If it was decided to equip the underfloor heating system in the house, then it is not enough just to buy the required materials - you also need to know how much they will need. And these calculations are not easy, given that you want not to buy too much and at the same time make sure that the purchased materials will be enough to achieve the required temperature level in the rooms. How to calculate a warm floor? Let's try to figure it out.
To begin with, I would like to dwell on what the correct and high-quality warm floor should be, regardless of which coolant - electricity or water - it will work on. So, such a heating system will work differently depending on the thickness of the base or the quality of the heat insulator, which means that all these points must be taken into account. It is believed that the thickness of the heat-insulating material should not be more than 3 cm, while it is better to purchase the material with a reflective layer - this way it will be easier to keep the heat inside the room.
Advice! As a heat insulator, it is advised to purchase polystyrene foam with a density of about 35 kg / m 3.
The thickness of the concrete screed should be about 4-10 cm, especially when it comes to laying a cable or water floor. Inside, it is reinforced with a reinforcing mesh, on which, by the way, coolants can be fixed. Due to this, heat will be redistributed better. If it is planned to equip a water floor, it is recommended to purchase pipes made of metal-plastic or cross-linked polyethylene with a diameter of 16-20 mm - with them it is easiest to endow the system with optimal power, sufficient to warm up the rooms.
What factors should be taken into account?
In order to make all the necessary calculations that will help determine the amount of materials for a warm floor, the following should be taken into account:
- the total area of the room where the floor heating will be equipped. It is from this figure that the number of circuits in the system will depend;
Important! One heating circuit effectively heats up to 40 m2. At the same time, its length should not be more than 100 m. And the step between the laid pipes should not be more than 30 cm.
- number of collectors. It is important to remember that each heating circuit can only be connected to one collector;
- layout of rooms where heating is arranged;
- sizes of windows and other places where heat will be lost. Glazing type. Door types;
- can affect the power output the thickness of the walls of the house;
- indoor air humidity;
- arrangement of furniture and other interior items in the room. Under them, a warm floor does not fit if it is electric, as ventilation will be insufficient and the system may be damaged. Yes, and the safety of furniture and appliances, excessive heating can also have a negative impact;
- designation of the room where the installation will be carried out. Depending on this, the heating power is selected;
- other heat sources and their power.
The temperature regime in the region and the need to heat a particular room and adjust the temperature in it may turn out to be important. The type of floor finish can also have a significant impact on the power of the floor - some materials easily transmit thermal energy, others are worse.
Determining the desired temperature in the rooms
The final floor temperature depends on the purpose for which the room is used. For example:
- +29-30 degrees - halls, hallways;
- +27-29 - offices, living rooms;
- +30-35 - floors near windows, on verandas;
- +32 - bathrooms, toilets;
- +17-19 - sports halls.
In this case, the temperature of the coolant should not be less than +40 degrees or exceed +60. The heating system should be such that the difference between the temperature indicators of the direct and return pipes in the case of water floors does not exceed 15 degrees. Otherwise, the base will be heated absolutely unevenly.
The balance of thermal / hydraulic loads for the water floor must also be optimal and verified. Therefore, the heating circuits must have a certain length according to the diameter. The best option for a pipe is 18 mm, since even with a small amount of water, such a pipeline will work correctly and heat the base.
Calculation of heat losses
Usually, underfloor heating systems do not act as the only source of space heating, but some plan to heat the house that way. But before making this engineering decision, it is important to make sure whether it is possible to heat a particular room in general only in this way.
If during the period of use of the system, heat losses do not exceed 100 W / m 2, then the floor heating system will be quite enough to warm the room. However, it is quite difficult to make calculations in order to obtain the necessary data on your own, since complex formulas are used. So it is recommended to use the online calculator for calculating the heat loss of a room. If the heat loss exceeds 100 W / m 2, then the thermal insulation of the room must be improved or an additional heating system must be equipped.
Calculation for different types of premises
In each room, depending on its features, different floor heating power is required. It should be greatest in cool rooms, as well as on a loggia or balcony. In such a room, the power cannot be less than 180 W / m 2. In the bathroom or bathroom - at least 140 W / m 2 due to high humidity.
On a note! The power of the underfloor heating system cannot be low if there are unheated rooms under the room being equipped.
As for the electric floor, in this case, the minimum power should be equal to 120 W / m 2.
Table. The power of the floor heating system when used as an additional heat source.
How to calculate electric floor heating
In general, the floor heating system consists of several elements. This is a thermostat that helps control the level of floor heating, a temperature sensor that monitors how hot the floors are, a heating element, as well as a power cable for connecting all this equipment to the mains.
The thermostat is usually mounted on the wall, all wires are connected to it. The warm floor itself, as well as the temperature sensor, are installed under the floor covering (in the screed or on its surface, depending on the type of system - a heating mat, IR film or heating cable).
On a note! The easiest way is to install the infrared floor or heating mats. They can be laid simply under the floor covering. But the electrical cable will have to be filled with a screed. Yes, and the step between the wires in this case will have to be calculated independently.
For the arrangement of cable heating, a single or two-core cable is used. The first is the simplest, but at the same time difficult to work, albeit cheap. It will be quite difficult to calculate all the parameters for it, since both ends of the cable must be brought out to one place. Yes, and the electromagnetic field from it is formed extensive.
It is easier to buy a two-core cable, which, although it costs a little more, is still easy to install and operate due to the special arrangement of the wires.
Calculation formulas for electric field
Determining the power of a warm electric floor system is simple. To do this, it is enough to multiply the power of 1 m 2 of the selected system by the area that it will heat. By the way, the amount of cable used is already measured and marked in the purchased kit. The distance between the turns of wires should be 5-20 cm. It can be calculated exactly using the formula h = Sx100/L, where h is the required step width, L is the cable length, and S is the area of the room.
How to calculate a warm water floor
Let's see how many materials are required to equip the room with a water heating system. The calculation of the number of pipes per 1 m 2 in this case is as follows: you need to find out how much the heat loss in the room will be. The easiest way to determine them is with the help of an online calculator, in which data about the building itself is entered, as well as about the weather conditions on the street. Let them be equal to 80 W / m 2. The area of \u200b\u200bthe apartment where the floor heating system will be equipped will be taken equal to 80 m 2. As a result, the total heat loss can be found by multiplying the two values \u200b\u200bof 80x80 \u003d 6400 W. It is this value that will have to be compensated with the help of all heating systems with a power reserve of up to 20%.
Table. Pipe calculation depending on the loop pitch.
| Step cm | Consumption, m p. / 1 sq. m. |
|---|---|
| 10 | 10 |
| 15 | 6,7 |
| 20 | 5 |
| 25 | 4 |
| 30 | 3,4 |
Usually, the distance between water conduits is maintained at about 15 cm with a pipe cross section of 16 mm. Then the power of 1 m 2 of the floor will be about 100 watts. Dividing the total area of the room by the step size, we get: 80 / 0.15 \u003d 533 m. That is how many meters of pipe will be required to equip the water heating system in this apartment. The length of each contour is calculated in approximately the same way.
Attention! Near the walls of the room adjacent to the street, the step will be somewhat smaller (10 cm). With this in mind, the footage of the conduit is calculated.
In construction stores, pipes of a certain length are on sale - from 50 to 240 m. They are wound into coils. And to connect the entire system to the collector, you will have to buy water conduits of a larger diameter.
