How to calculate the heat load for heating

For any homeowner, making sure their house stays warm and comfortable throughout the winter is a top priority. But finding the ideal mix between efficiency and comfort necessitates carefully weighing a number of variables, the heat load calculation for heating being one of the most important. To ensure your heating system is operating at its best, you must determine how much heat your home needs to maintain a comfortable temperature.

Determining your home’s heat load entails evaluating a number of crucial components that affect the amount of heat gained or lost in the living area. The heat load is influenced by a number of factors, including your home’s size and layout, insulation levels, climate, and even the number and kind of windows. You can accurately assess these factors to find the right heating capacity needed to maintain a comfortable temperature in your home.

Understanding the idea of thermal resistance, also known as R-value, is one of the core components of calculating heat load. This number indicates a material’s capacity to thwart heat transfer, such as insulation. Better insulation has lower heat gain in the summer and lower heat loss in the winter, as indicated by a higher R-value. Proper insulation not only lowers utility costs and energy consumption, but it also enhances comfort.

When calculating heat load, other factors like air leakage and infiltration need to be taken into account. If there are gaps or cracks that allow warm air to escape and cold air to seep in, even the best-insulated homes can suffer from significant heat loss. It is essential to locate these air leaks and fix them with appropriate weather-stripping and sealing in order to reduce heat load and increase energy efficiency.

Moreover, your home’s heat load is greatly influenced by the climate in which it is situated. While milder climates might require less heating power, colder climates need higher heating capacities to withstand the bitter cold outside. Comprehending the distinct heating requirements imposed by your climate facilitates more precise computations and guarantees that your heating system is suitably sized for maximum efficiency.

Calculation of the thermal load on the heating of the building: Formula, examples

Whether you are designing a heating system for a residential or commercial building, you must perform accurate calculations and create a circuit that shows the shape of the heating system. Experts advise paying close attention to calculating the volume of fuel consumed and heat released at this point, as well as any potential thermal load on the heating circuit.

Thermal load: what is it?

The number of heat-heating devices provided by devices is understood by this term. The initial estimation of the heat load can help to prevent needless costs for the purchase and installation of the heating system’s components. Additionally, this computation will support accurate and equitable distribution of the released heat throughout the building.

These computations contain a lot of subtleties. For instance, the region, thermal insulation, the material used to construct the building, etc. In order to get a more accurate result, experts attempt to consider as many variables and characteristics as possible.

Erroneous or imprecise thermal load calculations result in inefficient heating system operation. Even with functional structures, there are times when they need to be redone in certain areas, which leads to unforeseen costs. Yes, and the heat load is used by housing and community organizations to determine how much services will cost.

The main factors

A well-thought-out heating system should compensate for heat losses that occur while maintaining a set temperature in the space. You must consider the following when determining the building’s heating system’s heat load:

– Is the building intended for residential or industrial use?

– attributes of the structure’s structural components. The walls, doors, roof, windows, and ventilation system are among them.

– The size of the residence. The heating system should be more powerful the larger it is. The area of doorways, windows, exterior walls, and the volume of each interior must all be considered.

– the availability of unique rooms (sauna, bath, etc.).

– level of technological device equipment. Specifically, the availability of a hot water supply, air conditioning, ventilation systems, and heating systems of a certain kind.

– the ideal temperature for a solitary room. For instance, you do not need to keep storage rooms at a temperature that is suitable for people.

– the quantity of dots representing the hot water supply. The system is loaded more when there are more of them.

– the area covered by glass. French windows let in a lot of cold air into a room.

– Extra prerequisites. It may refer to the quantity of bathrooms, loggias and balconies, and rooms in residential buildings. Industrial: the number of workdays in a year, shift work, the production process’s technological chain, etc.

The region’s climate conditions. Street temperatures are considered in heat loss calculations. Recompense will require a tiny amount of energy if the differences are negligible. While through the window at -40 ° C will necessitate its substantial costs.

Features of existing techniques

SNiPs and GOSTs contain the parameters used in the thermal load calculation. Additionally, their heat transfer coefficients are unique. Digital features pertaining to a particular heating radiator, boiler, etc. are extracted from the passports of the heating system’s equipment. Additionally, customarily:

– the heating system’s maximum heat consumption for one hour,

– the most heat that can be produced by a single radiator,

– the total cost of heating during a specific time frame, usually a season; In the event that an hourly computation of the heating network’s load is necessary, the computation must account for the variations in temperature throughout the day.

The computations are contrasted with the system’s total area of thermal return. The indicator has a high degree of accuracy. Occasionally, deviations occur. For instance, it will be important to account for the fact that thermal energy consumption decreases in residential buildings at night and on weekends and holidays in industrial buildings.

There are various levels of accuracy in heating system calculation techniques. Very intricate computations must be used in order to reduce the error. If minimizing the cost of the heating system is not the primary objective, less precise schemes are employed.

The main methods of calculation

Currently, one of the following approaches can be used to calculate the thermal load on the building’s heating system.

Three basic

1. For calculation, enlarged indicators are taken.
2. Indicators of structural elements of the building are accepted for the base. Here it will be important to calculate the losses of heat going to heated the internal volume of air.
3. All objects included in the heating system are calculated and summarized.

One approximate

There is one more choice. Because the indicators are either too few or very average, there is a sizable error. Qfrom = Q0 * A * VH * (tYun – tNRO) is the formula in question. Where:

• Q₀ – the specific thermal characteristics of the building (most often determined by the coldest period),
• A – correction factor (depending on the region and is taken from ready -made tables),
• V_H – volume calculated on external planes.

An example of a simple calculation

You can use a straightforward parameter ratio with a regional adjustment to the coefficient for a structure with standard parameters (rooms, ceiling heights, and good heat-insulating qualities).

Assume that a residential structure with a total area of 170 square meters is situated in the Arkhangelsk region. There will be a 27.2 kW/h thermal load (17 * 1.6).

This definition of thermal loads ignores a number of crucial elements. For instance, the temperature, the number of walls, the proportion of windows to walls, the structure’s design elements, etc. As a result, these calculations are inappropriate for significant heating system projects.

Calculation of the heating radiator by area

It is dependent upon the material used to make them. Nowadays, radiators made of bimetallic materials, steel, aluminum, and very seldom cast iron are used. Every one of them possesses a unique thermal power indicator for heat transfer. Bimetallic radiators with 500 mm between the axes typically have 180–190 watts of power. The indicators on aluminum radiators are nearly identical.

One section calculates the heat transfer of the radiators that are described. Radiators with steel plates are not elegant. As a result, the size of the entire device is used to calculate their heat transfer. For instance, a two-row radiator measuring 1,100 mm in width and 200 mm in height will have a thermal power of 1,010 watts, and a steel panel radiator measuring 500 mm in width and 220 mm in height will have a thermal power of 1,644 watts.

The heating radiator calculation on the area is based on the following fundamental parameters:

– the standard ceiling height of 2.7 meters,

– thermal power (100 watts on a kV m basis),

– A single outside wall.

According to these calculations, 1,000 WT of thermal power are needed for every 10 kV.m. The thermal return of one section is separated out of this result. The necessary number of radiator sections is the solution.

Reducing and increasing coefficients have been developed for both the southern and northern regions of our country.

Averaged calculation and accurate

The following scheme is used to calculate the average given the factors that have been described. A room in 20 kV should receive 2,000 watts of heat flow if one square meter requires 100 watts of heat flow. Out of eight sections, the radiator (commonly bimetallic or aluminum) emits approximately 150 watts. 2,000 divided by 150 yields 13 sections. However, this is a fairly extensive thermal load calculation.

The precise appears a little unsettling. Nothing difficult, really. This is the equation:

• Q₁ – type of glazing (ordinary = 1.27, double = 1.0, triple = 0.85);
• Q₂ – wall insulation (weak, or absent = 1.27, the wall laid out in 2 bricks = 1.0, modern, high = 0.85);
• Q₃ – ratio of the total area of window openings to the floor area (40% = 1.2, 30% = 1.1, 20% – 0.9, 10% = 0.8);
• Q₄ -street temperature (the minimum value is taken: -35 o C = 1.5, -25 o C = 1.3, -20 o c = 1.1, -15 o C = 0.9, -10 o C = 0.7);
• Q₅ – the number of external walls in the room (all four = 1.4, three = 1.3, corner room = 1.2, one = 1.2);
• Q₆ – type of estimated room above the bank room (cold attic = 1.0, warm attic = 0.9, housing heated room = 0.8);
• Q₇ – ceiling height (4.5 m = 1.2, 4.0 m = 1.15, 3.5 m = 1.13.0 m = 1.05, 2.5 m = 1.3).

Any of the methods that have been described can be used to determine an apartment building’s thermal load.

Approximate calculation

These are the requirements. During the cold season, the lowest temperature is -20 o C. This 25 square meter room has triple double-glazed windows, double windows, a 3.0 meter ceiling, two brick walls, and an unheated attic. This is how the calculation will be done:

Q is equal to 100 W/m 2 × 25 m 2 × 0.85 × 1 × 0.8 (12%) × 1.1 × 1.2 × 1 × 1.05.

Divide the result, 2,356.20, by 150. It turns out that 16 sections must be installed in the room with these specifications.

If you need a calculation in gigacalories

The heat load for heating the building is determined using the formula Q = v * (t1 – T2) / 1000 in the event that there isn’t a heat energy meter at the open heating circuit, where:

• V – the amount of water consumed by the heating system is calculated in tons or m 3 ,
• T₁ – the number showing the temperature of hot water is measured in O C and for calculations, a temperature corresponding to a certain pressure in the system is taken. This indicator has its own name – enthalpie. If there is no way to remove temperature indicators in practical way, resort to the average indicator. It is located in the range of 60-65 o.
• T₂ – cold water temperature. It is quite difficult to measure it in the system, so constant indicators have been developed, depending on the temperature regime on the street. For example, in one of the regions, in the cold season, this indicator is taken equal to 5, in the summer – 15.
• 1,000 – coefficient for obtaining a result immediately in gigacalories.

The thermal load (Gcal/hour) in the event of a closed circuit is computed differently:

• α – coefficient designed to adjust climatic conditions. It is taken into account if the street temperature differs from -30 o C;
• V is the volume of the building on external measurements;
• Q_O – specific heating indicator of the structure with a given T_n.R = -30 o C, measured in kcal/m 3 *s;
• t_V – estimated internal temperature in the building;
• t_n.R – estimated street temperature for the preparation of the heating system project;
• K_n.R – infiltration coefficient. It is due to the ratio of thermal losses of the estimated building with infiltration and heat transfer through external structural elements at street temperature, which is specified within the framework of the compiled project.

Although the heat load calculation is somewhat expanded, the technical literature uses this formula.

The inspection of the thermal imager

Thermal imaging of the structure is being used more and more to improve the heating system’s efficiency.

These tasks are completed in complete darkness. You should note the temperature differential between the room and the street, which should be at least 15 degrees for a more accurate result. All incandescent and daylight lamps are off. It is best to remove as much furniture and carpets as possible because they can cause the device to malfunction.

Data is meticulously recorded, and the examination is conducted slowly. The plan is straightforward.

The work is done indoors during the initial phase. Moving the device gradually from doors to windows requires close attention to joints and corners.

The thermal imager’s assessment of the building’s exterior walls constitutes the second phase. The joints are still closely inspected, particularly the one that connects to the roof.

The processing of data is the third step. This first powers the device. The readings are then sent to the computer, where the necessary software completes processing and displays the outcome.

If a licensed organization performed the examination, it will produce a report with required recommendations as a result of the work. If the work was completed by hand, you will have to rely on your own expertise and perhaps the assistance of the Internet.

In understanding how to calculate the heat load for heating your home, it"s crucial to consider various factors that affect how much heat your house needs. These factors include the size of your home, its insulation, the local climate, and even the number of occupants. Essentially, heat load calculation involves determining the amount of heat required to keep your home comfortable during the coldest times of the year. By accurately calculating this load, you can choose the right heating system size and type, ensuring optimal comfort and energy efficiency while avoiding unnecessary costs. This calculation typically involves assessing the heat loss through walls, windows, doors, and the roof, as well as factoring in internal heat gains from appliances and occupants. With a thorough understanding of your home"s heat load, you can make informed decisions about heating system installation, energy-saving measures, and overall home comfort.

Calculation of heat loads for heating, methodology and calculation formula

The heating structure is completed and the related computations are completed at the outset of setting up the heat supply system of any real estate object. To determine the amount of fuel and heat consumption required to heat the building, make sure to compute thermal loads. To make an informed decision about buying contemporary heating equipment, these data are needed.

Thermal loads of heat supply systems

The amount of heat produced by heating devices installed in residential buildings or at objects serving different purposes is determined by the concept of thermal load. This computation is done prior to equipment installation in order to prevent unforeseen costs and other issues that might arise while the heating system is in use.

You can arrange for the efficient operation of the heating devices by being aware of the primary operating parameters of the heat supply structure. The computation aids in carrying out the duties pertaining to the heating system and ensures that all of its components adhere to the standards and specifications outlined in the SNiP.

Оогда тепловая нагрузка на отопление, даже малейшая ошибка может привести к большим проблемам, поскольку на основании полученных данных в местном отделении ЖКХ утверждаят лимиты и другие расходных параметры, которые станут основанием для определения стоимости услуг.

The modern heating system’s total heat load is comprised of multiple fundamental parameters:

• load on heat supply design;
• load on the floor heating system if it is planned to be installed in the house;
• load on the system of natural and/or forced ventilation;
• load on the hot water supply system;
• load related to various technological needs.

Characteristics of an object for calculating thermal loads

If every detail—even the smallest ones—is considered throughout the calculation process, the corrective heat load on heating can be ascertained.

The details and parameters are listed in a very long list:

• appointment and type of real estate object. For calculation, it is important to know which building will be heated – a residential or non -residential house, an apartment (read also: “The apartment metering device of thermal energy”). The load rate, determined by companies supplying heat, and, accordingly, the cost of heat supply, depends on the type of construction;
• Architectural features. The dimensions of such external fences as walls, roofs, flooring and sizes of window, door and balcony openings are taken into account. It is important to be the number of storeys of the building, as well as the presence of basements, attics and their inherent characteristics;
• temperature regime for each room in the house. The temperature is implied for a comfortable stay of people in the living room or the administrative building zone (read: “Thermal calculation of the room and building, the formula of thermal losses”);
• Features of the design of external fences. including the thickness and type of building materials, the presence of a thermal insulation layer and the products used for this;
• The purpose of the premises. This characteristic is especially important for industrial buildings in which certain conditions for each workshop or site must create certain conditions regarding the provision of the temperature regime;
• the presence of special premises and their features. This applies, for example, pools, greenhouses, baths, etc.D.;
• The degree of maintenance. The presence/absence of hot water supply, centralized heating, air conditioning systems and other things;
• The number of points for the fence of a heated coolant. The more of them, the more significant the thermal load shown to the entire heating structure;
• the number of people in the building or living in the house. The humidity and temperature directly depend on this value, which are taken into account in the formula for calculating the thermal load;
• Other features of the object. If this is an industrial building, then they may be the number of working days throughout the calendar year, the number of workers per shift. For a private house, take into account how many people live in it, how many rooms, bathrooms, etc.D.

Calculation of heat loads

When a property is designed for any purpose, the building’s heat load in relation to heating at that stage is determined. This is necessary to select the appropriate heating equipment and avoid needless financial outlays.

In addition to GOSTs, TKP, and SNB, norms and standards are considered when performing computations.

Many considerations are made when calculating the value of thermal power, including:

• degree of heat loss of external fences;
• the power necessary for heating the coolant;
• the amount of thermal energy required for heating air for forced supply ventilation;
• the heat that is needed for heating water in a bath or pool;
• possible further expansion of the heating system. This can be the creation of heating in the attic, in the attic, in the basement or in various extensions and buildings.

Calculating the building’s thermal loads with a specific level of stock is essential to avert future unneeded financial outlays.

When setting up a suburban cottage’s heat supply, these kinds of actions are crucial. Installing extra equipment and other heating structure components will be extremely expensive in such a real estate object.

Features of calculating thermal loads

The special literature or the technical documentation that is attached to the manufacturers’ products, including heat units, contain the estimated values of the temperature and humidity of the air within the premises as well as the heat transfer coefficients.

A country house’s annual heat consumption for heating is determined by first determining the maximum heat flow from heating devices (heating radiators) and then calculating the maximum thermal energy consumption per hour. This is the standard methodology for calculating the thermal load of the building to ensure its effective heating. Additionally, the total heat consumption of thermal power over a specific time period—such as the heating season—must be known.

For various real estate objects, the computation of heat loads—which considers the surface area of the devices involved in thermal exchange—is employed. With the help of this calculation option, you can accurately determine the system’s parameters, ensuring efficient heating, and assess a building’s energy efficiency. This is the best method for figuring out the specifications of an industrial object’s on-duty heat supply, which suggests a drop in temperature during off-peak hours.

Methods of calculating thermal loads

To date, there are a few primary techniques used to calculate thermal loads, such as:

• calculation of heat loss using enlarged indicators;
• determination of heat transfer of heating and ventilation equipment installed in the building;
• calculating the values, taking into account various elements of the enclosing structures, as well as additional losses associated with air heating.

Enlarged calculation of thermal load

In situations where there is insufficient information available about the intended object or where the necessary data do not match the actual characteristics, the enlarged calculation of the building’s thermal load is employed.

This kind of heating computation is done using an easy formula:

ΑXVHQ0x (tv-tn.R.) x10-6 is QMax from, where:

• α is the correction factor taking into account the climatic features of a particular region where the building is built (used in the case when the calculated temperature differs from 30 degrees of frost);
• Q0 – a specific characteristic of heat supply, which is selected based on the temperature of the coldest week throughout the year (the so -called "five -day");
• V – external volume of construction.

Make an enlarged calculation of the heat load using the data above.

Types of thermal loads for calculations

Various thermal loads are considered when performing calculations and selecting equipment:

1. Seasonal loads. having the following features:

– they are inherently subject to variations based on the temperature of the air outside the house; – there are variances in the quantity of thermal energy used in accordance with the local climate where the house is located; – the heating system’s load varies with the time of day. This parameter is deemed irrelevant because external fences are heat resistant; – the ventilation system’s heat expenses vary with the time of day.

• Constant heat loads. In most objects of the heat supply and hot water supply system, they are used throughout the year. For example, in the warm season, thermal energy expenses in comparison with the winter period are reduced somewhere by 30-35%.
• Dry warm. Is thermal radiation and convection heat transfer due to other similar devices. Determine this parameter using a dry thermometer temperature. It depends on many factors, among which windows and doors, ventilation systems, various equipment, air exchange occurring due to the presence of cracks in the walls and ceilings. Also take into account the number of people in the room.
• Hidden warmth. It is formed as a result of the evaporation and condensation process. The temperature is determined using a wet thermometer. In any of the purpose of the room, the humidity is affected by:- the number of people who are in the room;
  – the availability of technological or other equipment;
  – flows of air masses penetrating through the cracks and cracks available in the enclosing structures of the building.

Thermal load regulators

The RTN (heat loading regulators) is a component of contemporary industrial and residential boilers. These components (see photo) are designed to maintain the heat unit’s power at a specific level and prevent failures and jumps while they’re in use.

RTNs let you pay less for heating because, for the most part, there are caps that cannot be gone over. This is particularly valid for businesses that are industrial. The truth is that fines ought to be applied in excess of the thermal load limit.

Since it can be challenging to independently create a project and calculate loading systems for HVAC (heating, ventilation, and air conditioning), experts are typically consulted for this stage of work. Yes, you can do the calculations yourself if you’d like.

DIA and ventilation loads

The heat load on the heating, ventilation, and hot water systems is typically calculated within the complex. Seasonal loads are referred to as ventilation, which is meant to heat air to a specific temperature and replace previously exhausted air masses with clean air.

The following formula can be used to determine the load on the ventilation system:

Determination of heat loads for heating

Factors affecting thermal load

• Wall material and thickness. For example, a brick wall of 25 centimeters and a wall of aerated concrete of 15 centimeters can skip different amounts of heat.
• Roof material and structure. For example, heat loss of a flat roof from reinforced concrete plates differs significantly from the heat loss of the insulated attic.
• Ventilation. The loss of thermal energy with spent air depends on the productivity of the ventilation system, the presence or absence of a heat recovery system.
• Glazing area. Windows lose more thermal energy compared to continuous walls.
• The level of insolation in different regions. It is determined by the degree of absorption of solar heat with external coatings and the orientation of the planes of buildings in relation to the cardinal points.
• The temperature difference between the street and the room. It is determined by the heat stream through the enclosing structures, provided that the heat transfer resistance is constant.

The distribution of thermal load

When using water heating, the boiler’s maximum thermal power should match the total thermal power of all the home’s heating appliances. Regarding the distribution of heating appliances The ensuing elements impact:

• The area of the room and the height of the ceiling;
• Location inside the house. The corner and end rooms are lost more heat than the premises located in the middle of the building;
• Remoteness from the heat source;
• Desired temperature in the rooms.

SNiP suggests the following numbers:

• Living rooms in the middle of the house – 20 degrees;
• Corner and end living rooms – 22 degrees. In this case, due to a higher temperature, the walls do not freeze;
• The kitchen is 18 degrees, since it has its own heat sources – gas or electric slabs, etc.
• Bathroom – 25 degrees.

When using air heating, the air sleeve’s throughput determines how much heat flux enters a different room. Changing the location of the ventilation gratings with temperature control is frequently the easiest way to make the necessary adjustments.

The thermostat in a heating system that uses a heat distribution source (such as a convector, heated floors, electric heaters, etc.) is set to the appropriate temperature mode.

Step	Description
1	Determine the area of ​​each room in square meters.
2	Identify the materials used in walls, floors, and ceilings.
3	Find the U-values ​​of the materials (how much heat they let through).
4	Calculate the heat loss for each surface by multiplying area by U-value.
5	Estimate the heat loss due to air leakage.
6	Add up all the heat loss values ​​to get the total heat load.

To ensure efficiency and comfort when heating your home, it is essential to calculate the heat load. Knowing how much heat your home requires will help you select the best heating system and use less energy. This computation considers a number of variables, including the size of your house, the amount of insulation, the local climate, and even the number of occupants.

Evaluating your home’s thermal properties is a crucial step in calculating heat load. This entails figuring out how insulated the windows, floors, ceilings, and walls are. Better heat retention in well-insulated homes lowers the energy required for heating. Accurate heat load calculations require a thorough inspection of the insulation in your home.

Heat load is significantly influenced by climate as well. While milder climates may require less heating, colder climates do. Your home’s overall heat load is influenced by various factors such as temperature extremes and prevailing winds, which can cause significant heat loss. You can customize your heating system to meet specific needs and maximize efficiency by taking into account the climate data for your area.

The size of your home is another important consideration when calculating your heat load. Generally speaking, larger homes need more heating power to keep the temperature comfortable. Determining the total heat load involves calculating the area of each room and evaluating heat loss through windows and walls. You can prevent energy waste and guarantee peak performance by precisely sizing your heating system according to the size of your house.

Additionally, lifestyle variables that affect heat load calculations include occupancy and usage patterns. In order to maintain comfort, homes with more occupants or higher activity levels might need to use more heating. It is possible to improve heat load estimates and make sure that your heating system can effectively meet demand by having a better understanding of how your household uses space.

To sum up, figuring out how much heat your house needs to be heated involves taking a variety of factors into account, including insulation, climate, size of the house, and lifestyle. You can ascertain the right amount of heating capacity required for maximum comfort and energy efficiency by carrying out a comprehensive assessment and utilizing precise data. Making the time to calculate your heat load correctly up front can save you money in the long run and make your house more comfortable.

Video on the topic

Temperature graphs. Straight and reverse network water. Graphs of thermal loads

Graphs of thermal loads

005. Calculation of heat loads. Heating ventilation of the DHW inside CTP

Calculation of thermal load and design of the Audytor OZC + Audytor C heating systems.O.

Calculation of heat loads for enlarged indicators. Heating and ventilation.