Multi-layer pipe (MLP) vs Copper: The Hidden Costs Every Plumber Should Know

Choosing the right pipe isn’t just a technical decision; it’s a financial one. It affects your install time, the client’s long-term costs, and your reputation. Here’s the real story behind multi-layer pipe (MLP), copper, and Unitwist specific PPR.

Multi-layer pipe (MLP)

What Is MLP? Multi-Layer Pipe (MLP) is a mix of plastic, aluminum, and adhesive. It’s flexible and fast to install. That’s why many plumbers love it at first.

Pros:

• Flexible
• Low cost
• Quick installation

Cons:

• Unreliable Under UV Exposure: If exposed to sunlight (common in outdoor runs or poor ceiling installations), MLP’s plastic layers can degrade and become brittle.
  
• Joint Reliability Depends on Tools: While some versions are tool-free, many MLP systems rely on proper calibration of crimping tools. If tools are off or used incorrectly, fittings can leak later.
  
• Not Ideal for Surface-Mounted Installations: MLP is more prone to visible wear and pressure damage when installed externally or without sufficient protection.
  
• Limited Compatibility Across Brands: Some fittings and pipes from different MLP suppliers are not interchangeable, increasing chances of leaks or incorrect installs.
  
• Poor Performance in Long Hot Runs: For long-distance hot water lines (like from a geyser to a distant bathroom), MLP may soften or deform slightly, increasing stress on fittings.

Copper Pipe

Why It Was Trusted: Copper piping has long been one of the most widely used materials in plumbing, valued for its strength, durability, and resistance to high temperatures. Its ability to handle both hot and cold water applications made it the go-to choice for many decades in residential, commercial, and industrial systems. However, while it performs well under the right conditions, it does have vulnerabilities, such as corrosion, pitting, and theft. Risks that are increasingly important to consider in regions with aggressive or mineral-rich water supplies, like many parts of South Africa.

Pros:

• Long lifespan (in clean water)
• Handles high heat
• Recyclable

Cons:

• Internal Corrosion Often Goes Unnoticed: Copper can develop internal pitting in aggressive water conditions, and early warning signs are rare. Leaks tend to appear suddenly, often after ceilings or walls are already damaged.
  
• Increased Theft Risk on Job Sites: Copper’s high resale value makes it a common target for theft, especially in township areas or unsecured developments. This can delay jobs and increase insurance claims.
  
• Vulnerable to Acidic or Chloride-Rich Water: South African municipal water often contains elements that accelerate copper corrosion. In these zones, even professionally installed copper systems may degrade prematurely.
  
• Requires Skilled Labour and Open Flame: Proper copper installation demands flame work and advanced skills. This introduces safety risks, especially in confined spaces or timber-rich structures.
  
• Thermal Conductivity Can Lead to Energy Loss: Because copper transfers heat quickly, hot water can cool down before reaching the tap, especially in long runs. This affects energy efficiency and user comfort.
  
• Noisy Expansion in Roof Voids or Walls: Copper expands and contracts with temperature changes. In enclosed areas, this can cause ticking or knocking sounds that are difficult to trace or silence.
  
• Oxidation Staining in Exposed Installations: Over time, copper exposed to air and moisture can develop greenish stains or discolouration. In visible pipework, this can look aged or unclean.

An Optimistic Alternative

What is PPR? Unitwist specific PPR (polypropylene random copolymer) is a high-performance plastic pipe made for modern plumbing. Unlike MLP and copper, it thrives under South African conditions.

Unitwist PPR Benefits

Unitwist PPR offers a practical solution to many of the challenges faced in South African plumbing. Its single-layer construction means there are no adhesives that can weaken or delaminate over time, especially under heat or pressure. The material is chemically inert, making it resistant to corrosion, pitting, or damage from aggressive water conditions, including high mineral content and fluctuating pH levels. It performs reliably in both hot and cold water applications, including geyser connections. Since it contains no metal, it is not a target for theft. The system is designed for quick, tool-free installation, reducing labour time and complexity. Unitwist PPR is also fully recyclable and comes with a 25-year guarantee, offering long-term confidence in demanding environments. 

Frequently Asked Questions

Is multi-layer pipe (MLP) reliable for South African plumbing?

While MLP is flexible and quick to install, it struggles in the real world. South African plumbing often involves outdoor runs, heat, UV exposure, and inconsistent installation conditions. MLP’s plastic layers can degrade under sunlight, and its joints depend heavily on proper tool calibration. That means leaks down the line if anything’s even slightly off.

How does Unitwist PPR piping help save time and reduce plumbing costs?

PPR (polypropylene) piping systems are known for their fast and efficient installation. Unlike copper or multi-layer pipes, most PPR systems don’t require specialist tools, crimping equipment, or flame work. This speeds up installation time and lowers labour costs especially valuable for high-volume or budget-sensitive plumbing projects.

Because PPR pipe is non-metallic, it’s also less likely to be stolen from job sites. And its corrosion-resistant material means fewer leaks or repairs over time, reducing costly callbacks.

Tool-free PPR systems like Unitwist PPR offer a practical and affordable way to complete plumbing installations faster, safer, and with long-term reliability.

What’s the best pipe for hot water in South African homes?

When choosing the best pipe for hot water systems in South Africa, it’s important to consider durability, heat resistance, and installation performance. Copper pipes handle high temperatures well but can lose heat over long distances, affecting energy efficiency. Multi-layer pipes (MLP) are easy to install but may soften under sustained hot water use, especially in long geyser runs.

PPR (polypropylene random copolymer) piping offers a reliable alternative. It’s thermally stable, resists pressure drops over distance, and is well-suited for both residential and high-demand hot water applications. Unitwist PPR piping, for example, is specifically designed for South African conditions and performs effectively in geyser-to-bathroom connections, making it a smart, energy-efficient choice for long-term use.

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