Brass PEX Fittings VS Plastic PEX Fittings, Which Should I Use?

We at Precision Homes & Design (PHD), feel that quality is evident in every detail of a home. One of these details is the selection of PEX fittings. PEX is the most common form of water distribution used in residential construction these days. It consists of plastic PEX tubing (Cross-linked Polyethylene) connected by fittings, i.e.: couplings, elbows, tees, and reducers. Fittings are available in many options with the most common being BRASS and PLASTIC (Poly Alloy, or Polymer). The fitting is connected to the tubing by sliding a copper crimp ring over the end of the tubing, then inserting the fitting into the tubing. A crimp tool is used to crimp or squeeze the crimp ring down around the tubing, forcing the ridges of the fitting into the inside wall of the tubing. This creates a super tight connection that is very reliable. In 20 years, we have never seen a brass fitting leak. We cannot say the same about plastic fittings.

The Value of Quality.

What is quality? People place value in different things, but I think most of us put a high value on quality. When we purchase something for the long term, we want it to last. In the last 23 years of building custom homes, I have seen many areas of quality that are thrown out the window in a misguided effort to make more money. I have seen some homes that are so poorly built, they bounce, creek, and heave, yet still pass the building code inspections. I could not sell a product like this and still feel like an honest person.

Pros and Cons of using Brass PEX over Plastic PEX fittings.

Brass PEX Fittings

Pro: The mechanical connection of the tubing to fitting is best when using the brass fittings because the brass is much stronger than the tubing. The tubing is pressed over the fitting and crimped around the ridges of the brass fitting. The plastic fitting uses the same logic, but as it is crimped, the ridges can smash down from tool pressure which does not create a strong connection and seal.

Pro: The structural strength of the brass fitting is also superior to the plastic.  If a PEX connection is made and it has any lateral stress on the joint, the plastic fitting can break. I have spoken with plumbers who say it is particularly important to make sure a plastic fitting does not have any stress on it caused by the tubing pulling on it.  Even if the plumber is very careful with this at installation, the tubing can be pulled many times by other trades as they install their products.

Con: We are aware that there are others with opposing opinions, stating that the brass is more susceptible to corrosion or water erosion.  If an inferior alloy of brass were used, this argument could hold water (Pun). Most brass fittings that are available from most supply houses are of good quality. 

Con: Another argument for using plastic instead of brass is cost. Brass is more expensive…but not that much. In a new home, with all the PEX fittings, we estimate that using brass fittings would be about $100.00 more than using plastic. This is a simple decision in our minds. $100.00 is a very small amount when the total cost of a home is considered.

Plastic PEX Fittings

Pro: Cost savings. (Only saves approximately $100 dollars.)

Con: The plastic fitting has thicker walls to increase strength which reduces the area inside the fitting.  This acts as a bottleneck and restricts the water flow resulting in lower water pressures at the faucet or showerhead.

Con: High failure rate from cracking and sealing issues from soft barbs that do not stay sealed.

So, who is the winner of Brass PEX VS Plastic PEX fittings?

Using some of the details already presented we have created this table to make it easier to compare the differences between Brass PEX and Plastic PEX fittings.

Summary

In consideration of the above, it is a clear choice of quality over price for us to use brass PEX fittings.