How Much Time Can PEX Save on Installations?
By now, you’ve probably heard the accounts of plumbers saying they can save so much time — up to half, in some cases — plumbing with crosslinked polyethylene or PEX. These savings are mostly due to the flexible nature of the plastic piping and the fewer connections required to plumb a structure. But, really — how much time can you actually save? Is there quantifiable data to prove these statements?
Jason Edwards, owner of Green Plumbing in San Antonio, Texas, had been installing copper and CPVC plumbing systems for years. He was a die-hard believer in soldering or cementing straight lengths of rigid pipe. Then, in 2001, after learning about the benefits of PEX from a manufacturer’s representative, Edwards thought he’d give the product a try.
“Southwest Sales gave us a demo of [a name brand] PEX plumbing system, and we decided to give it a try on our next job,” he said. After completing their first PEX job in 2001, Edwards was impressed enough to continue using the flexible pipe. He estimates that he has since installed PEX in more than 120,000 tract homes, custom homes, multifamily houses and commercial jobs: “I wouldn’t use anything else.”
So, what exactly is PEX? It’s a flexible plastic piping product manufactured by chemically crosslinking polyethylene. This manufacturing process links the polyethylene molecules in a way that produces a very durable, very flexible piping product that’s been installed in millions of residential and commercial structures since the 1970s.
PEX is extruded in coils up to 1,000 feet long and those flexible coils allow the pipe to be installed easily and efficiently, with fewer fittings and faster connections. It was that time-saving element, as well as the other benefits PEX provides — like corrosion resistance and greater freeze-damage protection due to the pipe’s ability to expand up to three times its diameter — that convinced Edwards to try it on his next job.
“The time savings was key but needing to use fewer fittings and the benefit of the added freeze protection were also big selling points” he said.
Since flexible PEX can be quickly fished through walls, easily bent around tight corners and cut to any length, dozens or even hundreds of metal or plastic fittings can be eliminated on a job. There’s no need to solder or cement a union every 20 feet, as required when installing long runs of rigid pipe.
And since PEX is flexible enough to bend around obstacles and tight turns, it greatly reduces the need for many elbows, as well as the considerable time used to install them. Every installer knows that reducing the number of fittings on a job doesn’t just save valuable time and money — it also eliminates potential leak points, reducing the potential for callbacks.
Some PEX manufacturers also offer what are called “multiport tees,” made from sophisticated engineered polymers. These durable fittings combine several tees into a single, molded, multiport fitting. They are available in dozens of configurations, with several diameters and varying numbers of ports.
For example, a single, six-port, pass-through multiport tee can supply six fixtures and requires only eight connections. Using metal or plastic tees to feed the same number of fixtures requires six tees and 18 soldered or cemented connections. As you might expect, it requires significantly more time to make those 18 connections in a rigid-pipe system than it takes to assemble the eight connections in the single multiport tee.
Simple, Quick Connections
To ensure a proper connection, rigid pipe systems require several precise steps: cutting the pipe, deburring the inside and outside of the cut end, cleaning the ends of the pipe, applying the correct amount of flux or cement, then applying an open flame to a metal joint or twisting and holding a plastic joint together.
With PEX, a watertight connection can be made in seconds by simply cutting the pipe with a PEX cutter, then either expanding the end of the pipe with an expander tool and inserting a fitting or inserting the fitting and crimping the connection.
According to data from the Mechanical Contractors Association of America sweating a connection can take two to four times longer than the same diameter PEX connection. Cemented fittings require cure times of 30 minutes to 24 hours, while a PEX connection can be completed and ready for system-testing in a fraction of the time.
To compare the total time required to install a PEX system with the total time required to install a rigid-pipe system, one PEX manufacturer built a wood-frame room in a laboratory setting. In this controlled environment, professional contractors with extensive experience with each type of system installed an identical three-fixture bathroom layout.
Two different types of PEX installations were compared with typical rigid system installs. The metal installation, which included soldering numerous tees and elbows, required more than 1 hour and 19 minutes to complete. The plastic system took over 33 minutes. The first PEX system, using standard tees and elbows, required less than 27 minutes to complete. The second PEX system, using multiport tees, required less than 18 minutes to finish.
That means the PEX system with multiport tees was installed 49 percent faster than plastic and a 79 percent faster than metal.
That’s what can happen in a laboratory setting. What about a real-world installation? Well, in 2001, after some simple training, a PEX manufacturer’s technical team, Edwards and his crew began installing PEX for the first time on a job for Shea Homes. Although there was an expected learning curve, the installers quickly became accustomed to the simple system. They soon discovered they could eliminate many of the fittings they’d been using to install in their similar metal or plastic jobs.
The installation eliminated elbows because the installers could simply bend the flexible PEX around corners and unions were rarely required due to PEX’s long coil lengths. The Green Plumbing team also realized the remaining connections could be made much quicker than the rigid systems they’d installed in the past. According to Edwards, “Our labor versus [metal] was 30 to 40 percent less on residential applications.”
But the time to install a plumbing system isn’t the whole story. There is also the time and cost associated with callbacks to repair any leaks. Even in the PEX manufacturer’s laboratory experiment, the completed plastic system installation had a leak due to a connection that had been dry-fitted but not cemented. The PEX systems had zero.
In fact, PEX systems that use expansion fittings (which require the pipe to first be expanded before a fitting can be inserted) are impossible to dry-fit. There can never be a leak due to a dry-fit connection with a PEX system that uses expansion fittings.
Returning to a job to repair these types of leaks can cost significant time and money — not to mention the damage it can cause on a contractor’s hard-earned reputation. (And any contractor knows that once a reputation is marred, it is very difficult to rebuild.) Based on his own experience, Edwards agreed, saying “PEX has all but eliminated leaks in my applications.”