PPR vs. copper vs. PEX – comparison of materials for water supply pipes

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PPR vs. copper vs. PEX – comprehensive comparison of materials for water supply systems

When it is time for a bathroom renovation, new construction, or replacement of old steel piping, one of the first questions every plumber and DIY enthusiast addresses is: what material should be used for the water supply? Today, there are three dominant materials available – polypropylene (PPR), copper, and cross-linked polyethylene (PEX). Each has its strengths, each is suitable for a different environment, and each also has its weaknesses, which are often omitted in catalogs.

In this guide, I will thoroughly examine all three materials – technical parameters, installation, lifespan, cost, hygiene properties, and real-life experiences from practice. Not generic phrases, but specific values and situations that make the difference on a construction site.

PPR – polypropylene: the workhorse of modern piping systems

PPR (polypropylene random copolymer, type 3) is today probably the most widely used material for cold and hot water supply systems in apartment buildings, single-family homes, and commercial constructions. Its rise to the market in the 90s was rapid, and the reasons are clear.

Technical parameters of PPR

Basic types of PPR pipes are differentiated according to pressure load class – PN10, PN16, PN20, and PN25. The number indicates the maximum working pressure in bars at a temperature of 20 °C. For hot water supply systems (up to 70 °C), PN20 is most commonly used in practice, with PN25 used for systems with higher pressure or for circulation.

Thermal resistance: up to 95 °C in the short term, up to 70 °C in the long term (for PN20). A PN25 pipe can withstand 8.1 bar at 70 °C for a lifetime of 50 years.
Diameters: standard range from DN 16 to DN 110, with DN 20, DN 25, and DN 32 most commonly used for residential water supply.
Coefficient of thermal expansion: 0.15 mm/(m·K) – this is about 7–8 times higher than copper. For 10 m of pipe and a temperature difference of 50 °C, this means a length change of about 75 mm, which must be considered in design using expansion loops.
Thermal conductivity: 0.24 W/(m·K) – compared to copper (380 W/(m·K)), PPR is almost an insulator, which is an advantage in terms of heat loss and safety when touching hot pipes.
Weight: density 0.9 g/cm³, a DN 25 PN20 pipe weighs only about 0.35 kg/m – copper of the same size weighs about 1.2 kg/m.
pH range: resistance to media with pH 1–13, which means resistance to most common disinfectants and cleaning agents.

In terms of lifespan, manufacturers state 50 years when the design parameters are followed. Real-life experience is positive – in systems installed in the 90s, we do not find typical degradation phenomena, provided the pipes were not exposed to UV radiation or exceeded temperature limits.

PPR installation – polyfusion welding

The main advantage of PPR compared to copper is the method of joining. A polyfusion welder heats the outer surface of the pipe and the inner surface of the fitting to 260 °C, after which the two parts are pushed into each other, and the material is molecularly fused – a monolithic joint is created, which is stronger than the pipe itself. There is no soldering paste, no open oxidation, no flux residue.

Experience shows that a properly welded PPR joint never leaks – if it does leak, it is a mistake in installation (wrong temperature, surface contamination, incorrect insertion depth). You will read about common mistakes and how to fix them in a separate article Sealing of PPR joints – most common installation errors and how to fix them.

For pipe preparation before welding, it is essential to measure and cut the pipe accurately and perpendicularly. For this, special shears up to 63 mm STANDARD are used – single-blade shears with a revolver head that provide a clean cut even in a PN25 wall without deforming the cross-section. A good cut is the basis for a tight joint – a skewed or uneven cut will cause uneven welding depth and future problems. More about the correct use of this tool can be found in the article How to properly use shears for PPR pipes and a polyfusion welder.

Advantages and disadvantages of PPR in practice

Advantages:

Lowest material and installation costs among the three compared options
Monolithic welded joints – zero corrosion at the connection point
Smooth inner surface reduces friction and prevents scaling
Complete resistance to electrolytic corrosion and aggressive water with low pH
Biologically neutral – Legionella bacteria do not multiply in it as easily as in soldered or rubber connections
Quiet operation – absorbs hydraulic shocks better than rigid materials

Disadvantages:

High thermal expansion requires proper dimensioning of expansion joints
UV sensitivity – external piping must be covered or UV-stabilized variant used
Requires more fittings for branched systems compared to PEX (which can be bent)
Thicker wall reduces light diameter for the same outer diameter
Requires special tools (welder, pipe cutters) – initial investment for DIY installation

Copper – a traditional standard with proven properties

Copper pipe has long been synonymous with quality plumbing work. In countries like Austria, Germany, or Switzerland, copper is still the dominant material, although its position in Central and Eastern Europe has declined in favor of PPR and PEX. Copper still maintains a justified position in certain applications.

Technical parameters of copper

Thermal resistance: copper operates reliably up to 200 °C – a significant reserve for water supply, real hot water distribution runs at 55–70 °C
Working pressure: for standard copper pipe dimensions (Cu 15×1, Cu 18×1, Cu 22×1), working pressures at 110 °C range from 40–60 bar – again, a multiple reserve for domestic distribution
Thermal expansion: 0,017 mm/(m·K) – about 9× lower than PPR, expansion issues are minimal for standard lengths
Thermal conductivity: 380 W/(m·K) – excellent, an advantage for solar collectors and floor heating, but a disadvantage for cold water heat losses
Antimicrobial properties: copper actively kills bacteria including Legionella – even at low concentrations of Cu²⁺ ions. This is a proven and normatively recognized property.
Lifespan: 50–100 years with proper water quality (pH 7–8,5, hardness >1°dH)

Soldering vs. pressing copper

Copper piping is traditionally joined using hard soldering (silver solder at high temperatures) or soft soldering (tin-silver, lead-free in accordance with EU regulations). An alternative is pressing using special pressing fittings (e.g. Viega Profipress, Geberit Mapress system), where the fitting is deformed onto the pipe using a pressing plier.

Soldering requires experience, an open flame, and precise adherence to the procedure – soft solder at 183–230 °C must evenly flow around the entire joint by capillary action. An error such as insufficient heating or a dirty surface leads to a joint that looks correct but leaks. That is why many plumbers today prefer pressing – faster, safer, and more controllable.

Advantages and disadvantages of copper

Advantages:

Highest thermal and pressure resistance among all three materials
Minimal thermal expansion – simple routing without compensation
Active antimicrobial properties
Rigid construction – ideal for exposed piping, roof and technical rooms
Environmentally recyclable (100% without loss of properties)
Compatibility with existing copper piping during renovations

Disadvantages:

Highest material cost (copper prices have doubled in recent years)
Corrosion with aggressive water (soft, acidic water pH <7, possibly chloride corrosion at pH >8,5 with higher Cl⁻ content)
Galvanic corrosion when improperly connected to steel (without a dielectric transition piece)
Higher demands on craftsmanship for soldering
Higher weight – relevant for large buildings
Condensation on cold piping without insulation

PEX – flexible polyethylene for modern systems

PEX (cross-linked polyethylene) came to the market later than PPR, but in some applications – especially floor heating and MLCP (multi-layer pipe) systems – it dominates today. There are three cross-linking production methods: PEX-a (peroxide), PEX-b (silane), and PEX-c (electron irradiation), each type having slightly different mechanical properties.

Technical parameters of PEX

Thermal resistance: short-term 95 °C, long-term 60–70 °C (depends on class and manufacturer)
Working pressure: up to 10–16 bar at 60 °C, depending on dimension and class
Flexibility: bending radius 5–8× outer diameter – in practice, a DN 20 pipe can be bent to a radius of about 100–160 mm without kinking or deformation
Thermal expansion: 0,2 mm/(m·K) for pure PEX, only 0,025–0,03 mm/(m·K) for MLCP (with an aluminum middle layer) – almost like copper
Shape memory (PEX-a): after cold bending, the pipe gradually tries to return to its original shape – in practice, this can be a problem with fittings, where the pipe may loosen over time
Sensitivity to chlorine: pure PEX is prone to degradation at high chlorine concentrations in drinking water – manufacturers therefore offer a variant with an oxygen barrier (PEX-O2) or MLCP with an aluminum layer

Connection systems for PEX

PEX is not joined by melting like PPR, but mechanically. There are four basic methods:

Press-fit fittings: the fitting is inserted into the pipe and a metal ring is pressed onto it using special pliers
Expansion fittings (for PEX-a): the end of the pipe is expanded using an expansion tool, the fitting is inserted, and the pipe returns to its original diameter, gripping the fitting
Threaded fittings: used for smaller diameters, common for repairs and branch-offs
Electrofittings: a special case for selected systems

Important practical note: mechanical PEX connections must always be accessible for possible inspection and maintenance. Unlike the monolithic PPR weld, a mechanical connection may gradually lose tension over time due to creep relaxation of the polymer matrix. This is not a common issue, but it should be considered when embedding pipes in walls or floors.

Direct price comparison – real figures

One of the most common questions from customers is: how much does it cost? The following figures are approximate and correspond to the current market situation, but reflect the actual material cost ratios:

For a family house with an area of 150 m² with typical piping (approx. 80–100 m of pipe, 40–60 fittings):

PPR PN20 DN 20–32: material 180–280 € (without fittings), fittings 120–200 €, tools (welder, pipe cutters) 80–150 € one-time. Total material cost: 350–500 €.
Copper Cu 15/18/22×1: material 420–680 € (at current copper prices), soldered fittings 200–350 €, possibly crimping +150% on fittings. Total material cost: 650–1 100 €.
PEX MLCP 16/20/25: material 220–360 €, fittings 250–400 € (crimping), tools 150–300 €. Total material cost: 500–800 €.

From the labor perspective, the difference is less dramatic, as PPR saves on material costs, but each elbow requires welding – PEX leads the pipe directly to the point of use (manifold-star system), thus eliminating many connections. Overall, the PPR system is still cheaper than copper with a competent plumber, while PEX depends very much on the system and the number of points of use.

Hygienic safety and drinking water

This is an area where marketing differs from standards. For drinking water distribution in the European Union, the standards EN 15876 (PPR), EN 1057 (copper), and EN ISO 15875 (PEX) apply. All three materials must be certified for contact with drinking water – meaning the materials themselves are safe when used correctly.

From a microbiological perspective, copper is actively bactericidal – Cu²⁺ ions destroy both Gram-positive and Gram-negative bacteria, including Legionella pneumophila. PPR and PEX are biologically inert – they do not support bacterial growth, but also do not actively destroy it. With a properly designed system (hot water circulation, temperature ≥55 °C, no dead-end branches), the risk of Legionella is low for all three materials.

A critical factor is stagnation. Long dead-end branches where water stands for several days are problematic regardless of the material. In copper systems, you also need to be careful with the first water from the tap after prolonged stagnation – the Cu²⁺ content may temporarily exceed the limit of 2 mg/l (standard STN EN 15664-1). Therefore, it is important to let the water run after returning from vacation.

Practical application scenarios – where to choose what

Scenario 1: New family house construction, complete cold and hot water distribution

In this situation, PPR PN20 is a long-term proven and economically most advantageous choice. Cold water (CW) distribution in PN16 or PN20, hot water (HW) and circulation in PN20 or PN25. Design as a branched system with shut-off valves on each floor. For isolating individual branches, ball valves DN50 are suitable in the main branches, smaller ball valves before each group of outlets. A separate article Ball Valves in PPR Systems – Selection, Installation and Maintenance discusses the selection, installation, and maintenance of ball valves in PPR systems.

Scenario 2: Renovation of an older apartment with existing copper piping

This is a classic dilemma. If the existing copper piping is in good condition, complete it with copper – galvanic compatibility is guaranteed, soldering or crimping is quick. If switching to PPR, you must ensure the transition copper ↔ PPR with special transition fittings with a brass insert, and on the copper side, there must be no galvanic contact between PPR and copper without such a fitting. PEX MLCP is also a good choice for renovation – the pipes can be routed in existing grooves without the need to remove all wall coverings.

Scenario 3: Floor heating + hot water distribution

For floor heating, PEX-EVOH or PEX-O2 with an oxygen barrier is the standard solution – flexible pipes are easily laid in a spiral, no welding is needed in the floor area. For hot water distribution in the same house, it is logical to continue with PEX MLCP (metal-plastic pipe) for consistency of tools and fittings. PPR could also be used, but combining two systems in one building complicates material supply and tools.

Scenario 4: Technical room, boiler room, industrial piping

Copper or steel win here. Temperatures at boilers, safety valves, and fittings may briefly exceed 95 °C, and pressures are variable. PPR and PEX must be separated from the heat source by a sufficient section (minimum 0.5 m of metal piping) to avoid thermal stress on plastics. In a technical room, the rigidity and resistance of copper or steel piping to mechanical damage is also valued.

Expansion and piping routing – practical details

Thermal expansion of PPR is the property that causes the most problems in practice for amateur plumbers. According to the formula ΔL = α × L × ΔT, a 10-meter PPR hot water distribution line from a cold position (15 °C) to operating temperature (65 °C) will extend by: 0,15 × 10 000 × 50 = 75 mm. That is almost 8 cm – if the pipe is rigidly fixed at both ends, enormous internal stress will arise.

The solution is expansion compensators – the simplest is an expansion loop (so-called lyra) made from the PPR pipe itself in the shape of the letter U, or an L-loop using natural turns in the route. Straight sections longer than 6–8 m must have a free (sliding) clamp at one end and a fixed point at the other end. More about this issue and specific calculations can be found in the article Thermal and pressure resistance of PPR pipes – what you need to know before buying.

Copper has a thermal expansion 9 times lower, so a 10 m route with the same ΔT = 50°C gives only 8.5 mm – most installations can tolerate this directly without special measures. With PEX it depends on the variant: pure PEX has expansion similar to PPR, MLCP (with an aluminum layer) has expansion close to copper.

Compatibility and combining materials

In practice, it often happens that the system is not purely single-material. For example: cold water from the public water supply brought in via copper, PPR distribution in the apartment section, PEX in floor heating. A few important rules:

PPR → copper: transition through a PPR transition fitting with a brass insert. On the copper end, standard soldering or compression fitting. Never put a PPR fitting directly into the flame of a soldering torch.
Copper → steel (galvanized): requires a dielectric transition piece – otherwise galvanic corrosion will destroy the joint within 3–5 years.
PEX → copper: transition through a compression or threaded fitting. MLCP fittings are typically made of brass and are copper-compatible.
PPR → PEX: only through a mechanical fitting (valve, splitter) – direct connection between PPR and PEX does not exist.

Ecological footprint and long-term sustainability

This topic is becoming increasingly relevant. From the life cycle perspective:

PPR: production from propylene monomer is energy-intensive, but lower weight reduces emissions during transport. PPR can be mechanically recycled (granulation), but not back to original applications – it typically ends up as secondary raw material for less demanding products. The inert nature of the material means it degrades in the environment over decades.
Copper: mining and production of primary copper is extremely energy-intensive (production of 1 ton of Cu requires about 17 GJ). On the other hand, recycling secondary copper consumes only 10–15% of the energy of primary production and copper is 100% recyclable without loss of properties. If copper pipes from a 50-year-old distribution system are replaced, the material almost entirely returns to circulation.
PEX: cross-linked polyethylene is thermally non-recyclable due to cross-linking – it cannot be melted and reformed like regular PE. This is its environmental weakness. It can be processed via pyrolysis or burning with energy recovery, but it is more difficult than with PPR.

From a long-term sustainability perspective, copper is the greenest option with proper maintenance and recycling, although its initial carbon footprint is high. PPR and PEX are significantly less sustainable from a carbon perspective, which is an argument for their installation only where their technical advantages justify it.

Most frequently asked questions (FAQ)

Can I combine PPR and copper in one system in a single-family house?

Yes, the combination is common and technically problem-free as long as you use the correct transition fittings. PPR fittings with a brass insert allow a smooth transition between systems. Never connect PPR directly to copper without such a transition fitting – the difference in thermal expansion would eventually damage the joint. Also, make sure there is no galvanized steel in direct contact with copper in the system without a dielectric piece.

What is the actual lifespan of PPR piping compared to copper?

Certified lifespan of PPR at the designed parameters (PN20, max. 70 °C, pressure max. 10 bar) is 50 years according to ISO 9080 standard. Copper with favorable water quality (pH 7–8.5) has proven lifespan of 70–100 years, and in some historical buildings, copper distribution systems from the 1950s are still functioning. PEX has a certified lifespan of 50 years, but it is a younger material and real long-term data (50+ years) are still missing. In practice, for PPR and PEX, the quality of installation plays a bigger role than the material's lifespan itself – a poorly welded PPR joint may fail within 5 years, while a properly welded one can last for decades.

Is PEX suitable for potable water supply or only for heating?

PEX for potable water supply must be certified for contact with drinking water (EN ISO 15875, or KTW certification in Germany, WRAS in the UK). Standard PEX-O2 with an oxygen barrier for floor heating does not have such certification – the EVOH film is not certified for potable medium and may release undesirable substances during long-term contact. Always check the manufacturer's certificate. PEX without an oxygen barrier (for potable water) on the other hand cannot be used in heating systems, where oxygen would corrode steel components.

How does PPR installation differ for a DIY enthusiast compared to a professional plumber?

DIY PPR installation is realistic and common – the system is designed for it. Three key things are important: proper tools (a polyfusion welder with tongs for the required dimensions and quality scissors up to 63 mm STANDARD), thorough surface preparation (cleanliness, square cut) and adherence to welding times according to the manufacturer's table. A professional does the welds faster and more routinely, but the physical results should be the same. I do not recommend starting with pressure piping – first practice welding on a piece and perform a pressure test (at least 1.5× working pressure for 30 minutes). You can read about the entire installation process in the article PPR pipe installation step by step – welding, tools, procedure.

What to do if I have soft, acidic water from a well?

Soft acidic water (pH <7, hardness <1°dH) is aggressive towards copper – it causes corrosion, blue color in water, and in extreme cases, pipe damage within 5–10 years. PPR and PEX are resistant to such water, making them the clear choice for well water systems without water treatment. An alternative is a neutralization filter before the distribution system, which adjusts pH to 7.2–7.8 – then copper is safe. When designing a system for well water, always start from the water analysis.

Can I use PPR for piping behind a condensing boiler?

Not directly. Condensing boilers typically operate with an output temperature of 55–80 °C, which is acceptable for PPR PN20. The problem, however, is in the fittings and temperature fluctuations – in case of a fault or incorrect boiler setting, the temperature may briefly exceed 90–95 °C. In addition, pressure fluctuations with boilers are greater than in a standard distribution system. Practical recommendation: the first 0.5–1 m from the boiler should always be copper or steel braiding, then transition to PPR via a transition fitting – this protects the PPR from thermal peaks while still benefiting from its advantages on long routes.

Conclusion – which material to choose?

There is no one correct material for all situations – and anyone who tells you otherwise is trying to sell something. The right decision depends on a combination of factors: water quality in the area, system temperatures and pressures, the experience of the person who will install it, availability of tools, planned building lifespan, and of course the budget.

For most new apartments and single-family homes, PPR PN20 is the optimal choice – excellent price-to-lifespan ratio, hygienic safety, and ease of installation. Copper has an irreplaceable role in technical rooms, aggressive temperatures, reconstruction of existing copper distribution systems, and where the customer values proven century-old tradition and biological properties. PEX dominates in floor heating and systems with flexible routing, where PPR would require too many fittings.

Before the actual installation, always read the other articles in this Knowledge Center as well – for example What PPR pipe diameter do I need – calculation according to pressure and flow and How to choose the right PPR piping system for your household. Good preparation and the correct choice of material will save you more money than any other measure.

Do you have a question about this topic?

Having trouble making a decision or dealing with a specific situation in your home? Write to us – we will be happy to help.