How to calculate heat loss at home: features, recommendations and program

Of course, the main sources of heat loss in the house are doors and windows, but when viewing a picture through the thermal imager's screen it's easy to see that these are not the only sources of leakage. Heat is lost and through the illiterately mounted roof, cold floor, not insulated walls. Heat losses at home today are calculated using a special calculator. This allows you to choose the best option for heating and additional work on the insulation of the building. It is interesting that for each type of structure (from timber, logs, silicate or ceramic bricks), the level of heat loss will be different. Let's talk about this in more detail.

Basics of calculating heat loss

Control over heat loss is systematically carried out only for premises heated in accordance with the season. Premises that are not intended for seasonal living do not fall into the category of buildings that can be thermally analyzed. The home heat loss program in this case will not have any practical significance.

To conduct a full analysis, calculate the thermal insulation materials and choose the heating system with the optimal power, you need to know about the real heat loss of the home. The walls, the roof, the windows and the floor are not the only sources of energy leakage from the house. Most of the heat leaves the room through improperly installed ventilation systems.

Factors affecting heat loss

The main factors affecting the level of heat loss are:

• A high level of temperature difference between the internal microclimate of the room and the temperature in the street.
• The nature of the thermal insulation properties of enclosing structures, which include walls, floors, windows, etc.

Measurements of heat loss

The enclosing structures fulfill the barrier function for heat and do not allow it to freely flow out. This effect is due to the thermal insulation properties of the products. The value used to measure thermal insulation properties is called the heat transfer resistance. Such an indicator is responsible for reflecting the temperature difference when passing through the n-th amount of heat through a section of protective structures of 1 m ^2. So, let's figure out how to calculate the heat loss at home.

The main values necessary for calculating heat loss at home are:

• Q is the quantity indicating the amount of heat leaving the room outside through 1 m ^{2 of the} barrier structure. Measured in W / m ² .
• ΔT is the difference between the temperature in the house and on the street. Measured in degrees ( ^o C).
• R is the resistance to heat transfer. Measured in ° C / W / m² or ° C · m² / W.
• S - area of the building or surface (used if necessary).

The formula for calculating heat loss

The heat loss program for the house is calculated according to a special formula:

R = ΔT / q

When calculating, remember that for structures consisting of several layers, the resistance of each layer is added together. So, how to calculate the heat loss of a frame house, bricked outside? Resistance to heat loss will be equal to the sum of the resistance of the brick and wood, taking into account the air layer between the layers.

Important! Note that the calculation of the resistance is carried out for the coldest time of the year, when the temperature difference reaches its peak. In reference books and manuals, it is always this reference value used for further calculations.

Specific features of calculating the heat loss of a wooden house

Calculation of heat losses at home, the features of which must be taken into account when calculating, is carried out in several stages. The process requires special attention and concentration. Calculate the heat loss in a private house according to a simple scheme can be as follows:

• Determine through the walls.
• Calculate through the window structure.
• Through the doorways.
• Calculate through the overlap.
• Calculate the heat loss of a wooden house through a floor covering.
• Add the previously obtained values.
• Considering the thermal resistance and loss of energy through ventilation: from 10 to 360%.

For the results of paragraphs 1-5, the standard formula for calculating the heat loss of the house (of timber, brick, wood) is used.

Important! The heat resistance for window constructions is taken from SNIP II-3-79.

Building directories often contain information in a simplified form, that is, the results of calculating the heat loss of the house from the beam are given for different types of walls and ceilings. For example, calculate the resistance at a temperature difference for atypical premises: corner and non-corner rooms, single and multi-storey buildings.

The need to calculate heat loss

Arrangement of a comfortable home requires strict control of the process at each stage of the work. Therefore, the organization of the heating system, which is preceded by the choice of the method of heating the room, can not be overlooked. Working on the construction of the house, a lot of time will have to be given not only to the design documentation, but also to the calculation of heat loss at home. If in the future you are going to work in the field of design, then the engineering skills of calculating heat losses will be useful for you. So why not train to perform this work on experience and make a detailed calculation of heat loss for your own home.

Important! The choice of method and capacity of the heating system depends on the calculations you made. Calculating the heat loss indicator is incorrect, you run the risk of freezing in cold weather or exhaust from heat due to excessive heating of the room. It is necessary not only to choose the right device, but also to determine the number of batteries or radiators that can heat one room.

Estimation of heat losses in the calculation example

If you do not need to study the calculation of heat loss at home in detail, we will dwell on an evaluation analysis and determination of heat loss. Sometimes in the calculation process there are errors, so it is better to add a minimum value to the expected capacity of the heating system. In order to begin the calculations, it is necessary to know the index of wall resistance. It differs depending on the type of material from which the construction is made.

Resistance (R) for houses made of ceramic bricks (with a brickwork thickness of two bricks - 51 cm) is 0.73 ° С · м² / W. The minimum thickness index at this value should be 138 cm. When using claydite concrete (with a wall thickness of 30 cm) as base material, R is 0.58 ° С · м² / W at a minimum thickness of 102 cm. In a wooden house or building of timber With a wall thickness of 15 cm and a resistance level of 0.83 ° C · mВ / W, a minimum thickness of 36 cm is required.

Building materials and their resistance to heat transfer

Based on these parameters, you can easily carry out calculations. Find the resistance values you can in the directory. In construction, most often used brick, logs from timber or logs, foam concrete, wood floor, ceiling slabs.

The values of resistance to heat transfer for:

• Brick wall (thickness of 2 bricks) - 0,4;
• Log house from a bar (thickness 200 mm) - 0,81;
• Log house from a log (diameter 200 mm) - 0,45;
• Foam concrete (thickness 300 mm) - 0,71;
• Wooden floor - 1,86;
• Ceiling ceiling - 1,44.

Based on the information given above, it can be concluded that for the correct calculation of heat loss, only two values are required: the temperature drop and the resistance to heat transfer. For example, the house is made of wood (logs) 200 mm thick. Then the resistance is 0.45 ° С · м² / W. Knowing these data, you can calculate the percentage of heat loss. For this, a division operation is performed: 50 / 0.45 = 111.11 W / m².

Calculation of heat loss by area is as follows: heat loss is multiplied by 100 (111.11 * 100 = 11111 W). Taking into account the interpretation of the value (1 W = 3600), the resulting number is multiplied by 3600 J / h: 11111 * 3600 = 39.999 MJ / h. Having conducted such simple mathematical operations, any landlord can learn about the heat loss of his house in an hour.

Calculation of room heat loss in online mode

On the Internet there are many sites offering online calculation of heat loss in real time. The calculator is a program with a special form for filling in, where you enter your data and after the automatic counting you will see the result - a figure that will mean the amount of heat output from the living quarters.

Residential premises - this is the building in which they live during the entire heating season. As a rule, dacha buildings, where the heating system works periodically and if necessary, do not belong to the category of residential buildings. In order to re-equip and achieve the optimum heat supply, it will be necessary to carry out a number of works and, if necessary, increase the capacity of the heating system. Such re-equipment can be delayed for a long period. In general, the whole process depends on the design features of the house and the indicators of increasing the capacity of the heating system.

Many did not even hear about the existence of such a thing as "home heat loss", and afterwards, having made a constructively correct installation of the heating system, they suffer all their lives from the lack or excess of heat in the house, even without realizing the true reason. That is why it is so important to take into account every detail when designing a home, to engage personally in control and construction, in order to obtain a qualitative result. In any case, the dwelling, regardless of what material it is built from, should be comfortable. And such an indicator as the heat loss of a residential structure will help make staying at home even more pleasant.