A very large part of the heat loss, from 30% before 60% , happens through the windows.

1. Experts have calculated that at a temperature of minus twenty-seven degrees Celsius outside the room Triple glazed windows become much more economical in total cost than windows with double glazing.
2. In the case of split or paired sashes, the best and simplest solution to the problem of reducing heat loss through windows is adding an additional third glass to the window design.
3. Also used instead ordinary glass heat reflective, or install double-glazed windows instead of one of the glasses.
4. In some cases use an additional screen, made of heat-reflecting film. All these methods make it possible to increase the thermophysical performance of windows up to 30-50% .
5. Now the most common way to reduce heat loss through windows is increase in the number of air layers in its glazed part. In order to raise the temperature on the inside of the glass and reduce the heat transfer of the window, usually a special translucent screen is installed between the paired sashes in the lower part, which has a height of eighty to one hundred and twenty millimeters. The material used to make the screen is plastic, film or glass with a heat-reflecting coating. Most efficient design The screen is considered a volumetric curtain that reduces heat loss by almost forty percent. Curtains-blinds installed between the glass increase the heat-insulating properties of windows by approximately 20% . And sheer roll-up curtains made from fabric or polyethylene film, - on average by 28%.

One more no less effective way heat conservation is installation quality window sill . It must be correctly selected, taking into account the characteristics of the window opening and the overall design of the double-glazed window.

High quality and reliable window sill Verzalit You can purchase it using the link provided. Company - official dealer German window sills - guarantees loyal prices and convenient system delivery and payment.

Keep your home warm - provide comfort and coziness to your family!

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Every building, regardless of design features, skips thermal energy through the fences. Heat loss in environment needs to be restored using a heating system. The sum of heat losses with a normalized reserve is the required power of the heat source that heats the house. To create in a home comfortable conditions, heat loss calculations are made taking into account various factors: building arrangement and room layout, orientation to the cardinal directions, wind direction and average mild climate during the cold period, physical qualities of building and thermal insulation materials.

According to the results thermotechnical calculation choose a heating boiler, specify the number of battery sections, calculate the power and length of underfloor heating pipes, select a heat generator for the room - in general, any unit that compensates for heat loss. By and large, it is necessary to determine heat losses in order to heat the house economically - without excess power reserves of the heating system. Calculations are performed manually or choose a suitable computer program into which the data is inserted.

How to perform the calculation?

First, it’s worth understanding the manual technique to understand the essence of the process. To find out how much heat a house loses, the losses through each building envelope are determined separately and then added up. The calculation is performed in stages.

1. Form a base of initial data for each room, preferably in the form of a table. The first column records the pre-calculated area of ​​door and window blocks, external walls, ceilings, and floors. The thickness of the structure is entered in the second column (this is design data or measurement results). In the third - the thermal conductivity coefficients of the corresponding materials. Table 1 contains standard values ​​that will be needed in further calculations:

The higher λ, the more heat is lost through the meter thick surface.

2. Determine the thermal resistance of each layer: R = v/ λ, where v is the thickness of the building or thermal insulation material.

3. Calculate the heat loss of each structural element according to the formula: Q = S*(T in -T n)/R, where:

• Tn – outside temperature, °C;
• T in – indoor temperature, °C;
• S – area, m2.

Of course, during the heating season the weather varies (for example, the temperature ranges from 0 to -25°C), and the house is heated to the desired level of comfort (for example, up to +20°C). Then the difference (T in -T n) varies from 25 to 45.

To make a calculation, you need the average temperature difference for the entire heating season. For this purpose, in SNiP 23-01-99 “Construction climatology and geophysics” (Table 1) they find average temperature heating season for a specific city. For example, for Moscow this figure is -26°. In this case the average difference is 46°C. To determine the heat consumption through each structure, the heat losses of all its layers are added up. So, for walls, plaster, masonry material, external thermal insulation, cladding.

4. Calculate the total heat loss, defining it as the sum Q external walls, floors, doors, windows, ceilings.

5. Ventilation. From 10 to 40% of infiltration (ventilation) losses are added to the addition result. If you install high-quality double-glazed windows in your house and do not abuse ventilation, the infiltration coefficient can be taken as 0.1. Some sources indicate that the building does not lose heat at all, since leaks are compensated by solar radiation and household heat emissions.

Manual counting

Initial data. Cottage area 8x10 m, height 2.5 m. The walls are 38 cm thick and made of ceramic bricks, the inside is finished with a layer of plaster (thickness 20 mm). The floor is made of 30mm edged boards, insulated with mineral wool (50 mm), sheathed chipboard sheets(8 mm). The building has a basement, the temperature in which in winter is 8°C. The ceiling is covered with wooden panels and insulated with mineral wool (thickness 150 mm). The house has 4 windows 1.2x1 m, an oak entrance door 0.9x2x0.05 m.

Assignment: determine the total heat loss of a house based on the assumption that it is located in the Moscow region. The average temperature difference during the heating season is 46°C (as mentioned earlier). The room and the basement have a difference in temperature: 20 – 8 = 12°C.

1. Heat loss through external walls.

Total area (minus windows and doors): S = (8+10)*2*2.5 – 4*1.2*1 – 0.9*2 = 83.4 m2.

Thermal resistance is determined brickwork and plaster layer:

• R clade. = 0.38/0.52 = 0.73 m2*°C/W.
• R pieces = 0.02/0.35 = 0.06 m2*°C/W.
• R total = 0.73 + 0.06 = 0.79 m2*°C/W.
• Heat loss through the walls: Q st = 83.4 * 46/0.79 = 4856.20 W.

2. Heat loss through the floor.

Total area: S = 8*10 = 80 m2.

The thermal resistance of a three-layer floor is calculated.

• R boards = 0.03/0.14 = 0.21 m2*°C/W.
• R chipboard = 0.008/0.15 = 0.05 m2*°C/W.
• R insulation = 0.05/0.041 = 1.22 m2*°C/W.
• R total = 0.03 + 0.05 + 1.22 = 1.3 m2*°C/W.

We substitute the values ​​of the quantities into the formula for finding heat loss: Q floor = 80*12/1.3 = 738.46 W.

3. Heat loss through the ceiling.

The ceiling surface area is equal to the floor area S = 80 m2.

Determining the thermal resistance of the ceiling, in in this case don't take into account wooden boards: They are secured with gaps and do not act as a barrier to the cold. The thermal resistance of the ceiling coincides with the corresponding insulation parameter: R sweat. = R insulation = 0.15/0.041 = 3.766 m2*°C/W.

Amount of heat loss through the ceiling: Q sweat. = 80*46/3.66 = 1005.46 W.

4. Heat loss through windows.

Glazing area: S = 4*1.2*1 = 4.8 m2.

For the manufacture of windows, a three-chamber PVC profile was used (occupies 10% of the window area), as well as a two-chamber double-glazed window with a glass thickness of 4 mm and a distance between glasses of 16 mm. Among technical characteristics the manufacturer indicated the thermal resistance of the glass unit (R st.p. = 0.4 m2*°C/W) and profile (R prof. = 0.6 m2*°C/W). Taking into account the dimensional fraction of each structural element, the average thermal resistance of the window is determined:

• R approx. = (R st.p.*90 + R prof.*10)/100 = (0.4*90 + 0.6*10)/100 = 0.42 m2*°C/W.
• Based on the calculated result, heat loss through the windows is calculated: Q approx. = 4.8*46/0.42 = 525.71 W.

Door area S = 0.9*2 = 1.8 m2. Thermal resistance R dv. = 0.05/0.14 = 0.36 m2*°C/W, and Q dv. = 1.8*46/0.36 = 230 W.

The total amount of heat loss at home is: Q = 4856.20 W + 738.46 W + 1005.46 W + 525.71 W + 230 W = 7355.83 W. Taking into account infiltration (10%), losses increase: 7355.83 * 1.1 = 8091.41 W.

To accurately calculate how much heat a building loses, they use online calculator heat loss This computer program, into which not only the data listed above is entered, but also various additional factors that influence the result. The advantage of the calculator is not only the accuracy of the calculations, but also an extensive reference data base.

As practice shows, very large share heat from the house escapes through the windows. Since many houses have plastic windows installed, which practically eliminate drafts and cooling of rooms due to the influx of cold air, this has an advantage over ordinary windows. And yet, plastic windows can lose heat from 20 to 40% of the total heat loss at home, let's look at the reasons for this and how to prevent heat loss through windows.

Heat loss through a double glazed window

They are able to retain heat very well and this indicator is higher, the thicker the double-glazed window. As practice shows, it is not so important how many chambers your double-glazed window consists of. Two, or three cameras, or one - it’s not so important. Heat leaks through the entire glass area. This radiation lies in the infrared region of the spectrum.

Modern technologies cope with this task in the following way: so-called energy-saving double-glazed windows have been invented. They differ from ordinary ones in that a special layer of low-emissivity coating is applied to its glass. Thanks to this layer, heat is reflected back into the room. Thanks to this double-glazed window, it is possible to prevent heat loss through the window by 50%. At the same time, the glass does not lose its transparency and aesthetic appearance at all. At the same time, solar radiation also does not penetrate through such glass, which is very good for regions with hot climates.

Double-glazed window will provide you with required thickness windows for better heat conservation. And at the same time, it is necessary to remember that such a double-glazed window is noticeably heavier than usual, which can lead to sagging of the sashes over time. Among other things, it has been noted that such a double-glazed window can begin to emit low-frequency sounds due to street noise. This is due to the fact that a standing sound wave can arise between the glasses, which can contribute to the occurrence of resonance and the appearance of characteristic chatter.

In some double-glazed windows, neutral gas is pumped in instead of air. However, after two to three years, no trace remains of this advantage, since this gas evaporates and is replaced by ordinary air.

Another unpleasant moment is the freezing of windows in winter, as well as the appearance of ice on the double-glazed windows. Most often, this is an indicator that the window sealant has become unusable. This happens due to its destruction. To ensure that the foam sealant does not collapse, it must be covered with moisture-proofing mastic during installation.

Also check the tightness of the protective sealing rubber window. In order for the rubber to retain its insulating functions, it is necessary to lubricate it at least twice with a special lubricant from the plastic window care kit. You will be surprised how much dirt can accumulate on tires in six months when you finally decide to wash them. detergent. If this is not done, the rubber will crack and lose its elasticity. Silicone Grease will help extend the life of the sealing rubber plastic windows. If, nevertheless, the rubber has lost its qualities and is not able to perform its functions, replace it.

Let's get on simple example Let's look at the option of calculating heat loss at home through windows and front door home for which insulation can be used ecowool extra . For the calculation, we take two windows according to different walls houses measuring 100x120 cm (1x1.2 m), another window of a smaller size which is 60x120 cm (0.6x1.2 m).

To calculate the heat loss of a house through the front door, we take following parameters doors 80x120x5 cm (door width - 0.8 m, door height - 2 m, thickness door leaf- 0.05 m). The structure of the door leaf is solid pine. The door on the street side is protected from direct exposure to atmospheric phenomena by an unheated terrace, therefore, according to the rules for calculating heat loss, it is necessary to apply a reduction factor equal to 0.7.

Calculation of heat loss through windows

To begin calculating the heat loss of a house through windows, it is necessary to calculate the total area of ​​​​all previously specified windows. We will carry out the calculation using the formula:

S windows = 1 ∙ 1.2 ∙ 2 + 0.6 ∙ 1.2 = 3.12 m2

Now, to continue calculating the heat loss of a house through windows, we find out their characteristics. For example, take the following technical indicators:

• The windows are made of three-chamber PVC profile
• The windows have a double-glazed unit (4-16-4-16-4, where 4 is the thickness of the glass, 16 is the distance between the glass units of each window).

Now you can proceed to further calculations and find out thermal resistance installed windows. Thermal resistance of a two-chamber double-glazed window and a three-chamber profile of this window design:

• Rst = 0.4 m² ∙ °C / W - thermal resistance of the double-glazed window
• R profile = 0.6 m² ∙ °C / W - thermal resistance of a three-chamber profile

Most of the window - 90% - is occupied by double glazing and 10% - PVC profile. The thermal resistance of a window is calculated using the formula:

R window = (R installation ∙ 90 + R profile ∙ 10) / 100 = 0.42 m² ∙ °C / W.

Having data on the area of ​​​​the windows and their thermal resistance, we calculate the heat loss through the windows:

Q windows = S ∙ dT ∙ / R = 3.1 m² ∙ 52 degrees / 0.42 m² ∙ °C / W = 383.8 W (0.38 kW), this is what you and I get at home heat loss through the windows, now Let's calculate the heat loss of the house through the front door.

You are here: Home >> Insulating a house with your own hands >> How to properly insulate a house with your own hands: home insulation technology >> How does heat escape through windows?

How does heat escape through windows?

In this article we list what affects heat loss through windows. And we list this so that, when insulating windows with our own hands, we do it with an understanding of what we are doing and why.

Factors influencing heat loss through windows

So, here's what affects heat loss through windows:

• size of windows and their number (light opening area);
• window block material;
• glazing type;
• location;
• compaction

Now let’s look at each factor separately and find out what it should be optimal for.

What should the area of ​​the windows be?

Obviously, the larger the area window opening, the more heat can leave the room through it. But you can’t do without windows at all... The area of ​​the windows should be justified by calculation: why did you choose this particular width and height of the window?

Hence the question: what window area is optimal in residential buildings?

If we turn to GOSTs, we will get a clear answer:

The area of ​​the window opening must provide a coefficient of natural illumination (KEO), the value of which depends on the construction area, the nature of the terrain, orientation to the cardinal points, the purpose of the room, and the type of window frames.

It is believed that enough light enters the room if the area of ​​all glass surfaces in total is 10...12% of total area rooms (calculated by floor). According to physiological indications, it is believed that optimal condition lighting is achieved with a window width equal to 55% of the width of the room. For boiler rooms, the light opening area is 0.33 m2 per 1 m3 of room volume.

Individual premises (for example, boiler rooms) have their own requirements, which you need to learn about in the relevant regulatory documents.

How to reduce heat loss with a large glass area?

Heat loss through glass can be significant, which is why heating costs are high.

To reduce heat loss through windows, special coatings are applied to the glass with one-way transmission of short- and long-wave radiation (the long-wave part of the spectrum is infrared rays emanating from heating devices, they are delayed, and the short-wave part is ultra-violet rays- skipped). As a result, in winter sunlight passes into the room, but heat does not leave the room:

And in summer it’s the other way around:

Why is multi-layer glazing more effective?

Experience shows that increasing the thickness air gap between panes in a double sash window does not increase the thermal efficiency of the entire window. It is more effective to make several layers, increasing the number of glasses.

The “classic” double frame is ineffective. And the greatest effect can be achieved with triple glazing. That is, a double-chamber double-glazed window is more effective in all respects (thermal insulation, sound insulation) than a single-chamber one.

(Chambers here are the gaps between the glasses; two glasses - one gap, a single-chamber double-glazed window; three glasses - two gaps, two chambers... etc.)

Optimal thickness The air gap between the glasses is considered to be 16 mm.

When you are offered double-glazed windows, and you need to choose from several types, for example, from these (the numbers above the double-glazed windows are the thickness of the glass and the spaces between them):

Then the second and third are optimal.

Well, again, you need to keep in mind the glass seal. In modern double-glazed windows, not only the number of chambers has been increased, but also the air in the space between the glasses has been pumped out, some inert gas has been pumped in instead, and the chambers are sealed.

Location of windows and heat loss through them

Window glass almost completely transparent to solar heat, but not transparent to “black” radiation sources (with temperatures below 230 degrees).

Much more heat passes through the glass from the outside than can pass through from the inside. Such one-sided conductivity can lead to the fact that in winter heating rooms on the sunny side may not require significant expenditure. In the summer, on the contrary, we get overheating of the rooms, which creates the need to cool the rooms.

The least amount of light comes from the north, northeast and northwest sides.

Conclusion: you need to take into account the location of windows and their impact on the climate in the house at the stage of designing a house. Otherwise, all that remains is to “fight” with the help of blinds, films on glass, restoration of old frames or replacing them with new ones, insulation of slopes and other measures, which will be discussed in the following articles.

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