PEX manifold systems, along with PEX plastic piping, create several potential advantages for homeowners, contractors, and remodelers compared to the standard rigid plumbing system designs of previous generations. Although this method of water distribution is relatively new for residential projects, the home-building industry has come to accept this type of setup as a best practice.
Under the typical system, the manifolds will serve as the control centers for the plumbing in the building. Cold or hot water is then delivered through the flexible PEX supply lines, creating connections to the individual fixtures in the home or building. That means each fixture goes straight to the manifold instead of a trunk line.
Separate manifold chambers are used to serve the cold and hot water lines. The cold line is served by the primary supply to the building, whereas the hot line is fed from the water heater or tankless system.
If you’re thinking about a remodeling project at home or your work involves new construction, then here are some of the PEX manifold system pros and cons to evaluate.
List of the Pros of a PEX Manifold System
1. PEX plumbing can expand without bursting.
If you install the flexible PEX tubing in your home (a requirement if you’re using the PEX manifold system in most situations), then there is a greater resiliency built into the system for changing temperatures. The tubing used can expand by up to 15% without bursting. If the water freezes in your pipes, the expansion caused by the action makes it resistant to damage during the winter months.
2. You can turn off the water at a central location.
When you’re trying to work on a specific fixture, you may find it necessary to turn off the supply before it enters your plumbing system. That drains your plumbing, which can lead to odor, sediment, and other problems when you restore water access.
When you use a PEX manifold system, you’re able to turn off the supply from a central location. That means you can work on your fixture by turning off the specific manifold that runs tubing to the unit. You’re no longer forced to restrict water access for extended periods to the entire home.
3. It is a scalable system that is appropriate for most buildings.
Although the PEX manifold system is often promoted as a residential option, you can install them in commercial buildings as well. Just count the number of fixtures that will be used, or the location of your cold and hot water supplies. Make sure outdoor fixtures and automatic units, such as an ice maker, are included in the calculation. Then install the manifold at each location, ensuring there are enough ports available to adequately support every fixture. That gives you a water distribution method that is often more efficient than the traditional systems which are still being used in many of today’s structures.
4. All standard supply line sizes are accepted by the PEX manifold system.
The plumbing manifolds associated with this system will accept all common supply line sizes. You can even use 3/8-inch supply lines with this system. Because PEX provides flexible tubing, it can be bent in ways that traditional plumbing options cannot. That means you need fewer fittings for this system when compared to rigid piping, reducing the amount of time required to install the system.
Most homes experience fewer pressure drops when accessing water through their PEX manifold system as well.
5. PEX piping provides better insulation for your water compared to rigid piping.
Most homes and buildings are equipped with copper plumbing pipes. This system creates a rigid network of water delivery that is reliable, but not always energy-efficient. The flexible piping that is used with PEX manifold systems insulates the hot water better, which means you see fewer losses at the fixture. Adding rings or loops to the system provides a further increase of this benefit.
6. PEX manifold systems are less susceptible to rust.
Because you’re not using metal components with the water distribution system, a PEX manifold system is not as susceptible to corrosion as a standard system. You’re using non-metallic pipes that will reduce micro-biological buildups, scaling issues, and rust. That means your water quality remains consistent as the system ages, allowing you to have confidence in the supply at every fixture of the home.
7. You have access to a long-term warranty with PEX products.
PEX offers a limited 25-year warranty on their pipes and fittings. For the PEX manifold systems and accessories, there is a 10-year warranty which applies. If non-PEX items are used in conjunction with the systems, the warranty may be limited to 5 years or less in some situations. For the terms of the warranty to apply, you may be required to have the PEX products installed by an authorized party. That means if you’re planning to DIY the project, your warranty may either be extremely limited in nature or not protect you at all.
Most PEX systems are expected to last anywhere between 25 to 50 years when they are properly installed.
8. There are many cost advantages to consider with PEX.
If cost is your primary concern when dealing with the installation of your plumbing, then PEX will be a top choice. The cost of installing the pipes and manifold systems is about 25% of the what it takes to install copper pipes or other rigid systems. When you look at the cost of replacing an entire home or building with this technology, the savings can be tremendous.
9. PEX pipes are color-coded for added convenience.
There are three colors of pipe available when you install a PEX system in your home or building: red, white, and blue. Although that makes the system sound patriotic, the colors match the temperature of the source water when installing it with the manifold system. Red pipes are for hot water, blue pipes are for cold, and white pipes are meant for either. That’s a handy feature for installers when comparing it to the older rigid networks that feature copper pipes.
10. Installation is much easier than it is for copper pipes.
If you’re installing a copper plumbing system, then you’re forced to sweat the metal to create a proper connection. When you’re using a PEX manifold system and corresponding flexible tubes, you can install the items using crimp rings, cinch rings, or cinch clamps. Stab-in fittings or compression fittings are also suitable with this technology. Not only does this make the PEX system easier to install, the initial work is also less toxic.
11. It is approved for installation in most communities.
PEX plumbing products are approved for installation across the United States. At the national level, it has been deemed to be just as safe (if not safer) than standard copper and brass networks.
12. PEX manifold systems require a smaller installation profile.
The installation of a PEX network is very fast. You can thread it through your walls without even cutting out large sections of drywall to do it. Each connection at the manifold can be visually inspected to ensure you have safe water access. You have better precision with your measurements using this type of system and can run it through a smaller installation profile. Even if you opt for a DIY installation, you’ll discover that several companies support this type of system with connectors, accessories, and specialty adapters.
List of the Cons of a PEX Manifold System
1. You can’t get around the fact that you’re using plastic piping.
If you install a PEX manifold system and using the flexible plumbing options with it, then your network becomes more susceptible to pests than a traditional copper system. Mice and rats can do a lot of damage to PEX systems quickly, and you’re unable to know that there is something wrong until it may be too late. Although the cost of PEX systems is less than standard copper systems, some homes may see higher maintenance costs over the long run.
Some homes have used poisons to get rid of the pests that were chewing through their plumbing types. Evidence suggests that using poison causes the pests to become thirsty, so they seek out a water source. Rats can hear the water running through the PEX pipes, which means the poison can make your leaks worse since you’re encouraging the rats to chew through the piping.
2. Some PEX systems may be vulnerable to specific contaminants.
Because PEX systems are based on plastic piping technologies, they may be vulnerable to some contaminants when they are placed in soil. Any pesticides, benzene, or oils that are in the dirt that is around the tubing may leach into the water supply for the building. To prevent this issue, California requires that all PEX systems be wrapped in an impermeable sleeve if the system uses underground pipes to deliver potable water.
3. Chemicals from the plastic may leach into the water as well.
During the first uses of PEX piping through the manifold system network, there may be chemicals that leach from the plastics into the water that is meant for drinking. This creates the potential hazard of having contaminated water for household use. To prevent this issue, the entire system must be flushed a minimum of twice over the course of 7 days to prevent any accidental chemical contamination exposure.
4. You cannot expose your PEX manifold system to sunlight.
The plastics used for PEX systems cannot be exposed to sunlight whatsoever. The product quickly degrades under the exposure of direct light from the sun. This issue is so problematic that the State of California requires contracts to have PEX systems carry a 30-day UV protective coating on all installations.
Even if your manifold system installation goes smoothly, if the tubing is compromised from sunlight exposure, the quality of your plumbing system severely diminishes.
5. PEX manifold systems may not be permitted under local building codes.
Even though PEX tubing is approved for all major model plumbing codes and primary building codes at the national level in the United States, it is not approved by specific local codes in places around the world. California was one of the primary holdouts for using this technology, only approving the tubing in the last few years.
Before starting your project, make sure to contact the local authorities in your jurisdiction to ensure that you can use a PEX manifold system in your building. If you’re not sure who to contact, then try speaking with a trusted licensed and bonded plumber.
6. PEX pipes are sensitive to chlorine exposure.
Many municipalities use chlorine as a disinfectant for the water supply. Its presence helps to remove biologics which may be potentially dangerous when consuming potable water. Although the PEX manifold system is durable, the piping used to connect the system to each fixture is vulnerable to chlorine in the water. You may need to install a filter that removes the chlorine from the supply before water enters the plumbing system of your home.
Some evidence suggests that PEX may be susceptible to copper ions also. To deal with this issue, the temperature rating of the water must be followed at all times, without exception.
7. It removes zinc from brass fittings when they are used.
If the zinc content in a brass fitting is too high, then PEX systems will cause corrosion to the extent that a failure occurs. That means there is a higher risk of leaks or a breach that could occur in a pressurized line. When working with a PEX manifold system, you should always use low-zinc brass fittings if you do not want to use the components that are made from engineered plastic to finalize the installation.
8. There are three types of PEX that can be used, which can be confusing to some homeowners.
There are three types of PEX, which are appropriately called A, B, and C. Type B PEX is the only known formulation which does not cause leaching concerns once it is installed. If you’re installing the system on your own, your homeowner’s insurance carrier might ask you what type of PEX you installed with your manifold system. Then make sure that you’re giving attention to the temperature and strength ratings of the type you’ve installed for best results. If you think Type A was installed, but it was really Type C, that could create some user issues over time.
9. It can be punctured easier than copper or metal pipes.
Since PEX plumbing is plastic, it is vulnerable to future punctures from a nail or a screw. You can shield the tubing that runs between the fixtures and manifold station to prevent this issue. If you approach a wall with a saw, however, then you’re facing a greater risk of a devastating leak when compared to other products.
These PEX manifold pros and cons suggest that plumbing technologies are ready for an upgrade. Although copper systems have served their purpose over the years to provide safe access to potable water, flexible PEX tubing provides a similar result for a fraction of the cost. Although there are no long-term studies to determine the safety of this product, it is approved for use in all major building codes through standards ASTM F876 and F877.
Natalie Regoli, Esq. is the author of this post and the editor-in-chief of our blog. She received her B.A. in Economics from the University of Washington and her Masters in Law from The University of Texas School of Law. In addition to being a seasoned writer, Natalie has almost two decades of experience as a lawyer and banker. If you would like to reach out to contact Natalie, then go here to send her a message.