The maximum number of contours of the warm floor. Guidelines for calculations for arranging a warm floor
The laying of heating pipes under the floor covering is considered one of the the best options heating a house or apartment. They consume fewer resources to maintain the specified temperature in the room, exceed standard wall-mounted radiators in terms of reliability, evenly distribute heat in the room, and do not create separate "cold" and "hot" zones.
The length of the water floor heating circuit is the most important parameter that must be determined before starting installation work. The future power of the system, the level of heating, the choice of components and structural units depend on it.
Styling options
There are four common pipe laying patterns used by builders, all of which are better suited for indoor use. various shapes. From their "drawing" to a large extent depends maximum length underfloor heating circuit. This is:
- "Snake". Sequential laying, where the hot and cold lines follow each other. Suitable for elongated rooms with division into zones of different temperatures.
- "Double snake". Applied in rectangular rooms but no zoning. Provides uniform heating of the area.
- "Corner snake". Sequential system for a room with equal wall lengths and a low heating zone.
- "Snail". Dual routing system suitable for square-shaped rooms with no cold spots.
The chosen laying option affects the maximum length of the water floor, because the number of pipe loops and the bending radius change, which also “eats” a certain percentage of the material.
Length calculation
The maximum length of the underfloor heating pipe for each circuit is calculated separately. To get the required value, you need the following formula:
W*(L/Shu)+Shu*2*(L/3)+K*2
Values are in meters and mean the following:
- W is the width of the room.
- D is the length of the room.
- Shu - “laying step” (distance between loops).
- K is the distance from the collector to the connection point with the circuits.
The length of the contour of the warm floor obtained as a result of calculations is additionally increased by 5%, which includes a small margin for leveling errors, changing the bending radius of the pipe and connecting with fittings. 
As an example of calculating the maximum pipe length for a warm floor for 1 circuit, let's take a room of 18 m2 with sides of 6 and 3 m. The distance to the collector is 4 m, and the laying step is 20 cm, the following is obtained:
3*(6/0,2)+0,2*2*(6/3)+4*2=98,8
5% is added to the result, which is 4.94 m and the recommended length of the water floor heating circuit is increased to 103.74 m, which are rounded up to 104 m.
Dependence on pipe diameter
The second most important characteristic is the diameter of the pipe used. It directly affects maximum value length, the number of circuits in the room and the power of the pump, which is responsible for the circulation of the coolant.
In apartments and houses with an average size of rooms, pipes of 16, 18 or 20 mm are used. The first value is optimal for residential premises, it is balanced in terms of costs and performance. The maximum length of the water floor heating circuit with 16 pipes is 90-100 m, depending on the choice of pipe material. It is not recommended to exceed this indicator, because the so-called “locked loop” effect may form, when, regardless of the pump power, the movement of the coolant in the communication stops due to high fluid resistance.
To choose optimal solution and take into account all the nuances, it is better to contact our specialist for advice. 
Number of circuits and power
The installation of the heating system must comply with the following recommendations:
- One loop per room of a small area or part of a large one; it is irrational to stretch the contour over several rooms.
- One pump per manifold, even if the declared capacity is enough to provide two "combs".
- With a maximum length of the underfloor heating pipe of 16 mm in 100 m, the collector is installed on no more than 9 loops.
If the maximum length of the underfloor heating loop 16 of the pipe exceeds the recommended value, then the room is divided into separate circuits, which are connected into one heating network by a collector. To ensure even distribution of the coolant throughout the system, experts advise not to exceed the difference between individual loops of 15 m, otherwise the smaller circuit will warm up much more than the larger one.
But what if the length of the underfloor heating contour of 16 mm pipes differs by a value that exceeds 15 m? Balancing fittings will help, which changes the amount of coolant circulating through each loop. With its help, the difference in length can be almost two times. 
Temperature in the rooms
Also, the length of the underfloor heating circuits for 16 pipes affects the level of heating. To maintain a comfortable indoor environment, a certain temperature is needed. To do this, the water pumped in the system is heated to 55-60 °C. Exceeding this indicator may adversely affect the integrity of the material. engineering communications. Depending on the purpose of the room, on average, we get:
- 27-29 °C for living rooms;
- 34-35 °C in corridors, hallways and walk-through rooms;
- 32-33 °C in rooms with high humidity.
In accordance with the maximum length of the underfloor heating circuit of 16 mm in 90-100 m, the difference at the "inlet" and "outlet" of the mixing boiler should not exceed 5 ° C, a different value indicates heat loss on the heating main.
"Warm floors" are no longer perceived as a kind of exotic - more and more homeowners are turning to this technology for heating their residential properties. Such a system can completely take on the function of full-fledged heating of housing, or work in tandem with classic heating appliances or convectors. Naturally, these features are taken into account in advance, at the stage of general design.
There are more than enough proposals for project development, installation and debugging of systems. And yet, many homeowners, according to the good old tradition, strive to do everything with their own hands. But such work "by eye" is still not done - one way or another, calculations are required. And one of the key parameters is the overall allowable length pipes of the same circuit.
And since in the conditions of an ordinary average private residential building, as a rule, a pipe with a diameter of 16 mm is quite enough for laying, we will focus on it. So, we are considering the question of what can be the maximum length of the underfloor heating circuit with a 16 pipe.
Why is it better to use a pipe with an outer diameter of 16 mm?
To begin with, why is a 16 mm pipe being considered?
Everything is very simple - practice shows that for "warm floors" in a house or apartment of this diameter is enough. That is, it is difficult to imagine a situation where the circuit does not cope with its task. This means that there is no really justified reason to use a larger, 20-millimeter one.
And, at the same time, the use of a 16 mm pipe provides a number of advantages:
- First of all, it is about a quarter cheaper than the 20mm counterpart. The same applies to all the necessary fittings - the same fittings.
- Such pipes are easier to lay, with them it is possible, if necessary, to perform a compact step of laying out the contour, up to 100 mm. With a 20mm tube, there is a lot more fuss, and a small step is simply impossible.
- The volume of coolant in the circuit is significantly reduced. A simple calculation shows that in running meter A 16 mm tube (with a wall thickness of 2 mm, the inner channel is 12 mm) holds 113 ml of water. And in 20 mm (inner diameter 16 mm) - 201 ml. That is, the difference is more than 80 ml per just one meter of pipe. And on the scale of the heating system of the whole house - this literally translates into a very decent amount! And after all, it is necessary to ensure the heating of this volume, which entails, in principle, unjustified energy costs.
- Finally, a pipe with a larger diameter will also require an increase in thickness. concrete screed. Like it or not, but at least 30 mm above the surface of any pipe will have to be provided. Let these "unfortunate" 4–5 mm do not seem ridiculous. Anyone who was involved in pouring the screed knows that these millimeters turn into tens and hundreds of kilograms of additional concrete mortar- It all depends on the area. Moreover, for a 20 mm pipe, it is recommended to make the screed layer even thicker - about 70 mm above the contour, that is, it turns out to be almost twice as thick.
In addition, in residential premises very often there is a “struggle” for every millimeter of floor height - simply for reasons of insufficient “space” to increase the thickness of the overall “pie” of the heating system.
A 20 mm pipe is justified when it is necessary to implement a floor heating system in rooms with a high load, with a high intensity of people's traffic, in gyms, etc. There, simply for reasons of increasing the strength of the base, it is necessary to use more massive thick screeds, for which heating is required and big square heat exchange, which is exactly what a pipe of 20, and sometimes even 25 mm, provides. In residential areas, there is no need to resort to such extremes.
It may be objected that in order to "push" the coolant through a thinner pipe, it will be necessary to increase the power indicators of the circulation pump. Theoretically, the way it is - the hydraulic resistance with a decrease in diameter, of course, increases. But as practice shows, most circulation pumps are quite up to the task. Below, attention will be paid to this parameter - it is also linked to the length of the contour. This is what calculations are made in order to achieve optimal, or at least acceptable, fully functional performance of the system.
So, let's focus on the pipe exactly 16 mm. We will not talk about the pipes themselves in this publication - that is a separate article of our portal.
What pipes are optimal for a water "warm floor"?
Not all products are suitable for creating a floor heating system. Pipes are embedded in the screed for many years, that is, their quality and performance characteristics there are special requirements. How to choose - read in a special publication of our portal.
How to determine the length of the contour?
The question seems to be quite simple. The fact is that on the Internet you can find a lot of recommendations on this matter - both from pipe manufacturers and from experienced craftsmen, and from, let's be honest, absolute amateurs who simply "rip" information from other resources, without particularly going into subtleties.
So, in the installation instructions that manufacturers often accompany their products, you can find the established limit for the length of the circuit for a 16 mm pipe reaches 100 meters. Other publications show a border of 80 meters. Experienced installers recommend limiting the length to 60 ÷ 70 meters.
It would seem, what else is needed?
But the fact is that the contour length indicator, especially with a vague definition of “maximum length”, is very difficult to consider in isolation from other system parameters. Lay out the contour "by eye", just so as not to exceed the recommended limits - an amateurish approach. And with such an attitude, it is quite possible to soon encounter deep disappointments in the operation of the system. Therefore, it is better to operate not with an abstract “permissible” contour length, but with an optimal one corresponding to specific conditions.
And it depends (more precisely, it does not depend as much as it is closely interconnected) on a host of other parameters of the system. This includes the area of the room, its purpose, the estimated level of its heat loss, the expected temperature in the room - all this will allow you to determine the step of laying the circuit. And only then it will be possible to judge its resulting length.
So we will try to “unravel this tangle” in order to come to optimal length contour. And then - check the correctness of our calculations.
A few basic requirements for the parameters of the "warm floor"
Before proceeding with the calculations, it is necessary to familiarize yourself with some of the requirements that a water floor heating system must meet.
- "Warm floor" can act as the main heating system, that is, fully provide a comfortable microclimate in the premises of the house and compensate for heat losses. Another option, more rational - he acts as an "assistant" conventional radiators or convectors, assuming a certain share in common work systems, increasing the overall comfort in the home. In this case, the calculation should be carried out in close relationship - the owners must decide in advance in what proportion the overall system will work. For example, 60% is taken over by the high-temperature radiator system, and the rest is given to the "warm floor" circuits. It can also be used autonomously, for example, maintaining comfort in the premises during the off-season, when it still (or already) does not make sense to “drive the entire heating system to full”.
- The temperature of the coolant at the supply to the "warm floor" is limited - a maximum of 55 degrees. The temperature difference at the inlet and return must be in the range from 5 to 15 degrees. A drop of 10 degrees is considered normal (optimally, it is desirable to bring it up to 5 - 7).
The following modes of operation are usually taken into account.
Table of modes of operation of the water "warm floor"
- There are quite strict restrictions on the maximum surface temperature of the "warm floor". Overheating of floors is not allowed for a number of reasons. This is an uncomfortable feeling for a person’s legs, and difficulties in creating an optimal microclimate, and possible damage to the finish.
The following limit values for surface heating have been established for different rooms:
- Before starting calculations, it is desirable to immediately draw up sample diagram contour layouts in the room. There are two main pipe laying patterns - "snake" and "snail" with multiple variations.
A - the usual "snake";
B - double "snake";
B - angular "snake";
G - "snail".
The usual "snake" seems to be laid out easier, but it turns out too many 180-degree turns, which increases the hydraulic resistance of the circuit. In addition, with this layout, a temperature difference can be clearly felt from the beginning of the circuit to the end - this is well shown in the diagram by a color change. The disadvantage can be eliminated by laying a double snake, but such installation is already more difficult to perform.
In the "snail" heat is distributed more evenly. In addition, 90-degree turns predominate, which reduces head losses. But laying such a scheme is still more difficult, especially if there is no experience in such work.
The circuit itself may not occupy the entire area of \u200b\u200bthe room - often pipes are not laid in those places where it is planned to install stationary furniture.
However, many masters criticize this approach. Stationarity of furniture - the value is still quite arbitrary, and the "warm floor" is laid for decades. In addition, the alternation of cold and heated zones is an undesirable phenomenon, at least from the point of view of the possible appearance of pockets of dampness over time. Unlike electrical systems, water floors are not threatened by local overheating due to closed areas, so there should be no concerns from this side.
So there is no strict framework in this regard. It is possible, in order to save material, to leave unfilled areas, or to lay the contour completely over the entire area. But if at some site it is planned to install furniture or plumbing devices that require fastening to the floor (for example, fastening the toilet with dowels or anchors), then this place, of course, remains free from the contour. There is simply a high probability of damaging the pipe when installing fasteners.
Which contour laying scheme is better to choose?
More details about the choice of laying schemes, with theoretical justifications, are described in a separate article on our portal.
- The pipe laying step can be from 100 to 300 mm (usually it is a multiple of 50 mm, but this is not a dogma). Less than 100 mm is neither possible nor necessary. And with a step of more than 300 mm, the “zebra effect” can be felt, that is, the alternation of warm and cold stripes.
But which step will be optimal - the calculations will show, since it is closely related to the expected heat transfer of the floor and the temperature regime of the system.
- One more caveat - all subsequent thermotechnical calculations shown for optimal pie sizes for underfloor heating systems.
It was said above that the thickness of the screed should be at least 300 mm above the surface of the pipes. But in order to ensure full accumulation and uniform distribution heat, it is recommended to adhere to a thickness of 45-50 mm (specifically for a pipe with a diameter of 16 mm).
Learn how to do it right, choose mixtures, prepare a solution, and also get acquainted with the technology of pouring water and electric underfloor heating.
And so that the generated heat is not wasted on heating interfloor overlap or other base of the "warm floor", a thermal insulation layer is necessarily provided under the pipe circuit. Usually, expanded polystyrene with a density of about 35 kg / m³ is used for this (extruded is better, as it is more durable and efficient). Minimum Thickness, ensuring the correct operation of the "warm floor" should be:
| Features of the base of the "warm floor" | The minimum thickness of the thermal insulation "cushion" |
|---|---|
| Floor over the ceiling above the heated room, the temperature in which is ˃ 18 °C | 30 mm |
| 50 mm | |
| Floor over the ceiling above the heated room, the temperature in which is from 10 to 17 °C | 70 mm |
| Floor on the ground, including in basements or basements with a depth from ground level up to 1500 mm. | 120 mm |
| Floor in basements or basements with a depth from ground level of more than 1500 mm | 100 mm |
A prerequisite is that the floor heating system must be laid on a carefully insulated base, otherwise the heat will be spent extremely inefficiently. All these last remarks have been made because the following calculations will be valid precisely for such recommended "ideal" conditions.
Carrying out calculations of the main parameters of the contour
In order to lay the pipe contour with the optimal pitch (and its total length will subsequently depend on this), it is first necessary to find out what heat transfer is expected from the system. This is best shown by the specific heat flux density g, calculated per unit floor area (W/m²). Let's start with this.
Calculation of the specific density of the heat flux of the "warm floor"
Calculating this value, in principle, is not difficult - you just need to divide the required amount of thermal energy needed to replenish the heat loss of the room by the area of \u200b\u200bthe "warm floor". This does not mean the entire area of \u200b\u200bthe room, namely the “active”, that is, involved in the heating system, on which the circuit will be laid out.
Of course, if the "warm floor" will work in conjunction with conventional system heating, this is also immediately taken into account - only the planned percentage of the total heat output is taken. For example, 1.5 kW is required to heat a room (replenish heat loss), and the share of "warm floor" is assumed to be 60%. So, when calculating the specific heat flux density, we operate with the value 1.5 kW × 0.6 = 0.9 kW
Where can I get the total required power to make up for heat loss? There are many recommendations based on the ratio of 1 kW of energy per 10 m² of floor space. However, this approach turns out to be too approximate, not taking into account a lot of important external factors and features of the room. Therefore, it is better to carry out a more thorough calculation. Don't worry - with our calculator it won't be too difficult.
Calculator for calculating the specific heat flux of "warm floor"
Warm floor perfect solution to improve your home. The floor temperature directly depends on the length of the underfloor heating pipes hidden in the screed. The pipe in the floor is laid in loops. In fact, the total length of the pipe is added up from the number of loops and their length. It is clear that the longer the pipe in the same volume, the warmer the floor. In this article, we will talk about restrictions on the length of one contour of a warm floor.
Approximate design characteristics for pipes with a diameter of 16 and 20 mm are: 80-100 and 100-120 meters, respectively. These data are approximate for approximate calculations. Let's take a closer look at the process of installing and pouring underfloor heating.
Consequences of exceeding the length
Let's figure out what consequences an increase in the length of the underfloor heating pipe can lead to. One of the reasons is an increase in hydraulic resistance, which will create an additional load on the hydraulic pump, as a result of which it may fail or simply may not cope with the task assigned to it. The resistance calculation consists of many parameters. Conditions, styling parameters. The material of the pipes used. Here are the three main ones: loop length, number of bends and thermal load on it.
It is worth noting that the thermal load increases with the increase in the loop. The flow rate and hydraulic resistance also increase. There are restrictions on the flow rate. It should not exceed 0.5 m/s. If we exceed this value, various noise effects may occur in the piping system. The main parameter, for the sake of which this calculation is made, also increases. The hydraulic resistance of our system. It also has limitations. They are 30-40 kP per loop.
The next reason is that with an increase in the length of the underfloor heating pipe, the pressure on the pipe walls increases, causing this section to elongate when heated. The pipe in the screed has nowhere to go. And it will begin to narrow at its weakest point. The constriction can cause blockage of the flow in the coolant. For pipes made from different material, different expansion coefficient. For example, at polymer pipes expansion coefficient is very high. All these parameters must be taken into account when installing a warm floor.
Therefore, it is necessary to fill in the underfloor heating screed with pressed pipes. It is better to pressurize with air with a pressure of about 4 bar. Thus, when you fill the system with water and start heating it, the pipe in the screed will expand somewhere.
Optimum pipe length
Considering all the above reasons, taking into account the corrections for the linear expansion of the pipe material, we take as a basis the maximum length of the underfloor heating pipes per circuit:
The table shows optimal dimensions underfloor heating lengths that are suitable for all modes of thermal expansion of pipes in various operating modes.
Note: In residential buildings 16 mm pipe is enough. Larger diameter should not be used. This will lead to unnecessary spending on energy.
1. What temperature should the coolant be in the warm floor and how can its temperature be controlled?
The temperature should not be higher than 55 ° C, and in some cases not higher than 45 ° C.
To put it even more precisely: the temperature should be in accordance with the temperature calculated in the project, which takes into account the need for a particular room in heat and the material from which the finished floor is made.
You can control the temperature with the help of such a thermometer, and preferably two.
One thermometer shows the temperature of the heat carrier at the underfloor heating supply (temperature mixed water), and the other is the return temperature.
If the difference between the readings of two thermometers is 5 - 10 ° C, then the underfloor heating system is working correctly for you.
2. What should be the temperature on the surface of the warm floor?
The surface temperature of a working underfloor heating must not exceed the following values:
29 ° C - in the premises of long-term stay of people;
35 o C - in the boundary zones;
33 o C - in bathrooms, bathrooms.
3. What forms of pipe laying are used for underfloor heating?
For pipe laying floor heating use different forms: snake, corner snake, snail, double snake (meander).
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Also, when laying one contour, you can combine these forms.
For example, the edge zone can be arranged with a snake, and then the main part can be passed with a snail.
4. What is the best installation for underfloor heating?
For large square, rectangular or round rooms without geometric exclusivity, it is better to use a snail.
For small rooms, rooms with complex shapes or long rooms, use a snake.
5. What should be the laying step?
The laying step must be designed in accordance with the calculations.
For edge zones, a step of 10 cm is used. For other zones with a difference of 5 cm - 15 cm, 20 cm, 25 cm. But not more than 30 cm.
This limitation is due to the sensitivity of the human foot.
With a larger pipe pitch, the foot begins to feel the temperature difference in the floor sections.
To do this, you can use a very simple formula: L=S/N*1.1, where
S is the area of \u200b\u200bthe room or circuit for which the pipe length is calculated (m 2);
N - laying step;
1.1 - pipe margin of 10% for turns.
To the result, do not forget to add the length of the pipe from the collector to the underfloor heating, including supply and return.
For example, consider a problem in which you need to calculate the length of a pipe for a room in which the floor occupies a usable area of 12 m 2. The distance from the collector to the warm floor is 7 m. The pipe laying step is 15 cm (do not forget to convert to m).
Solution: 12 / 0.15 * 1.1 + (7 * 2) = 102 m.
7. What is the maximum length of one circuit?
Everything depends on the hydraulic resistance or pressure losses in a particular circuit, which, in turn, directly depend on both the diameter of the pipes used and the volume of coolant that is supplied through the cross section of these pipes per unit time.
In the case of a warm floor, (if you do not take into account the above factors), you can get the effect of the so-called locked loop. A situation in which no matter how powerful the pump you install in terms of pressure, circulation through this loop will be impossible.
In practice, it has been found that pressure losses of 20 kPa or 0.2 bar just lead to this effect.
In order not to go into calculations, we give some recommendations that we use in practice.
For metal-plastic pipe With a diameter of 16 mm, we make a contour no more than 100 m. Usually we stick to 80 m.
The same applies to polyethylene pipes. For 18 XLPE pipes, the maximum loop length is 120 m. In practice, we adhere to 80 - 100 m. For 20 metal-plastic pipes, the maximum loop length is 120 - 125 m.
8. Can there be underfloor heating contours of different lengths?
The ideal situation is when all loops are the same length. You don't need to balance or adjust anything.
In practice, this can be achieved, but most often it is not advisable.
For example, at the facility there is a group of rooms where you need to make a warm floor. Among them there is also a bathroom, the usable floor area of which is 4 m 2 . Accordingly, the length of the pipeline of this circuit, together with the length of the pipes to the collector, is only 40 m.
Do all rooms really need to be adjusted to this length, splitting the usable area of the remaining rooms by 4 m 2?
Of course not. This is not advisable. And then what is the balancing valve for, which is precisely designed to help equalize the pressure loss along the contours?
Again, you can use the calculations through which you can see to what maximum limit you can allow the spread of pipe lengths of individual circuits at a particular facility with this equipment.
But again, without plunging you into complex boring calculations, let's say that at our facilities we allow a spread in the lengths of pipes of individual circuits of 30 - 40%. Also, if necessary, you can "play" with pipe diameters, laying steps and "cut" the areas of large rooms not into small or large, but into medium pieces.
9. How many circuits can be connected to one mixing unit with one pump?
This question is physically similar to the question: "How much cargo can be taken away by car?"
What else would you like to know if someone asked you this question?
Absolutely correct. You would ask: "What car are we talking about?"
Therefore, in the question: “How many loops can be connected to the underfloor heating collector?”, It is necessary to take into account the diameter of the collector and what volume of coolant is able to pass through the mixing unit per unit of time (it is customary to consider m 3 / hour). Or, which is also equivalent, what kind of heat load can the mixing unit of your choice carry?
How to find out? Very simple.
For clarity, let's show an example.
Let's say you have chosen Valtec's Combimix as your mixing unit. What heat load is it designed for? We take his passport. See the clipping from the passport.
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What do we see?
Its maximum ratio bandwidth is 2.38 m 3 /hour. If we put the Grundfos UPS 25 60 pump, then at the third speed with this coefficient this unit is able to "drag" a load of 17000 W or 17 kW.
What does this mean in practice? 17 kW is how many circuits?
Imagine that we have a house in which there are some (unknown) rooms of 12 m 2 of usable floor space in each room. Our pipes are laid in increments of 20 cm, which leads to the length of each circuit, taking into account the length of the pipes from the warmest floor to the collector, 86 m. In accordance with the design calculations, we also found that the heat removal from each m 2 of this warm floor gives 80 W , which leads us respectively to the thermal load of each circuit
12 * 80 = 960 W
How many rooms or similar circuits can our mixing unit provide with heat?
17000 / 960 = 17.7 similar circuits or rooms.
But this is the maximum!
In practice, in most cases, it is not necessary to calculate the maximum performance. So let's stick with number 15.
Valtec itself has a manifold for this node with a maximum number of outputs - 12.
10. Do I need to make several contours of the warm floor in large rooms?
In large rooms, the design of the warm floor must be divided into smaller areas and several contours should be made.
This need arises for at least two reasons:
limiting the length of the circuit pipe is necessary in order not to get the effect of a "locked loop", in which there will be no coolant circulation through it;
the correct operation of the cement slab itself, the area of \u200b\u200bwhich should not exceed 30 m 2. Withthe ratio of the lengths of its sides should be 1/2 and the length of one of the edges should not exceed 8 m.
11. How do I know how many underfloor heating circuits I need for my house?
In order to understand how many loops of a warm floor will be needed and, on the basis of this, to choose a suitable collector with the same number of outlets, you need to start from the area of \u200b\u200bthe premises themselves in which this system is planned.
After that, you calculate the useful area of \u200b\u200bthe warm floor. How to do this is described in question 12 " How to calculate the usable floor area?".
Then, use the following method: starting from the step of the warm floor, break the usable area of the warm floor in each room into the following dimensions:
- step 15 cm - no more than 12 m 2;
- step 20 cm - no more than 16 m 2;
- step 25 cm - no more than 20 m 2;
- step 30 cm - no more than 24 m 2.
If the floor area in the room is less than the specified dimensions, then it does not need to be broken.
We recommend reducing these values by 2 m 2 if the length of the pipe connection from the underfloor heating to the collector exceeds 15 m.
When dividing the useful floor area in the premises, also try to ensure that the length of the pipes in these circuits is either the same, or the difference between the individual circuits does not exceed 30 - 40%.How to find out the length of pipes in each circuit, read question 6 " How to calculate pipe length?".
Step back 30 cm from each of the walls of the room. Shade the resulting space. Mark on the plan the areas where the furniture will constantly stand: a refrigerator, furniture wall, sofa, large closet, etc. Shade these areas as well. The unshaded part of the room plan will be the usable floor area you are looking for.
For clarity, let's calculate the useful area of the dining room, where there will be a warm floor. The total area of the dining room is 20 m 2, the length of the walls is 4 m and 5 m, respectively. The kitchen will have kitchen set, refrigerator and sofa, which we will mark on the plan. Let's not forget to step back from the walls by 30 cm. Let's shade the occupied areas. See drawing.
And now let's calculate the usable floor area.
13. What is the total thickness of the underfloor heating cake?
It all depends on the thickness of the insulation, since the remaining values \u200b\u200bare known.
With the next thickness of the insulation, you will get the following values (the thickness of the finishing coating is not taken into account):
- 3 cm - 9.5 cm;
- 8 cm - 14.5 cm;
- 9 cm - 15.5 cm.
14. What do you use to calculate the water floor heating system?
For the calculation of both radiator heating systems and underfloor heating systems, we use the company's Audytor CO program.
Below we post a screenshot of the module of this program for the preliminary calculation of a warm floor and a screenshot of the module for calculating the layers of a warm floor pie.
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Upon careful consideration of these screenshots, you can understand how serious the correct calculation of the warm floor is.
You can also see the work of the program itself, which does possible visual control over such important parameters like pipe length, pressure loss, floor surface temperature, heat going down uselessly, useful heat flow, etc.
15. How to determine the dimensions of the collector cabinet in order to place all the necessary components in it?
Determining the dimensions of the collector cabinet is not difficult. We once again invite you to use Valtec products and their ready-made recommendations presented in the table, provided that you are using ready-made underfloor heating units manufactured by this manufacturer.
Linear dimensions of manifold cabinet
(SHRN - external; SHRV - internal)
| Model | Length, mm | Depth, mm | Height, mm |
|---|---|---|---|
| SHRV1 | 670 | 125 | 494 |
| SHRV2 | 670 | 125 | 594 |
| SHRV3 | 670 | 125 | 744 |
| SHRV4 | 670 | 125 | 894 |
| SHRV5 | 670 | 125 | 1044 |
| SHRV6 | 670 | 125 | 1150 |
| SHRV7 | 670 | 125 | 1344 |
| SHRN1 | 651 | 120 | 453 |
| SRN2 | 651 | 120 | 553 |
| SHRN3 | 651 | 120 | 703 |
| SRN4 | 651 | 120 | 853 |
| SHRN5 | 651 | 120 | 1003 |
| SHRN7 | 658 | 121 | 1309 |
Selection of manifold cabinet
Collector groups 1 |
cabinet model |
cabinet model SHRN/SHRV + Dualmix + ball valve |
cabinet model SHRN / SHRV + crane |
| Collector 1*3out | SHRN3/SHRV3 | SHRN4/SHRV4 | SHRN1/SHRV1 |
| Collector 1*4out | SHRN3/SHRV3 | SHRN4/SHRV4 | SHRN2/SHRV2 |
| Collector 1*5out | SHRN4/SHRV3 | SHRN5/SHRV4 | SHRN2/SHRV2 |
| Collector 1*6out | SHRN4/SHRV4 | SHRN5/SHRV5 | SHRN3/SHRV3 |
| Collector 1*7out | SHRN4/SHRV4 | SHRN5/SHRV5 | SHRN3/SHRV3 |
| Collector 1*8out | SHRN5/SHRV4 | SHRN6/SHRV5 | SHRN3/SHRV3 |
| Collector 1*9out | SHRN5/SHRV5 | SHRN6/SHRV6 | SHRN4/SHRV4 |
| Collector 1*10out | SHRN5/SHRV5 | SHRN6/SHRV6 | SHRN4/SHRV4 |
| Collector 1*11out | SHRN6/SHRV5 | SHRN7/SHRV6 | SHRN4/SHRV4 |
| Collector 1*12out | SHRN6/SHRV6 | SHRN7/SHRV7 | SHRN5/SHRV5 |
16. At what height should the manifold cabinet be installed?
There are no specific rules in this regard, but there are recommendations.
On the one hand, it is clear that when mounting a collector cabinet, it is necessary to take into account the height of the future screed and finish, so that a situation does not turn out when it will not even be possible to open the cabinet door.
On the other hand, serviceability and the need to possible replacement individual elements of the system with the possibility of disconnection of the pipeline.
The shorter the pipe section, the greater its rigidity and vice versa.
Considering this factor, it is possible to raise the collector cabinet by 20 - 25 cm from the level of the finished floor.
However, we must not forget about a very important design element. If lifting the cabinet leads to an unacceptable violation of the design and it is impossible to solve this problem in another way, lower the cabinet to the floor level, but in such a way that it can open.
It is not feasible without preliminary calculations. To get the length of the pipes, the power of the entire heating system and others desired values, you will need to enter only accurate data into the online calculator. You can find out more about the rules and nuances of the calculation below.
General data for calculation
The first parameter that needs to be taken into account before calculations is the choice of the 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 surface of the floor of the dwelling 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 optimum temperature- 33 degrees.
If the arrangement of the warm floor is carried out under the bottom parquet board, then you need to consider that the temperature should not exceed 27 degrees, otherwise the floor covering will quickly deteriorate.
The auxiliary parameters are:
- total length pipes and their pitch (installation distance between pipes). It is calculated thanks to the 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 deterioration.
- Flooring. The choice of floor covering affects the thermal conductivity of the floor. The use of tiles and porcelain stoneware is optimal, since they have high thermal conductivity and quickly warm up. When choosing linoleum or laminate, it is worth purchasing a material that does not have a heat-insulating layer. From wood flooring it is worth refusing, since such a floor will practically not heat up.
- The climate of the area, in which there is a building with a floor heating system. It is necessary to take into account the seasonal change of temperatures in this region and the lowest temperature in winter.
Most of the heat of a home escapes through its thin walls and poor-quality window construction materials. Before performing 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 consumption of its owner.
Calculation of pipes for underfloor heating
Water heated floor - 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.On graph paper, on a scale or in full size, draw the future contour " heating element”, after selecting the type of pipe laying. As a rule, the choice is made in favor of one of two options:
- snake. Selected for small living spaces with low heat losses. The pipe is located as an elongated sinusoid and is extended along the wall to the collector. The downside of this installation is that the coolant in the pipe gradually cools down, so the temperature at the beginning and end of the room can be very different. For example, if the length of the pipe is 70 m, then the difference can be 10 degrees.
- Snail. Such a scheme assumes that the pipe is initially laid along the walls, and then bent 90 degrees and twisted. Thanks to this laying, it is possible to alternate cold and hot pipes, obtaining a uniformly heated surface.
Having chosen the type of laying, the following indicators are taken into account when implementing the scheme on paper:
- The pitch of the pipes allowed in the 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– step (m);
1,1 is the safety factor for bending.It should be understood that the pipe should be located in 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 up the room to a temperature of 25 to 37 degrees, you need the system itself to heat up to 40-55 °C.
- To reduce the temperature in the circuit to 15 degrees, a pressure loss in the housing of 13-15 kPa will help.
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. Draw scaling: 0.5 meters = 1 cm.For this, several conditions must be taken into account:
- Pipes must necessarily be located along the windows to prevent significant heat loss through them.
- The maximum area for arranging a warm floor 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 mandatory 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 the scale factor, add 2 m to the resulting length to bring the circuit to the riser. Given that the allowable length of the pipes is in the range from 100 to 120 m, you need to divide the total length by the selected length of one pipe.
The parameter of the substrate for 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 calculate the area of each of them.
Examples of calculating a water heated floor
Below you can find two examples of calculating a water-heated floor:Example 1
In a room with a wall length of 4 × 6 m, in which furniture occupies almost a quarter of it, a warm floor should occupy at least 17 m2. For its implementation, 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 in the most appropriate scale. In total, 11 rows of pipes will fit in such a room, each of which will be 5 m long, in total you will get 55 m of the pipeline. Another 2 m is added to the resulting pipe length. It is this 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 double-circuit heating. Then you should stock up at least 140 m of pipes, such a length of the pipeline will help compensate for the strong pressure drop at the outlet and at the 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 performed with a length of 76 m, and the second - 64 m.
Calculation of a warm floor can be carried out in two ways:
- For the first method, the formula is applied:
L=S? 1.1/B, where
L- pipeline length;
B- laying step, measured in meters;
S- heating area, in m2. - In the second option, the tabular data below is used. They are multiplied by the area of the contour.
Example 2
It is required to carry out a warm floor in a room with a wall length of 5x6 m, the total area of \u200b\u200bwhich 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, specific heat losses will be 1680 W / m2 (21x80). The desired temperature in the room is 20 degrees, while pipes with a diameter of 20 mm will be used. 7 cm screed and tiles are laid on them. The relationship between the pitch, the heat of the coolant, the heat flux density and the diameter of the pipes is shown in the diagram:
So, if there is a 20 mm pipe, to compensate for the heat loss of 80 W / m2, 31.5 degrees at a step of 10 cm and 33.5 degrees at a step of 15 cm will be required.
The temperature on the floor surface is 6 degrees lower than the temperature of the water in the pipes, due to the presence of screed and coating.
Video: Calculation of a warm water floor
From the video it will be possible to learn the theory of hydraulics related to the arrangement of underfloor heating, 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 their more complex options, in which all nodes of the underfloor heating system will be calculated:Self-calculation may result in errors. To avoid them and check the correctness of the calculations, you should use computer programs that contain correction factors. To calculate the underfloor heating, you need to select the pipe laying interval, their diameter, as well as the material. The error of calculations by the online program does not exceed 15%.
