What Type of PEX is the Best to Use for Your Outdoor Wood Furnace? PEX A or PEX B?

What Type of PEX is the Best to Use for Your Outdoor Wood Furnace? PEX A or PEX B?

 Is PEX the best choice to transfer heat from your outdoor wood furnace to your house?

You may be having this question on your mind for quite some time. And I cannot blame you for that!

Who would want to waste all his effort and time he spent preparing firewood and everything for the winter season and only end up frustrated because he did not get the warmth that he expected? Literally NO ONE! 

Also, you don’t want to end up heating the ground instead of heating your home.

So, the answer to your question is absolutely YES!

Since an outdoor wood furnace burns firewood to heat water up to 180 degrees F, you need the best way to get that hot water from your outdoor wood boiler to your home and to any building you want to heat in order to avoid losing any of those precious BTUs. 

And Insulated Underground PEX is the best product in the market to use! It has become the number one option of contractors in the heating and cooling industry and is designed for the efficient transfer of hot water to your house or buildings. 

 What is PEX


PEX—short for Cross-Linked Polyethylene—has been gaining popularity in both the residential market and commercial sector. PEX pipe is made from cross-linked HDPE (high-density polyethylene). The HDPE is melted and continuously extruded into a tube to form a high-performing pipe suitable for a variety of potable and non-potable plumbing applications. It has also been overtaking copper and CPVC because of its flexibility compared to copper and although PEX might freeze, unlike PVC, it would not burst. 

PEX comes in different colors–red, white, blue, white, and grey, but the most commonly used are red for the supply line and blue for the return line However, there are no performance differences between these colors. They are only used to easily distinguish between hot and cold distribution lines. 

But what type of PEX should I use for my outdoor wood furnace?

Well, you are not the only one who asks this question. We get this question once in a while. But some outdoor wood-burning boiler owners already know what they should use. 

There are three types of PEX that are commonly used in the market but only two of these are ideal for underground burial.

Three Types of PEX Tubing

Here are the three types of PEX tubing, but only one is an ideal option for underground systems:


PEX A tubing is the most flexible and softest tubing available, with the maximum degree of cross-linking for the strongest chemical bond. It is manufactured using peroxide. PEX-A tubing is appropriate for burying because its flexibility allows it to expand, especially when exposed to freezing water. PEX A

We got calls from customers who were looking for PEX A. Because they thought that this is the best choice for their outdoor wood stove system. Well, that’s not always the case. 

PEX-A tubing is more likely to leach chemicals from the manufacturing process into the water supply so be mindful that this product still poses some risk. This is why this type is only second when it comes to burying underground.


PEX BPEX B tubing has the highest bursting pressure among the three types of PEX. This is the reason why although PEX-B tubing is less flexible and has a lower cross-link ratio than PEX-A, it is the ideal choice for burying and it is also cost-effective. So if you are determined to bury a length of PEX tubing, the PEX-B tubing should be your first choice. 

PEX B uses insert-type fittings or crimp fittings You just need to fasten it in place with a copper ring, using the crimp tool.

This highest bursting characteristic of PEX B makes it ideal for burying tubing that may be exposed to freezing conditions.  Its non-corrosive substance and a lower likelihood of chemical leaching make PEX-B a more viable choice. Underground Insulated PEX Pipe HEAT MIZER brand uses PEX B tubing



PEX-C tubing is so rigid and is by far the most troublesome PEX tubing to work with. It is made by an irradiation process, thus unsuitable for burying. This means that when exposed to freezing temperatures, the tubing is more prone to kinking and cracking.

What Is The BEST Insulated PEX Pipe Underground For Your Outdoor Wood Stove?

We at OutdoorBoiler.com designed our Underground Insulated PEX Heat Mizer brand with the following important factors:

  • Forever Waterproof
  • Almost zero heat loss
  • Durability
  • Best value, less cost 

    Underground Insulated PEX For Your Outdoor Furnace | Expert Advice on Lowest Heat Loss (Best Value)

Underground Insulated PEX

Those are only the common types of PEX but there is still a lot in the market. Knowing which PEX product to use for your project is important because each is suitable for certain plumbing or heating operation.

Insulated PEX

We are using PEX B tubing with the Wrap style-radiant barrier PEX insulation which uses polyethylene closed-cell material with strong impact damping and chemical resistance characteristics. Its physical properties make it well suited to protecting PEX from cold weather while keeping the heat loss to less than a degree.

Our Heat Mizer pre-insulated pipes for outdoor boilers are protecting thousands of customers nationwide, giving them huge savings each year. Since we have sold more than four million feet of our insulated PEX lines, we have learned a LOT about how to make the best PEX underground water lines over the years and there is a lot of science to our pipe.

Visit OutdoorBoiler.com for the best insulated PEX pipe in the world! Or you can simply call our office at 231-861-8200 with any questions that you may have.