Warm flooring is one of the ways to heat an apartment. Radiators do not heat up the lower part of the apartment, so to create a comfortable temperature you need to make a separate system. Before you install the heating system, you need to calculate in advance the electricity consumption of a warm floor per 1 m2 and choose the best offer. Wrong choice threatens with excessive costs and inefficiency of heating.
Types of underfloor heating systems
Underfloor heating systems are distinguished by their design, characteristics and energy consumption.
Resistive heating cable
The design, working on resistive heating cables, is simple and low cost. The basis is a single or two-wire wire with a certain resistance. The outer shell is a protective shield. The wire has a fixed length, which should remain unchanged.
It is laid in a screed with a thickness of about 5 cm. It is not recommended to make it thicker, since heat losses will increase. The cable power is low, it can be increased up to 200 W / sq.m. Heat is distributed evenly over the entire surface.
Self-regulating heating cable
Compared to mats and resistive cables, a self-regulating cable is characterized by a dependence of linear power on temperature. It does not require a constant heat sink, which can disrupt the resistance cable. A semiconductor polymer acts as a heating element, which changes its resistance depending on temperature. These cables can be cut anywhere, as overheating is independent of length. Specific power is 120-150, W / sq.m.
Heating mats
Already have a heating cable in construction. The standard width of the mat is 45 cm, the length may vary. It is forbidden to cut products, since they are based on a heating element.
Main characteristics:
- The voltage is usually 220-230 V.
- Length from 1 to 24 m.
- The recommended laying area is usually from 0.5 to 12 square meters.
- Specific power on average 100-150 W / sq.m. Less commonly available with a specific power of 200 W / sq.m.
The main advantage of mats is the ease of installation and calculation.
Film infrared floor
Infrared floors are a fairly new type of heating. The design contains emitters made in the form of graphite strips. They are connected to copper wires. The entire system is placed on a polyester film up to 0.4 mm thick. An important difference from other types of floors is radiation energy. It is aimed at heating not the floor itself, but the objects that are located on it. This is well felt by a person, so IR floors are one of the most comfortable.
The power of the film underfloor heating is 110-220 W / m2.
The width of the rolls is different - there are floors of 50 cm, 80 cm and 1 m. The length is from 1 m to 20 m.
Core infrared underfloor heating
The most modern solution in floor heating is a rod infrared floor. The heater is a flexible element made of carbonate, graphite and silver. The main property that distinguishes the core floor from others is the drop in power consumption at temperatures from +20 to +60 degrees. Thanks to this, the floors can be laid even at the locations of furniture, which will periodically be rearranged.
The power of the core floor is 70-160 W / m2. Efficiency reaches 95%.
Energy calculation
Before you start calculating and selecting components, you need to develop a floor plan in which a warm floor will be installed. It can be drawn on paper or compiled in a computer program.
What you need to know for calculations:
- heated area (70-80% recommended);
- floor covering characteristics;
- quality of walls and floors;
- the ability to carry loads.
Rod IR floors can be laid on the entire surface, including under furniture.
General heating is recommended using resistive cables, and for comfort - with heating mats or IR floors.
To determine the heating efficiency, use the formula P = S * k, where P is the floor power, S is the area that will be heated, K is the specific power.
Power density is different for each room. For living rooms and kitchens on the 1st floor it is 140-150, W / sq.m., on the 2nd floor and above 110-120 W / sq.m.
For balconies and loggias with insulation, the specific power is 140-180 W / sq.m. A bathroom on the 1st floor is 120-150 W / sq.m., On the 2nd floor and above - 110-130 W / sq.m.
If the floor is used as primary heating, the specific power should be at least 180 W / sq.m. 110-120 W / sq.m is enough for additional heating.
Calculation Example
The calculation will be made for the bathroom on the top floor, used for the main heating. The total area of the premises is 10 sq.m. The heated area is 10 * 0.7 = 7 sq.m. (with an occupied area of 70%). Specific power 180 W / sq.m. Then the resulting value will be 7 * 180 = 1260 watts. This is the total heat transfer. Similarly, calculations are made for other rooms.
You need to be able to calculate power consumption - the size of the monthly electricity charge directly depends on this value.
The calculation was made for a room with an area of 20 sq.m., heated with a capacity of 14 sq.m and a floor work time of 6 hours per day. Specific power is 150 W / sq.m. Then the energy consumption is 150 * 14 = 2100 watts. The monthly rate is 6 * 2100 * 30 = 37800 W / h or 378 kW / h. This value is then multiplied by the regional cost of 1 kW.
Features of the calculation of infrared structures
When choosing and calculating film floors, a number of features must be taken into account. First of all, they should be laid on a surface free of furniture. Secondly, the minimum distance to the wall or furniture should be 20 cm. Laying only in a "dry" way. It should also be borne in mind that installation and calculation depend on all electrical connections located below the surface.
Recommendations for choosing film systems:
- additional heating requires 120-150 W / sq.m .;
- for the main 170-220 W / sq.m.
Calculation Algorithm:
- Calculation of the heated area.
- Calculation of the share of heated power. You need to multiply the heated area by 100% and divide by the total area of the room. With an indicator of more than 60%, the specific power of the film should be from 160 to 220 W / sq.m. If the proportion is less than 60%, the specific power is 220 W / sq.m.
- Accounting for large heat losses. If the room is located on the ground floor, above an arch or in an old building without thermal insulation, the specific power should be 220 W / sq.m.
- Calculation of installed capacity. Specific power is multiplied by the heated area.
Based on the calculated data, a suitable IR film is selected. Better to take in small pieces for proper installation. For each segment, your temperature regulator should be selected.
Rod infrared floors can be installed over the entire surface of the room. It is necessary to choose additional accessories and a temperature regulator. Wood and thin coatings are best installed using temperature controllers with two temperature sensors (floor and air surfaces).
When creating heating systems, it must be borne in mind that not all coatings can be used. You can not put a warm floor under the linoleum on a rubber basis, thick carpets, a wooden floor with a thickness of more than 0.25 cm. When buying a coating, you must definitely determine whether they are compatible with the heating system. This can be understood by the special icon on the packaging and in the documentation.
Cost Reduction Tips
You can reduce energy costs, for this it is worth using the following recommendations:
- Using a temperature controller. You can save up to 40% energy.
- Reduced heat loss. It is recommended that the walls be insulated - this will consume less than 2 times less electricity.
- Installation of a multi-tariff system. At night, power consumption is 1.5-2 times less. The value depends on the region.
- Indent as necessary and do not place electric heaters under furniture.
In advance, you should calculate the entire system and the required power of an electric floor heating per 1 m2. You can perform calculations in special online calculators.
