The device of underfloor heating in apartments is not recommended, since there is a possibility of leakage and flooding of the neighbors from below. An alternative solution - an electric heated floor (ETP) - is much safer, cheaper and easier to install. Stages of implementation:
- Choose a type of heating elements that meet the operating conditions (type of coating, height of the “pie”, purpose).
- Calculate the required power for the heating circuits.
- Correctly mount the electronic circuit.
All work can be done independently, having previously studied our manual. The only exception is the connection to the home electrical network, which is better to entrust to the master.
Types of electrical TP
In specialized online stores and ordinary construction supermarkets you can buy 4 types of electric heaters for floor heating:
- resistive and self-regulating cables;
- cable mats;
- thin polymer film;
- carbon rods.
Reference. Products are sold in the form of a ready-made set of ETP of fixed power. For automatic temperature control, a sensor with a corrugated tube and a room thermostat are purchased. You will also need a power cable with copper conductors - to connect the heating circuit to the mains.
Each type of heater is used in certain conditions, differs in characteristics and installation method. Therefore, we consider all the options individually.
Features of heating cables
A flexible ETP conductor is made of the following materials (the device is shown below in the diagram):
- heating core (happens 1 or 2);
- internal insulation made of heat-resistant plastic like FEP, TXLP or PVC;
- shielding layer of aluminum foil or copper braid;
- PVC outer sheath;
- additional grounding conductor.
Note. The screen serves as a barrier to electromagnetic radiation emitted by any live electrical conductor.
A single-core cable (otherwise - a heating section) ends with two connecting sleeves - cold ends. The two-wire type is connected on one side, which greatly simplifies installation work.
The usual resistive section is heated due to its own resistance, selected from the calculation of the specific heat transfer of 100 ... 150 W / m² of floor area. The self-regulating cable functions differently: between 2 current-carrying conductors a semiconductor matrix is embedded, which changes the resistance depending on the heating. The price of such products is corresponding - from 10 c. E. per meter running.
Features of cable heating sections:
- The conductor is afraid of overheating and requires heat removal over the entire surface, the critical temperature threshold is 90 ° C. An exception is a self-regulating cable that can reduce heat transfer with increasing temperature.
- The finished circuit cannot be shortened and rearranged - the section resistance will drop, the core temperature will increase. How long the internal insulation will last under extreme conditions is unknown.
- Heat transfer from 1 m² can be adjusted by reducing or increasing the pitch of the conductors. But you must understand that the heated area will also change, the optimal power is 100 W / m².
- Most cables are designed for wet installation - pouring cement-sand mortar 3 cm high above the outer sheath (minimum).
- The heating section cannot be laid on top of the insulation, like water pipes TP. The material will reflect the heat flux, the cable will begin to overheat. Therefore, the foundation is made of concrete.
Note. There is an exception to any rule.Some brands, for example, Devi, manufacture cable sections for "dry" installation - under a laminate or parquet on wooden floors.
Circuits from heating cables work without problems in humid rooms - bathrooms, showers, and kitchens. It is only necessary to select a regulator of a high degree of protection plus install an RCD in the apartment (operating current 30 mA), if there was no such device before.
Here is a list of trusted brands that produce quality floor-mounted electric heaters:
- Devi (production Denmark - Poland);
- Nexans (France);
- Shtoller (Germany);
- Teplolux (Russia);
- Profitherm (Poland).
You can familiarize yourself with the electrical floor heating systems in more detail on the Heating-Systems website.
Cable mats
Heaters of this type are the same cable attached to a solid nylon mesh 0.5 m wide. There are a number of design differences:
- smaller diameter in comparison with resistive sections - 3 ... 3.5 mm;
- fixed distance between the loops;
- reinforced external insulation.
Do-it-yourself mats are easier than classic cables. The heating elements are integrated directly under the tile, there is no need to fill the screed on top. Conversely, a thick monolithic layer will impair heat transfer from heaters.
An important point. The grid between the wire loops can be cut to fan out the power cable or to make a 180 ° turn and roll the roll in the other direction.
Cons of cable mats:
- the cost of electric heaters is higher compared to the classic sections;
- you can not configure the layout step to your needs;
- with the help of mats it’s not possible to organize full-fledged heating - there will not be enough power density per 1 m².
Film underfloor heating
This type of TP is made on the basis of an ultra-thin (0.4 mm) polymer film. Heating carbon paths are applied to the surface, then they are torn from above by a protective layer. Characteristics of film ETP:
- heat transfer from 1 square meter - 130 ... 230 W, depending on the type of product;
- thermal film width - 50, 80, 100 cm;
- the melting point of the base is 110 ... 130 degrees;
- installation method - “dry” installation directly under the floor covering - linoleum, laminate, carpet, parquet board.
Manufacturers call the film infrared, since carbon lanes emit radiant heat. Another question is how infrared radiation penetrates the room through the carpet - it is impossible physically. But our task is not to destroy myths, but to objectively indicate the pros and cons of heaters.
Advantages of carbon film:
- The material is thin, very compact.
- TP is mounted easier than cables, you can put and connect the film yourself.
- Stripes are allowed to be cut across, the permissible step is indicated by the manufacturer.
- Acceptable price.
Of the drawbacks, it is worth noting the fear of overheating and the limited scope of application - you can not put infrared film under tile glue or screed. The reasons are poor adhesion to a smooth surface and interaction with cement mortar (consequences unknown).
Clarification. New types of self-regulating ETPs appeared on sale, which automatically reduce the heating intensity in case of an increase in the operating temperature. An example is CALEO PLATINUM film.
And the last: because of the fixed size, it is inconvenient to lay out the material in narrow rooms. Example: the width of the corridor is 1300 mm, and the heater is 500, 800 and 1 m. You will have to cut the film into pieces and lead to each individual power wires.
Rod heaters
The design of the elements is as follows: carbon heating rods are connected to two parallel power lines. As a result, we get mats laid under a screed or tile, only with the self-regulation function. Thanks to it, ETPs do not overheat.
The effectiveness of core floors in comparison with other options has not yet been confirmed. The manufacturer himself indicates the conflicting technical parameters that we give in the table:
Note. Note: heat transfer 1 m.p. declared at 116/138 watts, and energy consumption - only 24 watts per meter. Although it is well known that electric heaters produce 0.98 kW of heat, spending 1 kW of energy.
According to user reviews, core TPs are not very reliable. Individual elements burn out, the circuit continues to work, but sections of the floor become cold. Homeowners also report insufficient surface heating. Products are clearly unfinished.
Selection recommendations
In the vast majority of cases, ETPs are purchased for heating bathrooms or bathrooms in apartments. Organizing a complete electrical heating is not profitable - unlike water systems, cable circuits cannot be connected to a gas boiler. Hence the advice: combine heaters with traditional radiator heating.
Which electric underfloor heating is better to choose depending on the operating conditions:
- For comfortable heating of the tiles in the bathroom, a resistive cable or mats are suitable. The second option is preferable, the costs are approximately the same.
- Cable sections should be placed under the screed - self-regulating or inexpensive resistive. If heating the house is assigned to the ETP, then the installation interval is selected with a calculation of 120-150 W / m².
- Lay the film under the cover in living rooms and corridors. Keep in mind that “dry” installation is cheaper to do yourself. If there is not enough heat generated, the rolled material can be mounted in ceilings and even walls, as the masters do in the photo.
- Acquisition of core mats for pouring is a risky undertaking. If you really liked these heaters, then choose products from serious manufacturers, for example, CALEO.
Together with ETP, a temperature regulator is bought that maintains the surface temperature and protects the circuit from burnout. To regulate a small area, any device is suitable - mechanical or electronic. It is more convenient to control the heating of 3-5 rooms using sensory or programmable thermostats.
The origin of the temperature regulator does not play a role, the combination of different manufacturers is quite acceptable.
Calculation of heating power
Heat transfer, respectively, electricity consumption by any ETP depends on the operating mode:
- floor surface temperature does not exceed +26 ° C (comfortable heating);
- floor circuits operate in main heating mode.
In the first case, an apartment or a private house is heated by a water system, a warm electric floor is made in some rooms and serves exclusively for comfort. Examples of such rooms: bathroom, balcony (loggia), corridor, washing in the bath.
To bring the coating temperature to 26 degrees, you will need about 70 watts of heat per 1 square meter of area. We will make a reservation: we are talking about an insulated ceiling, 200-250 W / m² will easily go to the concrete floor of a cold balcony.
Reference. The finished data on heat consumption were taken from the book of V. V. Pokotilov “Water heating systems”, the calculation procedure is described in another article of our resource.
Knowing the specific power, it is not difficult to calculate the total energy consumption by multiplying 70 W by the area of the heaters laying. Problem: a similar method does not take into account the thermal resistance of the screed and topcoat. Hence the advice: for comfortable heating, select the ETP according to the quadrature specified by the manufacturer of the particular product. The minimum value is 100 W / m².
Example. It is necessary to warm the area of the tiled floor of the bathroom 2 m². If you take a DEVIflex 18T resistive two-wire cable as a heat source, then a ready-made kit with a power of 310 W, designed for 2.1 m², is suitable. The length of the circuit will be 18 m (manufacturer's data).
To apply electric floors to the main heating, we perform the following calculation:
- We determine the heat loss of the room in any convenient way - by area, volume of the room or by following the SNiP method.
- We draw a plan of a room with furniture, then we calculate how much space it occupies (in m²).Subtract the resulting figure from the total quadrature and find out the free area where you can lay ETP.
- According to the value of heat loss, we select a finished heating element of suitable power from the line of finished products.
- We find out the laying interval of the heating wire - divide the quadrature of the free area of the room by its length.
Another calculation example. Above the diagram shows a bathroom with an area of 6 m², 2.5 m² are occupied by furniture and sanitary fixtures. For heating, you need 600 watts of heat distributed over the remaining 3.5 m². From the catalog, we select the DEVIflex cable with a heat transfer of 622 W and a length of 37 m. We consider the installation step: 3.5 / 37 = 0.095 ≈ 10 cm.
Tip. The power indicated in the passport is enough to heat the coating of laminate, linoleum and tile. When you need to choose electric heaters for parquet or a thick carpet, you should consult with the manager of the manufacturer.
Installation instructions for cable and mats
Before starting work, prepare supplies and accessories:
- temperature sensor;
- temperature regulator;
- corrugated tube sensor;
- mounting strip metal (or plastic);
- electrical tape, heat shrink tube;
- power wire copper type VVG.
Recommendation. The cross-section of the wiring depends on the power consumption of the circuit. To find out the required core size, see the table.
Before laying an electric underfloor heating, insulate the ceiling of the balcony. Otherwise, economical energy consumption is not seen. As a heat-insulating material, use a substrate of extruded polystyrene foam (Penoplex) with a thickness of 20 ... 50 mm, density - 30 ... 45 kg / m³. If the height of the thresholds allows, do insulation in all rooms where it is planned to mount the ETP.
Preparation consists in the layout of the insulation and the device of the preliminary coupler - it is unacceptable to lay the cable on the insulation. Then we work according to the instructions:
- We mark the area under the heating section - we draw lines with an indentation of 100 mm from the walls and furniture. Ideally, we draw a cable route, mark the installation point of the sensor (between the loops).
- We perform a recess in the wall, mount the thermostat box, bring the main power line to it. We cut the furrow, install a corrugated pipe under the sensor.
- We fix mounting strips to the floor with dowels. We lay out the cable with the required interval, fix the clamps on the tape.
- At the floor level, we connect the supply wires to the "cold" ends of the section, we put them in a box. We put the sensor into the corrugation, close the end with a plug (so that the solution does not get into it).
- We are convinced of the reliability of the connections - with a multimeter we measure the resistance of the circuit from the box, we check with the passport.
- We prepare a cement-sand mortar M150, fill the screed with a thickness of 3-6 cm (above the surface of the section). We install the thermostat and test run after the solidification of the monolith is complete.
ETP device made of infrared film
The preparatory phase includes leveling the concrete surface and warming with a special material - foamed polyethylene 4 ... 6 mm (Penofol, Izolon). A prerequisite is the use of insulation without aluminum foil.
Installation technology looks like this:
- Roll the roll of thermal film and lay it with a copper strip down. If necessary, cut the heater to size, guided by the factory lines. Back 10 cm from furniture and walls.
- Adjacent canvases may be placed with an overlap - the width of the transparent edge. Glue the joints with tape.
- With bits of bitumen insulation, close unused contacts at the ends of each sheet. At the connection points of the wires, install special clamps (included), fix them with pliers.
- Bring the wires to the contacts, insert the bare ends into the sockets and crimp. Then seal the connection with 2 bitumen strips.
- Attach the temperature sensor with a bitumen patch to the black track on the film (bottom).Cut a recess in a heater where the measuring instrument will hide. Previously connected clamps must also be recessed.
- Make the grooves for wires in the insulation that lead to the mounting point of the thermostat. Lay the cables in the grooves, cover with tape on top.
- Mount the thermostat on the wall, connect the wires of the wires. Installation is complete.
Recommendation. After assembling the film ETP, check the electrical circuits with an ohmmeter, only then lay the coating. You can do without appliances - just turn on the floors and try heating by hand.
The last thing about profitability
According to the principle of operation, ETPs do not differ from other electric heaters, converting current into heat with an efficiency of 98–99%. This suggests the conclusion: sellers who claim energy savings of 10–20–30% compared with other options for electric heating are simply deceiving you. Cost reduction is achieved in other ways - by warming the building, regulating the heating temperature and installing a multi-tariff electric meter.