Contents
The power of a gas boiler is an important parameter on which the comfort of living in the premises heated by it depends. To choose the best option for a house or apartment, you need to consider their size. The required performance of heating equipment depends on the area of heated premises and some other, less significant factors.
What affects the calculated power
The boiler must not only make up for all the heat losses of a particular building or room, but also have a certain power reserve. Why is it necessary to take a value greater than the calculated one:
- equipment should not work at its limit – this leads to premature wear;
- the possibility of abnormal temperatures must be taken into account;
- for a private house, it is useful to consider the possibility of expanding the area.
Some buyers do not know in what units the main parameter of gas equipment is calculated, which determines its performance. The thermal power of the devices is measured in kilowatts (kW). This value is always indicated in the technical data sheet of each model.
What affects heat loss
To find out what equipment performance is needed, in addition to the area, you need to take into account other factors:
- climate in a particular region;
- the volume of the residential building/apartment;
- degree of insulation;
- likely heat loss.
When using turbocharged devices, it is also necessary to take into account the amount of energy spent on heating the air.
To determine the performance of the boiler, you must first calculate the heat loss. Thermal engineering calculation is characterized by increased complexity, since it takes into account a huge number of components:
- materials from which walls, floors, roofs, etc. are built;
- type of wiring of the heating system;
- the presence of a “warm floor” system;
- household appliances that generate heat.
Professionals use thermal imaging cameras and then perform complex formula calculations. It is clear that the average user does not have to understand the nuances of heat engineering – there are available methods for them that allow you to quickly and accurately calculate the optimal heat output of the equipment.
What are the calculation options
To make the right choice of gas equipment, we suggest using three calculation options:
- Accurate thermotechnical – not suitable for ordinary consumers, complex and requires the use of a thermal imager.
- On the online calculator – to get the result, the user enters the initial data into a special program: the number of windows, doors, wall thickness and other information. Based on them, the program produces a result.
- Manual calculations. The most accessible way to find out the optimal heat output of a heater is to use the elementary ratio of area and power. The formula used is: 10 m² = 1 W. Such a simple option is correct for structures characterized by an average degree of thermal insulation and having ceilings about 000 m high.
Developers, when calculating the power characteristics of heating devices, often take into account the volume of the premises. In the technical documentation of imported models, the parameter “heating in m³” is often found.
Calculation of the power of a boiler with one circuit
After performing the simplest calculation for a single-circuit wall or floor boiler using the ratio: 10 kW per 100 m², you need to increase the calculated value by 15–20%.
Let’s give an example of calculations. It is necessary to equip a house with an area of 80 m². For its heating, you will need a device for 9 W = 600 W + 8%. If there is no exactly suitable option on sale, you should take a modification with greater productivity. This method of calculation is only suitable for devices with one circuit, without an indirect heating boiler.
Calculation of boiler power with two circuits
We calculate based on the following ratio: 10 m² = 1 W + 000% (reserve) + 20% (water heating). If the house has an area of 20 m², then the desired value will be: 200 W + 20% = 000 W.
Determining the power of a model with a boiler
First, the required volume of the boiler is determined so that it can meet the needs of the household for hot water. Water consumption is calculated taking into account the operation of all water intake points:
- bath – 8-9 l / min;
- shower — 9 l/min;
- toilet – 4 l / min;
- washing – 4 l / min.
The technical documentation for the boiler indicates what boiler performance is required to provide water heating. For a boiler for 200 liters of water, a heater with a power of approximately 30 kW is suitable. Then calculate the performance required for heating. The results obtained are summarized. At the end of the calculations, 20% must be subtracted from the result obtained, since the heating of water for hot water supply and heating occurs simultaneously.
Calculation of boiler power for typical houses, taking into account the climatic zone
For houses built according to standard projects, the formula is used: M u10d S * UM / XNUMX, where
- М/УМ — design/specific power, kW;
- S – area, m².
UM depends on the region, kW:
- south — 0,7–0,9;
- the middle band is 1,0–1,2;
- Moscow region – 1,2–1,5;
- North – 1,5–2,0.
Let’s perform calculations for a house with an area of 300 m², located in the suburbs: 300 * 1,3 / 10 u39d 25 kW. This result is suitable for the installation of single-circuit models. To calculate the power of a dual-circuit apparatus, it is necessary to increase the final number by XNUMX%.
Do you need extra power?
You should not buy a model with a performance that significantly exceeds the maximum rate (taking into account the surcharge of 15-20%). Excess leads to negative consequences:
- High price. The more powerful the model, the more expensive it is. It is irrational to acquire equipment, the capabilities of which will not be used.
- Rising costs for consumables.
- Low burner efficiency – this will affect the gas flow.
- At minimal loads, automation often fails.
- If the equipment is not optimal for a specific area, accelerated wear of components and parts occurs.
How to calculate expenses
Knowing the power characteristics of the equipment, it is possible to calculate the gas consumption. The calculation takes into account the efficiency. Standard versions have an efficiency of 92-93%, condensing type models – 108-109%. With 100% heat transfer, 10 kW of thermal energy is generated after the combustion of 1 m³ of natural gas. Thus, to create a power of 10 kW with an efficiency of 92%, the fuel consumption will be 1,12 m³, and with an efficiency of 108% – 0,92 m³.
When calculating the volume of fuel consumed, the performance of the devices is taken into account. The 10 kW model burns 1,12 m³ of gas per hour, and the 40 kW model burns 4,48 m³. Manufacturers often indicate in the technical documentation the average value of fuel consumption, but still it is different for each model.
To know the upcoming heating costs when using volatile versions, you must also calculate the electricity costs.
How to take into account the height of the ceilings
The above calculation formulas are suitable for buildings whose ceiling height does not exceed 3 meters. If the ceilings are higher, you need to use other formulas: M uXNUMXd Q * K, where:
- M is the calculated power, kW;
- Q is heat loss, kW;
- K – safety factor.
K u1,15d 2-15, or 20-XNUMX%.
To calculate heat loss, use the formula:
Q = V*P*k/860, where:
- V is the volume of premises, m³;
- P is the difference between the temperatures in the house and outside, °C;
- k is the dissipation factor, which depends on the thermal insulation characteristics of the structure.
The value of the coefficient is determined by the type of structure:
- not having thermal insulation: wooden structures, buildings made of corrugated iron sheets – 3,0-4,0;
- with low thermal insulation – 2,0-2,9;
- with medium thermal insulation – 1-1,9;
- with high thermal insulation – 0,6-0,9.
If the building is small and has good thermal insulation characteristics, a large boiler capacity will not be required. It happens that there is no option for sale with suitable characteristics. Then you need to take the option with a heat output slightly higher than the calculated value. The difference will be smoothed out by automatic control systems.
Online calculator
The most advanced manufacturers have thought about the comfort of consumers by placing online calculators on their websites that allow you to easily and quickly find out the required performance of gas equipment. The following information is entered for the calculation:
- the temperature that the consumer wants to have in the house;
- the average temperature outside during the coldest week;
- availability of hot water supply;
- number of storeys;
- ceiling height;
- floor material;
- the thickness of the walls and the materials from which they are built;
- wall length;
- number of window openings;
- window features – design details;
- window dimensions.
By filling in the fields, you can quickly calculate the calculated value of heat output.
Choose wall or floor boilers
The choice of the type of heater installation depends not only on the preferences of the consumer, but also on the calculated heat output.
Wall-mounted boilers, unlike floor-standing ones, have a smaller power range. They are compact, they can be placed in the kitchen, attic, in the basement.
Floor models are more bulky, they are usually installed in separate rooms. Wall versions are presented with a power range of 12-36 kW, the performance of floor models can reach 160 kW.
The functionality of the wall and floor versions is not much different. Modern devices of both types involve manual or automatic control.
In apartments, as a rule, they buy wall-mounted models – they are compact and easily fit into the interior of the kitchen. For heating large houses and cottages, more powerful floor heaters are used. Atmospheric versions are installed in separate, well-ventilated rooms. For rooms in which turbocharged devices are mounted, the requirements are much lower.
What else affects the choice
In addition to heat output, you need to consider:
- number of circuits (only heating or heating and hot water is needed);
- installation method (wall or floor);
- combustion chamber (open or closed; in the first case, air is taken from the room, in the second – from the street through a coaxial chimney);
- design – for consumers, appearance is not the last thing. Modern devices are not only functional, efficient, safe, but also beautiful.
The correct choice of the thermal performance of the gas boiler will allow you to use the equipment with maximum efficiency. An optimally selected model will not only provide a comfortable temperature in the house, but will also serve with minimal wear on parts and assemblies.