Multilayer Pipe vs. HEPWORTH: Which is Better for Your Plumbing
Multi-layer pipe vs. HEPWORTH: which is better for your drinking water supply?
When it comes to choosing pipe for a home drinking water supply, two candidates appear most frequently in practice: multi-layer aluminum-plastic pipe (also known as multilayer or PEX-AL-PEX) and copper pipe, very well known in our country under the trade name HEPWORTH. Both solutions work reliably, both have decades of experience in European construction, but each is suitable for a different type of project, different budget and different level of plumber. If you think the answer is simple, you probably haven't seen enough projects yet. This article will help you make the right decision – with specific numbers, real scenarios from practice and without unnecessary simplification.
What it actually is – a brief technical description of both materials
Multi-layer pipe (PEX-AL-PEX / multilayer)
Multi-layer pipe is a composite product made of several layers. The outer and inner layers are made of cross-linked polyethylene (PEX-a or PEX-b), and between them is a welded aluminum foil. Aluminum performs several key functions at once: it prevents oxygen diffusion into the medium, keeps the pipe shape after bending (which is an advantage during installation, as you don't need an elbow at every corner), and significantly reduces linear thermal expansion compared to pure plastic.
You can find these diameters on the market: multi-layer pipe 16×2 mm is standard for supplies to individual outlets (sink, shower, WC), 18×2 mm is used where you need a slightly higher flow or shorter sections of main branches, and 20×2 mm is suitable for the main branch or a supply with multiple outlets. All these dimensions work at pressure class PN10, temperature up to +70 °C (at reduced pressure even +95 °C – more about this can be found in the article Pressure classes PN10 and temperatures +70 °C vs. +95 °C: what they mean for your supply).
Copper pipe HEPWORTH
Copper pipe is the oldest technical material used in sanitary supplies – and still one of the most reliable. HEPWORTH is a British manufacturer with a long tradition, whose copper pipes meet the EN 1057 standard (semi-hard copper R250). On the Slovak market, dimensions from 10 mm to 54 mm are commonly available, and for family houses, HEPWORTH pipe 15 mm (equivalent DN13, for individual outlets) and HEPWORTH pipe 22 mm (for main branches and connections to water heaters) are most frequently used. Copper is inert to drinking water, has natural antibacterial properties and does not corrode in typical Slovak water supply.
Dimensioning and available diameters: what can be used where
One of the first practical questions when designing a supply is: what diameter do I need? Here, both systems differ slightly in the logic of selection and available dimensions.
With multi-layer pipe, you start from the outer diameter and a wall of 2 mm. This means that 16×2 mm has a light (inner diameter) of 12 mm, 18×2 mm has a light of 14 mm and 20×2 mm has a light of 16 mm. For orientation: a standard cold or hot branch to a sink or shower in a family house was long solved exactly by 16×2. For a combined branch (WC + sink + shower) a better choice is 20×2. The main backbone branch, if it supplies multiple rooms, should be at least 25×2.5 mm – this is a dimension outside the above mentioned range, but it is part of a broader product family.
Copper pipe HEPWORTH is marked by the outer diameter according to EN 1057: 15 mm has a light of 13 mm, 22 mm has a light of 20 mm. For a family house, 15 mm is equivalent to multi-layer 16×2 (with slightly larger light), 22 mm corresponds more to 25 mm multi-layer. A more detailed calculation can be found in the article Dimensioning pipe for drinking water: how to calculate diameter and length.
An important practical note: with copper 15 mm, the flow resistance is lower than with PEX-AL-PEX 16×2, because the light is 1 mm larger. On short runs this does not make a measurable difference, but on longer runs (15+ meters to an outlet) it can mean better pressure in the shower.
Installation in practice: where is it easier and where more complicated
Multi-layer pipe – bends without elbows, but demands on fittings
Multilayer pipe is bent manually or using a spring bender. The bending radius depends on the diameter – for 16×2, the minimum bending radius is about 50–60 mm (approximately 5× the outer diameter). The pipe retains the bend by itself, without special support, which is a big advantage over copper: bending a supply line around a corner in a drywall partition without an elbow saves time and money.
Fittings are either pressed (press) or threaded (compression). Press fittings require a pressing plier, which is an investment, but the connection is fast, reliable and does not require an open flame. Compression fittings do not require special tools, but they must be tightened properly. If installed incorrectly (e.g., a missing ring, damaged sealing insert), they may leak after some time. More about the installation process can be found in the article Installation of multilayer pipe step by step: tools, procedure, mistakes.
Copper pipe HEPWORTH – soldering or pressing, higher level of expertise required
Copper is traditionally joined by soldering (soft or hard soldering). Soft soldering (up to 200 °C, using tin-silver solders) is common for potable water – it is simpler and faster. Hard soldering is used for higher pressures or temperatures. Both methods require a propane-butane torch, cleaning and fluxing agents, and some experience. A poorly soldered joint will show up immediately after a pressure test, but sometimes only after several months of operation – a gap in the joint, insufficient wetting of the solder, or an unclean surface. I have seen both scenarios in practice.
An alternative is pressing (press-fit) for copper as well – press fittings for copper are standardized, do not require a flame, and are suitable for places where you cannot safely use a torch (e.g., near thermal insulation, wood, or in a narrow shaft). HEPWORTH also produces its own fittings compatible with pressing. More about this can be found in the article Installation of HEPWORTH copper pipe: soldering or pressing.
Key difference from a DIY perspective: multilayer pipe with compression fittings can be handled by an experienced handyman. Copper soldering requires experience and tools – it is not a task for a first encounter with a torch. Pressing copper is technically more accessible, but the pliers are even more expensive than for PEX-AL-PEX.
Durability, lifespan and hygienic safety
This is a topic where customers often make mistakes in both directions. I’ll say it straight.
Copper has a declared lifespan of 50 or more years when installed correctly and with suitable water quality. It is inert to biological contamination – it has natural bacteriostatic properties (so-called oligodynamic effect of copper). In practice, this means that biofilm (i.e., a layer of bacteria on the inner wall, which is a problem for plastic pipes) forms much more difficult on copper. Copper is also immune to UV radiation and most chemicals used for water disinfection.
Where copper can fail: aggressive water with low pH (below 6.5), high CO₂ content, or a combination of soft water with high flow velocity can cause so-called erosive corrosion – visible as blue-green spots or holes in the wall after years of operation. This situation is local in Slovakia, but in mountainous areas with soft water, it is worth checking.
Multilayer pipe has a declared lifespan of 50 years from manufacturers when parameters (temperature, pressure) are followed. The inner PEX layer is approved for contact with potable water, and the aluminum is enclosed between PEX layers, so it does not get into the water. The inner surface of PEX is slightly rougher than copper or stainless steel, which theoretically facilitates biofilm deposition – in practice, with proper system design (flushing, disinfection according to STN EN 806), it is not a clinically relevant problem for a typical family home.
Important: the inner PEX layer is not a barrier to oxygen diffusion – this is why the aluminum middle layer is so important, especially if the potable water supply is directly adjacent to or connected with a heating system without a separating heat exchanger. More about this topic can be found in the article Hygiene and material safety of pipe for potable water: what you need to know.
Thermal expansion: in practice, it speaks in favor of each differently
Copper expands by 0.017 mm/m/°C with an increase in temperature. On a 10-meter section with a temperature difference of 50 °C (e.g., hot water at 60 °C vs. installation temperature at 10 °C), this is a length change of 8.5 mm – minimal, rarely problematic without compensation.
Multilayer pipe has its expansion suppressed to about 0.026 mm/m/°C due to the aluminum layer – that is about 1.5 times more than copper, but dramatically less than pure PEX (0.14 mm/m/°C) or PP (0.18 mm/m/°C). On a 10-meter section with ΔT = 50 °C, this is 13 mm. Still manageable without special compensators in a typical home installation, but for long straight sections in the floor or in a shaft, it is good to leave a slight free run (a slight wavy path of the route).
In this respect, copper comes out slightly better for long straight sections, while multilayer pipe is significantly better than pure plastic.
Price: what you actually pay for and what you get
The price of the material is not the whole truth. You need to consider a trio: price of pipe + price of connecting material + price of labor.
Multilayer pipe is more cost-effective per meter – especially in 100 or 200 meter rolls (which is a common delivery form, such as the mentioned 200 m rolls for 16×2 and 18×2, or 100 m for 20×2). Compression fittings are cheaper than soldered fittings, but press fittings for PEX-AL-PEX are comparable in price or more expensive than soldered copper fittings in larger quantities.
Copper pipe is more expensive per meter – copper is a commodity and its price fluctuates, but on average you pay 2 to 3 times the price of multilayer pipe per meter. Soldering as a technique is cheap in material (solder, flux, flame), but requires skill and time. Pressing copper is more expensive in material (press-fit fittings are premium), but faster to install – for an experienced plumber.
Total calculation for a typical family house (distribution for 2 bathrooms + kitchen, approx. 80 m of pipe including hot and cold water): the material cost difference is 300–600 EUR in favor of the multilayer solution. With professional installation, the time required is equal – a plumber with crimping tools for PEX-AL-PEX works quickly, and a plumber used to copper brazes just as fast. However, hot water from brazing requires drying/cooling before pressure testing.
Where multilayer pipe clearly leads
- Renovations without demolition – multilayer pipe can easily be pulled through existing protective sleeves, bent around corners in a concealed shaft, and without elbows.
- Underfloor distribution – bending PEX-AL-PEX in concrete is simple, brazed joints in a mezzanine are risky and with copper we try to avoid them.
- DIY installation projects – compression fittings do not require special tools or a flame.
- Cost in larger projects – in apartment buildings or developments, the difference in material costs is significant.
- Hybrid systems – if you want one type of fitting for both heating and potable water, multilayer pipe covers both (with appropriate sizing).
Where copper pipe HEPWORTH clearly leads
- Replacing an old copper installation – you preserve the compatibility of fittings, the type of connection, without transition adapters.
- Exposed areas without a wall – copper looks good even when exposed (in a basement, technical room), and does not require cover strips.
- High temperatures and pressure resistance – copper EN 1057 R250 (semi-hard) can handle higher operating temperatures over the long term without material degradation.
- Resistance to mechanical damage – copper is harder, does not deform when screwed, and does not crack from accidental impact.
- Hygienic strictness (e.g., food, medicine) – for facilities with strict hygiene requirements for drinking water, copper is traditionally the preferred material.
- Long service life with more aggressive water – paradoxically, with mild water aggressiveness (acidic pH), copper may be more suitable if the flow velocity is properly dimensioned.
Combination of both materials – it is not a taboo
In practice, I often encounter customers who perceive the choice as either/or. In reality, the combination is not technically problematic, provided that the correct transition fittings are used. A typical scenario: the main backbone from the connection to the water heater is copper (22 mm or 28 mm), because it is long, accessible, and the plumber has always worked with copper here. The distribution to individual rooms, where it runs into concealed walls, is multilayer – it is easier to bend, faster to install, and it does not matter if it is hit by a demolition hammer.
A transition fitting from copper to PEX-AL-PEX (or vice versa) is a standard product, available in every type of connection (compression, press, brazed). The only condition is that both parts of the distribution system are mutually compatible in terms of pressure and temperature – which is easily satisfied with PN10 and normal drinking water temperatures.
Real scenarios from practice
Scenario 1: New family house construction – the developer and investor are looking for a compromise between cost and quality. Most of the distribution is in the floor or in drywall concealed walls. Clear choice: multilayer pipe for the entire distribution. Fast installation, no flame required, trouble-free passage through SDK profiles, cheaper material. The plumber uses press pliers and that’s it.
Scenario 2: Renovation of an old panel apartment block from the 80s – the original installation is copper, but clogged and worn out. New copper is a logical choice: the plumber knows the system, fittings easily connect to existing distribution, the visual result looks professional. HEPWORTH 15 mm for room distribution, 22 mm for the apartment entrance.
Scenario 3: Recreational house with occasional use – the pipe will be drained (emptied before winter) several times a year. Multilayer pipe handles repeated temperature cycles well, is more flexible when frozen (not immune, but less prone to cracking than rigid copper). PEX-AL-PEX may be more advantageous here.
Scenario 4: Technical room with heat exchanger, water heater, and filtration – the distribution is visible, many fittings and valves, and the customer wants aesthetics. Copper HEPWORTH shines here: exposed installation looks professional, clean, and can withstand mechanical load during equipment maintenance.
Standards, certificates, and approvals for potable water
Both materials must meet the requirements for contact with drinking water. In Slovakia, STN EN 1057 is applied for copper pipes, STN EN ISO 21003 (or EN ISO 15874 for PP, EN ISO 15875 for PEX) for plastic and composite systems. Manufacturers of both product ranges – IVAR TURATEC (multilayer) as well as HEPWORTH (copper) – provide the relevant certifications and declarations of conformity. Always verify that the specific series/batch has a valid certificate for drinking water in your country – not every type of PEX or every batch of copper automatically meets the strictest hygiene standards.
Watch out for one detail: some pressed fittings for multilayer pipes (especially made of brass) may contain a higher percentage of lead. Today, most serious manufacturers offer fittings made of "low-lead" brass (DZR, CW602N and similar) or stainless steel – verify this when purchasing, especially if it concerns the distribution of drinking (cold) water.
Most frequently asked questions (FAQ)
Can I use multilayer pipe for hot domestic water (temperature 60–70 °C)?
Yes, you can. Multilayer pipe in class PN10, T=+70 °C is directly intended for hot domestic water distribution. With a boiler with a thermostat set to 60 °C (which is a hygiene standard for legionella prevention), the values are with sufficient reserve. If you have heating at 75–80 °C (e.g., direct heating in a tank without a mixing group), choose version PN10, T=+95 °C or pipe directly dimensioned for higher temperatures. More on this topic can be found in the article Pressure classes PN10 and temperatures +70 °C vs. +95 °C: what they mean for your distribution.
What is more convenient for DIY installation – copper or multilayer pipe?
Undoubtedly multilayer pipe with a compression connection system. It does not require a torch or licensed equipment, can be bent manually, and any mistake (e.g., an underscrewed nut) is immediately detected during a pressure test. Soldering copper requires experience – a poorly soldered joint may look fine from the outside and start leaking only after months of operation under heat.
Can I connect an existing copper distribution with a new multilayer pipe?
Yes, this is a common procedure during renovations. There are standard transition fittings (compression or press-fit) on the market with one side for copper (soldering or compression) and the other for PEX-AL-PEX. The only condition is correct dimensioning of the diameters on both sides to avoid significant narrowing of the bore.
How long will the HEPWORTH copper pipe and multilayer pipe last?
Copper EN 1057 has a real lifespan of 50–80 years with correct installation and suitable water quality – old copper distributions from the 1950s and 1960s in many apartment buildings are still functioning. Multilayer pipe has a manufacturer-declared lifespan of 50 years when operating parameters (temperature, pressure, UV protection) are followed. In practice, it is not yet comparable on the same basis – copper has centuries of history, while PEX-AL-PEX is a product of the last 30–40 years. However, both materials are long-term solutions for a typical family home when installed correctly.
Is multilayer pipe safe for drinking water – can it affect the taste or quality of the water?
Certified multilayer pipe (PEX-AL-PEX) approved for drinking water does not change the taste, smell, or chemical composition of the water when used correctly. After the initial filling of the system, it is recommended to flush the distribution before the first water withdrawal for drinking – the same procedure applies to any new distribution (copper, PP, PEX). Further information can be found in the article Hygiene and material safety of pipe for drinking water: what you need to know.
Which material is better if I have higher chlorine or more aggressive water composition?
It depends on the specific water parameters. Copper is sensitive to low pH (below 6.5) and high free CO₂ content. Multilayer PEX-AL-PEX is generally more resistant to aggressive water – PEX does not chemically react with common disinfectants including chlorine. If you have doubts, have your water tested and consult the material choice with a designer or plumber. Help with diagnosing problems can also be found in the article Common failures and leaks in drinking water pipes: causes and solutions.
Conclusion: it is not that one is better – it is that one is more suitable for your case
After years of practice and dozens of projects, I can say the following: the question "multilayer vs. copper" is poorly phrased if you do not have a specific situation in mind. Both materials are technically excellent for drinking water distribution in family homes and apartments – each has its own strengths.
If you are building a new house, doing a renovation with drywall and false walls, or want to save on materials without compromising quality, multilayer pipe 16×2 for distribution to outlets and 20×2 for main branches will be an excellent choice. Fast installation, flexible routing, without an open flame.
If you are renovating an old copper distribution, want an exposed installation, prefer a material proven over centuries, or work in an environment with higher hygiene requirements, HEPWORTH 15 mm for distribution within rooms and 22 mm for main branches is a safe choice with a long history of reliability.
And if you are still undecided – start from the right end: find out who will install the distribution for you. An experienced plumber with copper will work faster and more reliably with copper, while a plumber accustomed to PEX-AL-PEX will be more efficient with a multilayer system. The material is only half the story – the other half is the craft that installs it. More on choosing the overall concept can be found in the article How to choose pipe for drinking water distribution: multilayer vs. copper vs. plastic.
Do you have a question on this topic?
Can't decide or are dealing with a specific situation in your household? Write to us – we are happy to advise.