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Pex-A and PEX-B, what are the differences?

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4 Dec, 2023

What is the Difference Between a PEX-A and A-PEX-B Pipe for a Hydronic Radiant Floor?

The hydronic floor heating system is a popular choice among owners and many opt for PEX pipes (or tubes). The latter are considered the ideal option due to their durability and their ability to circulate hot water under the floor efficiently, thereby helping to offer a comfortable and efficient heating system. In addition, they are easy to install, which makes them especially suitable for new construction projects. 

But what exactly is a PEX pipe and how does it work? In this blog post, we will explain the difference between the PEX-A and P EX-B pipes. Although these two options have similarities, there are also significant differences between them in terms of flexibility, crack resistance, deformation, and cost.

We will also discuss the specific advantages of each type of pipe, as well as the reasons why it's important to understand their differences. At the end of this article, you will know better which type of PEX pipe is best suited to your needs.

Characteristics of PEX pipes

What is a PEX Pipe?

It's a networked polyethylene material, used for plumbing and heating of commercial and residential buildings, but also in drinking water pipes. Polyethylene chains are chemically modified and glued to each other to produce high-density polyethylene, which is then melted to shape a flexible and durable tube. A PEX pipe is therefore made of a resilient material with a very long service life. 

Used to conduct heated water or glycol from heating floors, it's extremely strong, resistant to corrosion and temperature changes – it can withstand temperatures of up to 100 degrees Celsius. In addition, it requires fewer fittings than traditional copper tubes, which makes installation easier and faster.

Level of resistance

A specific code provides information on resistance to chlorine, UV rays, and minimum rupture pressure, which measures the deformation and rupture of the pipe at the slightest stress. These indications are provided by manufacturers who must perform laboratory tests in accordance with the requirements of ASTM F876. This standard is therefore the guarantee that the product can be used for the installation of a hydronic floor heater.

This code consists of three sections:

  • The first digit is the resistance to chlorine, the highest rating is class 5;
  • The second digit is UV resistance, the highest rating is class 3 which indicates a six-month resistance to UV;
  • The last two digits correspond to the hydrostatic resistance value, i.e. the pressure level (depending on the water temperature) that the pipe can withstand for several years. 

The highest code is PEX 5306.

Not all connections are compatible with a PEX. To know which ones work best with the pipe brand you choose, it's recommended to carefully read its technical data sheet if you install your own floor heating. HCW has released a video that guides self-builders in the installation of the pipe with its unique hydraulic floor heating systems. 

The categories of PEX pipes for hydronic floor heating

PEX-A Pipe

Made by a peroxide reticulation process, it has all the general qualities of the PEX - solidity, resistance to corrosion, and temperature variations - and great flexibility. It's the pipe that best withstands high temperatures, permanent deformations and that is resistant to cracks.

Its cost is about $6 for 10 ft long.

PEX-B Pipe

The Pex-B type pipe is usually used for plumbing and heating such as floor heating. It's made from high-quality polyethylene reticulated (PEX) and is considered the most rigid type of Pex pipe. Its manufacturing method involves a networking process using a peroxide process that allows polymer molecules to bind together, thereby increasing the material’s resistance to heat, pressure and corrosion. They are preferred for residential and commercial plumbing installations due to their resistance to permanent deformation and pressure.

Its price is about 5 $ for 10 ft long.

The two products are visually very similar, but some details distinguish them. Read on to find out how to avoid the traps. 


What Is the Difference Between PEX-A and Pex-B?

The two pipes are not connected in the same way, their flexibility and break point are not the same. Here are the points to consider:  

Assembly Process

When you see these two pipes side by side, you get the impression that their circumference is identical, so that it's the same product. You should not rely on this criterion: one allows a fluid flow, the other can create clogging gaps due to their connection method.


It requires an expansion tool to widen the end of the pipe in order to drag a fitting into it because it employs fittings with substantially greater diameters than PEX-B. There is no chance of leaking because the elastic material tightens hermetically.


  • Reduces the possibility of leaking;
  • Ideal for limited or difficult-to-access spaces: the few seconds between expanding and then narrowing when inserting a connection allows you to work in a comfortable position throughout installation.


  • In cold climates, it takes a lot of time to the narrowing that ensures the sealing of the attachments ;
  • The solution? Using a thermal pistol to heat the connection can speed up the process. So you will understand that their installation requires the services of a professional. 


It requires an insert type connection. After inserting the connector into the pipe, it's fixed with a copper sleeve, using a drawing tool.


  • Because PEX-B does not require an extension tool, the assembly is faster and simpler;
  • Regardless of the temperature, the method remains the same. 


  • Since the joints are smaller, this process reduces the diameter of the pipe at the joint level. This results in a certain resistance to the flow of water that flows through the pipes;
  • The result is not as ergonomic as for the PEX-A, so the P EX-B can be used for large surface installations. 


The PEX A is very flexible, which allows for closer radial turns. Another big advantage: if there is a fold, you can remove it with a heat gun. The heat activates the material, which will bring it back to its original shape.

Since the PEX-B comes from a different manufacturing process, its flexibility is limited, so it's intended to be installed in floors and walls without excessive curvature or without additional support. This can simplify the installation process and reduce the required working time.

Bursting pressure

Living in a cold environment means your ground heating system is at risk of freezing during extreme temperatures. And when the pipes freeze, they can break out at any time. PEX-A and B react differently to this risk.

Although the PEX-B is also resistant to shocks and fractures, it's generally considered to be less efficient than the P EX-A in terms of low temperature resistance.


In conclusion

You now understand the differences between PEX-A and PEX-B pipes in terms of resistance, geographical application, and installation.

Knowing how to identify PEX tubes and their qualities can save you time and money. It's also vital to arm yourself with the proper equipment in order to create attachments that ensure the smoothest flow possible, allowing you to experience uniform heat throughout your home.

If you install your underfloor heating without the assistance of a professional, you will know what materials and attachments to select at the hardware store to ensure the successful installation and operation of your floor heating.

But there is an even simpler solution: HCW has devised a pre-assembled panel that lets you install your own floor heating, and this ready-to-use package includes everything you need.

By speaking with our experts, you can confidently begin your project. You can watch our videos for step-by-step instructions in addition to getting precise information about the pre-assembled kit and its accessories. 

To find out how much it will cost to install your heating floor, contact us! 

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