How to calculate the electric heated floor

Electric warm floor has undeniable advantages in terms of comfort and convenience. Those rooms in which is equipped with warm floors , immediately become the center of attraction for all households, because by lu can not only walk, but sit and even lie on the it .But before you mount and operate, you should find out how to calculate the warm electric floor yourself or contact a specialist for help. Otherwise, expensive heating cables and mats can be simply immobilized in concrete without the possibility of their extraction and recovery.

Kinds of electrical warm floors and their characteristics taken into account in calculations

The main details of any warm floors are heating elements or a combination of them. They have a different design. Let's note a feature of each system.

Resistive heating cable

systems for warm floors on this basis are most often used, since it is simple for and both and design is lower in comparison with other types of heaters price. It is based on a single- or double-core conductor, enclosed by in a protective shield and having defined resistance. In its essence, it is an elongated heating element, which, when connected to an electrical network, produces a certain amount of thermal energy from the .Resistive cables always have a fixed length, which can not be changed in any way, as this radically changes the entire system setting. Any attempt to shorten the resistive cable reduces its resistance, increases the current and this most often leads to failure of .

The main characteristics of the resistive cables are:

• Cable construction( single-core , two-core, zonal) and its purpose. Supply voltage and power. Generally, manufacturers specify two supply voltages of 220 / 230 volts and their corresponding Watt power, for example, the heating cable deviflex ™ DTIP-18, 22 meters in length, has a power of 360/395 watts, respectively.
• A very important characteristic of heating cables is the line power, that is, how many watts are emitted by one meter. In the of the above cable example, the line power is 18 W / m at 230 V supply voltage. This indicator is indicated in the cable marking, but it can also be calculated. If the power in 395 W divided by a length of 22 meters, it turns out 395/22 = 17.95 W / m.

Resistive cables are produced in different lengths( 7- 220 m ), different linear and total power, which can fully satisfy all needs. Naturally, the cable must be laid according to a special scheme to cover the entire area of ​​the room, but this will be discussed in detail in the following sections.

Heating mats

For the convenience of laying, heating mats have been invented where the heating resistive cable is woven by into the polymer mesh and is already packed with the required pitch. The mesh usually has an adhesive backing and can be glued to the floor surface, which only adds convenience to the installation. This is especially good when laying tiles, when the mats are hidden directly in the layer of tile glue or in the repair, if only a self-leveling thin screed is made, on which it is possible to subsequently laminate or carpet. Most heating mats are available in a width of 45 cm and different lengths, which allows you to choose a specific model for any room. In this case, do not forget that the basis of the mats is a resistive, usually two-wire, cable, so cut the mats on the conductors is strictly prohibited!

The main characteristics of heating mats are:

• Supply voltage, which is usually 220/230 In and the power of the heating mat.
• Mate length and recommended laying area, usually from 0.5 m2 to 12 m2 with a length of 1 to 24 m .
• One of the main indicators is the specific power, that is, how much heat generates a heating mat for 1 MW tr pad adrat. It is measured it in W / m 2( Watts per me tr unit adrat).For warm floors, mats with specific power of 100-150 W / m 2, very rarely 200 W / m 2 are usually produced.

Self-regulating heating cable

The main disadvantage of resistive cables and heating mats on their basis is the need for constant heat dissipationfrom them, since their resistance and, correspondingly, the amount of generated heat, are practically independent of the ambient temperature. If the cable does not remove heat, it will overheat and fail. That is why warm floors with resistive cables can not be equipped with stationary furniture without legs.

This lack of is devoid of the self-regulating cable, the power of which depends on the temperature. The heating element is a semiconductor polymer capable of changing the its resistance depending on the temperature. Such cables can be cut off without any fear of any length, it is not the that will cause the to overheat and fail. However, the high price limits their use as for warm floors, therefore they are used mainly for heating pipelines .

Film infrared warm floor

A relatively new type of floor heating is the infrared( IR) warm floors that are based on the radiators in the form of transverse graphite strips, connected to the longitudinal copper-silver conductors. The entire structure is located in the polyester film, which has a thickness of not more than 0.4 mm. Feature film floors is that most of the generated energy falls on the radiation component - infrared waves in the range of 4 to 20 nm. It is known that radiant infrared heat does not heat air, but surrounding objects, and this is perceived by the person very comfortably.

The main characteristics of the infrared floors of the calculations required by are:

• Supply voltage 220/230 In the and specific power consumption, which can be 130, 150, 170,200, 230 W / m 2, - depending on the room and its destination.
• Roll width film IR floor: 0.5, 0.8 or 1 meter. Length from 1 to 20 meters. This allows you to "fit" film for any premises.

The film floor also requires laying only on the floor area that is not occupied by stationary furniture without legs. Another one serious restriction of the application is the impossibility of laying in the screed, because the IR films do not "like" the wet processes in the construction. The best application for such heaters is to lay "dry" on absolutely flat surfaces with the subsequent laminate flooring intended for warm floor, linoleum or carpet.

Rod infrared warm floor

The most innovative and modern system for the warm floor is the rod infrared floors, where flexible elements from the carbon, graphite and silver composition are used as heaters. Such rods have very useful properties - when the floor temperature rises from 20 to 60 ° C, their peak power consumption decreases by 1.5 times. This makes it possible to use floor heating even where furniture is permanently located, which can be periodically changed.

Heating rods are connected in parallel to the longitudinal copper conductors, forming a heating mat. Even if one of them fails, others will continue to work. The width of the mat is 83 cm, the spacing between the rods can be 9 or 10 cm. The main characteristics of the infrared core floor are:

• Peak power consumption, which can be measured by the or W / m 2 or W / m. It can be either 130, or 160 W / m 2 with a line power of 116 or 138 W / m, respectively. These data are given for the UNIMAT RAIL or UNIMAT BOOST system.
• The minimum and maximum length of the thermometer is from 0.5 to 25 meters.
• Infrared wavelength: 8-14 microns.
• Supply voltage 220/230 V.

Rod IR warm the floor is designed for mounting mainly in thin - 2-3 cm screeds and in a layer of tile adhesive. Its novelty, manufacturability and remarkable characteristics determine high prices, that's why this warm floor is still quite rare.

Application of warm electrical flooring

Heating specialists and manufacturers of heating electrical systems warm floor recommend the use of cable heating in two basic modes:

• The heating cable system is installed in a concrete screed, at least 3-5 cm thick with the capability of its useas full heating, without the use of additional heating appliances. In this case, electric heating can compensate for all the heat loss and maintain the desired air temperature in the premises. Another option for is the use of cable heating in thermo-accumulating thick concrete floors( 10-15 cm), when during the action of the reduced electricity tariffs the is heated by the floor, and at other times for the account of the large thermal inertia of the massive screed, the heat is given to in the room.

• Heating systems in the form of electric heating cables, mats, tubular heaters or infrared film floors are mainly used only to maintain a comfortable floor surface temperature. Thus warm floors work together with the basic system of heating which compensates the lion's share of heat losses of an apartment or the house. To do this, use heating cables and mats that are mounted directly in the layer of tile adhesive or in the air gap of wooden floors, as well as infrared film floors laid directly under the cover.

Calculation of of building heat losses or of rooms

When designing any heating system, including the electrical of a warm floor as the main one, it is highly desirable to calculate the heat loss of each room in an apartment or house. In these calculations, the initial data are:

• The set temperature in each room and and and x is the relative position.
• Geographical location.
• Construction walls: which materials, which thickness are applied in walls, which is the walls are external.
• Floor and ceiling construction.
• Presence and area of ​​windows, their design and heat loss through them.
• Orientation of the building to the ends of the world.
• Outside air temperature( with considering the of the coldest temperatures of the year).
• Heat loss through ventilation.

All of the above is far from a complete list of input data for the estimation of heat loss. These calculations are made by heat engineers, but there are a lot of special free programs or online calculations of on the Internet, so anyone can make an assessment on their own. The main task of these calculations is that any heating system must fully compensate for all heat losses, even with considering the of the coldest winter days.

From the analysis of statistical data on the plurality of heat loss houses and flats can be said that in most modern flats and houses constructed from considering requirements for thermal protection, specific heating power per square IU mp mp oschadi must be 100-130 W / m 2 for all rooms and in bathrooms and lavatories 130-150 W / m 2. in older houses the power density can be up to 180 W / m 2 and in this case does not have to do without othersources of heat.

Justification of the use of thermal insulation in the systems of warm electric floors

Thermal insulation of the structural elements of the building will further greatly influence the comfort in the premises and significantly reduce the cost of heating. And one of the main is the insulation of the floor construction. Electric warm floors can be mounted directly under the floor covering, either with the use of various thin heaters, and without them, which is often the forced measure - when it is impossible to sacrifice the height of the room.

Heat losses through any enclosing structure occur the more intensively, the greater the temperature difference and the less thermal resistance. Even if in the adjacent rooms between floors there are the same temperatures, the heat all will inevitably be transmitted to the concrete slab of the floor. Therefore, if there is a possibility, then it is necessary to use heaters and the thicker they are, the better. The above diagram clearly demonstrates this.

If a system electric warm floor is used as a main heating in a thermal storage floor, the use of insulation required, since power heating cable mat will be simple and insufficient to compensate for heat losses.

How to calculate warm electric floor

After the idea of ​​the basic electrical systems of the warm floor and their characteristics is obtained, you can proceed to calculation .

Drawing plan of the premises and the calculation of the heated area

Before proceeding to calculations and choice of components, it is desirable to draw a plan of the premises of each individual apartment or house in a convenient scale on A 3 millimeter size paper or in a computer program.

After this, the total area of ​​the room is calculated - S total . Further, on the same plan, all stationary furniture without legs is made and the area occupied by the furniture is calculated - S MOB .Now you can get the area over which will be laid electric warm floor - S in :

S in = S total - S MEB .

It is desirable that the heated area occupy not less than 50% of the total area of ​​the premises, and preferably 70-80%, that is, the condition:

S for * 100% / Sob≥≥50%.

If as heating appliances IR core floors will be used, they can be laid all over the area, that is:

S for = S total .

Here is an example .There is a kitchen with a total area of ​​12 m2, and the area occupied by furniture and equipment 5 m2, means: S at = 12 - 5 = 7 m2.

Calculation of installed and specific power of electrical heating

With calculations of electrical warm floors it is absolutely necessary to calculate the installed power, called still connected, the electrical heating element that will heat the floor. How can I do that?

Using warm floor as the main heating

If the electrical warm floor is to be used as the basic heating system, then the installed P power must be at least not less than the heat loss in this room P n , which are received in the process of heat engineering calculations of .Experts recommend the installed power to calculate with a margin of 30%:

P set = 1.3 * P and .

If the heating cable is to be laid in the heat-retaining screed, the safety factor should be applied 1.4:

P set = 1.4 * P and .

For example, in the kitchen described above, the heat losses are 1000 W, so, in order to compensate them with the , taking into account the reserve, you need a heater with the installed power: P = 1.3 * 1000 W = 1300 W, and in case of thermo-accumulating floors P = 1.4 * 1000 W = 1400 watts.

The specific power of P can be defined as the ratio of the installed power to the heated area:

P ud = P / S from .

In our example: P ud = 1300 W / 7 = 186 W / m 2. or for accumulating floors - P ud = 1400 W / 7 = 200 W / m 2.

Using warm floor as a comfortable heating

In this case it is understood that the warm floors are designed for comfort, and the main heating system compensates for the heat loss. The calculates the installed capacity from the specific power that is prescribed in the regulations and recommendations of manufacturers of warm floors. Data on the specific power requirements, depending on the type of premises, are summarized in the following table.

In this case, the specific power selected from the table should be multiplied by the heated area:

P set = P ud * S from .

In our kitchen example, to select the warm for a comfortable floor, we choose P = 100W / m 2, and the heated area S in = 7m2 yields: P set = 100 * 7 = 700W.

Selection and calculation heating elements warm floor

After determining the required installed electric electrical power of the warm floor, it is necessary to determine which heaters are most suitable for use in each particular case. For basic heating, use resistive cables, and for comfort: heating mats, film or rod IR floors. Consider the features of choice.

Selection of a resistive heating cable and determination of the step

Consider this choice of on the for an example of kitchen heating using the deviflex ™ heating cable assortment from Devi .The selection procedure is exactly the same for of all resistive cables of all manufacturers.

Let's assume that a heat-shrinkage screed is planned as the main heat source. Previously, it was determined that the installed power should be at least P set = 1400 Watts. From the of the above table , is seen that the cables should be applied with a linear output of 18-20 W / m.the Devi range has cables deviflex ™ DSIG-20( 20W / m with 230 in ), which are better suited for the solution of the task.

From the proposed list should choose a cable whose power is not less than the installed capacity. This requirement is met by a cable with a capacity of 1465 W at 230 . In and 74 meters long: L = 74 m

For heating cables, there is a very important parameter - the laying step( h), - , the distance between the cable lines instyling. It is measured in centimeters. To find it, the heated area in square meters S in should be multiplied by 100 and divided by the cable length into meters L cab :

h = S from * 100 / L cab .

In the example considered, h = 7 * 100/74 = 9.46 cm. Often when laying a special mounting tape is used, greatly simplifying the installation. The step of fastening the cable to the mounting tape is 2.5 cm. The nearest value is 10 cm, which should be used. If the laying step will lie somewhere in the middle of the range, then you can alternate the adjacent hinges of the warm floor with steps of 7.5 and 10 cm.

The calculation of the resistive cable for comfortable floor heating is carried out in the same way. Let's remind its step by step.

• Based on the requirements for specific and continuous power, type premises and type of heating( full or comfortable), the type of cable that meets the with all conditions is selected from any manufacturer.
• Based on the previously calculated installed capacity, a specific cable with a capacity not less than the installed one is selected.
• Based on the heated area of ​​the room and the length of the selected cable, the stacking step is calculated.

At this stage, the layout of the room, drawn on millimeter paper, can be very useful. You can draw various ways of laying the heating cable with a pencil, and then choose the optimal one.

Calculators calculating the length of the heating cable and the pitch of its laying

We suggest the reader to use the built-in calculator - from quickly and accurately calculate the length of the required cable, and the laying step:

The required value is selected with the cable length closest to the value found. Now you only need to calculate the laying step:

Selection and calculation heating mat

Heating mats in warm floors are used mainly as additional or comfortable heating, mounted in thin concretetie or layer of tile adhesive. Choosing the right mat is greatly simplified, so the manufacturers have a wide range of t t such heaters. Consider on the as an example.

For the comfortable heating of the kitchen floor it was previously determined that the specific power of the P = 100 W / m 2 was sufficient. In the heated area of ​​7 m 2 , the installed power will be P set = 700 W.From the Devi product range, we select the heating mats devimat ™ DTVF -100( 100W / m 2).

For our purposes, the heating mat of the required area of ​​7 m2 is suitable for our purposes. Calculations of stacking steps do not require heating mats, because already has an cable with the required pitch on them. But when laying in rooms, especially a complex configuration, there are some nuances.

In order to lay the heating mat in the premises there are certain receptions of , which will allow to do this. The main rule - you can cut only the polymer mesh, but not the cable itself! The receptacles are clearly shown in the figure.

Obviously, the choice and calculation of the heating mat for floor heating is much simpler than the resistive cable. To select the tactics of correct styling, a plan on millimeter paper will help. The proverb: "Seven times measure and cut once!"

Features calculations infrared film floors

Film warm floors have a number of features that require a competent approach.

• First, they, like the resistive cable, must be stacked only in a place free from furniture.
• Secondly, the minimum distance from the film to the edges of the ( walls or stationary furniture) should be 20 cm.
• Third, film floors can only be laid in a "dry" way for suitable for this coatinglaminate, linoleum, carpet).Although there are technologies for laying tiles on film floors, but this assumes the presence of an intermediate waterproofing layer. As a result, the cost of warm floor with IR films will be much higher than with resistive cables or mats.
• Fourth , film floors can cut with defined multiplicity - often 25 cm. This will not affect the specific power.
• And finally, the apparent ease of calculating the and especially the mounting of the film floor is deceptive. Under the surface of the IR floor is the mass of electrical connections, which require only a highly qualified installation.

Video: Qualified installation of a film infrared floor

For the correct calculation of the film , a number of steps need to be taken:

• Calculates the heating space of the room. To do this, a plan is drawn on a sheet of paper in millimeters, "stationary" furniture is placed and the minimum of 20 cm of indentation from the borders is taken into account. As a result, should get the heated area of ​​ - S from .in S in = 15 m2, and total area of ​​ 24
• . Calculate the proportion of heated area in in in S : S in * 100% / S total = 15 m2 * 100% / 24 m2 =62.5%.If this figure is more than 60%( as in our case), then the specific power of heating IR radiation can be from 160 to 220 W / m to 2. If the share of heated area is less than 60%, then P ud =220 W / m 2. For our case choose P ud = 160 W / m 2.
• For rooms with large heat loss through the floor: the first floors, rooms above the arches, houses of old buildings with floors without insulation, - in any case P ud = 220 W / m 2.
• Calculatingetsya installed capacity warm floor. To do this, the specific power is multiplied with the heated area: P set = P * S for = 160W / m 2 * 15 m2 = 2400W.
• From the range of any manufacturer of films are chosen with a given specific power of the required length and width, which can cover the entire heated area. It should be noted that the width of rolls is 50, 80 and 100 cm, and the cutting ratio of film is every 25 cm. There are restrictions presented in the table. In this case, it is better not to choose the maximum length, but to gain smaller segments. The main rule of - is the smaller number of individual films ( the plan on millimeter paper will be of great help).

• For each individual section of the film , a connector kit is selected, and for the whole set - a temperature controller recommended by the manufacturer.

Features calculations rod infrared floors

The main distinguishing feature of rod IR floors is that they are self-regulating, that is, when the outside temperature rises, their peak power is reduced by approximately 1.5 times. This allows them to be applied to the entire area of ​​the room, regardless of the position of the furniture. For calculation core warm floors use the previous example room with S total = 24 m2 and calculate them for the whole area: S from = S total = 24 m2.

• For the comfortable heating of the floor, the system of warm rod infrared floors UNIMAT RAIL is selected with a peak power of 116 W / m. The width of the mat is 83 cm, they are stacked with an interval of up to 10 cm, so their length is chosen based on the required heated area.
• From the UNIMAT RAIL range, the UNIMAT HR-S-2500 kit is selected, 25 meters in length, with a peak power of 2900 W, capable of heating up to 25 m2.
• On the floor plan, previously drawn on millimeter paper, the heating mats are laid out. And power cables can be cut anywhere in the middle between the heating rods. Heating rods can not be cut.

• The number of additional components is determined.
• The thermoregulator recommended by the manufacturer is selected.

Requirements for flooring when operating warm electrical floors

When designing an electrical floor heating system, it is often forgotten that not all coatings can work with it. And this issue should be taken with all the care and seriousness .With which coatings work warm electric floors is contraindicated:

• Linoleum on a rubber or felt basis.
• Thick carpets or carpets on a rubber base.
• Board floor more than 25 mm thick.

When choosing linoleum, laminate, parquet board or carpet, you should definitely ask whether these coatings can work with the system of warm floors. Leading manufacturers indicate this always on the labeling and in the accompanying documentation.

To control the heating of wooden floors , as well as thin floors , it is recommended to use thermostats with two sensors: surface temperature and indoor air. If the thermal resistance of the RT floor covering is known, which can be specified in the documentation, then the is better than the to be guided by the following rules:

• With a specific power of 150 W / m 2 the maximum thermal resistance ( RTmax) can be up to 0, 13 m2 * K / W.
• With P ud = 125W / m 2 - R Tmax not more than 0.16 m2 * K / W.
• With P = 100W / m 2 - R Tmax not more than 0.18 m2 * K / W.

If multilayer coatings are used in a floor construction, for example a laminate with a substrate, then their thermal resistances are added up and the compliance with the above conditions is checked.

Calculation of electrical system warm floor

When designing the electric electric system, it is sometimes forgotten that not every electrical wiring can withstand the loads from a powerful energy consumer. In addition, not every power supplier is issued t t The technical conditions for allocating the required capacity. That is why the project of electricity supply and obtaining all permits must be entrusted to professionals, and focus only on what you can do yourself.

The choice of the thermostat

The heart of the system of warm floors is a thermostat that monitors surface or air temperature, or after that of and others at the same time - and, based on this, switches on or off the heating circuits. In addition, the thermostat can have a built-in timer and enable heating at the appointed time or have a program of including certain days of the week and hours in the .In thermoregulators there are still and other useful and useless functions. When choosing it, you should first of all follow the set of rules:

• is unthinkable. Every manufacturer of any poles in always recommends the certain models of temperature controllers and sensors working with them. It is better not to disregard these recommendations.
• All the thermostats can only work with the defined by the load current: 10 A - for heaters with installed power up to 2300 W, and 16 AS Pust ≥ 2300 W.It is for these indicators that the thermoregulator must first be selected.
• If you plan to use warm floor only for comfort, then you need to choose a thermostat with temperature sensor floor.
• If the warm floor is used for full heating purposes, then it is necessary to use the thermostat with air temperature sensor or with the combination of temperature sensors of floor and air.
• For the operation of heating systems with a wooden covering, it is mandatory to use thermostats with combination of temperature sensors for air and floor.
• If the electrical system is also planned in nearby rooms, it is advisable to use a multi-zone thermostat with remote sensors.

General rules for the design of electrical wiring warm floor

When designing the electrical wiring warm floor, several rules should be considered:

• All connections of the warm cables to each other and to the wiring must be carried out only on special terminals, thermoregulator contacts,boxes and electric boards. Any joints in the floor construction should be avoided except those that are unavoidable and recommended by the manufacturer.
• The heating cable and mats screens must be connected to the PE conductor and should be included in the common potential equalization system - EMS.
• The supply wires and cables must be a cross-sectional area not less than the supplying "cold" ends of the heaters of the warm floor. With the installed power up to 2300 W, the cross-sectional area of ​​the copper wire should be 1.5 mm 2 , and over 2300 W - 2.5 mm 2 .
• To protect a person from electric shock, the use of residual current protective devices( RCDs) with a differential current of no more than 30 mA is mandatory, and for the bathrooms - 10 mA .At least once a month, it is necessary to test the RCD.

• The wiring for supplying the electrical system of the warm floor must be laid directly from the electrical panels or the distribution and distribution( IED) to the thermostats. In this case, in the shields for the protection of the wiring must be automatic circuit breakers: for copper cables with a cross-sectional area 1.5 mm 2 with a rating of 10 A, and for 2.5 mm 2 - 16 A.
• If the heating elements warm floors are laid on a metal mesh, then it must necessarily be connected to a common system of potential equalization.

Results of

• Calculate warm the electric floor is completely self-sufficient, using the recommendations of the equipment manufacturer.
• Electrical warm floor is a system of increased danger, therefore, when designing and installing it is absolutely necessary to follow the rules for the installation of electrical installations of the latest edition.

Video: Example of calculation of a warm electric floor