Which pipe to use for a warm floor – copper, polyethylene or metal -plastic

Selecting the appropriate pipes for a warm floor system is essential to guaranteeing its effectiveness and durability. Knowing the advantages and distinctions between the different options—copper, polyethylene, and metal-plastic—is crucial. During the colder months, these pipes are essential to the circulation of heated water beneath your floors, which keeps your house comfortably warm.

For radiant floor heating systems, copper pipes have long been a popular option because of their exceptional thermal conductivity and longevity. Their effective transfer of heat from the water to the floor guarantees uniform warmth distribution. Copper pipes are a dependable choice for long-term use because they also resist corrosion. Even though copper pipes might cost more up front than other materials, over time they frequently save money due to their durability.

Since they are inexpensive, flexible, and simple to install, polyethylene (PEX) pipes have become more and more popular. PEX pipes require fewer fittings and joints because their flexible plastic construction makes it simple to move them around obstructions. PEX pipes are a dependable option for warm floor systems because of their seamless design, which reduces the possibility of leaks. PEX pipes also have resistance to scale accumulation and corrosion, which prolongs their lifespan.

Composite pipes made of metal and plastic combine the durability of plastic with the strength of metal. Usually composed of layers of plastic surrounding an inner layer of aluminum, these pipes offer flexibility and durability. The excellent heat transfer properties of metal-plastic pipes ensure effective floor warming. They can tolerate high temperatures and are resistant to corrosion, which qualifies them for usage in warm floor systems.

The kind of pipe you choose for your warm floor system will depend on a number of factors, including installation requirements, desired longevity, and budget. Prior to choosing a pipe, carefully consider your options as each type has specific advantages and considerations of its own. In the end, selecting premium pipes that work with your heating system will guarantee years of optimal comfort and performance.

Copper	Good heat conductivity, durable, but expensive.
Polyethylene	Flexible, easy to install, cost-effective, but may not distribute heat as efficiently.
Metal-plastic	Combines durability of metal with flexibility of plastic, moderate cost, good heat distribution.

Criteria for evaluating pipe materials

You must accurately depict the material’s operating conditions in order to select the appropriate pipes for a heated floor. The heating line experiences mechanical loads from water pressure and its own expansion in addition to transferring heat to the monolith because it is inside the screed.

As a result, the following rigorous standards are applied to the material:

1. Warm floors (abbreviated – TP) – low -temperature heating system, where water is heated up to a maximum of 55 degrees, the working mode is approximately 40 /30 ° C. For rapid energy transmission from the coolant of the concrete plate, pipe walls must have sufficient thermal conductivity.
2. The length of the loops of TP often reaches 100-120 meters (depending on the selected diameter of the pipeline). Large length = high hydraulic resistance aggravated by roughness of the inner surface. In simple language: the more iron the walls of the pipes, the easier it is to pump water along the long circuit and provide the required heat carrier consumption.
3. Heating causes lengthening pipes of a warm floor. Since there is nowhere to increase inside the concrete screed, one of the two conditions should be fulfilled: a small coefficient of thermal expansion of the material or high elasticity and shell strength, which allows the pipe to place in a limited space without destruction.
4. Emergency situation: Due to the breakdown of the regulatory reinforcement at the mixer"s mixing node, the heating contours are filled with boiler water heated to 70 … 90 ° C. The material of the frozen pipes should withstand such temperature surges without consequences.
5. Other important points are corrosion resistance, oxygen penetration, ease of installation and lack of joints inside the monolith.

Less strict guidelines apply to water circuits installed in wooden houses in the "dry" manner. There is plenty of room for thermal lengthening because the TP are mounted without a screed. The list’s third clause is no longer relevant.

The price of the pipelines, fittings, distribution crests, and other parts of TP is by no means the final factor. Thus, contrast the materials used based on the cost and the aforementioned parameters.

Choosing the right pipe for your underfloor heating system is crucial for efficient heating and long-term performance. Copper, polyethylene, and metal-plastic pipes are commonly used options, each with its own advantages and considerations. Copper pipes offer excellent heat conductivity and durability, but they can be costly and may corrode over time. Polyethylene pipes are flexible, cost-effective, and resistant to corrosion, making them a popular choice for many installations. Metal-plastic pipes combine the strength of metal with the flexibility of plastic, offering good durability and ease of installation. When selecting a pipe type, consider factors such as budget, installation requirements, and the specific needs of your heating system. Consulting with a professional can help you make the best choice for your home"s heating and insulation needs.

Characteristics of polymer pipes

The coolant in water heating systems of apartments and private homes is transported using the following kinds of plastic pipelines:

1. PP-R and PP-RCT-polypropylene with a random polymer reinforced with a layer of aluminum, basalt or fiberglass. Modification of PP-RCT plastic is characterized by increased thermal resistance.
2. PE-X-polyethylene stitched brands A, b and C. The products must have an oxygen -protective barrier – a thin layer of an impermeable polymer. For example, Rehau pipes use a complex connection of ethylenevinyl glycol (EvoH).
3. PE-RT-polyethylene thermostabilized products with oxygen barrier.
4. PE-X / Al / PEX and PE-X / Al / PE-five-layer metal-plastic pipelines.

Citation. Products made of polyvinyl chloride PVC-C, polyvinyl chloride of blockolimopolymer, and homopolymer (RP-V, RR-N) are also appropriate for the installation of heating networks, as per GOST 32415-2013. Because of the poorest technical specifications, these materials were not widely used in the construction of private homes.

A brief overview of the techniques used to join pipe polymers during home heating assembly:

• PP-R wiring is joined by polypropylene fittings using soldering (thermal polyfusion welding);
• stitched and thermostabilized polyethylene (PE-RT) is mounted by the axial method in the 3rd stage-the end of the end, tension on the fitting fitting, and the production of a perch sleeve;
• metal -plastic is connected in 2 ways – compression or press.

We will now briefly describe each type of pipeline, go over the list of specifications, and determine whether or not it is appropriate for water heating living room floors.

Polypropylene – material for radiator heating

We quickly observe that a warm floor cannot be created from polypropylene pipes, despite the cost-effectiveness and dedication of many masters to the use of PP-R. It is sufficient to closely examine the technical specifications of the material and read the testimonials of homeowners who wished to save money in this manner; you shouldn’t verify the statement in real life.

Examining the diagram, we can see how the polypropylene pipelines are organized:

• The inner layer of the pp-r forming the passage section of the highway;
• aluminum reinforcing foil, restraining thermal lengthening and preventing oxygen penetration;
• 2 adhesive layers fastening aluminum with polymer;
• The outer protective layer PP-R is white or gray (for some manufacturers-green).

Important addition. These days, producers of polypropylene place a layer of glass fiber or basalt inside the pipe rather than using perforated foil.

We will determine how the pp-r pipes adhere to the specifications for the floor heating branches:

1. Thermal conductivity 0.24 W/(m • ° C) – the worst among polymer products. If you take into account the thickness of the wall 3.4 mm at Ø20 mm (reinforced pp-r pipelines are not produced with a diameter of 16 mm), we obtain the heat transfer resistance R = 0.0034 /0.24 = 0.014 m² • ° C/WT. For active heat transfer, the resistance indicator is too high.
2. By the smoothness of the internal walls to polypropylene, there are no questions – roughness 0.01 mm does not create increased hydraulic resistance.
3. When heated by 50 degrees, the 100-meter pipe of the pp-r with an aluminum layer will add in a length of 150 mm, with a fiberglass-31 cm. The elasticity of polypropylene is very low, due to which the product inside the monolith will be under a high load. The material may crack, first of all, at the joints.
4. Pressure and temperature resistance is not in doubt. When the coolant is heated to 70 ° C Pp-R, the highway will calmly withstand the working pressure up to 13 bar. If you raise the temperature to 95 ° C, the pressure threshold will decrease to 9 bar.
5. Polymer has resistance to any chemical effects and practically does not pass oxygen into the coolant. The main problem is a large number of joints falling under the screed, because bending the polypropylene area is unrealistic.

Note: The technical specifications of PP-R products are based on the brand documentation of VALTEC, which is available on the company’s official website. For a fair comparison, we also included the costs and specs of other tube polymers from this manufacturer.

We’ll go over a few things. An average user cannot infer any meaning from the walls’ heat resistance value of r = 0.014 m² • °C/W without comparing it to the indicators of other plastics. The descriptions of polyethylene and metal-plastic pipes below include these computations.

One issue with heating polypropylene systems is that the joints’ quality of welding cannot be visually verified. Joints can occasionally flow a year after high pressure testing (crimping). Consider the aftermath of a leak inside a concrete monolith: finding a flaw, destroying the screed, and then fixing it.

A different query: there will be a lot of compounds in concrete, and installation will take a long time. The image above displays samples of heating contours that were gathered from pp-r by local artisans. The inexpensive cost of Ð20 – 51… 83 rubles (0.8… 1.25 e.) per linear meter – does not justify the use of these pipes in heated floors.

Parameters of stitched and heat -resistant polyethylene

There are two types: 3-layer and 5-layer PE-X PE-X plastic. The antidiffusion barrier is located differently in the two scenarios; in the first, the imperfect polymer EvoH acts as the pipe’s outer shell, while in the second, it is laid inside the wall and adhered to polyethylene on both sides. The exterior is red, silver, and brown.

Customers frequently inquire about the differences between PE-X and PE-RT polyethylene pipes and which is better for heating the floor. We respond:

• The molecular grate of plastic PE-X is sewn in 3 ways, hence three types of polyethylene-A, B and C;
• From the point of view of installation and operation of heating, pipe from PE-X / A do not differ from PE-X types B and C;
• The material of high thermal resistance of PE-RT is made of conventional polyethylene using cheaper technology-the complex polymer molecule is modified using branches;
• PE-RT loses PE-X in durability, strength and thermal stability;
• “Peak” is significantly more expensive than PE-RT, by about 20-40%;
• Perty pipe walls are deprived of the antidiffusion barrier, so the coolant is overtaken by oxygen at a speed of at least 0.1 g/m³ • day. (on open air);
• PE-RT material is thermoplastic, the pipeline can be melted many times and welded without loss of properties.

Citation. The stitched polyethylene Valtec 16 x 2 mm pipe costs 51 rubles per meter, or roughly 0.8 u. e. The price of a thermostable plastic PE-RT product with a comparable diameter is 33 rubles per meter (0.5 e.).

Now let’s discuss our list of prerequisites:

1. The pipe for the warm water floor "PEX" and "Perth" has the same thermal conductivity – 0.38 W/(m • ° C). We calculate the thermal resistance of the walls 2 mm thick: r = 0.002 /0.38 ≈ 0.005 m² • ° C/W – almost 3 times lower than that of PPR. That is, polyethylene contours are much better transmitted by heat screed.
2. Equivalent surface roughness – 0.007 mm is an excellent pipe smoothness indicator.
3. Heated by 50 ° C, the 100-meter free section of the PEX pipeline will lengthen by as much as 100 cm. But thanks to elasticity and some installation techniques, the expansion inside the concrete slab is calmly compensated by the material.
4. The maximum operating temperature of the PE-X material is 90 ° C, PE-RT-80 degrees, short-term permissible-95 and 90 ° C, respectively. The operational pressure of the coolant is 6 … 10 bar, depending on the degree of heating. The parameters satisfy the requirements for water heating contours.

The oxygen permeability of polyethylene systems is a weakness. With the barrier in place, "PEX" misses much more than 0.1 g/m³ per day in Perth. However, oxygen penetration is minimized and air access is severely restricted because the pipes are frozen with cement-sand mortar.

Polyethylene possesses two unique properties: its molecular memory compels the pipeline to revert to the bay’s initial shape. One feature makes attaching heating loops to the floor’s thermal insulation more difficult: the ends of the pipe will lift upward if it isn’t cranked up around its own axis. Watch our expert’s video to learn how to handle the phenomenon that has been described.

The ability to repair after a break is one of molecular memory’s benefits. To restore the original shape of the plastic without sacrificing its elasticity and strength, simply straighten the damaged area and apply heat using a construction hairdryer.

We analyze the properties of metal -plastic

This five-layer pipe is actually a counterpart to the PEX material, in which an anti-acid polymer called EVOH functions as an anti-liability polymer of aluminum, ranging in diameter from 0.25 to 0.4 mm. Inside is a shell made of the same plastic, and outside is a self-awaited tube of stitched polyethylene. Special glue is used to secure the structure’s layers together.

Citation. Metal polymer pipes fit into the PEX-L-PEX structural pattern. Fascinating fact: the Rautitan Stabi pipelines are available worldwide under the Rehau brand, with an external shell made of regular polyethylene that isn’t sewn.

Let’s examine the metal-plastic using the initial set of criteria:

1. Thermal conductivity of a five -layer structure – 0.45 W/(m • ° C), the thickness of the walls of pipes with a diameter of 16 and 20 mm – 2 mm. So, the resistance of the transmission of heat r is 0.002 /0.45 = 0.004 m² • ° C/WT.
2. Lengthening from heating a 100-meter segment by 50 ° C-only 13 cm.
3. The operating temperature when pressure is 10 bar – up to 95 degrees, short -term emergency – 130 ° C. The oxygen permeability of the walls is close to zero.
4. The price of the pipe Valtec Ø16 x 2 – 60 rubles. (0.9 u. e.), Ø20 x 2 – 97 rubles. (1.45 u. e.) in a meter linear.

Note that among all polymer pipes, the best indicators are those of thermal conductivity, operating temperature, and relative lengthening of metal-plastic structures. Since the material’s roughness value of 0.007 mm is the same as that of polyethylene, the smoothness of the material is not mentioned.

One significant distinction between metalloplasty is that molecular memory is not present. The brittle aluminum frame bends to the desired shape, overriding the plastic layers’ elasticity. The main benefit of having the specified property during installation is that it can withstand a minimum bending radius of 6 cm for pipes with an Ø of 16 mm and 8 cm for pipes with an Ø of 20 mm.

Metal pipes for heating floors

Modern rural homes’ heat supply networks use copper, stainless steel, and steel pipes. Two types of metal pipelines are utilized in the installation of floor water systems:

• Copper is annealed with an outer diameter of 15, 18 and 22 mm with a wall thickness of 1 mm (sold in bays of 25 m);
• HOFRA stainless annealed ½ and ¾ inch (Ø15 … 20 mm), meter of the bay – from 10 to 50 m.

Historical allusion. Kindergartens were designed with warm floors in compliance with USSR construction standards during that era. Black steel gas and water pipes were used to weld into the shapes of heating systems.

We shall assess the metal pipe’s parameters based on the following standards:

1. The coefficient of thermal conductivity of copper and steel is so large (389 and 45 W/m • ° C, respectively), what to make the calculations is pointless – according to this characteristic, the metal will plug in the belt of any plastic.
2. Equivalent roughness of new products – 0.01 mm. During operation, the smoothness of the walls worsens, the hydraulic resistance gradually increases.
3. Linear expansion of metals is slightly compared to polymers – 55 … 85 mm per 100 meters of the thermal line at a temperature delta of 50 ° C. The materials are quite elastic to lengthen inside the concrete and not break the screed.
4. Copper Ø18 x 1.0 mm calmly keeps working pressure up to 67 bar at a maximum temperature of 200 ° C. The parameters of the corrugated stainless steel – 15 bar and 150 degrees, respectively. The declared indicators cover the requirements for TP with a large margin.
5. Steel and copper absolutely does not pass oxygen, but are subject to slow exposure to corrosion. Weak places – sections crossing lines of home wiring.

A flexible stainless steel pipe’s issue is its wavy corrugated structure, which significantly increases fluid flow resistance hydraulically. At least 20 peaks higher than one millimeter at a length of one centimeter. Second moment: tiny sand will start to accumulate in the hollows and move through the system with the coolant.

Details regarding the cost of the materials. A meter of copper pipeline with dimensions of Ø18 x 1.0 costs approximately 500 rubles (7.5 e.), while a meter of stainless steel with dimensions of Ø20 mm (internal – 15 mm) costs 155 rubles (2.3 e.).

Even though copper works incredibly well, TP is rarely installed using it. Reasons:

• the material is several times more expensive than polymers;
• The difficulty of laying the pipe – for the neatly bending and the formation of the hinges of the warm floor, experience is required;
• The pipeline is afraid of fractures that can only be fixed with professional soldering.

Concerning the corrugation: Mistrust is a problem in addition to hydraulic issues. The material did not function well in floor systems for ten to twenty years after it was introduced to the market. That is to say, it is unknown how durable stainless steel actually is.

Choosing the best option for TP

After closely examining the analysis of each type of pipeline, we can make a tentative conclusion: copper is superior to polymers in terms of price, but it loses out in terms of all operational indicators. Since stainless steel corrugation costs twice as much and performs worse in hydraulics than polyethylene, it will not replace polyethylene either.

First, which pipe should be used for a warm floor?

1. Number 1 of our rating is a PEX-PEX metal-plastic proven by many years of practice. The material is relatively inexpensive, convenient when installing it with your own hands, durable, transfers heat well and is not much lengthened from heating.
2. Sewed PE-X polyethylene-pipes for professionals who know how to make the contours of TP qualitatively. “Peak” is easily restored after the break, but it conducts heat worse and expands greatly from the temperature increase.
3. Heat-resistant polyethylene PE-RT-a budget option for professional installation. The main disadvantages are oxygen permeability and a significant reduction in service life in case of overheating.
4. The fourth place of the copper pipe is due to a high price inaccessible to most ordinary householders. If this factor does not take into account, copper will be the perfect option for floor heating.
5. Stainless corrugation is good for short areas, for example, connecting carts and hoses. Laying wavy pipes under the screed is not a very good decision.
6. We do not use polypropylene at all.

Remark: Since the intra-floor contours are mounted without compounds, the cost of fittings was not considered when comparing different pipeline systems.

Advice on how to properly style and concrete PE-X and PE-RT pipelines. Try not to use more than 100 meters of pipe in a single circuit, preferably 80 meters, to prevent the heating threads from getting longer. Fill the system with water and pump the test pressure (it should be 1.5 times higher than the worker’s pressure) before adding the solution. A different article goes into detail about the technology used in TP installation.

Provide multiple justifications for selecting metal-plastic or polyethylene flooring materials. First, Europe has long been a successful user of polymers. Second, both the primary substance’s properties and chemical makeup are constantly improved. Thirdly, the average lifespan of polymer pipes is fifty years, making them incredibly robust.

The longevity and effectiveness of your warm floor system depend on the pipe you choose. Metal-plastic, polyethylene, and copper pipes are the three primary types that are offered on the market. Every variety has benefits and drawbacks of its own.

Copper pipes are renowned for their exceptional heat conductivity and robustness. They are a common option for heated floor systems since they can tolerate high temperatures and are corrosion-resistant. However, because of their rigidity, copper pipes can be costly and may need to be installed by a professional.

Polyethylene pipes are reasonably simple to install and provide flexibility. They also have good thermal conductivity and are resistant to corrosion. Nevertheless, if placed outside, polyethylene pipes may be more vulnerable to UV deterioration and may not be as strong as copper pipes.

Plastic flexibility and metal strength are combined in metal-plastic pipes. Compared to copper pipes, they are less expensive, easier to install, and resistant to corrosion. Additionally, metal-plastic pipes have good heat conductivity. In the long run, though, they might not be as resilient as copper pipes.

To sum up, the selection of pipe for your heated flooring system is contingent upon several factors, including financial constraints, installation inclinations, and long-term robustness. Polyethylene pipes provide flexibility and ease of installation, while copper pipes are the best choice for people who value heat conductivity and durability. Metal-plastic pipes offer a cost-effective and robust combination. You can choose the ideal home heating system for your needs by speaking with an expert and taking into account your unique situation.

Video on the topic

Which pipe can be safely used under a water warm floor

Choosing pipes for a warm floor. Metal -plastic, stitched polyethylene .