very simple formula:

W=S×Wud/10:

• here W is the required power of the thermal boiler;
• S – total heated area of ​​the house, taking into account all residential and domestic premises;
• Wud – specific power required to heat 10 square meters, adjusted for each climate zone.

Method for calculating the required power of a heat generation device
For clarity and greater clarity, let’s calculate the power of a heat generator for a brick house. It has dimensions of 10 × 12 m, multiply and get S - the total area equal to 120 m2. Specific power – Wsp is taken as 1.0. We make calculations using the formula: area 120 m2 multiplied by specific power 1.0 and we get 120, divide by 10 - the result is 12 kilowatts. A heating boiler with a capacity of 12 kilowatts is suitable for a home with average parameters. These are the initial data that we will adjust in the course of further calculations.

There are a lot of units on the market with similar characteristics, for example, solid fuel boilers from the “Kupper Expert” line from the Teplodar company, the power of which varies from 15 to 45 kilowatts. You can get acquainted with the other characteristics and find out the price on the official website of the manufacturer https://www.teplodar.ru/catalog/kotli/.

Typical device power calculations

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

Formula for a typical project

When calculating the required power for heating a house built according to a standard design, that is, with a room height of no more than 3 meters, the volume of the premises is not taken into account, and the power indicator is calculated as follows:

1. Determine the specific thermal power: Um = 1 kW/10 m2;
2. Next, calculate the required power to heat the house.

Rm = Mind * P * Kr, where

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

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

Some coefficient values ​​for different regions of Russia:

• Southern – 0.9;
• Located in the middle zone – 1.2;
• Northern – 2.0.
• For the Moscow region, a coefficient value of 1.5 is taken.

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

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

Example calculation for a single-circuit device installed in a room with an area of ​​100 m2, located in the Moscow region:

Рм = 1/10 * 100 * 1.5 = 15 (kW)

Calculations for dual-circuit devices

Double-circuit devices have the following operating principle. For heating, water is heated and supplied through the heating system to radiators, which release heat to the environment, thereby heating the rooms and cooling them. When cooling, the water flows back to be heated. Thus, water circulates along the heating system circuit, and goes through heating cycles and transfer to the radiators. At the moment when the ambient temperature becomes equal to the set one, the boiler goes into standby mode for some time, i.e. Temporarily stops heating the water, then starts heating again.

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

Double-circuit heating system Source idn37.ru

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

An example of calculation for a two-circuit device that is installed in a room with an area of ​​100 m2; the coefficient is taken for the Moscow region:

1. Рм = 1/10 * 100 * 1.5 = 15 (kW)
2. Ritogovaya = 15 + 15*20% = 18 (kW)

Determining the ideal ratio of power and economy

Several boilers included in one system

To follow the principles of economy, you need to take into account some more points when operating the boiler.

In cold weather, it is necessary to maintain a temperature in the house of 20-22 degrees; it is optimally comfortable for the human body. But given that the temperature changes during the winter, and the coldest days occur only a few times during the heating season, you can warm the house using a boiler with a power half lower than that obtained in the calculations.

For the normal functioning of the boiler for many years, it is better if it operates at rated rather than peak power. But during the heating season, the need to maintain a high temperature in the house sometimes disappears. To get out of this situation, mixing valves are used.

Mixing valve

They are needed so that you can regulate the temperature of the coolant in the batteries. For this purpose, hydraulic systems with thermohydraulic distributors or four-way valves are used. If they are installed in a heating system, the temperature can be changed with a regulator, leaving the boiler power constant.

After such upgrades, even a small boiler will operate in optimal mode, sufficient for high-quality heating of all rooms. This solution is quite expensive, but it will help save on fuel consumption.

• Another case is when the boiler has a power that is exceeded for a given room, and you don’t want to overpay for excess fuel, which should ensure its operation. To avoid these unpleasant expenses, you can install a buffer tank (battery tank), which is completely filled with water.

This addition will come in handy if solid fuel boilers are used for heating - the device will operate at full power, even if only short-term heat is required.

When the temperature outside rises and it is too early to turn off the boiler, the automatic valve begins to limit the flow of heated water into the radiators. He directs it to the heat exchanger of the buffer tank, and there it will heat the water that is already in the tank. The volume of the tank should be 10:1 in relation to the area of ​​the house, for example, for 50 square meters of area you will need a tank with a volume of 500 liters.

Installing a storage tank provides significant energy savings

This water, having heated up, begins to function after the water in the circuit cools down - it begins to flow into the radiators, and the system will continue to heat the rooms for some time.

Additional factors taken into account when installing the boiler

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

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

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

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

• The lowest level of heat transfer, corresponding to a K value from 0.6 to 0.9, is assigned to buildings made of modern materials, with insulated floors, walls and roofs;
• Kr is equal to from 1.0 to 1.9, if the external walls of the building are insulated and the roof is insulated;
• Kr is equal to from 2.0 to 2.9 in houses without insulation, for example, brick houses with single masonry;
• Kr is equal to from 3.0 to 4.0 in non-insulated rooms, in which the level of thermal insulation is low.

The level of heat loss Qt is calculated in accordance with the formula:

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

V is the volume of the room,

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

k – safety factor.

Modern gas boiler Source tr.decorexpro.com

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

This technique allows you to more accurately determine productivity and, therefore, approach the issue of choosing a boiler as efficiently as possible.

What parameters, besides volume and area, influence the choice of boiler? And why is this important?

A simplified calculation formula often leads to the purchase of an unsuitable boiler. Each house is individual, and heat loss percentage cannot be equal for all houses. Before calculating power, consider the data of a specific house:

1) Measure the area of ​​walls, windows, doors;

2) Specify the thickness of the walls, indicate the type of finishing and material, the height of the ceilings;

3) Observe the minimum temperature of the house in cold weather;

4) Determine the desired temperature as a result of installing the boiler;

5) Write down the thermal conductivity values ​​for the materials from which the house was built.

Thermal resistance of materials

Why is this necessary? The key parameter influencing the choice of boiler is the heat loss of the house. Houses with the same area and volume, but different degrees of insulation, will require equipment of different power.

Where does the heat go:

It also matters: how different the outside temperature is from the inside, the climatic region, the strength and direction of the wind, how the house stands relative to parts of the world.

What happens if you incorrectly calculate the required power

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

1. A low-power boiler will always work at the limit, trying to heat the room to the set temperature, and can quickly fail;
2. A device with an excessively high power level costs more and, even in economy mode, consumes more gas than a less powerful device.

Why count if you can buy a boiler with a power reserve?

Sometimes boilers have a capacity reserve. This is good when the reserve is no more than 25%. Especially when the family plans to develop the area: complete a swimming pool, sauna, or other heated area. When the required power is exceeded significantly, the owner spends extra money, and the equipment operates in abnormal mode:

• Breaks or malfunctions;
• The efficiency of the system decreases;
• A higher power boiler costs more;
• More fuel is consumed than is required to heat the house;
• A more powerful and expensive pump will be needed;
• The house will be very hot;
• Automatic regulation becomes difficult, the boiler may boil;
• The boiler begins to cycle - it turns on and off in a short period of time, equipment components wear out;
• Condensation appears in the chimney. When burned, the condensate reacts with the emissions and produces acid. It destroys the chimney and sometimes the boiler.

Conclusion: frequent switching on and off wastes more fuel than continuous operation. Buying a boiler with excess power not only makes no sense, but is also harmful to the budget and equipment.

Calculator for calculating boiler power

For those who do not like to do calculations, even if they are not very complicated, a special calculator will help you calculate a boiler for heating your home - a free online application.

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

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

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

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

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

Is it worth buying a boiler that is too powerful?

Modern heating equipment is equipped with automatic systems that allow you to regulate gas flow. This is very convenient because it eliminates unnecessary expenses. It may seem that an accurate calculation of the power of a heating boiler is not so important, because you can simply buy a boiler with high power ratings. But it's not that simple.

Correct selection of heating equipment will extend its service life

Unreasonably exceeding the thermal power of equipment can lead to:

• increasing costs for the acquisition of system elements;
• reducing the efficiency of the boiler;
• failures in the operation of automatic equipment;
• rapid wear of components;
• formation of condensation in the chimney, etc.

Thus, you need to try to “get into” exactly the power that suits your home.

Baxi gas boilers have proven themselves to be reliable heating equipment. Review of the model range with characteristics and features in our next material: .

Advantages of using gas boilers

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

• possibility of partial automation of the boiler operation process;
• unlike other energy sources, natural gas has a low cost;
• The devices do not require frequent maintenance.

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

Is excess power needed?

You should not buy a model with a performance that significantly exceeds the maximum value (taking into account the 15-20% premium). Excess leads to negative consequences:

1. High price. The more powerful the model, the more expensive it is. It is irrational to purchase equipment whose capabilities will not be used.
2. Increased costs for consumables.
3. Low burner efficiency - this will affect gas consumption.
4. At minimal loads, the automation often fails.
5. If the equipment is not optimal for a specific area, accelerated wear of components and parts occurs.

Boilers used in private homes

In private households, the main heat generator can be boilers that differ not only in power indicators, but also in other technical parameters, including type of fuel and functionality. The equipment produced operates on solid (wood, special pellets, coal), liquid, gaseous (main and bottled gas) fuels, as well as from a traditional electrical network.

Design features:

• according to the material of execution - cast iron or steel models;
• by installation method - floor or wall models;
• according to the number of circuits - single- or double-circuit models.

Non-volatile devices are able to function without being connected to the electrical network, and when installing volatile boilers, you must remember that systems with forced circulation of the coolant are not able to operate without the presence of electricity.

When purchasing a heat-generating device, you need to take into account a large number of criteria. In this regard, special attention is paid to the cost of the boiler, the features of the installation and installation of the heating system, the power of the device and the number of circuits, the type of fuel used, as well as the option for removing all exhaust gases.

The most affordable boilers in terms of price include domestic models, and you need to choose a device based on the type of fuel, taking into account the climatic conditions and existing capabilities inherent in the locality in which the house is supposed to be operated. If desired, it is quite possible to significantly increase the performance of the system and the uniformity of heating of the premises using a special heat accumulator attached to the installed heating boiler.

Performance reserve depending on the type of boiler

For a standard single-circuit boiler, regardless of the type of fuel used, we always recommend a power reserve of 15-25%, depending on the temperature in the coldest decade and the insulation of the house. However, in some cases a slightly larger margin is required:

• 20-30% reserve if the boiler is double-circuit. Most models operate on the principle of DHW priority, which means that at the moment the hot water consumption point is activated, the boiler does not heat the heating circuit; to operate on two circuits, higher performance is required;
• 20-25% of the reserve if supply and exhaust ventilation without heat recovery is organized or planned in the house.

A scheme with the connection of an indirect heating boiler is also often used (especially in conjunction with solid fuel boilers). In this case, excess capacity may exceed 40-50% (the figure is calculated according to the situation). It is worth understanding that in any of the cases, the provided reserve is not “idle”, but is used whether for the purpose of heating hot water, replenishing higher heat losses, or heating a buffer tank.

The tall white tank to the right of the boiler is an indirectly heated storage boiler that constantly maintains a large volume of hot water.

We focus on the volume of housing - we use SNiP standards

When calculating heating equipment for apartments, you can focus on SNiP standards. Building codes and regulations determine how much thermal energy is needed to heat 1 m3 of air in standard buildings. This method is called calculation by volume. SNiP provides the following standards for thermal energy consumption: for a panel house - 41 W, for a brick house - 34 W. The calculation is simple: we multiply the volume of the apartment by the rate of heat energy consumption.

Heating system

Here's an example. An apartment in a brick house with an area of ​​96 sq.m., ceiling height - 2.7 m. Let's find out the volume - 96 × 2.7 = 259.2 m3. Multiply by the norm - 259.2 × 34 = 8812.8 W. Converting to kilowatts, we get 8.8. For a panel house, we carry out the calculations in a similar way - 259.2×41 = 10672.2 W or 10.6 kilowatts. In heating engineering, rounding is carried out upward, but if you take into account energy-saving packages on windows, you can round down.

The obtained data on equipment power are initial. For a more accurate result, correction will be needed, but for apartments it is carried out according to different parameters. The first step is to take into account the presence of an unheated room or its absence:

• if a heated apartment is located on the floor above or below, we apply an amendment of 0.7;
• if such an apartment is not heated, we do not change anything;
• if there is a basement under the apartment or an attic above it, the correction is 0.9.

We also take into account the number of external walls in the apartment. If one wall faces the street, we apply an amendment of 1.1, two - 1.2, three - 1.3. The method for calculating boiler power by volume can also be applied to private brick houses.

So, you can calculate the required power of a heating boiler in two ways: by total area and by volume. In principle, the data obtained can be used if the house is average, multiplying it by 1.5. But if there are significant deviations from the average parameters in the climate zone, ceiling height, insulation, it is better to correct the data, because the initial result may differ significantly from the final one.

Method number 1 is the simplest

Using this method, you need to calculate the heated area, divide it by ten (based on the well-known formula - 0.1 kW of heat is needed to heat 1 m2). And then multiply by 1.5, that is, this coefficient takes into account heat losses through windows, walls, doors, floors, roofs, northern location of windows, non-density structures, etc.

This method is good for those who are not used to saving. Who cares whether to buy a boiler with a capacity of 50 or 100 kW. But for the majority of the population it is not suitable. In most cases, this calculation results in an unreasonably high required boiler power. And this is the main factor influencing its price. In addition, due to significant overpowering, the automation will turn off the equipment too often, which negatively affects its service life. The same can be said about a boiler model that operates at the limit of its capabilities.

Calculation of the number of sections of heating devices

The heating system will not be effective if the optimal number of radiator sections is not calculated. An incorrect calculation will lead to the rooms being heated unevenly, the boiler will work at the limit of its capabilities or, conversely, “idlely” wasting fuel.

Some home owners believe that the more batteries the better. However, this lengthens the path of the coolant, which gradually cools, which means that the last rooms in the system risk being left without heat. Forced coolant circulation partly solves this problem. But we must not lose sight of the power of the boiler, which may simply “not cope” with the system.

To calculate the number of sections, you will need the following values:

• the area of ​​the heated room (plus the adjacent one, where there are no radiators);
• power of one radiator (indicated in the technical specifications);

take into account that per 1 sq. m

living space will require 100 W of power for central Russia (according to SNiP requirements).

The area of ​​the room is multiplied by 100 and the resulting amount is divided by the power parameters of the installed radiator.

Example for a room of 25 square meters. meters and radiator power 120 W: (20x100)/185=10.8=11

This is the simplest formula; if the height of the rooms is not standard or their configuration is complex, other values ​​are used.

How to correctly calculate heating in a private house if the power of the radiator is unknown for some reason? By default, the average static power is 200 W. You can take the average values ​​of certain types of radiators. For bimetallic ones this figure is 185 W, for aluminum ones - 190 W. For cast iron, the value is much lower - 120 W.

If the calculation is carried out for corner rooms, then the result obtained can be safely multiplied by a factor of 1.2.

What is room heat loss

Any room has certain heat losses. Heat comes out of walls, windows, floors, doors, ceilings, so the task of a gas boiler is to compensate for the amount of heat coming out and provide a certain temperature in the room. This requires a certain thermal power.

It has been experimentally established that the largest amount of heat escapes through the walls (up to 70%). Up to 30% of thermal energy can escape through the roof and windows, and up to 40% through the ventilation system. Lowest heat loss at doors (up to 6%) and floors (up to 15%)

The following factors influence heat loss at home.

• Location of the house. Each city has its own climatic characteristics. When calculating heat loss, it is necessary to take into account the critical negative temperature characteristic of the region, as well as the average temperature and duration of the heating season (for accurate calculations using the program).
• The location of the walls relative to the cardinal directions. It is known that the wind rose is located in the north side, so the heat loss of a wall located in this area will be the greatest. In winter, cold wind blows with great force from the western, northern and eastern sides, so the heat loss of these walls will be higher.
• The area of ​​the heated room. The amount of heat lost depends on the size of the room, the area of ​​walls, ceilings, windows, doors.
• Thermal engineering of building structures. Any material has its own coefficient of thermal resistance and heat transfer coefficient - the ability to pass a certain amount of heat through itself. To find them out, you need to use tabular data and also apply certain formulas. Information about the composition of walls, ceilings, floors, and their thickness can be found in the technical plan of housing.
• Window and door openings. Size, modification of door and double-glazed windows. The larger the area of ​​window and door openings, the higher the heat loss. It is important to take into account the characteristics of installed doors and double-glazed windows when making calculations.
• Ventilation accounting. Ventilation always exists in the house, regardless of the presence of artificial hood. The room is ventilated through open windows; air movement is created when the entrance doors are closed and opened, people move from room to room, which helps warm air leave the room and circulate it.

Knowing the above parameters, you can not only calculate the heat losses of the house and determine the power of the boiler, but also identify places that need additional insulation.