PEX for the Home Run

Last winter we spent a long weekend at our new house before starting any work. We wanted some time to get to know the place better, to think, to dream, to plan. And we had visits from various family members and friends who wanted to see the “before”.

One of those visitors was our friend Harvey Williams with his wife DeAnn. As a retired engineer, Harvey was interested in some of Kevin’s ideas. When he learned that we were planning to re-do all the plumbing with traditional copper pipes, he asked whether we had considered PEX. “What is that?” Kevin asked, having never heard of it. Harvey explained that PEX (which, it turns out, stands for cross-linked polyethylene) is flexible tubing that is less expensive than copper, easier to install, and does not corrode. Hmmm. Worth investigating.

Thus began Kevin’s intense research of this product, which rather quickly became the obvious choice for our plumbing–especially because our plans included heated flooring. The more research he did, the more advantages of a PEX system were revealed. For example, traditional copper trunk-and-branch systems require a large number of fittings, which are costlier, slower to install, and more likely to leak than a single run of pipe. Also, a lot of water goes down the drain before hot water reaches the faucet. A PEX system is decidedly more energy efficient and cost effective.

Home Run!

After further research, Kevin chose the home-run manifold system. With the home-run system, you install a manifold in the utility room–or some area that’s close to the main water line and water heater–and run a separate PEX supply tube to each fixture. This system uses more tubing but is fast and only requires two connections: one at the manifold and another at the fixture end. The manifold may look intimidating, but it actually simplifies plumbing runs and reduces possible leaks by eliminating the need for tees and other fittings between the main supply line and the fixture.

Here Kevin has just finished the copper pipes that will bring water into the house from the well, and he is ready to install the PEX system which will route water throughout the house. You’ll note his excitement by the twinkle in his eye and his impish grin as he explains the efficiency of using PEX for radiant flooring heat. With the tedious prep work done, we are ready for the fun stuff.

And if we haven’t convinced you yet, here are a few more benefits of a home-run PEX manifold system (from The Balance):

Plumbing Manifold Benefits

Plumbing manifolds can accept all common supply line sizes, down to 3/8-inch.
Fewer fittings are required, so less pressure drop will occur in the lines.
Manifolds are corrosion resistant and make service relatively simple.
Flexible PEX piping is also a better insulator than copper and not susceptible to rust.
Less energy and water are wasted as hot water arrives faster at the tap, especially when a loop or ring is added to the system.
Flexible and non-metallic pipes result in a quiet and efficient plumbing system that doesn’t suffer corrosion, scaling or microbiological build-up.
Flexible polybutylene pipes reduce the chance of pipes bursting from freezing.
The PEX plumbing manifold system can save on labor costs.
Leaking is controlled due to the visibility of all connections at either the manifold or the fixtures in a parallel or home run system.
Turning off the supply can be done at a central location

So, you can see why we were so excited to get going on the plumbing. Here is the beginning of the project.

It took some elbow grease to get all those miles and miles of PEX pushed and pulled and threaded into place, but hey–no sweating of pipes, no solder to deal with, no leaks to worry about. Just those giant unwieldy rolls of red and blue tubing to wrestle into submission.

Too bad we’ll eventually have to drywall over the beautiful waves of all the PEX tubing–red for hot water and blue for cold water.

Heated Floors!

And then it was time to run the PEX for the heated floors. The center of the house will include an entryway coffee nook and the kitchen. This area, as well as the back hallway and office, will have travertine flooring (which looks like marble, but is actually limestone…but more on that design choice later). This flooring, as well as the tile in the first floor powder room, will be heated by the PEX flooring which will be embedded in the drypack floor leveling process (stay tuned for the next post).

This process included installing a special vapor barrier underlayment which looks like aluminum on one side and bubble wrap on the other side. Once this was laid, Kevin began the intricate placement of the tubing, based on his own custom design plan. The PEX tubing we used for the radiant flooring heat is different from the plumbing PEX in that it has an aluminum core that holds its shape when bent so you don’t have to tie it down every few feet, which made the installation a lot easier.