How to calculate the heated area

Comprehending the process of determining the heated area of your home is essential for effective insulation and heating. Determining the heated area precisely is important whether you’re building a new home or looking to renovate your current one. It guarantees that you make the appropriate investments in insulation and heating systems.

More than just warming the air in a house, heating it involves keeping all the living areas at a comfortable temperature while using as little energy as possible. You must determine the precise amount of space that requires heating, accounting for variables like room size, ceiling height, insulation quality, and local climate, in order to strike this balance.

The first step in calculating the heated area of your house is to do a thorough floor plan assessment. This entails determining the length, width, and height of every room. Unevenly shaped rooms or spaces with vaulted ceilings must be taken into consideration because they can greatly affect the total heated area.

After you have the measurements, multiply the length by the width to find each room’s square footage, or square meters. You must multiply the square footage by the height in order to determine the volume of rooms with different ceiling heights. The total volume indicates how much space needs to be heated.

Calculation of heating by area of the room – a detailed breakdown of methods

You should be able to determine the heating according to the area of the room if you need to replace outdated, broken radiators or if you are installing a new system in a home that is still under construction.

To ensure optimal heat transfer and heating, the number of radiator sections that need to be installed must be precisely determined for the system to function.

Insufficient sections will prevent the room from warming up adequately, and many of them will result in wasteful and excessive heat use, which will negatively impact your budget and finances. Standard rooms’ requirements can be ascertained through relatively straightforward computations; however, to attain higher precision, certain extra factors and characteristics must be considered.

Simple calculations by area

By concentrating on the area of a given room, you can determine the size of the heating radiators in that space. The easiest method is to follow the plumbing codes, which state that one square meter must be heated with an output of 100 watts per hour. It should be noted that the result is a little bit overestimated and that this method is only applicable to rooms with standard height ceilings (2.5–2.7 meters). Additionally, it disregards characteristics like:

• number of windows and type of double-glazed windows;
• the number of exterior walls in the room
• The thickness of the walls of the building and what material they consist of;
• type and thickness of the insulation used;
• temperature range in the given climatic zone.

The amount of heat that the room should be heated by the radiators: It is necessary to multiply the area by the heat output (100 W). For instance, the following heating battery capacity is needed for a room that is 18 square meters:

1800 Wx 18 sq. m x 100 W

That is, 1.8 kW of power are needed in an hour to heat 18 square meters. Divide this result by the total amount of heat emitted by a section of the radiator each hour. In the event that the information in its passport indicates that it weighs 170 W, the following computations would be made:

10.59 is 1800 W / 170 W.

When this number is rounded to the nearest whole (typically upward), you obtain 11. That is, an 11-section radiator must be installed for the ideal room temperature during the heating season.

This approach is limited to determining the battery value in rooms with central heating, where the coolant temperature does not exceed 70 degrees Celsius.

A less complex approach exists that can be utilized in typical panel house apartment settings. This rough computation accounts for the fact that one section is needed to heat 1.8 square meters of floor space. Stated differently, the room’s area needs to be divided by 1.8. For instance, a 25 square meter area requires the following 14 parts:

1,8 x 25 square meters / м = 13,89

However, this calculation technique is not appropriate for radiators with lower or higher power output (where one section’s average output varies from 120 to 200 W).

Consider the method of calculations for rooms with high ceilings

Nevertheless, for rooms with ceilings higher than three meters, the number of sections cannot be accurately calculated using the heating by area method. The formula that accounts for the room’s volume must be used in this situation. 41 W of heat are needed, per SNIP recommendations, to heat one cubic meter of volume. Thus, in the case of a room with a 3 m ceiling height and a 24 m square area, the computation will be as follows:

The room’s volume, calculated as 24 square meters times three meters, is 72 cubic meters.

72 cubic meters * 41 W = 2952 W is the radiator’s power to heat the space.

We now need to determine how many sections there are. It is necessary to divide the found power of the battery by 180 W if the radiator’s documentation indicates that one of its parts produces 180 W of heat per hour:

180 W / 2952 W = 16,4

It turns out that 17 sections will heat a room with a volume of 72 cubic meters when this number is rounded up to the whole.м.

You can quickly ascertain the necessary data with a few basic calculations.

Additional parameters to be taken into account

Once you’ve estimated how many radiator sections your apartment will need, don’t forget to adjust it to account for the unique features of each space. They ought to be considered in the following manner:

• for a corner room (two walls facing the street) with one window, the radiator capacity should be increased by 20%, and for two windows – by 30%;
• if the radiator is mounted in a niche under the window, its heat output will be reduced, this is compensated by an increase in power by 5%;
• 10% more if the windows face north or northeast;
• the screen, for beauty covering radiators, "steals" 15% of their heat output, which must also be taken into account in the calculation.

The total amount of heat capacity needed for the space must first be determined, accounting for all relevant variables and characteristics. And only then divide this figure by the heat output of one section per hour. Typically, the outcome of a fractional value is rounded up to the nearest whole number.

Specifics and other features

It’s also possible that the rooms for which the computation is done are not all identical and similar to one another. These could be signs like:

• The temperature of the coolant is less than 70 degrees – the number of parts is accordingly to be increased;
• absence of a door in the opening between two rooms. Then it is required to calculate the total area of both rooms to calculate the number of radiators for optimal heating;
• double-glazed windows prevent heat loss, so fewer battery sections can be installed.

The calculation is straightforward when switching out old cast iron batteries that kept the room at a consistent temperature for new aluminum or bimetallic ones. The heat output of one cast iron section (150 W on average) should be multiplied. Divide the outcome by one new part’s heat output.

Climatic zones are also important

It is a well-known fact that the demand for heating varies depending on the climate zone, thus these factors should be considered when designing the project.

Additionally, climate zones have unique coefficients:

• the middle strip of Russia has a coefficient of 1.00, so it is not used;
• Northern and eastern regions: 1.6;
• Southern regions: 0.7-0.9 (minimum and average annual temperatures in the region are taken into account).

The overall heat output should be multiplied by this coefficient, and the resulting number should be divided by the heat output of a single component.

Thus, there are no unique challenges in calculating heating by area. It suffices to take a seat, comprehend, and compute in a composed manner. Any homeowner or apartment owner can use it to quickly and easily measure how big a radiator should be installed in a room, kitchen, bathroom, or other location.

If you are unsure of your skills and knowledge, have the system installed by professionals. Paying experts once is preferable to doing it incorrectly, disassembling it, and then starting over. or take no action at all.

Carrying on with the subject, high-quality interior doors from www.dveri-tmk.ru will keep your home or apartment warm. and make the heating area’s computations simpler.

Calculation of the number of heating radiators according to the area and volume of the room

The question of how to determine the number of radiators and device sections arises when changing the apartment’s batteries or moving to individual heating. In the winter, the apartment will be cool if the batteries have insufficient capacity. In a heating system with a single-pipe distribution, an excessive number of sections not only results in needless overpayments but also leaves the lower floor residents without heat. Determine the ideal power and number of radiators based on the room’s area or volume, accounting for the unique characteristics of the space as well as the characteristics of various battery types.

Calculation by area

The most popular and straightforward method is to divide the area of the room that needs to be heated by the appliance capacity needed for heating. The average norm states that 100 W of heat capacity is needed to heat one square meter of area. Consider a room that is 15 square meters in size as an example. This method indicated that 1,500 watts of heat energy would be needed to heat it.

Taking into account a few crucial factors when applying this methodology are as follows:

• the norm of 100 W per 1 sq. meter of area refers to the average climatic strip, in the southern regions to heat 1 sq. km. meters of space requires a smaller power – from 60 to 90 watts;
• For areas with harsh climates and very cold winters for heating 1 sq. km. meter requires from 150 to 200 W;
• the method is suitable for rooms with standard ceiling heights not exceeding 3 meters;
• method does not take into account heat losses, which will depend on the location of the apartment, the number of windows, the quality of insulation, the material of the walls.

Calculation method based on the volume of the room

The approach that accounts for the volume of the ceiling will yield more accurate results because it considers both the material used to construct the apartment’s exterior walls and the height of the ceilings. The following is the calculation sequence:

1. The volume of the room is determined, for this purpose the area of the room is multiplied by the ceiling height. For a room of 15 sq. м. and a ceiling height of 2.7 m, it will be equal to 40.5 cubic meters.
2. Depending on the material of the walls, different amounts of energy are spent on heating one cubic meter of air. According to SNiP norms, for an apartment in a brick house this figure is 34 W, for a panel house – 41 W. So, the volume obtained must be multiplied by 34 or 41 W. Then for a brick building to heat a room of 15 squares will require 1377 W (40,5*34), for a panel building – 1660, 5 W (40,5*41).

Adjusting the results

If all the variables influencing the decrease or increase in heat loss are not considered, any of the chosen methods will only provide an approximative result. The calculated radiator capacity must be multiplied by the following coefficients, of which you should select the appropriate ones, for an accurate calculation.

The amount of heat lost through windows can range from 15 to 35 percent, depending on their size and insulation level. Thus, two coefficients related to windows will be used in our computations.

Window-to-floor area ratio in the room:

• for a window with a three-chamber double-glazed window or a two-chamber window with argon – 0.85;
• for a window with a normal double-glazed window – 1.0;
• for frames with conventional double glazing – 1.27.

Walls and ceiling

The quantity of external walls, the standard of thermal insulation, and the area above the apartment all affect heat losses. These factors will be taken into consideration by adding three more coefficients.

Count of exterior walls:

• no external walls, no heat losses – coefficient 1,0;
• one external wall – 1,1;
• two – 1.2;
• three – 1.3.

• normal thermal insulation (a wall 2 bricks thick or a layer of insulation) – 1.0;
• high degree of thermal insulation – 0.8;
• low – 1.27.

Considering the kind of room mentioned above:

• heated apartment – 0,8;
• heated attic – 0.9;
• cold attic – 1.0.

Ceiling height

In order to make the result more clear, the area method of calculation for a room with a non-standard wall height must be taken into consideration. The following is how to find the coefficient: the standard height divided by the available ceiling height, or 2.7 meters. As a result, the following numbers result:

Climatic conditions

The final coefficient accounts for the wintertime outdoor temperature. The average temperature during the coldest week of the year will serve as our starting point.

It is essential to calculate the heated area of your home to guarantee effective insulation and heating. Measure the length, breadth, and height of each room to get started. Next, take into account any atypical forms or regions that could impact the need for heating. Considerations for heat loss include windows, doors, and the quality of the insulation. If attics, basements, or garages are a part of your living area, don’t forget to include them. To find the heated area, add up the area of each room. This computation serves as the foundation for selecting the appropriate insulation requirements and heating system size, assisting you in building a cozy and energy-efficient house.

Calculation of the number of radiator sections

We can determine how many heating batteries are needed once we know how much power is needed to heat the space.

The computed total power must be divided by the power of one radiator section in order to determine the number of radiator sections. The average statistical values for various radiator types with a standard axial distance of 50 cm can be used to perform calculations:

• For cast iron batteries, the approximate power of one section is 160 W;
• for bimetallic – 180 W;
• for aluminum – 200 W.

For reference, the height between the centers of the holes that allow coolant to be supplied and discharged is known as the radiator’s axial distance.

For illustration, let’s figure out how many bimetallic radiator sections are needed for a 15 square meter room. м. Assume for the moment that you determined the power using the room’s area in the simplest possible manner. We divide the 1500 W of power needed for its heating by 180 W. The required number of sections for the bimetallic radiator is equal to 8, rounded off to the nearest whole number of 8,3.

Crucial! Determine the power of one section of the device passport if you choose to go with non-standard size radiators.

Dependence on the temperature regime of the heating system

Radiator capacities are given for systems with high temperature thermal regimes. To choose batteries with the appropriate number of sections, you will need to perform extra calculations if your home’s heating system runs in low- or medium-temperature thermal mode.

First, let’s calculate the system’s heat head, which is the difference between the air’s average temperature and the batteries’ temperature. The arithmetic mean of the coolant supply and return temperatures is used to determine the temperature of heating devices.

1. High-temperature mode: 90/70/20 (supply temperature – 90 °C, return temperature -70 °C, the average room temperature is taken as 20 °C). Heat head will be calculated as follows: (90 + 70) / 2 – 20 = 60 ° C;
2. Medium-temperature: 75/65/20, heat head – 50 °С.
3. Low-temperature: 55/45/20, heat head – 30 °C.

Multiplying the total power by the radiator’s passport head and dividing the result by the available heat head is how many battery sections you’ll need for systems with a heat head of 50 or 30. You will need 15 sections of aluminum radiators, 17 sections of bimetallic radiators, and 19 sections of cast iron radiators for a room that is 15 square meters.

The number of sections required for a heating system with a low-temperature mode is doubled.

Calculation of heat load for heating a building: formula, examples

Whether you are designing a heating system for a residential or commercial building, you must perform accurate calculations and create a schematic of the heating system circuit. Experts advise paying close attention to the computation of the potential heat load on the heating circuit at this point, along with the quantity of fuel used and heat released.

Heat load: what it is?

This phrase describes the quantity of heat that heating appliances release. The initial computation of the heat load helps to prevent needless expenditures on the installation and acquisition of heating system components. Additionally, this computation will support a fair and efficient distribution of the released heat throughout the building.

These computations involve a lot of subtleties. For instance, the region, thermal insulation, the material used to construct the building, etc. Experts strive to consider as many variables and attributes as they can in order to produce a more precise outcome.

Erroneous or imprecise heat load calculations result in inefficient heating system operation. Sometimes it even becomes necessary to remodel portions of the existing construction, which will undoubtedly result in unforeseen costs. Housing and community organizations use data on heat load to determine service costs.

The main factors

The desired room temperature should be maintained and any resulting heat losses should be offset by a precisely planned and calculated heating system. The following factors should be considered when determining the heat load on the building’s heating system:

– The building’s classification: residential or industrial.

– Features of the building’s structural components. These consist of the roof, ventilation system, doors, walls, and windows.

– The dwelling’s size. The heating system should be more powerful the larger it is. It is necessary to consider the area of doorways, windows, external walls, and the volume of each interior room.

– It is not necessary to have rooms designated for specific uses (such as saunas, baths, etc.).

– Level of technological device equipment. that is, the kind of heating system, air conditioning, ventilation, and hot water supply availability.

– The temperature schedule for a specific room. For instance, rooms intended for storage do not have to be kept at a temperature that is suitable for people.

The quantity of hot water supply locations. The system is under more stress the more of them there are.

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

– Extra prerequisites. This can include the quantity of bathrooms, balconies, and loggias in residential buildings. In the industrial sector, factors include the number of working days in a year, the number of shifts, the production process’s technological chain, etc.

– Local climate circumstances. Heat losses are calculated taking into account street temperatures. Additionally, a small amount of energy will be used for compensation if the variations are negligible. While using a lot of water outside the window will be necessary at -40 o C.

Peculiarities of existing methods

SNiPs and GOSTs contain the parameters used to calculate the heat load. Additionally, their heat transfer coefficients are unique. Numerical characteristics are obtained from the passports of the heating system’s equipment, pertaining to specific heating radiators, boilers, and so forth. In addition to customarily:

– the maximum amount of heat that the heating system will use in an hour of operation,

Maximal heat output from a single radiator,

– total amount of heat used during a specific time frame (usually a season); if hourly computation of the heat network load is required, the difference in temperature during the day should be taken into consideration.

The computations are contrasted with the system’s overall heat output area. The indicator has a high degree of accuracy. There are some exceptions. For instance, it will be important to consider reducing heat consumption in residential buildings at night and in industrial buildings on weekends and holidays.

There are different levels of precision in the methods used to calculate heating systems. Rather intricate computations must be used in order to reduce the error. If maximizing the heating system’s cost is not the aim, less precise schemes are employed.

Main methods of calculation

These days, there are several methods available for calculating the heat load required to heat a building.

Three basic ones

1. Aggregated values are taken for the calculation.
2. The values of the structural elements of the building are taken as a base. The calculation of the heat losses for heating the internal air volume will be important here as well.
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 little or very average, there is a significant amount of error. Qfrom = q0 * a * VH * (tEH – tNRO) is the formula in question, where:

• q₀ – Specific heat rating of the building (most often determined by the coldest period),
• a – correction factor (depends on the region and is taken from ready-made tables),
• V_H – volume calculated on the outer planes.

Example of a simple calculation

You can use a straightforward parameter ratio with a region-specific coefficient correction for a building with standard parameters (ceiling height, room size, and good thermal insulation characteristics).

Assume for the moment that the residential property is 170 square kilometers in size and is situated in the Arkhangelsk region. There will be a heat load of 17 * 1.6 = 27.2 kWh.

Numerous significant factors are ignored in such a definition of heat loads. For instance, the building’s structural characteristics, temperature, the quantity of walls, the proportion of wall to window openings, etc. As a result, these computations are inappropriate for significant heating system projects.

Calculation of heating radiator by area

Depending on the substance they are composed of. Cast iron radiators are used far less frequently than bimetallic, aluminum, and steel radiators nowadays. Every one of them has a unique rate of heat output, or heat transfer. Bimetallic radiators with 500 mm between the axes typically have 180–190 W. Aluminum radiators have nearly identical indicators.

Each section’s heat output for the radiators that are described is computed. Steel plate radiators do not require disassembly. As a result, the size of the entire unit determines their heat output. For instance, a double row radiator measuring 1 100 mm in width and 200 mm in height will produce 1 010 W of heat, while a steel panel radiator measuring 500 mm in width and 220 mm in height will produce 1 644 W.

The following fundamental parameters are included in the heating radiator calculation by area:

– the standard ceiling height of 2.7 meters,

– heat capacity (100 W per q. m).,

One wall on the outside.

According to these calculations, one thousand W of heat output is required for every ten square feet. This outcome is divided by one section’s heat output. The necessary number of radiator sections is the solution.

There are developed decreasing and increasing coefficients for both the southern and northern regions of our nation.

Averaged calculation and accurate

Considering the previously mentioned factors, the average computation looks like this. A room measuring 20 square feet should receive 2,000 W of heat flux if one square meter needs 100 W. About 150 Watts are produced by an eight-section radiator, which is commonly bimetallic or aluminum. 2,000 divided by 150 yields 13 sections. However, this is a very simplified computation of heat load.

The exact one seems a little intimidating. There isn’t really anything difficult. This is the equation:

• q₁ – type of glazing (normal =1.27, double = 1.0, triple = 0.85);
• q₂ – wall insulation (weak, or missing = 1.27, 2-brick wall = 1.0, modern, high = 0.85);
• q₃ – the 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 – number of exterior walls in the room (all four = 1.4, three = 1.3, corner room = 1.2, one = 1.2);
• q₆ – type of design room above the design room (cold attic = 1.0, warm attic = 0.9, residential heated room = 0.8);
• q₇ – ceiling height (4.5 м = 1.2, 4.0 м = 1.15, 3.5 м = 1.1, 3.0 м = 1.05, 2.5 м = 1.3).

It is possible to compute an apartment building’s heat load using any of the previously mentioned techniques.

Example calculation

These are the requirements. During the cold season, the lowest temperature is -20 o C. This 25 square meter space features triple glazing, double glazing, 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. Consequently, it transpires that sixteen sections must be installed in the room with the given dimensions.

If a calculation in gigacalories is required

In the event that the open heating circuit lacks a heat meter, the building’s heat load is determined using the formula Q = V * (T1 – ΢2) / 1000, where:

• V – the amount of water consumed by the heating system, calculated in tons or m 3 ,
• Т₁ – the number indicating the temperature of hot water is measured in o C and the temperature corresponding to a certain pressure in the system is taken for calculations. This indicator has its own name – enthalpy. If it is not possible to take temperature readings in a practical way, an averaged reading is used. It is in the range of 60-65 o C.
• Т₂ – 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 as 5, in summer – 15.
• 1 000 – coefficient to obtain the result immediately in gigacalories.

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

• α – a coefficient designed to correct climatic conditions. It is taken into account if the street temperature is different from -30 oÑ;
• V is the volume of the building according to external measurements;
• q_о – specific heating value of the building at a given t_н.р = -30 o C, measured in kcal/m 3 *C;
• t_в – is the design internal temperature in the building;
• t_н.р – calculated street temperature for the design of the heating system;
• K_н.р – infiltration coefficient. It is conditioned by the ratio of heat losses of the design building with infiltration and heat transfer through external structural elements at the street temperature, which is set within the framework of the project being prepared.

Although the heat load calculation ends up being somewhat expanded, this is the formula provided in the technical literature.

Step 1	Determine the dimensions of each room (length and width).
Step 2	Measure the height of the ceiling.
Step 3	Calculate the area of each room by multiplying the length by the width.
Step 4	For rooms with slanted ceilings, calculate the area separately using the slant height.
Step 5	Add up the areas of all rooms to get the total heated area of the house.

To ensure effective insulation and heating, one of the most important steps is to calculate the heated area of your house. You can prevent wasting energy and money by precisely identifying the area that requires heating. Make a sketch of your home’s layout, taking into account every room, closet, and hallway. To calculate the square footage of each room, multiply the length and width measurements. Don’t forget to take any asymmetrical shapes or alcoves into account.

Add the square footage of each room to determine the total area that is heated once you have it. Remember to factor in any heated areas, such as basements or garages. Depending on how they are used and how well-insulated they are, these areas might need different computations. In order to make sure that every heated space has been considered, thoroughness is crucial.

When determining the heated area, take your home’s insulation into account. It will take more heating in areas with inadequate insulation to keep the temperature comfortable. Look for cracks or openings in the walls, windows, doors, and ceiling that could contribute to heat loss. Lower heating costs and energy consumption can be achieved by improving insulation.

Getting expert advice can help you make sure your calculations are accurate. An expert contractor or energy auditor can evaluate the heating requirements of your house and make recommendations for upgrades. To maximise the efficiency and comfort of your house, they might also recommend insulation upgrades or energy-efficient heating systems.

To sum up, figuring out how much of your house is heated is a critical first step toward having effective insulation and heating. You can make educated decisions to increase energy efficiency and lower heating costs by precisely measuring and evaluating the square footage and insulation quality of your home. Take some time to assess the heating requirements of your house and think about getting professional advice by speaking with an expert.

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