One of the modern, energy-efficient heating systems is a warm floor. It can be water or electric. To properly mount the system, you must perform a preliminary calculation. It is necessary to determine not only the required amount of materials, but also the total capacity of the system. Otherwise, it will not be able to work effectively. How to calculate a warm floor will be discussed later.
General Description of Systems
To mount underfloor heating with your own hands in a private house or apartment, you need to know a few nuances. Before you go to the store to purchase the necessary elements of the system, you need to make an accurate calculation.
It is worth saying that a warm floor can be water or electric. In the first case, the coolant is supplied through a system of pipes, which according to a certain technology are laid out on the surface of the base. Heated liquid (special antifreeze or water) circulates through the system. In this case, the floor surface is heated to a predetermined temperature. This process is controlled by special automation. When coolant cools, the valve opens. The required amount of heated liquid enters the circuit.
A separate circuit is created for each room, which is fed to the boiler. It can operate on any fuel that is appropriate to use in a given area. Water floor heating is most often used in a private house. Installing a similar system in an apartment is difficult. At the same time, the calculation of a water heated floor in a wooden house or a brick building can differ significantly. The fact is that each material differs in certain indicators of thermal conductivity. This must be taken into account when calculating.
In an apartment it is much easier to install an electric heated floor. Systems that consist of special wires fall into this category. They can be mounted in a screed under tile adhesive. For laying under the laminate, an infrared heating film is used. It does not require a screed layer or other mortar.
In order for the system to fulfill the functions assigned to it in full, it is necessary to perform the correct calculation.
General data for calculation
Considering the method, how to calculate the heat of a warm floor, as well as the amount of materials for installation, it is necessary to determine a number of parameters that are involved in this process. You need to start with whether the water or electrical system will be primary or secondary. In the first case, there will be no other heating devices in the room, except for a warm floor. Its power must be high so that the room warms up to the desired level.
Auxiliary systems are used in combination with other heating systems. For example, batteries are installed in the room. But their power is not enough to warm the room. In this case, a warm floor is created, which will complement the operation of the heater. Some floor space, on which the hosts most often step, will be equipped with a heating system. Further, it is worth considering the recommendations of building codes:
- in a living room, the floor surface must be heated in the presence of a warm floor to 25-29 º;
- from the side of the walls that face the street, the temperature of the flooring reaches 34-35 º (to compensate for heat losses);
- for rooms with high humidity, floor heating up to 32-33 º is required.
This takes into account the type of flooring. The tile can be heated quite strongly, without fear of its destruction. The temperature of the laminate should not exceed 25-27 º.
When studying how to calculate the heat of a warm floor, it is necessary to take into account the step between pipes, wires, the area of the room. Also, heat losses must be taken into account. They depend on the type of construction, type of insulation and other parameters.
The type of flooring affects the calculation result. The best option is tile and similar materials. They are characterized by high thermal conductivity. Similar systems are not suitable for a wooden floor. For linoleum and laminate it is important to choose a coating that does not have an additional heat-insulating layer.
Pipes for water floor
How to calculate the power of a water floor heating? This system consists of pipes. They can be copper, plastic or corrugated. Pipes are connected to the manifold. It is necessary to correctly determine their extent. It is best to use the graphical method for this.
To do this, you need a sheet of graph paper. On it, the scale of the configuration of the room is drawn. Next, you need to draw a contour of the heating system. If the room will have dimensional furniture without legs (for example, a wardrobe), it is also applied to the circuit. Under furniture of this type, the system does not fit.
The heating system can be mounted in two ways. The first of these is called the "snake." This option is suitable for a small room. In this case, the room should not have large heat losses. A pipe in the form of an elongated sinusoid is laid out over the entire area of the room. When it comes to the opposite edge of the room, you need to stretch it along the wall back to the collector.
When choosing this type of installation, it should be noted that the coolant will gradually cool. At the end of the room, its temperature will be an order of magnitude lower than at the beginning. There is a certain dependence. Having passed 70 m through the pipe, the coolant cools by 10 º.
There is another technology for laying a warm floor. It is called a "snail." First, the pipe goes around the perimeter of the room. Then she turns smoothly, approaching the center spinning. With this scheme, you can alternate warm and cold pipes. This option is suitable for a spacious room. The created picture determines the length of the pipe.
What else needs to be considered?
Calculation of the pipe for the warm floor can be performed in a slightly different way. Choosing the appropriate styling scheme, you need to take into account a few more indicators. The step between the pipes should be from 10 to 15 cm. The wider it is, the larger the layer of screed you need to lay when arranging the floor. The length of the pipe in the circuit should not exceed 120 m. If the room is too large, two separate systems are brought into it.
You can determine the length by a simple formula:
D = P / W * 1.1, where: P is the area of the room covered by the system, W is the selected installation step.
The formula uses a coefficient of 1.1. It allows you to take into account the supply of the pipe to create its bends.
It should be noted that the diameter of the pipe, which is used to create a warm floor, is 16 mm. In rare cases, this indicator is increased to 20 mm or even 25 mm. This allows you to increase the power of the system.
After calculating the pipe for the warm floor, you need to determine the speed of movement and the temperature of the coolant in the system. So, with a standard pipe diameter (16 mm), the system is able to let through 27-30 liters of fluid per hour. Its temperature should be from 40 to 55 º. In this case, the floor temperature will warm up to 25-37 º.
Power calculation technology
Having studied how to calculate the contour of a warm floor, you need to consider in detail the technology for calculating the power of the system. This will also require a sheet of graph paper. The location and size of windows and doors are applied to it. All elements of the room are indicated in a certain scale.
When developing the scheme, you need to take into account that the pipes should pass near the walls with windows. So it will be possible to prevent heat loss. Most of the heat in the room leaves through the windows. The maximum area that can be covered with a single pipe circuit can be 20 m². If the room is larger, you need to divide it into 2 parts. For each of them, they separately calculate how many pipes are needed for a warm floor.
25 cm are required to retreat from the walls. This is a prerequisite for installing a water heating system.
Next, you need to determine how much system power will be determined per 1 m² of room. So, with a pipe pitch of 30 cm, this figure will be 50 W / m². This will be enough if it is planned to create additional heating. But for autonomous heating, capacity will need to be increased. By default, this indicator is 150 W / m². In this case, the step must be made minimal (10 cm) or increase the diameter of the pipes, the temperature inside the system.
When calculating a water heated floor in a wooden house or other building, you should determine the length of the system, which turned out on graph paper. They just measure it. Next, the result is multiplied by the selected scale. An additional 2 m is added to this amount (it will be required to approach the riser circuit).
Pipe length calculation example
To understand how to calculate the warm floor in the house, you need to consider an example of this process. So, in the room the length of the walls is 4.6 m. Since the room will have furniture, it will be necessary to cover 17 m² of area with a warm floor. The owners of the house plan to use pipes with a diameter of 20 mm for this. They are laid according to the "snake" scheme. It is necessary to maintain a step between turns of 30 cm, since the heating will be auxiliary.
Draws a diagram on graph paper. In total, 11 rows of pipes will pass in the room. Each of them has a length of 5 m. Therefore, the entire length of the system will be 55 m. Adding another 2 m to this result to create an approach, we get a result of 57 m.
The technology of laying a warm floor in a private house involves the creation of not only auxiliary, but also basic heating. In the presented room, it will be necessary to lay 140 m of pipe (it was installed using the graphical method). In this case, you need to do 2 circuits in one room. Their length may vary. However, the maximum deviation is 15 m. Therefore, for example, you can make, for example, the first circuit 75 m long, and the second - 65 m.
Power calculation example
Performing the calculation and installation of underfloor heating with your own hands in a private house, you need to determine the power of the system. These data are necessary for the selection of heating equipment. So, you need to heat a room with an area of 30 m². To effectively heat this room, you need to cover pipes with 70% of the floor. This figure is 21%.
For calculation, average heat losses are taken, which are 80 W / m². Their specific value in a particular room is 80 * 21 = 1680 W / m².
The hosts suggest heating the room to 20 º. The system provides for the installation of pipes with a diameter of 20 mm. Above them there will be 7 cm screeds, as well as tile. To compensate for heat loss, under specified conditions, the temperature of the coolant should be 31.5 º, if the laying step is 10 cm. When this indicator is increased to 15 cm, the heating in the system should be 33.5 º. This calculation was made possible due to the fact that with such a thickness of the floor covering and screed, the temperature of the coolant and surface will differ by 6 º.
Features of electric underfloor heating
There are a number of recommendations on how to calculate a warm floor for an apartment. In this case, an electrical system is used. It should be said that this may be a cable in the bay, which is laid out by a snake like a water pipe. It is placed in a screed layer of about 3 cm. To increase or decrease the power of the system, the installer can vary the installation step from 7 to 15 cm. For this system, it is important to know how to calculate the step of the warm floor in order for the system to be effective.
Heating mats are also used. The wire in this case is laid with a certain pitch on the polymer network. The manufacturer sets the system meter power during production. To calculate the electric underfloor heating under the tile with your own hands in this case will be easier. The same statement is true for film infrared heating systems.
The calculation begins with determining the area that needs to be heated in the room. If you plan to make autonomous heating using an electric system, you need to cover at least 70% of the room with a heating system. It should be noted that about 15 cm recede from the walls. Under furniture without legs, a wire or other type of warm electric floor is not laid.
To create additional heating, you can cover about 50% of the area of the room (or even less). Next, the calculation is carried out.
Calculation Data
To calculate the number and mount an electric heated floor with your own hands under a tile, laminate or in screed, you need to take into account some nuances. To perform the correct calculation, professionals use special tables and programs. They allow you to take into account heat loss in the room. The average buyer will not be able to perform such a procedure on his own.
To perform the correct calculation, you need to use the average indicators. To create an autonomous system in an ordinary residential building, it is required to provide a system power of 150 W / m². To heat the corridor, the kitchen, it is enough to install a system with a capacity of 130 W / m². If the room has a high level of humidity, this indicator is increased to 180 W / m². If necessary, make additional electric heating, it is necessary to equip a heated floor with a minimum power of 100 W / m².
Next, you need to take into account the data specified by the manufacturer. Choosing a mat or infrared film, you should purchase systems that meet your needs. The manufacturer on the packaging indicates the capacity of the system.
When calculating the cable on the bay, you need to perform a simple calculation. Let's say the useful area of the room (70%) is 10 m². To create autonomous heating, a bay with a capacity of 10 m² * 150 W / m² = 1500 W is required. When buying, you must choose a system that is as close as possible to this indicator. It is better to purchase a warm floor with a margin of about 30%. In this case, a 1950 W system is suitable.
Laying step
When considering how to calculate a warm floor, you should determine the laying step for the cable in the bay. Suppose a manufacturer has a suitable rated power system. The linear length of the wire in it is 100 m. To calculate the laying step, you will need to use the formula:
W = P * 100 / D, where: P is the usable (heated) area, D is the length of the system.
In the considered example, the laying step is calculated as follows:
W = 10 m² * 100/100 m = 10 cm.
It is with this step that you will need to lay the system in order to obtain the required power per square meter. Wanting to increase this figure, the turns of wire will need to be laid already. In this case, the system can be mounted in a humid room. It follows from the presented formula that a smaller area can be covered by the presented system. The laying step is reduced to the minimum allowable level of 7 cm. The heated area will be:
P = W / D / 100 = 7/100/100 = 7 m².
This calculation will allow you to choose the optimal system. The procedure must be performed before going to the store.
Having considered how to calculate a warm floor, you can calculate the required amount of materials for installation, as well as the required system power.