How to calculate the power of an electric boiler for heating a house

Each buyer, when choosing a gas boiler, must clearly know what power unit is suitable for his house or apartment. But it happens that the owner made a mistake in calculating the performance or the conditions changed during the operation of the unit: a boiler was connected, the heating area was increased due to an extension, the heating system was changed, etc.

How to increase the power of a gas boiler?

It happens that the power of the existing gas boiler is not enough to meet all the needs placed on it. Often an increase in unit performance is required in the following cases:

when re-equipping the heating system in order to increase its power, for example, adding the number of sections;
when connecting an indirect heating boiler, heating of which will require about 20% of the unit’s performance;
increasing the heated area due to extensions or adding previously unheated rooms.

There are different ways to increase the power of a gas boiler. The most reliable and optimal option is to call a service center specialist who can make settings and adjust the power of the unit so that it meets new needs.

It is worth noting that methods for increasing productivity may differ for different boiler models. If the unit has a modulating burner and the required indicator is within its power range, then you can simply adjust the burner device to the required performance.

If the required power is greater than the maximum capacity of the gas boiler, you will have to solve the problem using more complex methods:

The simplest, but also most expensive way is to install another unit, a convector or electric boiler.
Replace the burner device with a more efficient one.
Increase the cross-section of the nozzles, due to which they pass a larger volume of fuel - as a result, the boiler heat transfer increases. However, it should be taken into account that this option reduces the efficiency of the device, fuel consumption increases, and the process of burner failure also accelerates.

It is important to understand that the last two methods will not significantly increase the power of the gas device. It can be increased to a maximum of only 15%. To significantly increase the performance, you will have to change the gas boiler to a more powerful one or install additional heating devices.

To ensure that the gas boiler operates at maximum performance, all its components should be kept clean and in order. A clogged heat exchanger or soot accumulation in the burner reduces the power of the gas device. It is also necessary to periodically check the chimney to see if it has sufficient draft force. Soot, soot and deposits must be cleaned in time, otherwise the influence of these factors will lead to a decrease in the power of the unit.

Gas boilers

Based on the above, the power of boiler equipment for heating is calculated using one fairly simple formula:

N boiler = S x N beat. / 10.

Here the values of the quantities are deciphered as follows:

N of the boiler is the power of this particular unit;
S is the total sum of the areas of all rooms heated by the system;
N beats – specific value of the heat generator required to warm up 10 kW. m. area of the room.

One of the main determining factors for the calculation is the climatic zone, the region where this equipment is used. That is, the calculation of the power of a solid fuel boiler is carried out with reference to specific climatic conditions.

What is typical is that once upon a time, during the existence of Soviet standards for assigning the power of a heating installation, they considered 1 kW. always equal to 10 square meters. meters, then today it is extremely necessary to make accurate calculations for real conditions.

In this case, you need to take the following values N beats.

N beats = 1.7 - 1.8 kW per 10 sq. meters of area - for the regions of the North and Siberia.
N beats = 1.3 – 1.5 kW per 10 sq. meters of area - for areas of the middle zone.
N beats = 0.7 - 0.8 kW per 10 sq. meters of area - for the southern regions.

As an example, we will calculate the power of a solid fuel heating boiler relative to the Siberian region, where winter frosts sometimes reach -35 degrees Celsius. Let's take N beats. = 1.8 kW. Then, to heat a house with a total area of 100 square meters. m. you will need an installation with the following design value:

Boiler N = 100 sq. m. x 1.8 / 10 = 18 kW.

As you can see, the approximate ratio of the number of kilowatts to area as one to ten does not apply here.

It is important to know! If you know how many kilowatts a particular solid fuel installation has, you can calculate the volume of coolant, in other words, the volume of water that is necessary to fill the system. To do this, simply multiply the resulting N of the heat generator by 15.

In our case, the volume of water in the heating system is 18 x 15 = 270 liters.

However, taking into account the climatic component to calculate the power characteristics of a heat generator is in some cases not enough. It must be remembered that heat losses may occur due to the specific design of the premises. First of all, you need to consider what the walls of the living space are. How insulated the house is - this factor is of great importance. It is also important to consider the structure of the roof.

In general, you can use a special coefficient by which you need to multiply the power obtained from our formula.

This coefficient has the following approximate values:

K = 1, if the house is more than 15 years old, and the walls are made of brick, foam blocks or wood, and the walls are insulated;
K = 1.5 if the walls are not insulated;
K = 1.8, if, in addition to uninsulated walls, the house has a poor roof that allows heat to pass through;
K = 0.6 for a modern house with insulation.

Suppose, in our case, the house is 20 years old, it is built of brick and well insulated. Then the power calculated in our example remains the same:

Boiler N = 18x1 = 18 kW.

If the boiler is installed in an apartment, then a similar coefficient must be taken into account. But for an ordinary apartment, if it is not on the first or last floor, K will be equal to 0.7. If the apartment is on the first or last floor, then K = 1.1 should be taken.

Next, let's move on to consider the case with another type of fuel.

How to reduce power?

Reducing the power of a gas device is usually required in the following cases:

after alteration of the heating system, as a result of which its performance decreased;
if you lose the need for some additional functions: hot water supply, heated floor system, etc.

Find out here what is a gas boiler power calculator?

What is important to consider when calculating the power of a gas boiler for a house or apartment?

If the received power of the heating system is less than the minimum generated by the gas boiler, this often leads to “clocking” of the unit. As a result, the boiler constantly turns on and off, which causes increased wear on components: burner, three-way valve, pump. To prevent this, reduce the power of the gas boiler. This can be done in one of the following ways:

Replace the burner device with a modulating analogue.
Reduce the gas supply to the burner - this is done by changing the gas valve settings.
Change the service menu settings: anti-cycling time, heat exchanger temperature.
Adjust the operation of the circulation pump.

However, the listed methods for reducing the power of a gas boiler are not suitable for all models. Therefore, you first need to figure out which one is suitable for a particular device.

If the power of the gas boiler does not meet the needs of the existing heating system, then it is better not to engage in amateur activities, but to contact the service center specialists. They will take into account all the features of a particular device and provide qualified assistance.

It often happens that over time the number of heat consumers increases and, accordingly, the power of the boiler room no longer becomes enough. What to do if the capacity of the existing boiler house is not enough?

Basic data: determine thermal power

Before starting calculations, you need to analyze a number of parameters:

type of object, its purpose (private house, office building, warehouse, industrial facility, etc.);
architectural data (sizes of windows, doors, floors, walls and roofs, their thickness, type of materials and insulation, design);
temperature conditions (according to SNiP 2.04.05-91);
special information (according to the purpose of the facility: duration of the heating period, number of working days, how many people work per shift / permanently live in the house, how many hot water points, etc.).

Industrial boiler room for an enterprise

All these parameters provide basic information about the heating system and will allow you to determine the power that, depending on the type of object, will be spent on:

heating the object;
operation of the ventilation and/or air conditioning system;
DHW.

Boiler room power is the total heat consumption for all intended directions. It is necessary to take into account technological and heating needs, calculate the hot water supply system, etc. If the fuel is natural gas, for gasification of the boiler house you need to obtain project approval, and for this you need to provide an accurate calculation of the boiler house capacity and fuel consumption for the year.

Gas boiler room

In addition to the usual calculations, experts provide a power reserve, which allows the boiler room to operate even under increased loads, if necessary, to modernize it and increase its service life. Based on the calculation results, equipment is also selected for the boiler room and, if necessary, for objects supplied with heat.

How to increase the power of a gas boiler?

It happens that the power of the existing gas boiler is not enough to meet all the needs placed on it. Often an increase in unit performance is required in the following cases:

when re-equipping the heating system in order to increase its power, for example, adding the number of sections;
when connecting an indirect heating boiler, heating of which will require about 20% of the unit’s performance;
increasing the heated area due to extensions or adding previously unheated rooms.

If the required power is greater than the maximum capacity of the gas boiler, you will have to solve the problem using more complex methods:

The simplest, but also most expensive way is to install another unit, a convector or electric boiler.
Replace the burner device with a more efficient one.
Increase the cross-section of the nozzles, due to which they pass a larger volume of fuel - as a result, the boiler heat transfer increases. However, it should be taken into account that this option reduces the efficiency of the device, fuel consumption increases, and the process of burner failure also accelerates.

What you need to know to calculate

An elementary calculation of a boiler for a house based on its quadrature is as follows: 1 kW of power is consumed per 10 m² and 10% is added to the resulting number in reserve. However, with all the convenience of such mathematics, it should be taken into account that the layout of all houses is different, and everything cannot be adjusted to one template. In addition, the walls of houses are built from various materials, each of which has its own thermal insulation characteristics. Wood, for example, holds heat well, but stone and brick need additional insulation and more powerful heating.

A similar formula for calculating the required power was relevant during the Soviet era, when every second house was built from red baked brick. It does not take into account modern construction technologies; moreover, the formula may turn out to be completely unsuitable for areas with extremely cold climates. This is a very approximate and rough calculation, which, nevertheless, can give an initial idea of where to start when choosing a boiler. It is applicable for houses with small heat losses, for example, where the rooms have a maximum height of 3 m, and metal-plastic double-glazed windows are installed on the windows.

However, not all private houses and cottages can boast of such insulation, and therefore it is best to entrust the final calculation to professionals or use online calculators. In this case, you should take into account not only the square footage of the house, but also the material from which the walls are built, the thickness of the thermal insulation layer, the height of the ceilings, etc. But at the same time, one must understand that theoretical power does not in all cases correspond to conditions in reality.

In the image below you can see a graph of the power of the heating network depending on the square footage of the house:

To create a more detailed calculation of boiler power for a private home, it is necessary to take into account many factors:

climatic conditions of your region;
house square;
presence of an attic;
how well the house is insulated;
wall thickness;
the material from which the house is built;
Is the foundation insulated?
presence of a basement;
the amount of energy required to heat water.

In houses where a forced-type ventilation system is installed, the calculation of the boiler power should include the amount of energy needed to warm the air in the rooms. Usually, the easiest way to do this is to use special programs, which are a dime a dozen on the Internet. They allow you to avoid errors in calculations and give the most accurate results.

It should be noted that in fact, the specific power of the heating system of a house can increase to 127 W/m² with a square area of 100-150 m², and vice versa - drop to 85-80 W/m² in spacious houses with an area of 400-500 m². As you can see, these indicators differ from the generally accepted template value of 100 W/m² used for preliminary selection of equipment. This discrepancy is explained by the fact that in small buildings heat is wasted inefficiently from a heating engineering point of view. When the area is large, then inside the house there are many rooms with adjacent internal partitions and walls, so heat spreads through them and heat loss is reduced.

Helpful advice: When calculating the boiler power, it is better to add not 10%, but 20% in case of an unusually cold winter or system malfunction.

Some may think: “Why not immediately buy a very powerful boiler and forget about these calculations?” We hasten to warn you against such a decision, since exceeding the recommended power of the equipment will lead to increased costs and a decrease in the efficiency of the boiler itself. In addition, malfunctions in the operation of automation, rapid wear of components, the appearance of condensation in the chimney and other unpleasant events cannot be ruled out. When calculating a boiler, you need to try to “hit the bull’s eye” and select the power that is suitable specifically for your home.

How to reduce power?

Reducing the power of a gas device is usually required in the following cases:

after alteration of the heating system, as a result of which its performance decreased;
if you lose the need for some additional functions: hot water supply, heated floor system, etc.

Find out here what is a gas boiler power calculator?

What is important to consider when calculating the power of a gas boiler for a house or apartment?

Replace the burner device with a modulating analogue.
Reduce the gas supply to the burner - this is done by changing the gas valve settings.
Change the service menu settings: anti-cycling time, heat exchanger temperature.
Adjust the operation of the circulation pump.

However, the listed methods for reducing the power of a gas boiler are not suitable for all models. Therefore, you first need to figure out which one is suitable for a particular device.

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Good afternoon. I turn to professionals in the construction and repair business for intellectual assistance. In the fall, I installed individual heating in the house, that is, a gas boiler and changed the batteries. But for some reason the heat transfer is not very strong. What can be wrong? In the power of the boiler, or in the batteries themselves, maybe in their quantity?

(Registered visitors do not see this advertisement - registration)

Of course, this is a very pressing question; the boiler itself must be selected correctly, guided by the facts, namely the number of square meters of housing, and the number of batteries in your house. Each boiler is designed for a certain power, the consumption of which depends on the amount of water in the system.

Good evening! Without adjusting the minimum pressure using a pressure gauge, nothing good will happen. An increased flame will simply overheat the boiler and the automation itself will begin to clamp down on the pressure. The result is a small flame, very small.

Good evening! Without adjusting the minimum pressure using a pressure gauge, nothing good will happen. An increased flame will simply overheat the boiler and the automation itself will begin to clamp down on the pressure. The result is a small flame, very small.

When installing, you should take into account the square footage of the heated room and use it to determine the number of batteries. In each gas boiler, burner settings must be set, according to which the gas fittings and boiler electronics are adjusted in 4 stages. The settings determine the power and pressure of the gas boiler.

If I understand the question, then the picture turns out like this: I installed something and replaced it with something, and I want it to be hot!! what kind of boiler do you have there? Raise the heating temperature of the coolant; at the same time, it is necessary to increase the power of the coolant pump.

How to calculate boiler power?

PS I read the whole topic by chance and realized that there was no answer to the first question. Boilers are calculated based on fuel consumption.
Fuel consumption is easily regulated (nozzle diameter, air supply, etc.) And heat transfer for each type of fuel is well known. From here you can always calculate what happened. By the way, in any, even the oldest, heating design reference books, all these calculations are given.
Regarding the most economical difference, a difference of 10 degrees is a misconception. The greater the difference, the more economical it is. In Russia, a difference for housing of 25 degrees (95-70) is accepted; abroad, a difference of 20 degrees is often used: 90-70 and 60-40

You are mistaken, because the law of conservation of energy has not yet been canceled. And heating systems are different, as are all related equipment.

Regarding the calculation of the boiler:

The formulation of the question itself is not entirely correct here. It is not clear what a person wants to know - what power of boiler he needs for heating, or how to calculate (determine) the power of an existing boiler, or how to calculate a boiler based on the required power.

The theory is correct, but in practice many things are slightly different when designing a boiler. If you rely only on fuel consumption and calorific value, you can make many mistakes. For example, it is impossible to find out the efficiency of a boiler before its creation; you can only do all possible techniques to increase efficiency and minimize heat loss. For example, there are gas boilers with an efficiency of more than 100%, which use the principle of abrupt energy release during the condensation of water vapor, a product of gas combustion. In solid fuel boilers, the story is completely different; the efficiency is generally difficult to predict with sufficient accuracy. And the process of burning solid fuel also has its pitfalls - air supply, combustion or airless decomposition, firebox shape, etc. etc.

About the temperature difference:

I didn’t say that a delta of 10 degrees is the most economical. And the fact that it is the most rational in the conditions of small systems is for sure. The 95/70 mode is simply dangerous for life in unregulated systems, and the standards set the 70/50 mode. But in any case, with large networks, the adjustment follows a network schedule depending on the outside air temperature.

In small systems, especially with forced circulation, for example in cottages, it is practically impossible to achieve such a regime, because Imagine what temperature in the room would have to be to ensure a drop of 20 degrees in one radiator. Such a difference is possible only in systems with natural circulation with not the best thermal insulation of the room or at low power.

A difference of 25 degrees is also possible in urban systems, where heating networks with stripped insulation often run from some thermal power plant or boiler house or there are no doors in the entrances in winter, etc. So you get a difference of 25 degrees, where 30% goes to losses.

Also, the 95/70 mode is more used for air heating with heaters, i.e. heating with warm supply air or in air curtains, etc.

The boiler itself (I don’t pretend to be original). As for heating with electricity, I can argue a little with examples, but in the evening.

As far as I can tell, you are going to make a solid fuel boiler, and your design is heating tubes.

I'll take the responsibility to criticize your design a little:

Apparently you want to make a system with natural circulation, I can judge this from the unique location and diameter of the coolant inlet and outlet.

So, a mandatory criterion for such a boiler should be its volume! Heating boilers with a natural circulation system must have such a volume and design that it completely eliminates the possibility of boiling of the coolant in the boiler. This means a large boiler volume and a design without thin tubes and small thicknesses of the water jacket.

Boilers for systems with natural circulation boil and explode quite easily, especially if the system is not handled carefully.
Modified on 08/20/2009 21:09 by Gribnick

How to obtain permission to install and replace a gas boiler

Permission to use gas must be obtained from the regulatory organization operating in the given region. Usually this is Gorgaz or Oblgaz. To complete all the necessary documents, you will need to go through several stages of registration:

Specifications for connection to the main line - the expansion will indicate that the technical conditions of the building and the parameters of the gas pipeline allow the connection of boiler equipment.

To produce specifications, it will take from several weeks to a month.

Replacing a heating boiler

Emergency service on duty 24 hours a day Services for replacing a boiler in a private home:

Has the heat exchanger of the floor-mounted steel Ishma burned out?

Constant overheating of the Baxi Slim gas boiler?

The wall-mounted double-circuit Beretta is 7 years old, but there is bad hard water in the well and you have changed the secondary heat exchanger more than once? What to do in such cases? Don’t worry, with us you get full technical support and bringing your heating to perfect working condition, and the team of specialists from our service center is always ready to replace heating devices.

Making solid fuel boilers with your own hands

This article will discuss the assembly of a vertical solid fuel device with a metal body. It will be installed on a brick base.

The boiler parameters are designed for a house with an area of 90 - 100 square meters. Calculation of a heat accumulator for a solid fuel boiler showed that the unit will have 7 cast iron radiators and two-pipe wiring.

To make a homemade solid fuel boiler you will need the following tools:

Bulgarian;
cutting torch;
electric drill plus a set of drills;
pliers and forceps;
construction level, preferably laser;
metal square;
roulette;
protective face mask.

To make the case you need:

heat-resistant steel sheets 4-5 millimeters thick. You can use material of greater thickness, but then the boiler will heat up longer, but the service life of the unit will increase;
refractory brick (you can also use refractory brick);
grate;
doors for combustion and ash openings;
purified sand.

Calculation of the power of a gas boiler for a private house: recommendations and example calculations

For private houses built according to a standard design, with a ceiling height of about 3 meters, the calculation formula looks quite simple.

In this case, it is necessary to take into account the area of the building (S) and the specific power of the boiler (SPC), which varies depending on the climatic zone. He hesitates:

From 0.7 to 0.9 kW in the southern regions of the country
From 1.5 to 2 in the north of the country
From 1 to 1.2 kW in midland regions
From 1.2 to 1.5 kW in the Moscow region

Thus, the formula for calculating the gas power for a typical private house will look like this: Let's try to calculate the required power of the unit for a house of 80 m², located in the northern region.

How can you calculate thermal power

The minimum thermal power (Qt, in kW/h) can be calculated using the following formula:

Qt = V * ∆t * K / 860

The volume of the room (V) to be heated is taken into account (length*width*height, in m3), the difference between the planned temperature inside and outside (∆t, in °C) and the heat loss coefficient (K), which depends on the type of structure and its thermal insulation . In particular, a heat loss coefficient of 3 to 4 is a simple wooden or metal structure without thermal insulation, and 0.6 - 0.9 is a structure with good thermal insulation. As for ∆t, this indicator depends on the climatic conditions of a particular area and on the requirements for heating the object. SNiP 2.04.05-91 indicates regional features, with which designers check if necessary.

Insulated hangar

These simplified calculations do not take into account many data, such as the location of rooms. In particular, more heat is needed for corner rooms, as well as for rooms with wide windows and high ceilings, while rooms without windows and with good thermal insulation have minimal heat loss. Therefore, designers can use this calculation of heat supply to a boiler room, taking into account the specific heat loss (W/m2) and the area of the room to be heated (S):

Qt = (100 W / m2 * S * K1 * K2 * K3….) / 1000

The following factors are taken into account:

heat loss coefficients from windows (with values for different types of double-glazed windows, K1), from walls (with different types of thermal insulation, K2);
percentage ratio of window and floor area (K3);
outside temperature (K4, for example, at -25°C the coefficient is 1.3);
the number of walls facing the street (K5, for example, for two external walls 1.2);
type of room above the heated one (K6, for example, for a cold attic 1.0);
height of the heated room (K7, for example, for 3 m = 1.05).

A significant amount of data is taken into account, and this formula is applicable to indicate the thermal power of a boiler room that will operate on small objects. For large objects, even more data is provided.

the thermal power of the boiler room can be determined of which is done by professionals based on existing standards and deep knowledge in the field of heating engineering.

You can calculate the cost of a heating project using the calculator below: