Table of Contents

## Choosing a gas boiler for heating the cottage

Heating in the cottage, should be self-contained, efficient and economical. Equipment running on mains gas meets all these requirements. Modern gas boilers for heating the cottage, have a high thermal efficiency, operate in fully automatic mode and can simultaneously connect to multiple water heating circuits.

## Let’s make a correct calculation of the output of gas heating **boiler**

One of the first parameters that people pay attention to when choosing heating equipment, is the capacity. Calculation of gas heating boiler capacity, perform in several ways. The comfort during operation depends on accurate calculations.

## Why count when you can buy a boiler with a capacity reserve?

Sometimes boilers have reserve capacity. It is good when the reserve is not more than 25%. Especially when the family is planning to develop the area: to complete the pool, sauna, or other heated area. When the required capacity is significantly exceeded, the owner spends extra money and the equipment operates in an off-normal mode:

- Breaks down or malfunctions;
- The efficiency of the system decreases;
- The boiler of higher power costs more;
- fuel is consumed than required to heat the house;
- Will need a more powerful and expensive pump;
- It will be very hot in the house;
- Automatic control is difficult, the boiler can boil;
- The boiler begins to tumble. Switching on and off in a short period of time, the nodes of the equipment wear out;
- Condensation appears in the chimney. When burning, condensate reacts with emissions and acid is formed. It destroys the chimney and sometimes the boiler.

Conclusion; It wastes more fuel when it is turned on and off frequently than when it is run continuously. Buying a boiler with more power not only makes no sense, but is harmful to the budget and equipment.

## How to **choose** a gas boiler for a private house by area

Maximum efficiency, functionality and safety of the heating system is the key to comfort and warmth in any building. Choice of gas boiler for a private home is important enough, this equipment will provide autonomy of construction and will be the main source of heat.

Before you pay money for this device, you need to thoroughly understand all the features, I will share my experience, what you should pay attention to first.

Each owner will be interesting to compare foreign and domestic manufacturers, and the rating of different models will certainly help to **choose** the most practical and productive unit for a private home, how to **choose** a boiler for heating a private house will tell in detail.

**Boiler** selection **according** to the **area** of the private house. How to make a calculation?

This calculation is more accurate because it takes into account a huge number of nuances. It is produced **according** to the following formula:

- 0.1 kW. norm of the necessary heat for 1 m².
- S.
**area**of the room to be heated. - k1 shows the heat that has been lost due to the structure of the windows and has the following values:

- 1,27. the window has single glass
- 1,00. window with glazing
- 0.85 for a triple glazed window

- k2 shows how much heat is lost through the window area (Sw). Sw refers to the floor area Sf. Its values are as follows:

- 0,8. when Sw/Sf = 0.1;
- 0,9. at Sw/Sf = 0.2;
- 1,0. at Sw/Sf = 0.3;
- 1,1. at Sw/Sf = 0.4
- 1,2. at Sw/Sf = 0.5.

- k3 shows the heat leakage through the walls. Can be as follows:

- 1.27. poor insulation
- 1. building wall is 2 bricks thick or 15 cm thick insulation
- 0.854. good thermal insulation

- k4 shows the amount of heat lost due to the temperature outside the building. Has the following values:

- 0.7 when ts =.10 °С;
- 0.9 for ts =.15 °С;
- 1.1 for tz =.20 °С;
- 1,3 for ts =.25 °С;
- 1.5 for tz =.30 °С.

- k5 shows how much heat was lost through the outside walls. Has the following values:

- 1.1 for a building with 1 external wall
- 1.2 there are two external walls
- 1.3 in the building 3 external walls
- 1.4 the building has 4 exterior walls

- k6 indicates the amount of heat additionally required and depends on the ceiling height (H):

- 1. For a ceiling height of 2.5 m;
- 1,05. for a ceiling height of 3.0 m;
- 1,1. for a ceiling height of 3.5 m
- 1,15. for a ceiling height of 4.0 m;
- 1,2. for a ceiling height of 4.5 m.

- k7 shows how much heat has been lost. It depends on the type of building that is located above the heated room. Has the following figures:

- 0.8 heated room;
- 0.9 warm attic;
- 1 cold attic.

As an example, let’s take the same initial conditions, except the parameter of windows, which are triple-glazed and account for 30% of the floor **area**. The building has 4 exterior walls and a cold attic on top of it.

This figure must be increased by adding the amount of heat required for DHW, if it is connected to a **boiler**.

If there is no need to perform precise calculations, you can use the universal table. You can use it to determine the output of the boiler by the area of the house. For example, to heat a 150 sq. m. room, a 19 kW boiler is suitable, and for heating a 200 sq. m. room, a 19 kW boiler with a 19 kW output is suitable.м. will already require 22 kW.

Option | Home area, sqm.м. | Heating, kW | Number of devices | Number of people | DHW boiler, l/kW |

1 | 150 | 19 | 10 | 4 | 100/28 |

2 | 200 | 22 | 11 | 4 | 100/28 |

3 | 250 | 25,5 | 17 | 4 | 160/33 |

4 | 300 | 27 | 20 | 6 | 160/33 |

5 | 350 | 31 | 26 | 6 | 200/33 |

6 | 400 | 34 | 30 | 6 | 200/33 |

7 | 450 | 36 | 44 | 6 | 300/36 |

The above methods are very useful, calculate the boiler capacity to heat your home.

## Calculator for calculating the output of the heating boiler

Boiler output is one of the most important characteristics of heating equipment. Excess capacity will result in overpayment for the boiler, deficiency. the inability of the equipment to heat living space or heat water in the DHW system. Therefore, before choosing a boiler, we propose to estimate its parameters not without the help of our online calculator to calculate the capacity of the boiler heating. Let’s try to understand the values you will have to enter to get a reliable result.

## Calculating the capacity of the gas boiler depending on the **area**

In most cases, use an approximate calculation of the thermal capacity of the boiler unit by heating area, for example, for a private home:

Keep in mind that these standards were adopted in Soviet times and do not provide for the level of thermal insulation characteristics of modern building materials. They are also not applicable in areas, the climate of which differs significantly from the conditions of the central regions of Russia and the Moscow region.

Such calculations can be suitable for a not very large building with insulated attic floor, low ceilings, good thermal insulation, windows with double glazing, but no more than that.

Unfortunately, only a few buildings meet these conditions. In order to carry out the most thorough calculation of the boiler output indicator, it is necessary to take into account a full package of interrelated values, including:

- atmospheric conditions in the area;
- The size of the residential building;
- coefficient of heat conductivity of the wall;
- the actual thermal insulation of the building;
- system for regulating the power of the gas
**boiler**; - The amount of heat required for DHW.

### Calculation of single-circuit heating boiler

Calculation of capacity of one-circuit boiler wall or floor modification boiler using the ratio: 10 kW per 100 m2, you need to increase by 15-20%.

For example, to heat a building of 80 m2.

Calculation of the capacity of the gas heating boiler:

In the case where the trade network does not have the required type of device, purchase a modification with a larger size of kW. This method will be suitable for single-circuit heating sources, without the load on the hot water supply, and can be the basis for calculating the consumption of gas for the season. Sometimes, instead of the living space, the calculation is carried out taking into account the volume of the apartment building and the degree of insulation.

For individual premises built **according** to a typical project, with a ceiling height of 3 m, the calculation formula is quite simple.

This variant takes into account the area of the building (P) and the coefficient of specific power of the boiler unit (PMU), depending on the climatic location of the object.

Consequently, the formula for calculation is as follows: Mo=PUMK/10

For example, the required capacity of the heating source for a building of 80 m2, located in the northern region:

If the owner will install a dual-circuit boiler set for heating and DHW, professionals advise to add to the resultant power of another 20% of the heating water.

### How to calculate the capacity of a two-circuit boiler

Calculation of the heat capacity of a two-circuit boiler unit is performed on the basis of this proportion:

10 m2 = 1,000 W 20% (heat loss) 20% (DHW heating).

In the case of a building with an area of 200 m2, the required size would be: 20.0 kW 40.0% = 28.0 kW

This is an approximate calculation, it is better to clarify the norm of water use of DHW per person. Such data are given in SNIP:

In the documentation for the water heater specifies what the **boiler** heat output is required to ensure high-quality water heating.

For a 200 litre heat exchanger, a heater with a capacity of approximately 30.0 kW. After calculating the capacity, sufficient for heating, at the end of the calculation add up.

### Calculating the power of the indirect heating boiler

In order to balance the required capacity of a single-circuit gas-fired unit with a boiler of indirect heating, you need to establish how much heat exchanger needed to provide hot water to the tenants of the house. Using data on the norms of hot water consumption can be easily established that the flow rate per day for a family of 4 people will be 500 liters.

Performance of the indirect water heater is directly dependent on the **area** of the internal heat exchanger, the more the size of the coil, the more heat energy he transmits to the water in an hour. You can detail such information by studying the specifications on the passport of the equipment.

There are optimal ratios of these values for the average power range of indirect heating boilers and the time to obtain the desired temperature:

When choosing a water heater, it is recommended that it heats water in about half an hour. Based on these requirements, variant 3 of the BKN is preferable.

## Calculation of the power of the heating boiler by the **area** of the house

Autonomous heating system requires special equipment, the power of the boiler is as important as the fuel on which it will operate. There are devices on liquid, solid fuel, gas and with direct connection to the power grid.

### How to **choose** the proper size for your boiler

Regardless of the type of device to achieve maximum indoor comfort in winter, it is necessary to properly make calculations. If you miss this, you will not get a good temperature, some nuances will also lead to increased equipment costs, I want to give effective advice on this and help avoid fatal mistakes after starting the system.

## How to calculate the boiler capacity

Wattage of a heating boiler is a basic parameter determining its abilities for optimal heating of rooms during the peak loads. Here the main thing. competently calculate how much heat is needed for heating. Only in this case it will be possible to **choose** the right boiler for heating a private house **according** to its capacity.

To calculate the **boiler** capacity for the house use different methods, which are based on the area or volume of heated rooms. Quite recently the necessary boiler output was determined by means of the so-called house coefficients, established for various types of houses within the range (W/m2 ). kv.):

- 130200. houses without thermal insulation;
- 90110. houses with partially insulated facade;
- 5070. houses built
**according**to the technologies of the XXI century.

### Boiler power calculation **according** to geometric dimensions of the premises

Approximately, you can calculate the capacity of the boiler for heating the house by its area. In this case the formula is used:

- Wkot. calculated boiler power, kW;
- S is the total
**area**of the heated room, m. sq.m.; - Wud. boiler’s specific power, which falls on every 10 m. sq.m. of heated area.

In general, assume that, depending on the region in which the room is located, the value of specific power of the boiler is (kWh/m. kv.):

- For southern regions. 0,70,9;
- for areas of the middle belt. 1,01,2;
- for Moscow and Moscow region. 1,21,5;
- for the Northern regions. 1,52,0.

If it is assumed that the room will be set in a two-circuit boiler, which in addition to heating must provide users with hot water, the resulting calculated capacity must be increased by 25%.

If the height of heated premises exceeds 2,5 m., the obtained result is corrected by multiplying it by the coefficient Kv. Кв = Н/2,5, where Н is an actual room height, m.

In this case, the final formula looks as follows: P = (SWud/10)Kv

This method of calculating the necessary output that the boiler must have is suitable for small buildings with an insulated attic, insulated walls and windows (double glazing), etc. д. In other cases, the result obtained as a result of approximate calculation can lead to the fact that the purchased boiler will not work in the normal mode. At the same time, excessive or insufficient power contributes to a number of undesirable problems for the user:

- Reduction of the technical and economic performance of the boiler;
- malfunction of automation systems;
- fast wear and tear on parts and components;
- Condensate formation in the chimney;
- clogging of the chimney by products of incomplete combustion of fuel, etc.;

For a more accurate result the actual heat losses through the individual building components (windows, doors, walls, etc.) must be taken into account.).

### Refined calculation of the **boiler** output

The calculation of the heating system, which includes a heating boiler, should be performed individually for each object. In addition to its geometric dimensions, it is important to take into account a number of parameters:

- the presence of forced ventilation;
- climatic zone;
- the presence of hot water;
- degree of insulation of separate elements of the object;
- the presence of an attic and a cellar, etc.
- Qt. heat loss of the object, kW.
- Kzap. reserve coefficient, by the value of which it is recommended to increase the calculated capacity of an object. As a rule, its value is in the range 1,151,20 (15-20%).

Predicted heat losses are determined by formulas:

- V. volume of the room, m. cube.;
- ΔT. difference between outdoor and indoor air temperatures, °С;
- Кr. dissipation factor, which depends on the thermal insulation of the object.

The dissipation factor is chosen based on the type of building and its degree of thermal insulation.

- Facilities without thermal insulation: hangars, wooden huts, corrugated iron structures etc Kd = 3,04,0.
- Buildings with low level of thermal insulation: one brick walls, wooden windows, slate or iron roof. Kp is taken equal to within 2.02.9.
- Moderately insulated houses: two-brick walls, few windows, standard roofing, etc. д Kd is 1,01,9.
- Modern, well-insulated buildings: underfloor heating, double-glazed windows, etc. д Kp is in the range of 0.60.9.

To make it easier for the consumer to find a heating boiler, many manufacturers place special calculators on their websites and dealer sites. With their help, by entering the necessary information into the appropriate fields, you can determine with a high degree of probability the **area** for which the boiler is designed, for example, 24 kW.

Typically, this calculator calculates the following data:

- The average outside temperature during the coldest week of the winter season;
- the temperature of the air inside the object;
- the presence or absence of hot water supply;
- data on the thickness of the external walls and ceilings;
- materials of which the ceilings and exterior walls are made;
- ceiling height;
- geometric dimensions of all exterior walls;
- The number of windows, their dimensions, and a detailed description;
- information about the presence or absence of forced ventilation.

After processing the data, the calculator will give the customer the required heating boiler capacity, as well as indicate the type and brand of unit that meets the request. An example of the calculation of the line of gas boilers, designed for heating houses of different sizes, is shown in the table:

Note to column 11: Hs. hinged atmospheric boiler, A. floor type boiler, ND. wall mounted turbine boiler.

The above methods are used to calculate the capacity of the gas **boiler**. However, they can also be used to calculate the power characteristics of water heating units operating on other fuels.