At the household level, today more and more often you can hear a discussion about which method of heating is most effective at home. The most common in our conditions are water heating systems, which are based on the work of a heated coolant. Underfloor heating in this regard is of greatest interest among consumers. Especially popular is the decision to equip floor heating in country houses, in cottages and in the country, in conditions where a high degree of comfort is required. At this stage, most of the questions arise, which consumable to choose for laying heating circuits.
Main article: how to choose pipes for underfloor heating?
In each individual case, there is always the opportunity to make a choice, giving preference to pipes for warm water floors made of one or another material. Not only the cost of pipes is taken into account, but also technological characteristics, material parameters. Not only the efficiency of the future heating system, but also the installation method depends on these data. Installation of water circuits is one of the main stages in the creation of underfloor heating. Practical and technological material will greatly simplify and speed up the laying of pipes on the prepared coating. Consider the two most common options for solving the problem:
- warm floor made of metal-plastic;
- underfloor heating, which uses a polypropylene water circuit.
What pipes are used for underfloor heating? Why choose metal-plastic and polypropylene more often?
The pipeline is the main working part of the heating system «warm water floors», therefore, what consumable will be used, i.e. which pipe will go into operation, the main attention is paid during installation. For the design of heating floors, the quality of the consumable material, the high technological characteristics of the pipe are important. Due to the rapid growth in the popularity of water heating, the technology for the production of equipment and consumables for heating has stepped far ahead.
On the market of thermal, heating equipment, pipes of the following types are presented:
- corrugated pipes, steel;
- consumables made of cross-linked polyethylene.
Any of the options mentioned above will do the job well. The only point that distinguishes all options from each other is cost and performance. We will talk about copper pipes and a corrugated channel for a water circuit another time. These materials are not popular at the household level due to the high cost.
Now let’s look at another question. What is better for your floor, metal-plastic or polypropylene? What is the difference between these most common materials?
Metal-plastic is one of those materials with which you can work with any qualification. Pipelines made of metal-plastic pipes are quite easy to install, repair or replace damaged sections.
On a note: metal-plastic pipes are very convenient when laying water lines in autonomous heating systems. The radiator heating method is mainly mounted using metal-plastic pipelines.
A properly laid water circuit makes the floor of metal-plastic pipes reliable, practical and durable. Particularly captivating is the fact that water heating circuits made of solid metal-plastic are durable and tight, have a high degree of reliability. The mains are connected to the distribution manifold of the manifold using fittings, which most often have a metal base. Docking of fragments of a metal-plastic pipe with adapters is carried out by means of a threaded connection.
For reference: According to experts, if certain skills and dexterity are not applied, threaded connections in contact with metal-plastic pipes can leak.
A metal-plastic water floor pipe connected with press fittings is more reliable. As a result of crimping, a strong and tight connection is created.
Polypropylene pipes are also connected using fittings. The difference is that the docking is carried out by heating the edge of the pipe with special equipment. Using a soldering iron, polypropylene is tightly connected to the fitting, making the connection monolithic and reliable.
In order to make a choice in favor of metal-plastic or give preference to polypropylene materials, it is necessary to answer the question. What is better than polyethylene or metal-plastic, how practical are the products during the operation of warm water floors, and what will be the cost of installing a heating water circuit? Cost is often the deciding factor. The difficulties of installation will become known already in the process of work. Not the last role in terms of choice is played by the design features of both materials. What is the difference in consumables?
For water supply and water heating systems, both options are excellent. Due to the low cost of materials, it is possible to lay quite long pipelines, providing water and heat supply to the entire house. For a warm floor, the use of metal-plastic pipes is associated with a certain risk. Laying the heating circuit channel in a concrete screed or under a tile, if a leak occurs, the repair work will be quite extensive and difficult. Polypropylene pipes in this aspect are more reliable. Given the coefficient of thermal expansion, correctly laid polypropylene heating circuits will serve for a long time.
The first option — we use metal-plastic for a warm floor
A metal-plastic pipe is a high-tech product, marking (MP), which is a composite. Five layers form the basis of the structure, performing their specific functions. The inner and outer layers are polyethylene, tightly connecting with the inner layer made of foil. Between the foil and the polyethylene layers there are two adhesive layers that provide the entire structure with the necessary stability.
At first glance, the channel is a complex type-setting structure — a composite. However, this design was created specifically for underfloor heating. Due to the presence of a metal layer inside the channel, the maximum possible transfer of thermal energy occurs. Metal-plastic pipes for underfloor heating allow you to create uniform heating of the floor surface, using a fairly wide pitch when laying water circuits.
On a note: the permissible maximum values for the spacing of the water loop are 35 cm. surface areas not exposed to heat.
The inner layer has smooth walls, which makes such pipes resistant to the formation of calcium deposits. Corrosion to such material is not terrible. The combination of aluminum foil and polyethylene provides the entire circuit with the necessary strength, not inferior in strength to copper pipelines. This consumable has both its obvious advantages and disadvantages. However, for a number of reasons, MP pipes are often chosen for the installation of warm water floors.
Underfloor heating, in which metal-plastic pipes are used, has the following advantages:
- a metal-plastic pipeline has a low expansion coefficient, which has a beneficial effect on the state of the concrete screed;
- water circuits are resistant to corrosion and inert in terms of reaction to chemicals;
- water heating loops keep the working pressure of the coolant well;
- heating circuits made of this material have high sound insulation;
- the pipeline holds its shape during the process of pouring the surface with concrete.
The last advantages that influence the choice of this particular type of consumable include durability. Pipes laid in a concrete screed can function normally for 30-40 years.
Metal-plastic withstands operating pressure up to 10 atmospheres and retains its main technological characteristics at a coolant temperature of 950C. From the point of view of practicality and manufacturability, metal-plastic pipes behave perfectly during the installation of heating circuits. The channel is easily bent, which makes it possible to lay the contour in any way, serpentine or spiral, schemes in which a large number of bends are provided.
The disadvantages of metal-plastic are rather nuances of the technological use of pipelines made from this material. This may include the following:
- with poor manufacturing quality, delamination of the aluminum and polyethylene layer may occur (difference in the parameters of the coefficients of linear expansion);
- the use of metal fittings for connections can lead to the formation of scale on the inner surface of the joints;
- pinching the fitting during the installation of the pipeline can lead to the formation of a crack in the polyethylene;
Metal-plastic and underfloor heating in your home is a good combination, a reasonable, worthy and justified choice. In this case, you can get a reliable and efficient heating system, while saving quite a significant amount on consumables. Therefore, you can safely proceed to the calculation of the consumption of pipes necessary for the installation of heating circuits.
A water circuit made with XLPE pipes is the second most commonly used option for laying underfloor heating. Cross-linked polyethylene is a polymer subjected to additional processing. Under the influence of high pressure, new molecular bonds are formed in the polymer structure. From the point of view of technology, such a process is called cross-linked, therefore, the new material was called cross-linked polyethylene.
The three-dimensional molecular structure increases the stability of the entire material, making it inert to high temperatures. This means that the coefficient of linear expansion of a pipeline made of cross-linked polyethylene is less than the percentage of deformation as a result of work. The resulting structure does not respond at all to light mechanical stress. Scratches, abrasion and shrinkage for such a pipe are not absolutely not terrible.
When choosing a pipe for your floor, pay attention to the degree of crosslinking, it is this parameter that is key for the performance of the entire heating circuit in the future. There is a certain standard for the degree of crosslinking, which varies in the range of 65-80%.
From the point of view of technology, three types of cross-linked polyethylene pipes are produced today, differing in the method of stitching.
- REX-a or pyroxide method;
- REX-b or silane method;
- REX-c radiation crosslinking method.
In the first case, peroxides are introduced into the polymer composition, bringing the degree of crosslinking to a maximum value of -85%. In the second case, polyethylene is filled with organic silanides. In such a material, the degree of crosslinking reaches 65%.
The last third method of crosslinking, radiation provides a degree of crosslinking of 60%.
On a note: the lower the degree of crosslinking, the lower the rigidity and strength of the polyethylene. Too low a percentage of the degree of crosslinking can lead to unpleasant consequences in the future. Pipes with such parameters can crack over time and lose their tightness.
Finally, I would like to say the following. Both the first option and the second have the right to life. Metal-plastic and cross-linked polyethylene are modern high-tech materials. With correct thermal and hydraulic calculations, a warm floor equipped with water circuits made of metal-plastic or polymer pipes will serve for a long time and reliably.
The price of these consumables today allows you to make them affordable for most consumers. Thanks to these materials, it is possible to successfully lay the heating system throughout the house, using a minimum of connections and avoiding unnecessary pieces.