Comparison of the main characteristics of various heaters: thermal conductivity and density, hygroscopicity and thickness. Comparison of thermal insulation of wall materials Thermal insulation table
Recent years when building a house or renovating it great attention focused on energy efficiency. With already existing fuel prices, this is very important. Moreover, it seems that further savings will become increasingly important. In order to correctly select the composition and thickness of materials in the pie of enclosing structures (walls, floor, ceiling, roof), it is necessary to know the thermal conductivity of building materials. This characteristic is indicated on the packaging with materials, and it is necessary even at the design stage. After all, it is necessary to decide from what material to build the walls, how to insulate them, how thick each layer should be.
What is thermal conductivity and thermal resistance
When choosing building materials for construction, it is necessary to pay attention to the characteristics of the materials. One of the key positions is thermal conductivity. It is displayed by the coefficient of thermal conductivity. This is the amount of heat that a particular material can conduct per unit of time. That is, the lower this coefficient, the worse the material conducts heat. Conversely, the higher the number, the better the heat dissipation.
Materials with low thermal conductivity are used for insulation, with high thermal conductivity for transferring or dissipating heat. For example, radiators are made of aluminum, copper or steel, since they transfer heat well, that is, they have a high coefficient of thermal conductivity. For insulation, materials with a low coefficient of thermal conductivity are used - they retain heat better. If an object consists of several layers of material, its thermal conductivity is determined as the sum of the coefficients of all materials. When calculating, the thermal conductivity of each of the components of the "pie" is calculated, the found values are summed up. In general, we obtain the thermal insulation capacity of the enclosing structure (walls, floor, ceiling).
There is also such a thing as thermal resistance. It reflects the ability of a material to prevent heat from passing through it. That is, it is the reciprocal of thermal conductivity. And, if you see a material with high thermal resistance, it can be used for thermal insulation. An example of thermal insulation materials can be the popular mineral or basalt wool, foam, etc. Materials with low thermal resistance are needed to dissipate or transfer heat. For example, aluminum or steel radiators used for heating, as they give off heat well.
Thermal conductivity table of thermal insulation materials
To make it easier to keep the house warm in winter and cool in summer, the thermal conductivity of the walls, floor and roof must be at least a certain figure, which is calculated for each region. The composition of the "pie" of the walls, floor and ceiling, the thickness of the materials are taken in such a way that the total figure is not less (or better - at least a little more) recommended for your region.
When choosing materials, one should take into account that some of them (not all) conduct heat much better in conditions of high humidity. If during operation such a situation may arise for a long time, the calculations use thermal conductivity for this state. The thermal conductivity coefficients of the main materials used for insulation are given in the table.
| Material name | Thermal conductivity coefficient W / (m ° C) | ||
|---|---|---|---|
| Dry | At normal humidity | With high humidity | |
| Woolen felt | 0,036-0,041 | 0,038-0,044 | 0,044-0,050 |
| Rock mineral wool 25-50 kg / m3 | 0,036 | 0,042 | 0,045 |
| Rock mineral wool 40-60 kg / m3 | 0,035 | 0,041 | 0,044 |
| Rock mineral wool 80-125 kg / m3 | 0,036 | 0,042 | 0,045 |
| Rock mineral wool 140-175 kg / m3 | 0,037 | 0,043 | 0,0456 |
| Rock mineral wool 180 kg / m3 | 0,038 | 0,045 | 0,048 |
| Glass wool 15 kg / m3 | 0,046 | 0,049 | 0,055 |
| Glass wool 17 kg / m3 | 0,044 | 0,047 | 0,053 |
| Glass wool 20 kg / m3 | 0,04 | 0,043 | 0,048 |
| Glass wool 30 kg / m3 | 0,04 | 0,042 | 0,046 |
| Glass wool 35 kg / m3 | 0,039 | 0,041 | 0,046 |
| Glass wool 45 kg / m3 | 0,039 | 0,041 | 0,045 |
| Glass wool 60 kg / m3 | 0,038 | 0,040 | 0,045 |
| Glass wool 75 kg / m3 | 0,04 | 0,042 | 0,047 |
| Glass wool 85 kg / m3 | 0,044 | 0,046 | 0,050 |
| Expanded polystyrene (polystyrene, PPS) | 0,036-0,041 | 0,038-0,044 | 0,044-0,050 |
| Extruded polystyrene foam (EPS, XPS) | 0,029 | 0,030 | 0,031 |
| Foam concrete, aerated concrete on cement mortar, 600 kg / m3 | 0,14 | 0,22 | 0,26 |
| Foam concrete, aerated concrete on cement mortar, 400 kg / m3 | 0,11 | 0,14 | 0,15 |
| Foam concrete, aerated concrete based on lime mortar, 600 kg / m3 | 0,15 | 0,28 | 0,34 |
| Foam concrete, aerated concrete based on lime mortar, 400 kg / m3 | 0,13 | 0,22 | 0,28 |
| Foam glass, crumb, 100 - 150 kg / m3 | 0,043-0,06 | ||
| Foam glass, crumb, 151 - 200 kg / m3 | 0,06-0,063 | ||
| Foam glass, crumb, 201 - 250 kg / m3 | 0,066-0,073 | ||
| Foam glass, crumb, 251 - 400 kg / m3 | 0,085-0,1 | ||
| Foam block 100 - 120 kg / m3 | 0,043-0,045 | ||
| Foam block 121 - 170 kg / m3 | 0,05-0,062 | ||
| Foam block 171 - 220 kg / m3 | 0,057-0,063 | ||
| Foam block 221 - 270 kg / m3 | 0,073 | ||
| Ecowool | 0,037-0,042 | ||
| Polyurethane foam (PPU) 40 kg / m3 | 0,029 | 0,031 | 0,05 |
| Polyurethane foam (PPU) 60 kg / m3 | 0,035 | 0,036 | 0,041 |
| Polyurethane foam (PPU) 80 kg / m3 | 0,041 | 0,042 | 0,04 |
| Cross-linked polyethylene foam | 0,031-0,038 | ||
| Vacuum | 0 | ||
| Air + 27 ° C. 1 atm | 0,026 | ||
| Xenon | 0,0057 | ||
| Argon | 0,0177 | ||
| Airgel (Aspen aerogels) | 0,014-0,021 | ||
| Slag | 0,05 | ||
| Vermiculite | 0,064-0,074 | ||
| Foamed rubber | 0,033 | ||
| Cork sheets 220 kg / m3 | 0,035 | ||
| Cork sheets 260 kg / m3 | 0,05 | ||
| Basalt mats, canvases | 0,03-0,04 | ||
| Tow | 0,05 | ||
| Perlite, 200 kg / m3 | 0,05 | ||
| Expanded perlite, 100 kg / m3 | 0,06 | ||
| Linen insulating plates, 250 kg / m3 | 0,054 | ||
| Polystyrene concrete, 150-500 kg / m3 | 0,052-0,145 | ||
| Granular cork, 45 kg / m3 | 0,038 | ||
| Mineral cork on bitumen basis, 270-350 kg / m3 | 0,076-0,096 | ||
| Cork flooring, 540 kg / m3 | 0,078 | ||
| Technical plug, 50 kg / m3 | 0,037 | ||
Some of the information is taken from standards that prescribe the characteristics of certain materials (SNiP 23-02-2003, SP 50.13330.2012, SNiP II-3-79 * (Appendix 2)). Those materials that are not spelled out in the standards are found on the manufacturers' websites. Since there are no standards, different manufacturers they can vary significantly, so when buying, pay attention to the characteristics of each material you buy.
Thermal conductivity table of building materials
Walls, ceilings, floor, you can make from different materials, but it so happened that the thermal conductivity of building materials is usually compared with brickwork... Everyone knows this material, it is easier to associate with it. The most popular are diagrams that clearly show the difference between different materials. There is one such picture in the previous paragraph, the second is a comparison brick wall and the walls of logs are shown below. That is why thermal insulation materials are chosen for walls made of bricks and other materials with high thermal conductivity. To make it easier to select, the thermal conductivity of the main building materials is tabulated.
| Material name, density | Coefficient of thermal conductivity | ||
|---|---|---|---|
| dry | at normal humidity | at high humidity | |
| CPR (cement-sand mortar) | 0,58 | 0,76 | 0,93 |
| Lime-sand mortar | 0,47 | 0,7 | 0,81 |
| Gypsum plaster | 0,25 | ||
| Foam concrete, aerated concrete on cement, 600 kg / m3 | 0,14 | 0,22 | 0,26 |
| Foam concrete, aerated concrete on cement, 800 kg / m3 | 0,21 | 0,33 | 0,37 |
| Foam concrete, aerated concrete on cement, 1000 kg / m3 | 0,29 | 0,38 | 0,43 |
| Foam concrete, aerated concrete on lime, 600 kg / m3 | 0,15 | 0,28 | 0,34 |
| Foam concrete, aerated concrete on lime, 800 kg / m3 | 0,23 | 0,39 | 0,45 |
| Foam concrete, aerated concrete on lime, 1000 kg / m3 | 0,31 | 0,48 | 0,55 |
| Window glass | 0,76 | ||
| Arbolit | 0,07-0,17 | ||
| Concrete with natural crushed stone, 2400 kg / m3 | 1,51 | ||
| Lightweight concrete with natural pumice, 500-1200 kg / m3 | 0,15-0,44 | ||
| Concrete on granulated slag, 1200-1800 kg / m3 | 0,35-0,58 | ||
| Boiler slag concrete, 1400 kg / m3 | 0,56 | ||
| Concrete on crushed stone, 2200-2500 kg / m3 | 0,9-1,5 | ||
| Concrete on fuel slag, 1000-1800 kg / m3 | 0,3-0,7 | ||
| Porous ceramic block | 0,2 | ||
| Vermiculite concrete, 300-800 kg / m3 | 0,08-0,21 | ||
| Expanded clay concrete, 500 kg / m3 | 0,14 | ||
| Expanded clay concrete, 600 kg / m3 | 0,16 | ||
| Expanded clay concrete, 800 kg / m3 | 0,21 | ||
| Expanded clay concrete, 1000 kg / m3 | 0,27 | ||
| Expanded clay concrete, 1200 kg / m3 | 0,36 | ||
| Expanded clay concrete, 1400 kg / m3 | 0,47 | ||
| Expanded clay concrete, 1600 kg / m3 | 0,58 | ||
| Expanded clay concrete, 1800 kg / m3 | 0,66 | ||
| ladder made of solid ceramic bricks on CPR | 0,56 | 0,7 | 0,81 |
| Ceramic hollow brick masonry on CPR, 1000 kg / m3) | 0,35 | 0,47 | 0,52 |
| Ceramic hollow brick masonry on the central control center, 1300 kg / m3) | 0,41 | 0,52 | 0,58 |
| Masonry of hollow ceramic bricks on the central control center, 1400 kg / m3) | 0,47 | 0,58 | 0,64 |
| Solid sand-lime brick masonry on CPR, 1000 kg / m3) | 0,7 | 0,76 | 0,87 |
| Hollow sand-lime brick masonry on CPR, 11 voids | 0,64 | 0,7 | 0,81 |
| Hollow sand-lime brick masonry on CPR, 14 voids | 0,52 | 0,64 | 0,76 |
| Limestone 1400 kg / m3 | 0,49 | 0,56 | 0,58 |
| Limestone 1 + 600 kg / m3 | 0,58 | 0,73 | 0,81 |
| Limestone 1800 kg / m3 | 0,7 | 0,93 | 1,05 |
| Limestone 2000 kg / m3 | 0,93 | 1,16 | 1,28 |
| Building sand, 1600 kg / m3 | 0,35 | ||
| Granite | 3,49 | ||
| Marble | 2,91 | ||
| Expanded clay, gravel, 250 kg / m3 | 0,1 | 0,11 | 0,12 |
| Expanded clay, gravel, 300 kg / m3 | 0,108 | 0,12 | 0,13 |
| Expanded clay, gravel, 350 kg / m3 | 0,115-0,12 | 0,125 | 0,14 |
| Expanded clay, gravel, 400 kg / m3 | 0,12 | 0,13 | 0,145 |
| Expanded clay, gravel, 450 kg / m3 | 0,13 | 0,14 | 0,155 |
| Expanded clay, gravel, 500 kg / m3 | 0,14 | 0,15 | 0,165 |
| Expanded clay, gravel, 600 kg / m3 | 0,14 | 0,17 | 0,19 |
| Expanded clay, gravel, 800 kg / m3 | 0,18 | ||
| Gypsum boards, 1100 kg / m3 | 0,35 | 0,50 | 0,56 |
| Gypsum boards, 1350 kg / m3 | 0,23 | 0,35 | 0,41 |
| Clay, 1600-2900 kg / m3 | 0,7-0,9 | ||
| Refractory clay, 1800 kg / m3 | 1,4 | ||
| Expanded clay, 200-800 kg / m3 | 0,1-0,18 | ||
| Expanded clay concrete on quartz sand with porization, 800-1200 kg / m3 | 0,23-0,41 | ||
| Expanded clay concrete, 500-1800 kg / m3 | 0,16-0,66 | ||
| Expanded clay concrete on perlite sand, 800-1000 kg / m3 | 0,22-0,28 | ||
| Clinker bricks, 1800 - 2000 kg / m3 | 0,8-0,16 | ||
| Ceramic facing bricks, 1800 kg / m3 | 0,93 | ||
| Medium density rubble masonry, 2000 kg / m3 | 1,35 | ||
| Plasterboard sheets, 800 kg / m3 | 0,15 | 0,19 | 0,21 |
| Plasterboard sheets, 1050 kg / m3 | 0,15 | 0,34 | 0,36 |
| Plywood, glued | 0,12 | 0,15 | 0,18 |
| Fiberboard, chipboard, 200 kg / m3 | 0,06 | 0,07 | 0,08 |
| Fiberboard, chipboard, 400 kg / m3 | 0,08 | 0,11 | 0,13 |
| Fiberboard, chipboard, 600 kg / m3 | 0,11 | 0,13 | 0,16 |
| Fiberboard, chipboard, 800 kg / m3 | 0,13 | 0,19 | 0,23 |
| Fiberboard, chipboard, 1000 kg / m3 | 0,15 | 0,23 | 0,29 |
| Linoleum PVC on a heat-insulating basis, 1600 kg / m3 | 0,33 | ||
| Linoleum PVC on a heat-insulating basis, 1800 kg / m3 | 0,38 | ||
| PVC linoleum on a fabric basis, 1400 kg / m3 | 0,2 | 0,29 | 0,29 |
| PVC linoleum on a fabric basis, 1600 kg / m3 | 0,29 | 0,35 | 0,35 |
| PVC linoleum on a fabric basis, 1800 kg / m3 | 0,35 | ||
| Asbestos-cement flat sheets, 1600-1800 kg / m3 | 0,23-0,35 | ||
| Carpet, 630 kg / m3 | 0,2 | ||
| Polycarbonate (sheets), 1200 kg / m3 | 0,16 | ||
| Polystyrene concrete, 200-500 kg / m3 | 0,075-0,085 | ||
| Shell rock, 1000-1800 kg / m3 | 0,27-0,63 | ||
| Fiberglass, 1800 kg / m3 | 0,23 | ||
| Concrete tiles, 2100 kg / m3 | 1,1 | ||
| Ceramic tiles, 1900 kg / m3 | 0,85 | ||
| PVC roof tiles, 2000 kg / m3 | 0,85 | ||
| Lime plaster, 1600 kg / m3 | 0,7 | ||
| Cement-sand plaster, 1800 kg / m3 | 1,2 | ||
Wood is one of the building materials with a relatively low thermal conductivity. The table provides indicative data for different breeds. When buying, be sure to look at the density and thermal conductivity coefficient. Not all of them are the same as spelled out in regulatory documents.
| Name | Coefficient of thermal conductivity | ||
|---|---|---|---|
| Dry | At normal humidity | With high humidity | |
| Pine, spruce across the grain | 0,09 | 0,14 | 0,18 |
| Pine, spruce along the grain | 0,18 | 0,29 | 0,35 |
| Oak along the grain | 0,23 | 0,35 | 0,41 |
| Oak across the grain | 0,10 | 0,18 | 0,23 |
| Corkwood | 0,035 | ||
| Birch | 0,15 | ||
| Cedar | 0,095 | ||
| Natural rubber | 0,18 | ||
| Maple | 0,19 | ||
| Linden (15% moisture) | 0,15 | ||
| Larch | 0,13 | ||
| Sawdust | 0,07-0,093 | ||
| Tow | 0,05 | ||
| Oak parquet | 0,42 | ||
| Piece parquet | 0,23 | ||
| Panel parquet | 0,17 | ||
| Fir | 0,1-0,26 | ||
| Poplar | 0,17 | ||
Metals conduct heat very well. They are often the cold bridge in the structure. And this must also be taken into account, to exclude direct contact by using heat-insulating layers and gaskets, which are called thermal rupture. The thermal conductivity of metals is summarized in another table.
| Name | Coefficient of thermal conductivity | Name | Coefficient of thermal conductivity | |
|---|---|---|---|---|
| Bronze | 22-105 | Aluminum | 202-236 | |
| Copper | 282-390 | Brass | 97-111 | |
| Silver | 429 | Iron | 92 | |
| Tin | 67 | Steel | 47 | |
| Gold | 318 |
How to calculate wall thickness
In order for the house to be warm in winter and cool in summer, it is necessary that the enclosing structures (walls, floor, ceiling / roof) must have a certain thermal resistance. This value is different for each region. It depends on the average temperatures and humidity in a particular area.
Thermal resistance of the enclosing
structures for the regions of Russia
In order for heating bills to be not too large, building materials and their thickness must be selected so that their total thermal resistance is not less than that indicated in the table.
Calculation of wall thickness, insulation thickness, finishing layers
For modern construction the situation is typical when the wall has several layers. Besides supporting structure there is insulation, finishing materials. Each of the layers has its own thickness. How to determine the thickness of the insulation? The calculation is simple. Based on the formula:
R - thermal resistance;
p is the layer thickness in meters;
k - coefficient of thermal conductivity.
First, you need to decide on the materials that you will use in construction. Moreover, you need to know exactly what kind of wall material, insulation, decoration, etc. After all, each of them contributes to the thermal insulation, and the thermal conductivity of building materials is taken into account in the calculation.
First, the thermal resistance of the structural material is considered (from which the wall, floor, etc. will be built), then the thickness of the selected insulation is selected "according to the residual" principle. You can also take into account the thermal insulation characteristics of finishing materials, but usually they are a "plus" to the main ones. This is how a certain stock is laid "just in case." This reserve allows you to save on heating, which subsequently has a positive effect on the budget.
An example of calculating the thickness of the insulation
Let's take an example. We are going to build a brick wall - one and a half bricks, we will insulate mineral wool... According to the table, the thermal resistance of the walls for the region should be at least 3.5. The calculation for this situation is shown below.
If the budget is limited, you can take 10 cm of mineral wool, and the missing will be covered finishing materials... They will be inside and out. But if you want your heating bills to be minimal, better finish start up with a "plus" to the calculated value. This is your reserve for the most low temperatures, since the norms of thermal resistance for enclosing structures are calculated based on the average temperature over several years, and winters are abnormally cold. Therefore, the thermal conductivity of the building materials used for decoration is simply not taken into account.
The purpose of the building insulation work is to preserve heat in winter, save energy resources and reduce the cost of heating the dwelling. Years of practice have shown that the most effective way to insulate private house, this is to sheathe it on the outside with one of the heaters. The question is which one to choose, because a large assortment of new materials is offered on the construction market.
Table indicators
The table below will help you not to make a mistake in choosing a heat-insulating material. It indicates not only the thermal conductivity coefficient, but also the degree of vapor permeability, which plays an important role in the use of insulation in outdoor work.
|
Material |
Density |
Vapor permeability |
Thermal conductivity |
|
Expanded polystyrene |
150kg / m 3 |
0,05 |
0,05 |
|
Expanded polystyrene |
100kg / m 3 |
0,05 |
0,041 |
|
Minvata |
200kg / m 3 |
0,49 |
0,07 |
|
Minvata |
100kg / m 3 |
0,56 |
0,056 |
|
Polyurethane foam |
80kg / m 3 |
0,05 |
0,041 |
|
Polyurethane foam |
60kg / m 3 |
0,05 |
0,035 |
|
Foam glass |
400kg / m 3 |
0.02 |
0,11 |
Additional properties of building insulation materials that determine the reaction of materials to various physical influences, such as water absorption, thermal expansion, and heat capacity, can be found in reference books of building materials.
The table shows that mineral (basalt) wool has the highest vapor permeability. In addition, it has a rather low thermal conductivity, which makes it possible to use slabs of lesser thickness for insulation.
Foam glass has the lowest heat saving coefficient, so it is better to use it when the question of how to insulate the foundation of a house from the outside is urgent.
If we compare mineral wool with expanded polystyrene and other types of insulation given in the table, then they have less vapor permeability, having approximately the same thermal conductivity. Consequently, the walls sheathed with these materials will "breathe" less.
What to look for when choosing
The first thing that should be of interest when buying a heater is its thermal insulation performance, and the lower the thermal conductivity, the better it will keep the house warm in winter and cool in summer.
The heat capacity of a material depends on its ability to store and retain heat. The higher its density, the more the insulation can store energy, therefore the best heaters those in the structure of which there are many vesicular formations or microscopic isolated cavities.
The next indicator is vapor permeability. The higher it is, the better excess moisture will be removed from the building and less accumulated in the walls of the house. Materials with low vapor transmission properties reduce the building's ability to retain heat, and it is necessary to install an improved forced ventilation, and this is an extra cost.
Low-weight insulation is easier to transport, install, and always cheaper. But most importantly, it requires fewer fasteners to hang it, and there is no need to strengthen the walls and foundation. An important role is played by the indicators of the flammability of materials, especially when insulating wooden buildings. The most refractory are foam glass and basalt wool.
Modern insulation materials have unique characteristics and are used to solve problems of a certain spectrum. Most of them are designed for processing the walls of the house, but there are also specific ones designed for arranging door and window openings, joints of the roof with load-bearing supports, basements and attic spaces... Thus, when comparing thermal insulation materials, one must take into account not only their performance properties, but also the scope of application.
Main parameters
An assessment of the quality of a material can be based on several fundamental characteristics. The first of these is the coefficient of thermal conductivity, which is denoted by the symbol "lambda" (ι). This coefficient shows what volume of heat in 1 hour passes through a piece of material with a thickness of 1 meter and an area of 1 m², provided that the difference between the temperatures of the medium on both surfaces is 10 ° C.
Indicators of the coefficient of thermal conductivity of any heaters depend on many factors - on humidity, vapor permeability, heat capacity, porosity and other characteristics of the material.
Moisture sensitivity
Moisture is the amount of moisture that is contained in the insulation. Water conducts heat well, and the surface saturated with it will help to cool the room. Consequently, waterlogged heat-insulating material will lose its qualities and will not give the desired effect. And vice versa: the more water-repellent it has, the better.
Water vapor permeability is a parameter close to humidity. In numerical terms, it represents the volume of water vapor passing through 1 m2 of insulation in 1 hour, provided that the difference in the potential vapor pressure is 1 Pa, and the temperature of the medium is the same.
With high vapor permeability, the material can be moistened. In this regard, when insulating walls and floors of a house, it is recommended to install a vapor barrier coating.
Water absorption is the ability of a product to absorb liquid when it comes into contact with it. The water absorption coefficient is very important for materials that are used to equip external thermal insulation. High air humidity, atmospheric precipitation and dew can lead to a deterioration in the characteristics of the material.
Density and heat capacity
Porosity is the number of air pores expressed as a percentage of the total volume of the product. Distinguish between closed and open pores, large and small. It is important that they are evenly distributed in the structure of the material: this indicates the quality of the product. Porosity can sometimes reach 50%, in the case of some types of cellular plastics, this figure is 90-98%.
Density is one of the characteristics that affect the mass of a material. A special table will help determine both of these parameters. Knowing the density, you can calculate how much the load on the walls of the house or its floors will increase.
Heat capacity is an indicator showing how much heat the insulation is ready to accumulate. Biostability - the ability of a material to resist the effects of biological factors, for example, pathogenic flora. Fire resistance is the resistance of insulation to fire, while this parameter should not be confused with fire safety. There are also other characteristics, which include strength, bending endurance, frost resistance, wear resistance.
Also, when performing calculations, you need to know the U coefficient - the resistance of structures to heat transfer. This indicator has nothing to do with the qualities of the materials themselves, but you need to know it in order to make right choice among a variety of heaters. The U coefficient is the ratio of the temperature difference from the two sides of the insulation to the volume of the heat flow passing through it. To find the thermal resistance of walls and floors, you need a table where the thermal conductivity of building materials is calculated.
You can make the necessary calculations yourself. For this, the thickness of the material layer is divided by the coefficient of its thermal conductivity. The last parameter - when it comes to insulation - must be indicated on the packaging of the material. In the case of building elements of a house, everything is a little more complicated: although their thickness can be measured independently, the coefficient of thermal conductivity of concrete, wood or brick will have to be looked for in specialized manuals.
At the same time, materials are often used to insulate walls, ceilings and floors in the same room. different types, since for each plane the thermal conductivity must be calculated separately.
Thermal conductivity of the main types of insulation
Based on the U coefficient, you can choose which type of thermal insulation is better to use, and what thickness the material layer should have. The table below contains information about the density, vapor permeability and thermal conductivity of popular heaters:
Advantages and disadvantages
When choosing thermal insulation, you need to consider not only it physical properties, but also such parameters as ease of installation, the need for additional maintenance, durability and cost.
Comparison of the most modern options
As practice shows, the easiest way is to install polyurethane foam and penoizol, which are applied to the surface to be treated in the form of foam. These materials are plastic, they easily fill the cavities inside the walls of the building. The disadvantage of foaming agents is the need to use special equipment to spray them.
As the table above shows, extruded polystyrene foam is a worthy competitor to polyurethane foam. This material is supplied in the form of solid blocks, but can be cut to any shape using a regular carpenter's knife. Comparing the characteristics of foam and solid polymers, it is worth noting that foam does not form seams, and this is its main advantage over blocks.
Comparison of cotton materials
Mineral wool is similar in properties to polystyrene and expanded polystyrene, but it “breathes” and does not burn. It also has better resistance to moisture and practically does not change its qualities during operation. If there is a choice between hard polymers and mineral wool, it is better to give preference to the latter.
By stone wool comparative characteristics the same as for the mineral, but the cost is higher. Ecowool has a reasonable price and is easy to install, but has a low compressive strength and sags over time. Fiberglass also sags and, moreover, crumbles.
Loose and organic materials
For thermal insulation of a house, bulk materials are sometimes used - perlite and paper granules. They are water repellent and resistant to pathogenic factors. Perlite is environmentally friendly, it does not burn and does not settle. Nevertheless, bulk materials are rarely used to insulate walls; it is better to equip floors and ceilings with their help.
From organic materials, flax, wood fiber and cork... They are safe for environment, but are susceptible to burning if not saturated with special substances. In addition, wood fiber is susceptible to biological factors.
In general, if we take into account the cost, practicality, thermal conductivity and durability of heaters, then best materials for finishing walls and ceilings - it is polyurethane foam, foam insulation and mineral wool. Other types of insulation have specific properties, as they are designed for non-standard situations, and it is recommended to use such insulation only if there are no other options.
Heat retention requirements for private houses and apartments have increased significantly. Many resort to additional finishing of attic floors, outer walls due to the constant increase in the cost of energy carriers.
In recent years, enough materials have appeared that can significantly improve heat conservation in a private house or apartment. They also have a number of other properties, which in general make them an excellent alternative to major renovations.
Varieties and description
Materials with different mechanical properties are offered to consumers' choice.
Ease of installation and properties largely depend on this. According to this indicator, they are distinguished:
- Foam blocks... They are made of concrete with special additives. As a result chemical reaction the structure is porous.
- Plates. Building materials of various thicknesses and densities are made by pressing or gluing.
- Cotton wool. It is sold in rolls and has a fibrous structure.
- Granules (crumb). with foam substances of various fractions.
It's important to know: selection of material is carried out taking into account properties, cost and purpose. The use of the same insulation for the walls and attic floor will not allow you to get the desired effect, unless it is indicated that it is intended for a specific surface.
Various substances can be used as raw materials for insulation. They all fall into two categories:
- organic based on peat, reeds, wood;
- inorganic - made of foamed concrete, minerals, asbestos-containing substances, etc.
Basic properties
The effectiveness of a material largely depends on three main characteristics. Namely:
- Thermal conductivity... This is the main indicator of the material, expressed by a coefficient, calculated in watts per 1 square meter. Depending on the level of heat retention, a different amount of insulation is required. It is significantly influenced by the rate of moisture absorption.
- Density. An equally important characteristic. The higher the density of the porous material, the more efficiently heat will be retained inside the building. In most cases, it is this indicator that is decisive when choosing a heater for walls, floor slabs or roofs.
- Hygroscopicity. Resistance to moisture is very important. For example, basement floors, which are located in damp places, it is important to insulate with a material with the lowest hygroscopicity, which is, for example, plastic form.
It is necessary to pay attention to a number of other indicators. This is resistance to mechanical damage, temperature extremes, flammability and durability.
Comparison of key indicators
To understand how effective a particular insulation will be, it is necessary to compare the main indicators of materials. This can be done by reviewing Table 1.
| Material | Density kg / m3 | Thermal conductivity | Hygroscopicity | Minimum layer, cm |
| Expanded polystyrene | 30-40 | Very low | Average | 10 |
| Plastiform | 50-60 | Low | Very low | 2 |
| 60-70 | Low | Average | 5 | |
| Styrofoam | 35-50 | Very low | Average | 10 |
| 25-32 | low | low | 20 | |
| 35-125 | Low | High | 10-15 | |
| 130 | Low | high | 15 | |
| 500 | High | Low | 20 | |
| Aerated concrete | 400-800 | High | High | 20-40 |
| Foam glass | 100-600 | Low | low | 10-15 |
Table 1 Comparison of thermal insulation properties of materials
At the same time, many people prefer plastic form, mineral wool or aerated concrete. This is due to individual preferences, installation features and some physical properties.
Application features
Before deciding on the materials for finishing a private house or apartment, it is necessary to correctly calculate the thickness of the layer of a particular insulation.
- For horizontal surfaces (floor, ceiling), you can use almost any material. The use of an additional layer with high mechanical strength is mandatory.
- It is recommended to insulate basement floors with building materials with low hygroscopicity. Increased humidity must be taken into account. Otherwise, the insulation, under the influence of moisture, will partially or completely lose its properties.
- For vertical surfaces (walls) it is necessary to use plate-and-sheet materials. Bulk or roll will sag over time, so you need to carefully consider the method of fastening.
Installation of various types
When choosing this or that material for better preservation of heat in a house or apartment, you need to take into account the peculiarities of its installation. Complexity and set of tools for conducting installation works largely depends on the form of thermal insulation. Namely:
- expanded clay. It is used exclusively for floors and floor slabs... You need an entrenching tool and additional building materials (screed or boards). You will also need a waterproofing layer in the form of roofing felt or other similar material.
- mineral wool. Correct installation involves the use hand tool for fixing the frame. Mineral wool is very easy to install in pre-prepared cells, but an even fixation is required over the entire plane. Waterproofing layer on top of the insulation - required condition long-term operation. Can be used for vertical and horizontal surfaces.
Note: when installing any type of insulation, it is important to remember about hydro and vapor barrier. It is very important to protect the finish from direct exposure to moisture.
- Styrofoam. Plates are attached to the surface with dowels with "dimes". Among necessary tools screwdriver, hammer drill, construction knife and dowels. Building material shape and a light weight even allows you to independently perform the entire volume of work in a short period of time.
- foam glass... For a tight connection to the surface, mechanical fasteners or solutions (cement, mastics and other adhesives) are used. The choice depends on the material of the walls. Blocks are very popular, but there are also slabs and granules in the assortment.
What to choose
New building materials appear at various exhibitions every year. With their help, you can significantly reduce energy costs in the cold season. But which of them will be the best solution in all respects. Experts differ in many ways.
The selection of material is based on properties, cost and ease of installation. Manufacturers apply certain markings to products, which greatly simplifies the selection. For example, foam for walls, floors or roofs has different properties and special marks.
Many people prefer mineral wool in dry rooms, foam in rooms with high humidity, and sprayed insulation for hard-to-reach places.
Which insulation is better: ecowool, stone wool or expanded polystyrene, see the following video:
The ability of bodies and substances to transfer internal energy, defined in macro-processes by the term " thermal energy"Is called thermal conductivity. In engineering and construction, the thermal conductivity of external structures is one of the most important standardized criteria.
The thermal conductivity formula (Fourier's law), which is discussed below in more detail, relates the amount of heat energy transferred per unit time through a unit area through the thermal conductivity coefficient, which serves as the basic characteristic of building structures in terms of their heat transfer.
The thermal conductivity of some thermal insulation materials makes them unsuitable for use in building a house, although their other indicators are quite acceptable. The thermal conductivity of mixtures and composite materials used for the construction of houses is usually higher than that of other substances, since this property is taken into account when developing their compositions.
It is possible to numerically determine the coefficient of thermal conductivity of a material using special devices and techniques that are required to comply with the existing architectural standards in Russia.
Building insulation materials and their thermal conductivity
The thermal conductivity of a structure is not only a function of the components that make up it, the porosity of the insulation plays an important role, since air is a good heat insulator. The heat transfer of porous materials is significantly lower than that of monolithic materials.
Comparison of the spectrum of properties of structural products, which includes: strength characteristics, permissible loads, thermal conductivity of materials and the required thicknesses to comply with thermal conductivity standards leads to the conclusion that for the construction of high-quality modern home requires the use of heat-insulating materials with high insulating capacity per unit volume and weight.
A separate direction in the creation of heat-insulating materials is the insulation of pipelines. Pipes significantly affect the useful volume of living space, therefore, a significant reduction in the thickness of their thermal insulation, required for the normal functioning of the system, is one of the important requirements of modern design.
Environmental properties and heat transfer
Heat transfer in building structures depends not only on the properties of thermal insulation materials and temperature differences, but also on environmental parameters. The lower the dew point, that is, the less water in the air, the lower its thermal conductivity. In this case, cold air always has a lower dew point.
Therefore, in order to improve the thermal insulation of the living space, vapor barrier materials are used, the action of which is based on the principle of membranes. They separate humid air on one side of the thermal insulation materials, from the air at their surface, in order to significantly reduce the thermal conductivity of the wall.
Comparison of the thicknesses of heat-insulating materials required to ensure the permissible architectural norms of a house being built with and without vapor barrier leads to an unambiguous conclusion about the unequivocal need to use the proposed membrane fabrics together with heat-insulating fabrics in the wall and roof heat-insulating layers.
Thermal insulation materials used for arranging pipes for heating systems and water supply systems are mainly products made of porous materials with low thermal conductivity, having continuous films on their surfaces obtained by extrusion, which in turn ensures a constant dew point inside the pores. Therefore, the diameter of products for reliable pipe insulation is much smaller than would be required without the presence of such surfaces.
Thermal conductivity table
The thermal conductivity of some materials is shown in the table below. Information on other building construction products can be found in the reference book.
| Material | Coefficient of thermal conductivity | Required thickness | |
| 1 | Expanded polystyrene PSB-S-25 | 0,042 | 124 |
| 2 | Mineral wool Rockwool Facade Batts | 0,046 | 135 |
| 3 | Glued wooden beams or an array tree | 0,18 | 530 |
| 4 | Ceramic blocks Proterm | 0,17 | 575 |
| 5 | Aerated concrete blocks 400 kg / m3 | 0,18 | 610 |
| 6 | Polystyrene concrete blocks 500 kg / m3 | 0,19 | 643 |
| 7 | Aerated concrete blocks 600 kg / m3 | 0,29 | 981 |
| 8 | Expanded clay concrete blocks 800 kg / m3 | 0,31 | 1049 |
| 9 | Expanded clay hollow brick 1000 kg / m3 | 0,52 | 1530 |
| 10 | Clay building bricks | 0,52 | 1530 |
| 11 | Silicate building bricks | 0,76 | 2236 |
| 12 | Reinforced concrete (GOST 26633) 2500 kg / m3 | 0,87 | 2560 |
| Material name | Thermal conductivity, W / m * K | Water vapor permeability, mg / m * h * Pa | Moisture absorption,% | Flammability group |
| Minvata | 0,037-0,048 | 0,49-0,6 | 1,5 | NG |
| Styrofoam | 0,036-0,041 | 0,03 | 3 | G1-G4 |
| PPU | 0,023-0,035 | 0,02 | 2 | G2 |
| Penoizol | 0,028-0,034 | 0,21-0,24 | 18 | D1 |
| Ecowool | 0,032-0,041 | 0,3 | 1 | G2 |
Expanded polystyrene
Foamed insulation based on styrene and styrene-butadiene compositions. Possesses good thermal insulation properties, it is used for insulation of walls and pipes.
Extrusion boards
Various in basis (mainly - polyurethane foam and expanded polystyrene). Plates have docking grooves, which does not require sealing them together. This modern materials used to insulate any large and flat surfaces.
Penofol
Foamed polyethylene foam. It has a number of advantages: it is elastic, does not allow air to pass through, and has a reflective surface. It is used for thermal insulation of walls, pipes, floors, has good heat-insulating properties, but it does not "breathe", in other words, moisture can condense on its surface with a large temperature difference.
Mineral wool
Mineral fiber insulation. It is widely used for insulating walls, floors and roofs, it is indispensable for insulating complex non-planar surfaces. Can be used as a winding for pipes large diameter... More elastic than basalt wool, it has less weight. For the rest of the characteristics, it is slightly worse, with the exception of the price.
Basalt wool
One of the most modern premium elastic sheet insulation. Slightly less elastic than mineral wool. Has a larger specific gravity, large transport dimensions, higher cost.
Styrofoam
Foamed polyurethane foam. It is used in the form of "butt-joint" slabs. It is used for insulation of walls, floors and ceilings, roofing.
Loose and organic materials
Loose and organic materials (expanded clay, slag, sawdust, shavings) are used for filling cavities, hollow walls, ceilings). They have a number of disadvantages: hygroscopicity, compaction over time, low vapor barrier ability. The main advantages are availability and cost.
Comparison of vapor permeability of heaters
Name of material Thermal conductivity, W / m * K Vapor permeability, mg / m * h * Pa Moisture absorption,%
Flammability group
Minvata 0.037-0.048 0.49-0.6 1.5 NG
Polyfoam 0.036-0.041 0.03 3 G1-G4
PPU 0.023-0.035 0.02 2 G2
Penoizol 0.028-0.034 0.21-0.24 18 G1
Ecowool 0.032-0.041 0.3 1 G2
The thermal conductivity potential of the walls of the house, equal to the sum of the thermal conductivities of all layers of their structure, divided by their thickness, shows how much this structure can retain heat.
Comparative analysis of the data from the table of thermal conductivity of materials and heaters makes it possible to carry out calculations about their applicability in certain cases. The thermal conductivity of building materials at home, as mentioned above, also depends on the dew point of the environment between its surfaces.
Fourier's law of thermal conductivity
In conclusion, a few words about theoretical basis heat transfer phenomena and thermal conductivity. To calculate the coefficient of thermal conductivity of materials, Fourier's law is used, which describes the relationship between the rate of passage of thermal energy through a unit section.
Thermal conductivity through the coefficient λ is related to the physical parameters of the body. If a parallelepiped is considered as a heat-conducting body, then the amount of heat passing through it per unit time can be described by the following formula (Fourier's law):
P = λ × S∆T / l, where P is the power of heat losses, S is the cross-sectional area of the parallelepiped, T is the temperature difference between the edges, l is the length of the parallelepiped (the distance between the edges).
In other words, the coefficient determined by measuring the temperature difference is equal to the amount of heat that passes through a square centimeter of the material's cross-section per unit of time.