Difference Between CPVC, Copper Pipe and PEX Pipe

When it comes to installing new pipes or making repairs, plumbers have their favorites and first choices. Piping options include PVC, CPVC, copper, and PEX tubing. Knowing a little about each will help you understand the difference between CPVC and PEX pipe or copper pipe. Most importantly, the debate between CPVC, copper, and PEX rages for reasons ranging from price to ease of installation. We plan to cover all of them below.

Common Application: Replacing Galvanized Pipe

Many older homes we come across have galvanized pipes. Years ago, Pros used galvanized pipe as a practical way to bring potable water into the home. However, now it has several disadvantages. For one thing, galvanized pipes are subject to internal corrosion over time. The situation is bad enough, 30-40 years from now, the water flow may be significantly restricted. As a result, many homeowners replace galvanized piping at every opportunity when redoing a bathroom, kitchen, or other area that allows them to use the original plumbing from an older home.

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Copper has been the dominant form for years, showing up in as much as 80% of all new homes built over the past 30 years, but CPVC is a steady force and is sure to be popular with remodelers and do-it-yourselfers alike, as it No sweating and soldering pipes involved.

Each of these products has its uses, advantages and disadvantages. In most cases, the difference between CPVC and PEX depends on your familiarity with the material and the piping design and function you are after. You can use CPVC, copper or PEX pipe without any major issues. Just have someone familiar with each best practice install them properly. When deciding which material is best for you, or more likely, which material you should turn to when remodeling, we'll examine each material and explain the pros and cons of each.

CPVC for pipes

CPVC piping has been used for over 40 years and is the material of choice for amateur remodelers and do-it-yourselfers alike. CPVC is rated to 140 degrees or higher and is as safe to use as copper pipe. It has high elasticity and the ability to handle large amounts of heat. CPVC has a different outside diameter than copper or PVC, so this needs to be taken into account when planning connections to older pipes such as galvanized or copper pipe. Compared to copper, CPVC is extremely lightweight and easy to install. It's also less expensive overall than copper, especially as metal prices have risen steadily over the past few years.

Advantages of using CPVC

• Corrosion and wear resistance
• Smooth holes improve flow (also reduce water noise)
• high impact strength
• Simple, cost-effective installation
• Competitive price compared to copper (thus, less prone to theft on the job site)
• light
• Self-insulating to minimize heat loss
• Flame retardant, low smoke density
• Pressure rated to ~100 PSI @ 180° F, ~400 PSI @ 73° F (short term pressure rating > 200 PSI)
• Flexibility virtually eliminates water hammer (no need for water hammer arrestors under normal conditions unless deemed so by local regulations)
• Inert to acidic soils and corrosive water sources
• Can be directly buried under the floor, no chemical reaction with concrete
• non-conductive
• Eliminates pressure leaks at solder joints
• little sweating or condensation

Some Considerations When Using CPVC Piping

• Easy to crack during earthquake
• Typically requires a cure period of 24 hours or more in cold weather before pressurizing with water

To date, all national building codes have approved CPVC for potable water delivery in the United States and Canada. Extensive testing and QC standards have been established to set the consistency of these products during manufacturing (ANSI/NSF-61 standard).

Copper pipe : high-end main force

Copper pipe is a staple product in the United States. While some people hate household copper, copper has been around since the late 20's, and in 1932 the American Society for Testing and Materials (ASTM) Standard B88 was created as the standard for seamless copper piping.

By the early 1980s, copper water pipe production, sales and installations were said to exceed 5 billion linear feet per year. It is an excellent solution for home or commercial plumbing if the pH of the water supply is very close to 7 (neutral).

One of the most-concerned disadvantages of using copper tubing is the problem of pinhole leaks. Older homes with horizontal cold water supply lines most often experience pinhole leaks, the result of corrosion in the pipes that eventually break down the pipe walls in an uneven pattern, creating the leak. Possible causes of pinhole leaks include using a water softener, high pH, and excessive flow rates (among others).

Advantages of using copper pipe

• Proven long-term durability (15-20 years) in non-acid installations
• Biostatic – does not support bacterial growth
• anti-seismic
• Fireproof; its high melting point (1981°F) is 5 times that of CPVC
• Widely accepted by all building codes
• Contemporary American-made copper tubing is 99.9% pure (copper/silver) according to ASTM specifications (note that older copper tubing may contain more lead).
• High rated internal working pressure
• Fast "cure" time (pressure test possible in 10 minutes)
• Can bend to avoid obstacles, minimizing joints
• Annealed (soft) and stretched (hard) versions available
• Small outside diameter relative to CPVC
• joints are not bulky

Disadvantages of using copper pipes

• Some reports that the water has a "metallic taste"
• Prices are erratic, rising sharply due to market forces (more susceptible to job site theft)
• Can produce "pinhole" leaks in the presence of acidic water
• Restricted to water pH below 6.5 – 6.8 (acidic) in some areas
• Can leach lead or copper into water supply
• Labor-intensive installation process requires skilled plumbers
• Calcium buildup may occur, restricting water flow
• High initial installation costs (labor and materials)
• Heat loss – requires insulating jacket
• Condensation may occur if not properly insulated
• Loud noise at high water speeds
• Subject to water hammer at speeds greater than 5 FPS; may require water hammer arrestors to mitigate damage
• Copper joints are prone to failure at high temperatures (180°F and speed)
• Installation with gas torches is a potential fire hazard
• Repairs are difficult for DIY'ers and require special training and tools

While the health side effects of copper plumbing are relatively unheard of, the EPA, ironically, lists copper as a contaminant in drinking water. The highest allowable level is 1.3 mg/L. New copper fixtures tend to lose more copper initially, plus corrosive or acidic water can be a toxic combination. Older copper fixtures, including faucets, may also contain higher levels of lead, including lead solder commonly used before 1987.

PEX tubing (cross-linked polyethylene)

PEX stands for cross-linked polyethylene. That's a fancy way of describing the manufacturing process of this plastic tube. Crosslinking creates connections between the plastic's polymer chains. Manufacturers use this crosslinking process to make PEX tubing using three different methods. PEX A, B, and C represent different approaches (as opposed to "grades" of PEX). PEX tubing is extruded, where the material is heated under pressure and the tubing is eventually pulled through a die.

Although it has been around since the 1960's, PEX pipe has only been used commercially in US plumbing applications since the 80's. Many installers prefer PEX because it is flexible (1/2" can be bent 90 degrees in an 8" radius!) and can usually be run from supply to destination in one go. As you can imagine, this saves a lot of time during installation on copper or even CPVC.

Why use PEX tubing?

PEX can handle a wide temperature range, from subzero to over 180 degrees Fahrenheit, making it suitable for hot and cold potable water supply lines, service lines, and even hydronic radiant floor heating systems. It can be installed under a slab or even penetrate the slab directly with just one sleeve.

PEXs typically operate in a "home run" configuration, in which supply lines are split into multiple hot and cold runs and sent from a single source to each destination faucet, fixture or faucet. It also means homeowners can shut off just one line (hot or cold) to repair or modify fixtures—all without interrupting water flow to the rest of the house.

In short, PEX is pretty cool, even though it's new. For plumbers, this means you'll save a lot of time if you can get billed for the job. If you're billing by the hour, PEX (vs. copper) can seriously impact your billable hours – too fast to install!

PEX is available in diameters from 1/4" to 1" CTS (Copper Tubing Size) and is traditionally packaged in coil or 20' straight tubing. Installation is done by mechanical or compression fittings.

PEX overview

• Requires use of brass fittings
• Installation requires some special tools (not very user friendly for casual homeowners or remodelers)
• Extremely durable and expandable when properly installed

Of course, there are three types of PEX on the market, commonly referred to as PEX A, B and C. PEX C is less common in whole home applications, so we'll compare A and B (in layman's terms). In doing so, we discovered some key differences.

CPVC vs Copper vs PEX Material Comparison

We want to give a clear picture in the CPVC vs copper vs PEX debate. One way is to assume some facts and then create a grid. v

Let's assume a simple configuration consisting of two 100 ft lengths of 1/2" pipe, each connected from source to faucet, and each pipe must be wrapped around a 90 degree elbow. We don't count any fittings or adapters at each end, only those needed to run end-to-end. We do include some tools that may be special items that your tool kit would not have included. See the CPVC vs. Copper vs. PEX table below.

NOTE: Using PEX tubing in a home run configuration may cost an additional $100-250 for a multi-port manifold that splits incoming hot and cold and sends it throughout the home.

So who wins the CPVC vs copper vs PEX tubing race?

In summary, CPVC is the clear winner in terms of cost and ease of installation. PEX tubing is significantly less expensive and actually gets cheaper once you eliminate the tooling expense. Copper is still the most expensive way. Yet, for some odd reason, professionals and homeowners still consider it the premier high-end solution. We figured that if we were going to build new buildings, we'd build our own homes in PEX. For older houses we tend to convert all copper (where possible) to CPVC, and we only use copper to CPVC when it means saving a lot of time and effort and back again (i.e. repair in the middle of an all-copper something) to run.

There is no clear right or wrong answer in the CPVC, copper, and PEX debate. You really need to understand the methods and materials you or your builder choose. In the end, as a consumer, you probably don't have much choice.

However, as a tradesman, you can save a lot of money and even spend less time running pipelines, resulting in more job opportunities. Hopefully this guide has at least given you an idea of some of the variables involved in making the choice that's right for you.