We continue to disassemble design heated floors , started in the previous article, and now we will consider the main design recommendations.
What should the surface temperature of the heated floor be?
Actually, I already wrote about this in a separate article, but it would be worth repeating. Listed below maximum floor surface temperature limits for premises of various purposes:
- for living quarters and work rooms in which people mainly stand: 21...27 degrees;
- For living rooms and offices: 29 degrees;
- for lobbies, hallways and corridors: 30 degrees;
- for baths, swimming pools: 33 degrees
- for rooms where active activity takes place: 17 degrees
- in premises with limited presence of people ( production premises) a maximum floor temperature of 37 degrees is allowed.
In the edge zones up to 35 degrees.
What is the temperature of the coolant in the water heated floor system?
The supply water temperature should be between 40 and 55 degrees. The maximum temperature of the coolant at the entrance to the water heated floor system should not exceed +60 degrees.
The temperature difference of the coolant between the supply and return pipelines is optimal 5...15 degrees. Less than five degrees is not recommended due to the greatly increasing coolant flow through the circuit, which leads to large pressure losses. More than fifteen degrees is not recommended due to a noticeable difference in the temperature of the surface of the floor itself (in this case, under the windows we can have 27 degrees, at the end of the circuit 22 degrees, such a large difference is not comfortable). The optimal temperature drop is 10 degrees. Recommended temperatures at the inlet/outlet loops: 55/45 degrees, 50/40 degrees, 45/35 degrees, 40/30 degrees.
If thermal power is used as a heat source pumping unit(although this is very rare), it is advisable to set the temperature of the supply coolant to the heating circuit to 40 degrees. In all other cases, any other supply temperature within the above range can be used.
What should be the length of water heated floor pipes?
The maximum length of one circuit (loop) depends on the diameter of the pipes used:
- with a diameter of 16 mm - 70...90 meters;
- with a diameter of 17 mm – 90…100 m;
- diameter 20 mm – 120 m.
The difference in lengths is explained by different hydraulic resistance and thermal load of the pipes different diameters. Well, it’s clear: the thicker the pipe, the less hydraulic resistance it has (resistance to fluid flow).
Typically, one circuit heats one room. But if the area of the room is large, the length of the circuit is longer than optimal, then it is better to make two circuits per room than to lay a pipe that is too long.
If during design and calculations you take one pipe diameter and then install another, then the hydraulics of the system will be different. So it is better and correctly to allow all experiments at the design and calculation stage, compare the results, choose the best one and follow it.
If two or more circuits are installed in a room, you need to strive to ensure that their lengths are the same (the length of the circuit is the entire pipe, starting from the collector, and not just that part of it that is directly in the heated room itself).
Of course, in practice, it is impossible to adjust the length perfectly, but you need to strive for this and the difference should be no more than 10 m!
The premises in the house, as is known, have different area. To lay the same number of meters of pipe in a smaller room as in a larger one, you need to do smaller step between turns.
If the room is small and the heat loss from it is not great (toilet, hallway), then you can combine the circuits and heat from the return pipe of the adjacent circuit.
At what step should the underfloor heating pipes be laid out?
The pitch (distance between adjacent turns of pipes) of pipe laying is from 15 to 30 cm (15, 20, 25, 30 cm - that is, not 21; 22.4; 27, etc., but with a step of 5 cm in the specified range 15-30 cm). Allowed pipe laying pitch is 30, 35, 40, 45 cm in large rooms(gyms, etc.). And 10 cm near large windows, external walls (in the so-called edge zones).
The pipe layout step is selected depending on the thermal load, type of room, circuit length, coating material, etc.:
- edge zones - 100...150 mm (standard number of rows in the edge zone - 6);
- central zones 200...300 mm;
- bathrooms, bathrooms, shower rooms, etc. are completely laid in increments of 100...150 mm. The same step may not be possible due to the need to bypass the plumbing and due to the cramped space in the room;
- in rooms where the floor will be covered with a material with good thermal conductivity ( tiles, marble, porcelain stoneware) pipe laying pitch - 200 mm.
Attention! The above are the recommended numbers. In practice, it is often impossible to bend a metal-plastic pipe with a small radius without the danger of breaking it (when laid with a snake). Therefore, when laying with a snake, it is better and optimal to have a pitch of 150...200 mm. And in general, take note: despite any recommendations and clever justifications, make the pipe pitch in the edge zones 100 mm, and in the remaining 150 mm, and you will never go wrong.
A pitch of 300 mm will not provide uniform heating of the floor at all (again, when laying with a snake).
How to choose the diameter of pipes for underfloor heating systems?
IN residential buildings or apartments with an area ranging from 50 m2 to infinity - a pipe with a diameter of 16 mm is used. No need for more!
Even in well-insulated houses, it is desirable that the pipe pitch does not exceed 150, maximum 200 mm - and the 16th pipe makes it possible to meet all these conditions. In general, larger diameter pipes are not needed for a private home: they are optimal in terms of the ratio “ease of installation – price – coolant volume”.
Another pipe often used is 18 mm. However, you need to understand that a thicker pipe means extra costs, and not only for the pipe, but also for fittings and everything else.
Sometimes they lay a pipe with a diameter of 20 mm, without taking into account the characteristics. And in such a pipe the amount of water is already significantly greater, which is why heating will require more energy. And it’s difficult to install such a pipe: bending it for installation with a snake and a step of 150 mm is unrealistic, and larger step will not provide heat in the house, and the cost of coolant will be indecently decent. Such a pipe can be laid in some public buildings, With high ceilings, while simultaneously being there large number people. There will be a thick screed poured in there! For a 16 mm pipe, the thickness of the screed is sufficient 50 mm from the top of the pipe. Up to 80 mm is allowed.
What should be the diameter of the pipes from the boiler to the collector?
The task is to connect one, two or more underfloor heating collectors.
Almost every underfloor heating collector has a 1-inch (25 mm) thread for connection to the main line - it doesn’t matter whether it is internal or external.
There are manifolds with an inch and a quarter thread, but these are for large industrial or public institutions where a larger diameter pipe will be used, so you do NOT need to take such manifolds for a private home.
It makes no sense to initially narrow or “widen” the diameters of the main pipes (i.e., supplying coolant from the boiler), but it makes sense to take the same diameter as the collector inlet, i.e. 1 inch. For polypropylene pipe this is a diameter of 32 mm (this is the outer one, and the inner one is just 25 mm). For metal-plastic pipe this is a diameter of 26 mm. For copper – 28 mm. This - standard options on the use of pipes. But if there are doubts about the number of circuits, then you can increase the diameter of the main pipes by one size (40, 32 and 32 mm for polypropylene, metal-plastic and copper pipes respectively; To go 1 inch you will need an adapter).
Pipes made of cross-linked polyethylene (PEX) have the same dimensions as metal-plastic pipes in terms of wall thickness and diameters.
Other data for designing underfloor heating
It is not advisable to connect the concrete and deck systems to the same mixing unit (and manifold).
One circuit should be for one room (meaning, there is no need to get weird by laying out a loop, filling in the screed, and then dividing the room with a partition).
It is advisable to place the collector in the middle of the house. If this does not work, then the problem with the difference in loop lengths is solved by installing flow meters on the manifold: with their help, the uniform flow of coolant through loops of different lengths is regulated.
If the circuits are 90 m long (or even more), then a maximum of nine circuits can be “attached” to one collector. With loop lengths of 60...80 m, up to 11 loops can be mounted on one collector.
There is no need to “press” two (or more) collectors with one pump. It is correct to install separate pumps for each manifold group.
Mixing modules ( mixing units) not all are suitable for all pipe lengths of underfloor heating loops, so check when purchasing.
For an accurate calculation, it is necessary to take into account not only heat loss, but also the possible heat influx into the premises - for example, from operating equipment, household appliances, etc. (it hardly makes sense to fool around with this when calculating the heating of a private house), heat influx through the ceiling - if There is also a warm floor in the upper room. Calculation multi-storey buildings must be carried out starting from the premises of the upper floor to the lower ones. Because heat loss through the floor of the second floor is a useful heat gain for the premises of the first floor.
The thickness of the insulation on the first and ground floor not less than 50 mm (in reality, it depends on the climate zone: what is good for the south is not good at all in the north), on other floors - not less than 30 mm. A logical question: why insulate the ceiling between the first and second floors, even if the heat from the heated floor on the second floor also warms the first floor? Answer: if the floor is concrete, then insulation is installed so as not to heat the floor itself, because this is very expensive both in terms of money and time.
The maximum pressure loss in the circuit is 15 kPa (optimally 13 kPa). If the circuit has a pressure loss of more than 15 kPa, you need to reduce the coolant flow or divide the floor area in the room into several circuits. We’ll look at what this means in one of the following articles, when we perform calculations using a specific example.
The minimum coolant flow rate in one circuit is at least 27-30 liters per hour. Otherwise, the contours need to be combined. Why such a restriction? At a lower flow rate, the coolant will not have time to pass through the entire circuit, but will have time to cool down - the floor will be cold! The minimum coolant flow on each circuit can be set on the control valve (flow meter) installed on the manifold.
The above requirements for design of heated floors will need to be taken into account when performing calculations for heated floors, when we do this in a special program. So, if these terms don’t mean anything to you yet, don’t worry, everything will fall into place in due time. However, I recommend making a note for yourself somewhere so that you can return to the information in this article when making calculations.
design of heated floors
Almost every country house must have a heated floor installed. Before such heating is created, the required pipe length is calculated.
Each such private house has an autonomous heating system. If the layout of the premises allows, the owners of such country estates install a warm water floor themselves.
Of course, the installation of such a floor can be done in an ordinary apartment, but such work is very labor-intensive. Owners and employees have to deal with a lot of problems. The main difficulty will be connecting the pipe to the existing heat supply system. It is simply impossible to install an additional boiler in a small apartment.
The correctness of this calculation determines the amount of heat that needs to be supplied to the room so that it always has a comfortable temperature. The calculations carried out will help determine the power of the heated floor, and will also help make right choice boiler and pump.
It is very difficult to perform such a calculation. We have to take into account quite a lot of different criteria:
- Time of year;
- Outside air temperature;
- Room type;
- Number and dimensions of the window;
- Floor covering.
- Insulation of walls;
- Where is the room located, below or on the upper floors;
- Alternative heat sources;
- Office equipment;
- Lighting fixtures.
To make this calculation more convenient, average values are taken. If a double-glazed window is installed in the house and done good insulation, this parameter will be approximately equal to 40 W/m2.
Warm buildings with little thermal insulation constantly lose about 70–80 W/m2.
If you take old house, heat loss increases sharply and approaches 100 W/m2.
In new cottages where wall insulation has not been done, where panoramic windows, losses can be about 300 W/m2.
Having chosen an approximate value for your room, you can begin calculating the replenishment of heat losses.
How to determine the optimal room temperature
In this case, no special difficulties arise. For orientation, you can use the recommended values, or come up with your own. Moreover, the floor covering must be taken into account.
The living room floor should be heated to 29 degrees. At a distance from external walls more than half a meter, the floor temperature should reach 35 degrees. If the room humidity is constantly high, you will need to heat it floor surface up to 33 degrees.
If there is a wooden parquet, the floor cannot be heated above 27 degrees, as the parquet may deteriorate.
Carpet is capable of retaining heat; it makes it possible to increase the temperature by about 4–5 degrees.
How is the calculation done?
The calculation of the pipe for a heated floor is done according to the following scheme. For one square meter the floor surface requires 5 meters of pipe. The step length should be 20 cm. The required amount is calculated using the formula:
- L = S/N x 1.1
- Area – S:
- Laying step – N;
- Spare pipe for making turns - 1.1.
For greater accuracy, add the distance from the collector to the floor and multiply by two. An example of calculating the length of a heated floor pipe:
- Floor area - 15 sq. m;
- Length from collector to floor - 4 m;
- Laying step - 0.15m;
- It turns out: 15 / 0.15 x 1.1 + (4 x 2) = 118 m.
Calculation of contour length
To calculate the length of the circuit, it is necessary to take into account the diameter of the pipe and the material from which it is made. Let's take, for example, a 16-inch metal-plastic pipe. For a warm floor to function well, the length of the water circuit should be no more than 100 meters. The most suitable length for such a pipe is considered to be 75–80 meters.
If you take 18 mm, made of polyethylene, the length of the water circuit should be within 120 meters. Basically, a pipe of 90–100 meters is installed.
The pipe consumption for a warm floor made of a 20 mm metal-plastic pipe will be 100 - 120 meters.
When choosing a pipe, it is necessary to take into account the area of the room. It must be said that the material and method of installation have strong influence on the quality of the heated floor and its durability. Practical experience has shown that the most the best material for warm it will be metal-plastic pipes.
Calculation of the number of circuits
If we take into account all the rules, it becomes clear that one heated floor circuit is enough for small rooms. When the area of the room is much larger, you need to divide it into sections in a ratio of 1: 2. In other words, the width of the section will be less than its length, exactly half. To determine the number of plots, you need to know the following parameters:
- Step 15 cm - plot area 12 square meters. meters;
- 20 cm – 16 sq. meters;
- 25 cm - 20 sq. meters;
- 30 cm – 24 sq. meters.
Sometimes the supply section is made longer than 15 meters. Experts advise increasing the indicated values by another 2 square meters. meters.
Is it possible to install heated floors with different contour lengths?
A warm floor is considered ideal, where each loop is the same length. This will allow you to not have to deal with additional settings, no need to adjust the balance.
Of course, the length of the contour can be the same, but this is not always beneficial.
For example, an object consists of several rooms in which it is necessary to install heated floors. One of these rooms is a bathroom with an area of 4 square meters. meters. The total length of the pipe of such a contour, taking into account the distance to the collector, will be equal to 40 m. Of course, no one will adapt to this size, dividing the useful area into 4 square meters. meters. Such a division would be completely unnecessary. After all, there is a special balancing valve that can be used to equalize the pressure of the circuits.
Today you can also perform a calculation to determine maximum size pipe length relative to each circuit, taking into account the type of equipment and area of the facility.
We won't tell you how these complex calculations are done. Simply, when installing a heated floor, the spread in the length of the pipeline of a separate circuit is taken to be within 30 - 40%.
In addition, when necessary, it becomes possible to “manipulate” pipe diameters. It becomes possible to change the laying step and break large areas into several medium-sized pieces.
If the room is very large, is it necessary to create several circuits?
Of course, it is better to divide the heated floor in such rooms into parts and install several circuits.
This need is due to various reasons:
- The short length of the pipe will prevent the appearance of a “locked loop” when circulation of the coolant becomes impossible;
- The area of the concrete site should be less than 30 square meters. meters. The length of its sides should be in proportion 1:2. One of the ends of the slab must be less than 8 meters long.
Conclusion
Initially, the main thing is to know the initial data of your room, and formulas will help you determine how many pipes are needed for 1 m2 of heated floor.
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Correct calculation is the key to success in any business. However, it is not so easy to implement all the plans in practice. This statement fully applies to conducting communications to create. You can calculate everything down to millimeters, but still checking the resulting data will be necessary at each stage of work, since it is impossible to fully take into account everything. In addition, each apartment has its own characteristics of the floor surface, so it is often difficult to take into account all the bends and depressions. However, do not despair, because installing a heated floor system correctly, although difficult, is possible.
How to position heating pipes
A water heated floor system consists of many elements, the main one of which is tubes that release heat under the floor of the entire house.Based on what is more convenient for the master, communications can be arranged in 4 options:
- Snake.
- Corner snake.
- Double snake.
- A snail.
Correct calculation heating system- a difficult task, but quite feasible with a step-by-step approach. It is problematic to take into account absolutely all the nuances when installing a heated floor, so it is worth paying attention to the most important characteristics, namely the length of the pipes and the volume of water in them. In addition, it is worth remembering that even a slight excess of the circuit length of 100 m can seriously harm the system and produce an output temperature that is far from the expected one. The double-circuit model, in turn, will be much more efficient, which will allow you to heat the house without much hassle and with less resource consumption.
Today it is difficult to imagine country house no floor heating. Before you start installing heating, you need to calculate the length of the pipe used for the heated floor. Almost every country house has its own heating system; the owners of such houses independently install a water floor - if this is provided for by the layout of the premises. Of course, it is possible to install such warm floors in apartments, but such a process can bring a lot of trouble to both apartment owners and employees. This is due to the fact that it is impossible to connect the heated floor to the heating system, and installing an additional boiler is problematic.
The size and shape of the pipe for a heated floor can be different, therefore, in order to understand how to calculate a heated floor, you need to understand in more detail the system and structure of such a system.
How can I install a heated floor?
There are several ways to install heated floors. For example, we can consider 2 methods.
Grazing. This floor has a various materials, for example polystyrene or wood. It is worth noting that such a floor is faster to install and put into operation, since it does not require additional time for pouring the screed and drying it.
Concrete. This type of floor has a screed, which will take more time to apply, so if you want to make a warm floor as quickly as possible, then this option will not suit you.
In any case, installing a heated floor is a difficult task, so it is not recommended to carry out this process yourself. If there are no additional funds for workers, then you can install the floor yourself, but strictly following the installation instructions.
Concrete installation of heated floors
Despite the fact that it takes longer to lay heated floors this way, it is more popular. The pipe for underfloor heating is selected depending on the materials. It is worth noting that the price of the pipe will also depend on the material from which it is made. With this method, the pipe is laid along the contour. After laying the pipe, it is poured concrete screed without additional thermal insulation materials.
Calculation and installation of heated floors
Before you begin installing the floor, you need to calculate required quantity pipes and other materials. The first step is to divide the room into several identical squares. The number of parts in a room depends on the area of the room and its geometry.
Calculator - the simplest calculation of pipe length:
Calculation of the required amount of pipe
The maximum circuit length required for a warm water floor should not exceed 120 meters. It is worth noting that these dimensions are indicated for several reasons.
Due to the fact that water in pipes can affect the integrity of the screed, when it is incorrect installation you can ruin the floor. An increase or decrease in temperature negatively affects the quality wooden floor or linoleum. Choosing optimal sizes squares - you distribute energy and water through the pipes more efficiently.
Once the room has been divided into parts, you can begin planning the shape of the pipe.
Methods for laying pipes for heated floors
There are 4 ways to lay the pipe:
- Snake;
- Double snake (fits into 2 pipes);
- Snail. The pipe is laid in 2 folds (bends) coming from one source, gradually rounding towards the middle;
- Corner snake. Two pipes come out from one corner: the first pipe starts the snake, the second ends it.
Depending on which pipe laying method you choose, you need to calculate the number of pipes. It is worth noting that pipes can be laid in several ways.
Which installation method should you choose?
In large rooms that have a flat square or rectangular shape It is recommended to use the “snail” installation method, this way the large room will always be warm and cozy.
If the room is long or small, then it is recommended to use a “snake”.
Laying step
In order for a person’s feet not to feel the difference between sections of the floor, it is necessary to adhere to a certain length between the pipes, at the edge this length should be approximately 10 cm, then with a difference of 5 cm, for example, 15 cm, 20 cm, 25 cm .
The distance between the pipes should not exceed 30 cm, otherwise walking on such a floor will be simply unpleasant.
Calculation of pipes for heated floors
On average, 1 m2 requires 5 linear meters pipes. This method is easier to determine how many pipes per m2 are needed to install a heated floor. With this calculation, the step length is 20 cm.
You can determine the required amount of pipe using the formula: L = S / N * 1.1, where:
- S – area of the room.
- N – Laying step.
- 1.1 – pipe reserve for turns.
When calculating, it is also necessary to add the number of meters from the floor to the collector and back.
Example:
- Floor area ( usable area): 15 m2;
- Distance from floor to collector: 4 m;
- Laying step for heated floor: 15 cm (0.15 m);
- Calculations: 15 / 0.15 * 1.1 + (4 * 2) = 118 m.
What should be the length of the water heated floor circuit?
These parameters must be calculated based on the diameter and material from which the pipes are made. So, for example, for metal-plastic pipes with a diameter of 16 inches, the length of the water-heated floor contour should not exceed 100 meters. The optimal length for such a pipe is 75-80 meters.
For pipes made of cross-linked polyethylene with a diameter of 18 mm, the length of the contour on the surface for a warm floor should not exceed 120 meters. In practice, this length is 90-100 meters.
For metal-plastic pipe with a diameter of 20 mm maximum length the heated floor should be approximately 100-120 meters, depending on the manufacturer.
It is recommended to select pipes for laying on the floor based on the area of the room. It is worth noting that their durability and quality of work depend on what material the pipes are made of and how they are laid on the surface. The best option would be metal-plastic pipes.
Floor installation steps
After you have chosen high-quality and reliable pipes, it is recommended to begin installing the heated floor. This needs to be done in several stages.
Installation of thermal insulation
At this stage, preparatory work, the floor is cleared and a layer of thermal insulation is laid. Polystyrene foam can act as thermal insulation. Layers of foam plastic are laid on the subfloor. The thickness of the foam should not exceed 15 cm. It is recommended to calculate the thickness depending on the size of the room, its location in the apartment, as well as the individual preferences of the person.
Installation of waterproofing
After the foam has been laid, it is necessary to lay a layer of waterproofing. Polyethylene film is suitable as waterproofing. Polyethylene film it is fixed to the walls (near the baseboard), and the floor is reinforced with mesh on top.
Laying and securing pipes
Next, you can lay the pipes for the heated floor. Once you have calculated and chosen the pipe laying scheme, this process will not take you much time. When laying pipes, they must be secured to reinforcing mesh special braces or clamps.
Crimping
Pressure testing is practically the last stage of installing a heated floor. Pressure testing must be carried out within 24 hours at operating pressure. Thanks to this stage, mechanical damage to pipes can be identified and eliminated.
Pouring concrete mortar
All floor pouring work is carried out under pressure. It is worth noting that the thickness of the concrete layer should not exceed 7 cm.
After the concrete has dried, you can lay the floor. As flooring It is recommended to use tiles or linoleum. If you choose parquet or any other natural surface, due to possible temperature changes, such a surface may become unusable.
Manifold cabinet and its installation
Before calculating the pipe flow required for installation on the surface and underfloor heating, you need to prepare a place for the collector.
A manifold is a device that maintains pressure in pipes and heats used water. This device also allows you to maintain the required temperature in the room. It is worth noting that you need to buy a collector depending on the size of the room.
How and where should the manifold cabinet be installed?
There are no restrictions for installing a manifold cabinet; at the same time, there are several recommendations.
It is also not recommended to install the manifold cabinet too high, since ultimately the water circulation may occur unevenly. Optimal height to install the cabinet 20-30 cm above the bare floor.
Tips for those who decide to install heated floors themselves
There must be an air vent on top of the collector cabinet. Laying heated floors under furniture is strictly prohibited. Firstly, because this will lead to damage to the materials from which the furniture is made. Secondly, it may cause a fire. Materials that are flammable may easily catch fire if the room is exposed to high temperature. Thirdly, heat from the floor must constantly rise, furniture prevents this, thus the pipes heat up faster and can deteriorate.
It is necessary to select a collector depending on the size of the room. In the store, when purchasing, you need to pay attention to what dimensions this or that collector is designed for.
Pay attention to the advantages of certain materials from which the pipes are made.
Main qualities of pipes:
- Wear resistance;
- Heat resistance.
Buy pipes with a medium diameter. If the diameter of the pipe is too large, the water will circulate for a very long time, and when reaching the middle or end (depending on the installation method), the water will cool down; the same situation will occur with a pipe with a small diameter. That's why the best option pipes with a diameter of 20-40 mm will become.
Before calculating a heated floor, consult with those who have already done this. Calculation of the area and number of pipes is important stage preparation for floor installation. In order not to make a mistake, buy + 4 meters of pipe, this will allow you not to save on the pipe if it is not enough.
Before laying the pipes, step back 20 cm from the walls in advance, this is the average distance over which the heat from the pipes acts. Calculate your steps wisely. If the distance between the pipes is calculated incorrectly, the room and floor will be heated in strips.
After installing the system, test it, so you can understand in advance whether the collector was installed correctly, and also notice mechanical damage.
If you install a heated floor correctly, it will serve you for many years. If you have any questions, it is better to ask them to an expert on our website or contact specialists who will efficiently, quickly and reliably improve and prepare your room for installing heated floors.
Without preliminary calculations not feasible. To obtain the length of the pipes, the power of the entire heating system and other necessary values, you will need to enter only accurate data into the online calculator. You can learn more about the rules and nuances of calculation below.
General data for calculation
The first parameter that needs to be taken into account before making calculations is the choice of heating system option: whether it will be the main or auxiliary. In the first case, it must have more power in order to independently heat the entire house. The second option is applicable for rooms with low heat output from radiators.The temperature regime of the floor is selected according to building codes:
- The floor surface of the living room should be heated to 29 degrees.
- At the edges of the room, the floor can be heated up to 35 degrees to compensate for heat loss through cold walls and from drafts coming through opening doors.
- In bathrooms and areas with high humidity optimal temperature– 33 degrees.
If the installation of a heated floor is carried out underneath parquet board, then you need to take into account that the temperature should not exceed 27 degrees, otherwise the floor covering will quickly deteriorate.
The following are used as auxiliary parameters:
- Total length of pipes and their pitch (installation distance between pipes). It is calculated using an auxiliary parameter in the form of the configuration and area of the room.
- Heat loss. This parameter takes into account the thermal conductivity of the material from which the house is built, as well as its degree of wear.
- Flooring. The choice of floor covering affects the thermal conductivity of the floor. It is optimal to use tiles and porcelain stoneware, since they have high thermal conductivity and warm up quickly. When choosing linoleum or laminate, it is worth purchasing a material that does not have a thermal insulation layer. From wooden covering It is worth refusing, since such a floor will practically not heat up.
- Climate of the area, in which there is a building with a heated floor system. It is necessary to take into account the seasonal change in temperatures in this region and the most low temperature in winter.
Most of the heat in a home escapes through its thin walls and low quality materials window design. Before implementing the heating system in question, it makes sense to insulate the house itself, and then calculate its heat loss. This will significantly reduce the energy costs of its owner.
Calculation of pipes for heated floors
Water heated floor is a connection of pipes that are connected to the collector. It can be made of metal-plastic, copper or corrugated pipes. In any case, it is necessary to correctly determine its length. To do this, it is proposed to use a graphical method.The future outline is drawn on graph paper to scale or life-size. heating element", having previously selected the type of pipe laying. As a rule, the choice is made in favor of one of two options:
- Snake. Selected for small residential premises with low heat losses. The pipe is positioned like an elongated sinusoid and extends along the wall to the collector. The disadvantage of this installation is that the coolant in the pipe gradually cools, so the temperature at the beginning and end of the room can differ greatly. For example, if the pipe length is 70 m, then the difference may be 10 degrees.
- Snail. This scheme assumes that the pipe is initially laid along the walls, and then bent 90 degrees and twisted. Thanks to this installation, it is possible to alternate cold and hot pipes, obtaining a uniformly heated surface.
Having chosen the type of installation, the following indicators are taken into account when implementing the scheme on paper:
- The pipe pitch allowed in a spiral varies from 10 to 15 cm.
- The length of the pipes in the circuit does not exceed 120 m. To determine the exact length (L), you can use the formula:
L = S/N * 1.1, Where
S– area covered by the contour (m?);
N– pitch (m);
1,1 – safety factor for bending.It is worth understanding that the pipe must be located as a single piece from the outlet of the pressure manifold to the “return”.
- The diameter of the pipes being laid is 16 mm, and the thickness of the screed does not exceed 6 cm. There are also diameters of 20 and 25. Ideally, the larger this parameter, the higher the heat transfer of the system.
- Water consumption per hour with a pipe diameter of 16 cm can reach from 27 to 30 liters per hour.
- To warm the room to a temperature of 25 to 37 degrees, the system itself needs to heat up to 40-55 °C.
- A pressure loss in the housing of 13-15 kPa will help reduce the temperature in the circuit to 15 degrees.
Calculation of the power of a water heated floor
It begins in the same way as in the previous method - with the preparation of graph paper, only in this case it is necessary to apply not only the contours, but also the location of windows and doors. Drawing scaling: 0.5 meters = 1 cm.To do this, it is worth considering several conditions:
- Pipes must be located along the windows to prevent significant heat loss through them.
- The maximum area for installing heated floors should not exceed 20 m2. If the room is larger, then it is divided into 2 or more parts, and a separate circuit is calculated for each of them.
- It is necessary to maintain the required value from the walls to the first branch of the contour of 25 cm.
Determining the number of pipes is quite simple: first measure their length, and then multiply it by a scale factor, add 2 m to the resulting length to connect the circuit to the riser. Considering that the permissible length of pipes ranges from 100 to 120 m, you need to divide the total length by the selected length of one pipe.
The parameter of the underfloor heating is determined based on the area of the room, which is obtained after multiplying the length and width of the room. If the room has a complex configuration, to obtain an accurate result, it must be divided into segments and the area of each of them calculated.
Examples of calculating water heated floors
Below you can see two examples of calculating a water heated floor:Example 1
In a room with walls 4–6 m long, the furniture in which takes up almost a quarter of it, the heated floor should occupy at least 17 m2. To carry it out, pipes with a diameter of 20 mm are used, which are laid like a snake. A step of 30 cm is maintained between them. Laying is carried out along a short wall.Before laying pipes, it is necessary to draw a diagram of their location on the floor on the most appropriate scale. In total, such a room will fit 11 rows of pipes, each of which will be 5 m long, for a total of 55 m of pipeline. Another 2 m is added to the resulting pipe length. This is the distance that must be maintained before connecting to the riser. The total length of the pipes will be 57 m.
If the room is very cold, it may be necessary to install dual circuit heating. Then you should stock up on at least 140 m of pipes; this length of pipeline will help compensate for the strong pressure drop at the outlet and inlet of the system. You can make each contour of different lengths, but the difference between them should not be more than 15 meters. For example, one circuit is 76 m long, and the second is 64 m long.
Heated floor calculations can be carried out using two methods:
- For the first method, the formula is used:
L = S? 1.1/B, Where
L– pipeline length;
B– laying step, measured in meters;
S– heating area, in m2. - The second option uses the tabular data below. They are multiplied by the area of the contour.
Example 2
It is required to install a heated floor in a room with walls 5x6 m long, the total area of which is 30 m2. For the system to work effectively, it must heat at least 70% of the space, which is 21 m2. We will assume that the average heat loss is about 80 W/m2. So, the specific heat loss will be 1680 W/m2 (21x80). The desired temperature in the room is 20 degrees, and pipes with a diameter of 20 mm will be used. A 7 cm screed and tiles are placed on them. The relationship between pitch, coolant heat, heat flux density and pipe diameter is presented in the diagram:
So, if there is a 20 mm pipe, to compensate for heat loss of 80 W/m2 it will take 31.5 degrees with a step of 10 cm and 33.5 degrees with a step of 15 cm.
The temperature on the floor surface is 6 degrees less than the temperature of the water in the pipes, which is due to the presence of screed and coating.
Video: Calculation of a warm water floor
From the video you will be able to learn the theory of hydraulics associated with the installation of heated floors, its application to calculations, an example of calculating a water heated floor in a special online program. First, simple pipe connection circuits for such a floor will be considered, and then more complex versions of them, in which all components of the underfloor heating system will be calculated:If you do your own calculations, errors may occur. To avoid them and check the correctness of the calculations, you should use computer programs that contain correction factors. To calculate a warm floor, you need to select the pipe laying interval, their diameter, and material. The error of calculations by the online program does not exceed 15%.
