Which pipe is better for a warm floor - polyethylene or plastic?

Water floor heating is a rather complex design, the main elements of which are pipes. A lot depends on the quality of the pipeline - the temperature in the house, the absence of leaks, the durability of the floor itself. Therefore, you should especially carefully consider the choice of material. Which pipe is better for a warm floor - polyethylene or plastic? Let's look at the features of both types.

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What are the pipes?

To decide which pipe is needed for a warm floor - cross-linked polyethylene or metal-plastic, you need to familiarize yourself with other types of materials that are used to install horizontal heating systems. On sale you can find pipes from a variety of materials:

• metal plastic;
• polypropylene and polyethylene;
• copper;
• corrugated steel.

The most popular were polyethylene and metal-plastic pipes. Copper and steel are used relatively rarely, and those who make a warm floor on their own do not pay attention to them for several reasons:

• difficult to mount;
• special equipment required;
• it is almost impossible to make a system without seams;
• pipes are subject to corrosion;
• the whole structure is heavy, which is not always permissible in multi-storey buildings - however, in single-story wooden houses too.

Why is stainless steel not good?

It is almost impossible to find a metal pipe of the desired length and configuration. Steel and copper parts always have to be stitched together. That is why building codes forbid the use of such conventional steel pipes for underfloor heating, even if they are made of stainless steel.

Unacceptable and joints. This is understandable - the joints and seams are the weakest points, it is in these sections of the pipe that most often break. Only a solid pipe is suitable for a warm floor.

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Necessary qualities

Water floor heating is not done for one day. It is advisable that the system does not fail as long as possible, because not only the finish coating, but also the concrete screed is laid on top of the pipes. If the system stops working or leaks occur, you will need to disassemble part of the top layer.

Therefore, the material should be:

• durable;
• durable
• resistant to corrosion;
• resistant chemicals, including aggressive ones;
• the walls should not overgrow.

Important! The system should work stably. Accordingly, you need to choose a material that does not rust, because any corrosion ultimately causes leaks. A warm floor should serve as much as all the internal systems of the house.

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Some regulations

What load should the pipe withstand? Standards are determined by the goals, which are all the details of such a system:

• ensure uniform movement of water;
• provide heating of the air in the room to the standard temperature;
• prevent noise during the circulation of water.

All these determine the requirements by which you can decide for yourself which pipe is better for a warm floor - polyethylene or metal plastic:

• they must support the weight of the screed;
• they should not be harmed by water pressure from 7 to 10 bar;
• a material with high heat transfer is required at a coolant temperature of about 93 ° C, while the pipe should also withstand temperature differences without negative consequences;
• the inner surface should be smooth so that the water moves without obstacles and does not create noise;
• the outer surface should give good protection against noise;
• the pipe must be not only long, but also flexible, so that the entire circuit can be made without seams.

Dimensions

It is clear that all the necessary qualities are possessed only by pipes made of synthetic materials - metal-plastic and polyethylene. But what to take - cross-linked polyethylene or metal-plastic for a warm floor, the question is complex. Pipes of the required diameter are in both cases. But what should be the section? Most often used components with a thickness of 16-20 mm. Sometimes you can find systems where the diameter of the pipeline is 25 mm, but not more. Why such sizes? There are several reasons:

1. In pipes of a smaller section, too much pressure arises, there is formed a hydraulic reaction, which reduces the efficiency.
2. Oddly enough, the efficiency decreases with a larger diameter - this is due to a decrease in pressure on each site.

But it is important to consider not so much the cross section as the ratio of diameter to length. They look something like this:

1. With a small length of the pipeline (60-80 m), a pipe with a cross section of 16 mm will provide the greatest efficiency.
2. For a pipeline of 90-100 m in length, components with a diameter of 20 mm or so are taken.
3. If the length of the system is 100-120 m, a more solid pipeline with a cross section of 25 mm is suitable.

Important! If a pipe longer than 120 m is needed to heat a large room, it is best not to increase the cross section, but to make several contours.

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What is good metal plastic?

Both metal-plastic and polyethylene pipes are well suited for such systems. Their popularity is about the same. But what kind is suitable specifically for your conditions - you need to figure it out.

What is metal plastic? It consists of several layers:

• external;
• internal;
• foil or aluminum.

The inner and outer surfaces are cooked from polyethylene or polypropylene. Between them, another layer is glued - from a special foil or aluminum.

Metal-plastic pipes were created specifically for water floor heating, so its inventors took into account all the features of such systems:

• Such products have remarkable heat transfer, which allows the use of sections of shorter length than when using other materials. Aluminum heats up excellently, which makes the operation of the entire system very efficient.
• The inner surface is most often made of welded polyethylene absolutely smooth, deposits on it do not linger, so that the pipe itself does not collapse.
• The strength of metal-plastic is beyond praise; it is due to the fact that high-quality plastic is connected to aluminum or foil by very strong adhesive layers.
• In addition, aluminum prevents the ingress of oxygen.

For the manufacture of the outer layer, polypropylene is usually used, but pipes made of polyethylene are also found - there is practically no difference in quality. The outer surface protects the aluminum gasket from harmful effects. In addition, the pipe, consisting of several layers bonded together by a particularly high-quality adhesive, is extremely reliable.

Advantages and disadvantages

The main advantages of pipes made of metal-plastic include:

• ability to withstand very high pressure - 10 atmospheres do not harm them:
• resistance to high temperatures - the coolant warms up to 96 ° C, while nothing bad happens with the material;
• lack of reaction with oxygen;
• resistance to all types of corrosion, including electrochemical;
• the life of the system is 50 years, or even longer (unless, of course, the necessary conditions are met);
• the pipe is elementarily bent even without the use of special equipment, that is, you can create the necessary configuration with literally bare hands;
• metal-plastic expands very little when heated.

But can metal-plastic pipes be considered perfection without any flaws? Unfortunately, materials without flaws have not yet been invented. There are also disadvantages to pipes made of polyethylene and aluminum:

• aluminum and plastic have different coefficients of thermal expansion, which sometimes leads to delamination and the formation of leaks at the joints with other nodes;
• if excessive efforts are made when installing fittings, there is a risk of cutting through the pipe;
• freezing of water should not be allowed - the metal layer breaks from this;
• with inaccurate bending, creases occur, which must be prevented, especially when installing long sections, when the damaged circuit must be completely changed.

But with all these shortcomings it is quite easy to cope if you mount the pipeline carefully.

Important! Regardless of whether a short section has cracked or a long one, it should be replaced, because there should be no joints in the system.

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Crosslinked Polyethylene

Before you opt for polyethylene pipes, you need to figure out what kind of material it is and what it is good for.

Polyethylene is a polymer. It has a linear molecular structure, and it is thanks to this that the material bends perfectly and is able to take the desired shape. Conventional polyethylene, from which the bags are made, is hardly suitable for such complex systems as underfloor heating. It is simply not strong enough. Therefore, special technology is used for the manufacture of pipes - the polymer is crosslinked. It remains ductile, but becomes much more durable and reliable. In fact, its structure is changing, which from linear to three-dimensional.

How and when is it stitched?

Polyethylene is not sewn at all in the same way as, for example, fabrics. No one sits at the sewing machine and does not cut layers - there will be no sense from such a connection. Everything happens at the molecular level. The fact that the material has undergone this procedure, you will see on the labeling - there should be the letters PEX. What does it give? Much:

• strength increases;
• resistance to the most various influences, including mechanical, improves.

Advantages

Such products have a lot of useful properties that must be taken into account when choosing which pipe is better for a warm floor - polyethylene or metal plastic:

• they have an anti-oxygen barrier, because a layer is applied that does not allow free oxygen to penetrate into the material and into the system itself - for all pipes that go on sale, this figure is greater than zero, but does not go beyond German standards;
• polyethylene pipes are much easier to mount than metal-plastic ones, because they bend elementarily and rarely break;
• they withstand a constant temperature of 95 ° C and even 110 °, if not for long;
• maximum pressure - 20 atmospheres;
• water moves almost silently;
• the service life is up to 50 years and even more, but, as in the case of metal-plastic, the technical requirements must be observed;
• water may freeze, but the pipe will not break;
• the material has molecular memory.

Important! Of particular note is molecular memory. This makes life easier for those who make the floor. When creasing, you do not have to replace the pipe. It is enough to heat it to 100 ° C, and all your problems will be solved, because it will take its former position.

How is it connected?

On the marking, the letters of the Latin alphabet are assigned to the abbreviation. They indicate the quality of crosslinking:

• PEX-a - the pipe is expensive, but very flexible and durable, the crosslinking level is 85%;
• PEX-b - the material is cheaper, but the quality of cross-linking is lower - about 65%, respectively - the pipe is smaller in diameter and not so flexible;
• PEX-c - cheap polyethylene, bends poorly and is unstable on kink;
• PEX-d - this marking may occur, but this type of cross-linked polyethylene is rarely produced, and it is not suitable for a warm floor.

Are there any downsides?

Despite the fact that cross-linked polyethylene is a durable, reliable and easy-to-use material, you need to take into account some of its features so that the pipe lasts for a long time and does not cause you much trouble:

• Direct sunlight should not fall on the pipe - polyethylene is very sensitive to ultraviolet light. For underfloor heating, this, of course, is not particularly relevant, but if you want to make some more systems from this material in the house, the disadvantage should be borne in mind.
• When heated, polyethylene expands significantly more than metal plastic, which must be taken into account in the calculations.
• It should be noted that the layer that prevents diffusion is superimposed on the outer surface of the pipe, so it must be mounted carefully so that it is not accidentally removed and not damaged.

Important! Despite the fact that it is easy to bend polyethylene pipes, it is better to mount them under the guidance of an experienced craftsman.

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Stock footage

In a word, there is no clear answer to which pipes are better for a warm floor - from metal-plastic or cross-linked polyethylene. In apartments, metal-plastic is more often used, in public buildings - polyethylene. It all depends on the specific conditions and your financial capabilities.