What kind of insulation to put under the warm floor. What thermal insulation for a warm floor is better - we choose a heater consciously. The need for floor insulation

Set up a water-heated floor system country house and it's time to lay the insulating underlayment? Agree that among the variety of offers of heat-insulating materials offered by manufacturers, it is sometimes not easy to make the right choice.

We will help you determine which insulation for a warm water floor is better. Together with you we will deal with all the intricacies of assembling heat-insulating systems. We explore the characteristics of popular materials, evaluate the key advantages and disadvantages.

Independent home masters will find with us installation instructions. To make it easier to navigate the assortment offered by the building materials market, we have selected videos with recommendations for choosing insulation and installation.

In any instructions for installing a water heated floor for independent craftsmen indicates that it is necessary to use a heater.

The layer of insulation in the arrangement of the water floor performs several significant functions. It helps not only to ensure uniform heating of the room, but also, acting as heat shield, allows you to significantly reduce the energy losses of the system.

The screed, laid on top of the insulating layer, acquires the properties of a one-piece heat transfer element having large area surfaces.

The main purpose of the insulating layer is to evenly distribute heat in the heated room, preventing it from leaking through the floor slabs.

Due to the uniform distribution of energy, an ordered convection heat flow begins to move at the same speed and in the same direction. As a result, evenly distributed heat waves will not form cold and hot spots on the floor, creating maximum comfort for households. comfortable conditions.

In addition, due to the direction of flow warm air at one rate, you can reduce the cost of electricity for the operation of the system, while maintaining its capacity unchanged.

Types of heaters for underfloor heating

Insulation options for underfloor water heating systems on modern market presented a lot. The choice of substrate thickness is limited only by the material possibilities of the owner and technical parameters premises.

Absolutely all heat-insulating materials prevent the movement of sound waves through their thickness, and therefore are characterized by high noise absorption rates.

If there is a heated room under the base base, a heater with a thickness of 10-12 mm is sufficient, but if it is a basement or soil, a substrate of 30 mm or more will be required

Regardless of the version, special requirements are imposed on the heat-insulating material:

• it must have a low coefficient of thermal conductivity;
• perceive the load created by the pipes filled with water;
• withstand the load of the screed laid over the pipeline;
• be resistant to dynamic influences that may occur during the operation of the system, and after the pressure is reduced, it must return to its original shape.

To achieve the desired effect allows the use of insulating material, the density of which is at least 35 kg / m 3.

Option #1 - heat insulating boards

In rooms where the ceiling height reaches 260 centimeters and above, you can safely give preference to heaters on a rigid polymer base.

Styrofoam or Styrofoam. The basis for the manufacture of heat-insulating plates can be foam or expanded polystyrene.

The first option was created in a non-extrusion way, there are channels between its polymer cells for the passage of air and steam. Polyfoam is characterized by low specific gravity, as well as high vapor permeability.

In the manufacture of expanded polystyrene, the extrusion method is used, due to which the cells of the material are firmly sintered by the walls with each other. The vapor permeability of the insulation because of this is practically zero. But he has high strength and the ability to withstand significant mechanical stress.

The specific heat capacity of expanded polystyrene is slightly higher than that of polystyrene. In the first case, it is equal to 1.34 kJ / (kg ° C), in the second, 1.26 kJ / (kg ° C) is calculated. The difference is small, but in the calculations it can significantly affect the overall thickness of the floor heating system.

The standard size of thermal insulation, for example, 120 cm × 240 cm. GOST number 15588-86 regulates the width from 50 cm to 130 cm, length from 90 cm to 500 cm.

The density of foamed polystyrene is 150 kg/m³, the same characteristic of foam plastic is 125 kg/m³. Depending on the specifics of production and the properties invested by manufacturers in products, the characteristics of materials may vary.

Due to the unique composition, polystyrene boards act as good noise insulators, and their allowable load is about 50 kN/sq.m.

If we compare both types of material, then the foam is disadvantageous in that it is inferior in terms of density. Due to this, it is less resistant to deformation under the action of mechanical loads.

This significantly reduces thermal insulation properties. Styrofoam is recommended to be laid in the structures of flooring systems between the joists.

Cork. Often cork is used as a water and electric floor. Due to the special structure, which is a miniature prism correct form, cork insulation is characterized by significant compressive strength, as well as the lack of adhesion to cement mortar.

Due to the cost of the material cork more often they choose for residential premises in which the base base is already well insulated. Otherwise, to achieve the desired effect, you will need to purchase technical plug at least 30 mm thick, which can significantly “hit the wallet”.

The main advantage of mats made from several layers of glued cork oak bark fibers is environmental safety.

The only drawback of cork mats is that they are hygroscopic and also come in the form of one-component heat insulators. Therefore, when laying them, it is necessary to use additional layers that will provide steam and hydro protection.

Mineral wool. As an alternative affordable option - the use of mineral wool. It is available as a flexible mat or solid board.

Since when laying in a screed mineral wool collapses under weight, which negatively affects its heat-shielding properties, this material is also best combined with floor structures assembled from wooden logs.

With the use of mineral wool as a heat-insulating layer, the heat transfer of a water-heated floor will be maximum

The only drawback of the material is the presence of penofol in the composition, which carries a danger to human health, and low moisture resistance. But well-executed waterproofing easily eliminates these shortcomings.

Option # 2 - profile systems with guides

Profile systems help to facilitate the installation of water circuits. They are created using the technology of hydropellent stamping, as a result of which figured protrusions are formed.

Products are of two types: plain and laminated which are covered with a vapor barrier film.

Bosses or guide grooves are located on the surface of the profile mats in even rows, between which it is convenient to lay heating circuits

The basis for their manufacture is extruded polystyrene foam, which is created by extruding the molten composition through the holes of the extruder.

The polymer base is famous for its resistance to moisture and high mechanical strength. The thickness of the plate itself can vary from 10 to 35 mm. The main thing is that it should be proportional to the thickness of the finishing screed.

The side faces of each slab are equipped with locks, with which it is convenient to adjust the elements, forming a continuous field, devoid of thermoacoustic seams.

The height of cylindrical protrusions located on the surface of the plates reaches 20-25 mm. This is enough to conveniently place and securely fix water circuits with a diameter of 14 to 20 mm. Tightly planted rows of bosses exclude the possibility of shifting the laid contours during the pouring of the cement screed.

The only downside profile systems in fact, it is impossible to lay water circuits made of pipes of non-standard diameter in them

A feature of the installation of profile systems is that after laying water circuits in them, the structures are poured on top with a small layer of adhesive. And only after a day or two, when the glue is completely dry, the system is put into operation.

Image gallery

Option # 3 - thermal insulation of roll execution

Roll insulation is chosen for rooms in which the distance to the ceilings is critical. With the help of thin foil layers with a protective lavsan coating, the thickness of the “pie” can be significantly reduced. Max Thickness such a substrate is only 9-12 mm.

The foil layer applied on one side of the insulation reflects thermal radiation well, thereby preventing energy loss

Roll thermal insulation is equipped with a heat-reflecting sheath made of lavsan or thermal insulation. Thin metallized materials perfectly reflect heat rays, so you can safely reduce the thickness of the insulation without fear of reducing the insulating qualities.

Important requirement when using foil options is that you can not use materials with aluminum foil in the device of floors with cement-sand screed. The alkaline environment of the mixture during pouring will simply corrode the aluminum layer.

However, if a protective film is applied over the foil, installation is possible. Use is allowed if the solution is mixed with gypsum, and not with cement powder. Some manufacturers replace the foil layer with lavsan or polypropylene film by adding metallic inclusions to it.

In an effort to facilitate the installation process, many manufacturers apply special markings on the foil side of the produced roll materials, which serve as a guide for laying the heating circuit.

The disadvantage of foil materials is that they reflect heat well, but do not insulate well enough. If the floor is laid over basement, thin roll solutions are not enough.

Some craftsmen solve the problem by laying hard insulation mats not in one layer, but in two. But at the same time, the sheets are placed in such a way that the seams of the lower substrate overlap with the seams of the upper one. This minimizes heat loss.

Features of laying insulation

The substrate mounting scheme depends on the type of materials used. But in any case, it must be placed on the most even surface.

No. 1 - slab laying technology

The substrate, constructed from boards with mounting chamfer, is assembled easily - according to the principle of the designer. Plates are easy to fit and measure. You can cut the plates to the appropriate dimensions with an ordinary knife.

The ease of laying the substrate is convenient because during installation at any time you can change the configuration of the contours and the length of the pipelines. So that the plates of the material do not move relative to each other during installation and operation, their joints are glued with construction tape.

In order to prevent the formation of heat-conducting bridges, the contour seams between adjacent plates are glued with foil tape

The sequence of actions when laying insulating boards:

1. Styrofoam plates are laid on a cleaned and leveled base, fixing them with special plastic brackets, anchor dowels or planting them on an adhesive composition.
2. A foil layer is laid on top of the stacked and docked plates.
3. The top layer is lined with a reinforcing mesh, on which pipes are subsequently mounted.

If the concrete screed of the base floor is poured with significant deviations from the level or has gross cracks and irregularities, or concrete plates stacked with violations, it is better to build a frame before laying the substrate. For this, wooden logs are assembled from a dry and even beam with a section of 50x50, 50x100 or 100x100 mm.

Logs are placed at an equidistant distance of 60 cm, cuts of mineral wool or foam boards are laid between them

A distance of 60 cm between the lags is considered the most the best option, since with such a "step" the creation of an additional crate is not required. The main thing is that the logs are located in the same plane and lie strictly in level.

Thermal insulation boards should be tightly packed between wooden lags. If there are gaps - they must be blown out with mounting foam.

In laying plates made of extruded polystyrene foam, it is necessary to observe some nuances:

The damper tape is installed along the perimeter after the installation of the heat-insulating layer. Its edge must be partially brought under the insulation, partially placed on the wall

It is not necessary to lay waterproofing over extruded polystyrene foam. However, a substrate with lined cells will facilitate the installation of pipes with the required pitch.

No. 2 - installation of roll materials

The laying of the roll material is carried out on a carefully leveled base and fixed to the base base using tile adhesive or double sided tape. Slicing strips required size performed with ordinary office scissors.

To compensate for the thermal expansion of the screed, it is recommended to place the foil layer with a slight overhang on the wall.

The foil material is placed with the metal side up so that the metallized surface the best way reflected heat

When laying rolled materials, they are guided by the marking of printed mounting markings. It determines the distance between the contours and makes it easier. Usually roll materials edges have foil allowances polymer film for the possibility of connecting adjacent canvases.

When laying cuts, special attention is paid to expansion joints. To do this, the joints of the laid strips are glued with one-sided construction or metallized adhesive tape. If a cork coating is used as a substrate, then before laying it, it is necessary to take care of reliable vapor and waterproofing.

No. 3 - mat mounting scheme

The stage preceding the laying of mats is the arrangement of film waterproofing. After laying it around the perimeter of the room, strips of damper tape are glued along the bottom of each of the walls.

Mats are laid on the prepared base, fastening the plates together by means of lock system. To securely fasten plates of small thickness and light weight, apply adhesive method and use plastic harpoon brackets.

Some manufacturers, for ease of installation, complete with mats apply edge bands, with which it is convenient to mark the exit areas from the heating zone

An important point: when laying mats, it is not allowed to use metal fasteners, since it can damage the integrity of not only the heat insulator, but also the waterproofing.

In order not to make a mistake in choosing a heater for a water floor, be guided technical specifications premises, taking into account not only the thickness of the product, but also the maximum permissible load for compression.

Properly approaching the choice of a heat insulator and observing all the subtleties of installation, you can create solid foundation for the arrangement of a functional floor water system.

Do you want to talk about how you chose and installed insulation under the heating floor at home? Have questions or valuable advice? Please write your comments in the box below.

Designing heating system, you need to make every effort to create a uniform distribution of heat throughout the volume of the room. Using traditional species heating thermal energy heading up towards the ceiling while cold air remains on the floor - and such a distribution of heat is uncomfortable for the human body.

To get rid of such a problem, when choosing a heating system, you can pay attention to underfloor heating, which provides just such a distribution of thermal energy, which allows you to create the most comfortable atmosphere for living. In addition, to reduce heat loss at the lower level, good thermal insulation of the floor is needed. This article will consider thermal insulation for underfloor heating, the materials used for it and their features.

The need for floor insulation

The presence of high-quality thermal insulation provides a number of advantages:

• Heat loss through the floor is significantly reduced. The thing is that through the floor covering leaves the largest number heat - losses can reach 20%. Good thermal insulation for an electric warm floor will protect the room and keep thermal energy within it.
• Heat is distributed throughout the room more evenly. In a well-insulated building, heat energy is dissipated in such a way that every part of the room is properly heated. This is largely ensured by the fact that heat is spent on heating floors and other structural elements building.

• Since energy is not wasted on non-functional heating, the heating system becomes more economical and heating costs become lower.
• Good insulation for a warm floor also provides good protection against sound penetrating from outside.
• When using moisture-proof materials, reliable protection is created from water that can enter living quarters from the ground or basement levels.

The choice of thermal insulation

There are water, infrared and electric varieties of underfloor heating. Each type of system requires its own thermal insulation material, since the efficiency and reliability of heating depends on the final combination. In addition, when choosing a thermal insulation material, it is necessary to take into account the degree of stress that the floor covering will experience.

Insulation for electric underfloor heating should have the following characteristics:

• High strength characteristics, flexibility and good compression resistance;
• Ability to withstand external loads without deformation;
• High resistance to aggressive substances and environments;
• Low thermal conductivity;
• High density (at least 25 kg / m 3 in the case of materials used for underfloor heating);
• Minimum degree of moisture absorption.

Thermal insulation materials for underfloor heating

There are several materials that can be used as thermal insulation under a warm floor:

• Cork backing. This material environmentally friendly and high density. The thickness of cork thermal insulation is usually about 3-4 cm, which must be taken into account when designing the room so that its height does not decrease too much. Cork is expensive and requires the installation of a reflective layer, so it must be used very carefully as a thermal insulation.

• Polypropylene. Polypropylene thermal insulation is produced in the format of extruded plates. This material, in addition to good insulating qualities, is distinguished by the ability to delay sound waves. In addition, the plates do not absorb moisture. It is very easy to work with such material, and it is safe to use - polypropylene plates can withstand temperatures up to 130 degrees.

• Styrofoam. Extruded polystyrene foam is a material with high strength, low weight, resistance to temperature changes and low cost. In addition, it should be noted the excellent resistance to aggressive substances and the ability not to absorb moisture. All these qualities are preserved throughout the entire period of operation of the material, which is largely due to the air filling of the cells. Expanded polystyrene is the best thermal insulation for tiles under a water-type warm floor.

• Metallized lavsan film. This material is not used by itself, but in combination with expanded polystyrene foam, it gives reliable protection flooring from the aggressive environment that is created concrete screed. The aluminum layer is necessarily covered with a PVC film, since the metal cannot normally withstand corrosion.

Regardless of the material chosen, the laying of insulation under a warm floor should be carried out in such a way that a monolithic layer is obtained that has sufficient strength and performs its functions well.

Conclusion

Thermal insulation for a warm floor is an indispensable element, without which it will not be possible to create a high-quality heating system. Choice of the most suitable material and the method of its laying is carried out individually, depending on the characteristics of a particular building and heating project.

If it is planned to equip the house with underfloor heating, then it is understood that they should provide an atmosphere of warmth and comfort in it. This will be true if the technology was sustained in the process of creating such a heating system. One of the mandatory elements during installation is thermal insulation for underfloor heating, which largely ensures its efficient and economical operation.

About the floor heating system

The device itself is usually intuitive to everyone and seems like this - there is something heating on the floor, which is closed flooring. To some extent, such a representation is true, but if we touch on the implementation of the very idea of ​​\u200b\u200bheating, then there are very curious nuances here. In particular, this applies to the creation of thermal insulation for underfloor heating.

Its purpose is also clear without much explanation - it should prevent irrational heat loss. If there is a basement or other unheated premises, interfloor ceilings, then the warm floor will simply heat them. To eliminate this, thermal insulation is used for underfloor heating. It is a kind of basis on which the installation of the heating system itself takes place.

Here it is required to say that thermal insulation under a warm floor is usually in in full done when used as heating element special (electrical) cable. It releases heat when it flows electricity, and the value of its selection is normalized. Knowing the norms of heat dissipation, it is possible to calculate and install a warm floor, which allows to provide the desired temperature in the room.

The basis on which the installation of such a system is carried out is thermal insulation for a warm floor, electric or using a different type of heater.

In fact, part of the room turns into a kind of thermos, the floor and wall section are thermally isolated from all other structural units of the building, and heat can only flow into the right room.

Floor insulation how it works

In the classic version of underfloor heating, the thermal insulation layer is the basis for all subsequent installation. Before starting work, the subfloor is leveled, which is the surface interfloor overlap. To do this, a screed is made, after hardening of which a heat insulator for a warm floor is laid on top.

Here you need to pay special attention to the thickness of the heat insulator layer. If below, one floor below, there is a cold room, for example, a basement or soil, then the insulation layer must be at least 5 centimeters thick. In cases where there is nothing of the kind below, then a layer of thermal insulation of two centimeters is sufficient.

Also, don't forget about the walls. Those areas that are adjacent to the floor must also be covered with a heat insulator, at least to a height of at least twenty centimeters from the floor.

This is necessary to exclude heat losses through the walls, otherwise the heating of neighboring rooms will begin.

Thermal insulation materials for underfloor heating can be used in a variety of ways, the main requirement is that the coefficient of thermal conductivity be low (0.05 W / sq. M) and insignificant moisture absorption. In this capacity, extruded polystyrene foam, basalt fiber materials, sheet cork, etc. are often used.

When the heat insulator is laid, a screed is applied over it, three to five centimeters thick. It must be strong enough, because. it directly installs the heating system. The latter, in turn, will itself be closed in the future. cement screed, on top of which the floor covering will be laid.

Special cases of thermal insulation

The above method for creating thermal insulation concerns the option of a warm floor, in which heating is carried out by a heating cable. However, other elements of a similar purpose may be involved for this, in particular, infrared film. At the same time, they implemented a different heating principle and, as a result, simpler thermal insulation is used.

When IR rays are used, a heat-reflecting material must act as a heat insulator. It can be soft or hard, but it must be a heat insulator and have a reflective coating. In this capacity, it is best to use lavsan metallized film and metal foil is not allowed (for safety reasons).

The heat-reflecting material is laid directly on the subfloor with the reflective side up, an IR film is placed on top of it, which is subsequently covered with a floor covering. Due to the reflective surface, part of the IR radiation, which goes towards the interfloor ceilings, returns to the room and participates in its heating.

As another case of using thermal insulation, you can consider what it should be like when heating a loggia or balcony. In this case, it is necessary to prevent heat loss everywhere, so everything must be insulated - the ceiling, walls, floor of the loggia, regardless of the method of heating.

Thermal insulation when laying a warm floor should be considered an indispensable element that ensures its efficient and economical operation. It can be implemented different ways, depending on the principle of operation of the heating system.

Are you planning to insulate the floor? The insulation system itself is not as important as the insulation laid under it. It is he who requires careful selection both for the type of insulation and for the room itself. Next, we will reveal the structure of the warm floor and describe in detail how to choose a heater for it and not be mistaken.

First of all, why do we need thermal insulation for a warm floor? It is known that 20% of the heat from floor heating goes down, in other words, we will simply waste energy and not get the desired result.

Here is what thermal insulation materials will help us to cope with:

• reduce natural heat loss. Heat escapes to the cold surface directly to the outside or into the ground. As stated above, the loss is 20%.
• will help to evenly distribute heat around the perimeter, that is, on the floor. Energy will not be wasted on ceilings or elements below the heating area.
• save energy for additional heating
• reduce the cost of heating
• create additional sound insulation
• prevent moisture penetration through the floor covering
• protect the heating system

In the diagram we see the structure of a warm floor in a private house, regardless of its type. Whether it is an electric or water mechanism, the picture looks something like this:

The base may differ, depending on what is under the insulated surface. To choose the insulation itself, it is worth determining what is under it: soil, basement, living quarters. This aspect is very important for the selection of material.

For example, if there is soil or a basement under the insulated floor, the recommended thickness of the insulation is 50-100 mm. In the event that there is a residential heated room under the floor, 20-50 mm is enough.

Types of materials for insulation

To choose a material, you need to understand what qualities are most valuable in it. Here are the most important ones:

• low thermal conductivity, which is logical
• high compressive strength
• material elasticity
• low deformation rate, ability to withstand loads
• resistance to aggressive environments
• high density (minimum 25kg/m3, experts recommend 50kg/m3)
• moisture absorption - minimum

Regardless of whether it is an electric or water heated floor, the general list of heaters recommended for use is unchanged, and the selection is made depending on the situation. Consider the most popular heat insulators:

• polystyrene foam
• cork backing
• polypropylene
• mineral wool
• profile heat-insulating mats

Expanded polystyrene is rightfully considered the best insulation material. It applies to both electric and water heated floors. In terms of price - inexpensive, in terms of quality - perfect option. Extruded polystyrene foam performs especially well in combination with metallized lavsan film, which protects the floor from alkali and destruction.

Cork backing is good environmentally friendly material which can be applied. But there are a number of limitations. The price of the "cork" is quite high. This heater has limitations in the height of the premises. And the substrate requires an additional ray-reflective layer for maximum efficiency. The option takes place exclusively in electrical warm floors working as additional insulation.

Polypropylene - can both serve independently, and in addition with expanded polystyrene. It withstands temperatures well up to 130 * C, has a cellular structure, can be processed. The choice of polypropylene is an individual matter, depending on the characteristics of the insulation.

Mineral wool is also inexpensive and very useful. Provides additional sound insulation. It is advisable to use foil mineral wool, in order to avoid harm to health and ensure additional reflection heat rays. Important: it loses its properties at the slightest wetting, has a relatively high moisture absorption rate, therefore it is applicable only in electric heated floors.

Individual features of electric and water underfloor heating

A few more aspects about the choice of insulation. Let's start with electric underfloor heating. They are divided into three types: cable, mesh and infrared.

The first is mounted in the floor screed itself and is suitable for insulation ground floors, as a result - requires the greatest insulating layer. In this case, extruded polystyrene, foil-coated mineral wool is suitable. In general - materials with high density in a layer of about 100 mm.

The cable with reinforcing mesh is mounted on top of the screed. It is good for work when there is a heated room below the insulation. In this case, additional thermal insulation is not too important.

Infrared floor is suitable for those who do not want to exercise capital works. Used under linoleum or laminate. In this case, thermal insulation in the form of polyethylene foam with a foil coating is required to reflect the infrared rays. An additional layer of waterproofing must be added on top of the insulation installation.

Insulation for a warm water floor is also not a simple issue, but it is completely solvable. The structure of such a warm floor is a set of pipes carrying hot water around the perimeter. Consequently, the insulation material must have not only low thermal conductivity, but also zero moisture absorption, resistance to its effects. You should also think about vapor barrier. The best option serves extruded polystyrene foam. It withstands loads, perfectly retains heat, does not absorb moisture, and lasts a very long time. But the choice is situational.

This review of the main materials for warming warm electric and water floors can be completed. It is important to remember that the choice of material depends entirely on the goals. With knowledge of the quality of each insulation, you will undoubtedly find exactly what will provide maximum efficiency your warm floor.

For many specialists who are engaged in the design of heating systems, this question will seem unnecessary. Why? Because the answer to it is obvious - a heater is needed. For them, the question of warming sounds like this: "does a person need clothes in winter?"

Nevertheless, in addition to designers, there are many people who are far from designing and calculating heating systems, and, in this regard, do not have sufficient knowledge and specific numbers to answer the question: "Do I need a heater for a warm floor? And if necessary, then what thickness? First of all, customers who plan to build a house fall into the category of such people, but want to save on something and do not see the need to lay a layer of insulation. Among this category there are “experienced” ones who are not carrying out the first construction and, using only their feelings, they say: “I have already built one house, and there I have warm floors. I put my hand, but the floor is warm. I didn’t use insulation. Why is it needed at all? I saved it."

There are also specialists involved in the installation of underfloor heating systems, who continue to be interested in the question of the appropriateness of using insulation, its thickness and the conditions under which it can change.

Here, in fact, for these two categories, as well as for everyone who wants to explore this issue, this article was written.

So, we answer the question: "Do I need a heater for a warm floor?"

First, let's agree on something:

1. We will observe the solution of 8 tasks. The conditions for each will be the same. The difference will be only in the presence of insulation or in its absence, as well as in its thickness.
   For all other parameters, the "pie" of the warm floor will be the same. The area of ​​\u200b\u200bthe warm floor, the length of the circuit pipe, the pipe laying step, the temperature of the coolant and the finish coating will be the same - ordinary ceramic tiles.
2. Since we are solving the problem for small room, the floor, which is mounted on the ground (4 * 2.5 \u003d 10 m 2), then we will use the design temperature for outdoor air -26 0 C ( design temperature air for Voronezh and the Voronezh region).

General conditions for solving the problem:

Given:

The solution of the problem:
(click to enlarge)

no insulation	insulation 1 cm	insulation 2 cm	insulation 3 cm
As you can see, in a system without a heater, it is quite possible to get a good heat flow with square meter 90 W/m2. But the heat loss in this case is huge 118 W/m 2 . More than 1 kW of losses from 10 m 2 That would be such a "warm floor" turn upside down. It would be warmer. And what about our gas costs? If for heating season with a normally designed heating system, the owner would pay (conditionally) 10,000 rubles, then without a heater he will need 23,100 rubles (roughly) to pay. The surface temperature of such a floor, when touchedeat with your hand, it gives a tangible correct result, complemented by a bursting sense of pride from the realization of one’s own technical savvy and the fidelity of the chosen strategy for “saving” money on insulation.	This solution is already on the technically right track. This solution allows you to save not only heat, but, as we have already seen, the owner of the house. However, if you pay attention to the amount of heat flow down 59.1 W / m 2 through the insulation, it becomes clear that the thickness of the expanded polystyrene is still not enough. One of important characteristics, which directly affects the amount of heat loss - is the resistance to heat transfer, which is measured in m 2 * W / K and when installing underfloor heating on the ground should be equal to 2.25 m 2 K / W. And now what is our resistance to heat transfer? 0.409 m 2 K / W. This is five times less! Let's add another 1 cm of insulation.	What do we have with the heat flow going to heat the room? 98.5 W / m 2? Increased slightly in comparison with the previous thickness of the insulation? Is it worth it to spend more on insulation? What about heat loss? 37.8 W/m2!!! This is a direct savings for the owner of the house on operating costs! If things go on like this, then very soon we will shake your hand and say: "You are one of the best Specialists on right choice thickness of insulation for underfloor heating systems and we can safely recommend you to your customers." While we do not say it yet, but we cheer you up with cheers. Why? Because the losses are still too high and the heat transfer resistance of the layers of the underfloor heating pie located under the pipes is insignificant. Look, it is now equal to 0.659 m 2 * W / K. We follow further. plus 1cm	I would like to congratulate you. With what? Have we really reached that cherished value of the thickness of the insulation, which meets the standards and is the most optimal? I'll tell you: "Not yet." But pay attention to the amount of useful heat flux. You have reached 100 watts with 1 m2. This is a serious indicator. From an area of ​​10 m 2 you get 1000 W of heat flow. 1 kW! Do you remember how it started? Without insulation, such a flow was directed downwards for all the money! Thanks to the insulation thickness of only 3 cm, you managed to increase the useful heat flux from 90 to 100 W per 1 m2. Reduce heat loss to the ground from 118 to 27 W per 1 m 2 and reduce the cost of the house owner from 23,100 rubles to 13,000. However, it is too early to relax. What do we have with heat transfer resistance? 0.909 m2 * W/K. Already good. Add another 1 cm.
insulation 4 cm	insulation 5 cm	insulation 7 cm	insulation 8 cm
Don't pull the cat's tail. This is the name of adding 1 cm to the previous 3. The indicators have changed in better side slightly. And money for a heater is paid. Where is the profit? Where is the savings? I assure you it exists even in this case, although not as significant as in the previous one. Compare the readings at least with the option when there is no insulation. Feel the difference? Well, then go ahead plus another 1 cm. We will draw conclusions later.	Now that's something. Five centimeters is not one for you. That's four more! And what about our indicators? Useful heat flow - 103 W / m 2. Heat loss - 16.8 W / m 2. In fact, 168 W from our 10 m 2 floor heating area according to the conditions of the problem. What about heat transfer resistance? What about him? 1.409 m2 * W/K. Not bad. Quite good. We are close to the target. I propose to change tactics and add 2 cm at once.	This option actually achieved the goal (or maybe the previous one?). The useful heat flow almost does not increase, the heat loss does not decrease significantly. Only 4.9W (49W over the entire surface). Thermal power our 10 m 2 increased from 1030 to 1045 watts. Just 15 watts. The resistance to heat transfer increased significantly from 1.409 m 2 * W / K to 1.909 m 2 * W / K. But it should be 2.25 m 2 K / W.	Finally, we have reached the finish line! Here it is an option when, with a heater thickness of 8-8.5 cm, we achieve the desired resistance to heat transfer. What are our main indicators? Useful heat flow - 105 W per square meter; heat loss - 10 W from the same meter; heat transfer resistance 2.159 m 2 * W / K.

Findings:

1. Underfloor heating needed. As we noticed at the very beginning, this is as obvious as the need for warm clothes in winter.
2. Should the thickness of the insulation tend to be normalized? In design, yes. However, in agreement with the Customer, this value can be changed. There is always a reasonable optimization based, among other things, on the conditions in which the system will be operated.
3. Not so much a conclusion as an addition to all of the above.
   Sometimes there are house owners, and sometimes installers, who say that insulation has already been laid in the floor during construction. For example, sand was brought in as a soil, then it was thrombosed, then, after waterproofing, styrofoam or polystyrene foam 10 cm was laid on it. Then a screed 8 or 10 cm thick was poured on top of it. Now you need to do floor heating. And here the question arises: "Is it necessary to lay a heater in the" pie "of the warm floor?" Read no further. How would you answer this question?
   Do a thought experiment. November. You wanted to sit down. You sat on the curb. What are your feelings? Are you comfortable? The answer is obvious. At this time, your friend was walking by. He was carrying home some sheets of Styrofoam. Seeing your position, he gave you one sheet and you sat on it. There is already a layer of insulation between you and the curb. Did you get better? Again, the answer is obvious. Now imagine that you put polystyrene foam under the curb, and you yourself sat on top of it. What are the feelings now?
   And now attention to the question: do you need a heater for the "pie" of the warm floor, if under reinforced concrete slab already installed insulation?
   You decide. And this is another question: why did an architect or foreman, or someone else, put insulation in the ground in this place.