PEX Pipe Systems for Remote Outdoor Furnace Connection

PEX Pipe Systems for Remote Outdoor Furnace Connection

For more than a decade, PEX—short for Cross-Linked Polyethylene—has been gaining popularity in both the residential market and commercial sector. The development of outdoor wood boilers has enhanced the demand for underground PEX systems for remote boiler installations. Because it does not corrode and comes in vast lengths, PEX is perfect for connecting outdoor boilers to remote or detached structures.

If you will bury pex underground, it should be buried below the frost line and should be well insulated and enclosed in a plastic, durable, and flexible waterproof outer casing. If properly installed, these pex underground water lines lose very little heat and will last for many decades. 

Choosing the Proper Size and Length of Pex Pipe

For an outdoor wood boiler system, we recommend installing it at least 30ft away from your house or any building heated by the boiler. Many outdoor wood stove owners prefer to install their system 100ft away from their building or farther for safety purposes. Be sure to follow the Hearth, Patio & Barbecue Association (HPBA) Best Burn Guide. If you are done measuring the distance from your boiler to your building, we recommend adding 10ft to that length.

For the size of PEX, 1" is most common for the job. It can be used even up to 150-200 ft run. In fact, we do have customers who still use 1” PEX for 250 ft or longer. For non-pressurized boilers, PEX piping without an O2 barrier can be used. 

Underground PEX Insulation

Just like your outdoor wood furnace, PEX and its installation should  be considered as a heating system investment. Remember that you have spent a significant amount of money, time, and effort in buying and installing your pex buried underground, so it would be frustrating if you have to do everything all over again because your underground pipe has failed.Failed PEX Pipe

We have heard about some customers who attempted to insulate their pipes with homemade contraptions. 


These folks notice that snow melted between their boiler and their house. The water leaves their boiler at 180 degrees but reaches their house at 140 degrees. So they realized that instead of bringing that precious energy to their house, they ended up heating the ground.Heat Loss


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

  • Almost Zero heat loss
  • Durability
  • Best Value! Less Cost!

You are using an outdoor wood burner to heat your home in order to save money. You don’t have to overspend. Some products in the market cost more than double what they should spend. 

How To Get The Best Value On Insulated PEX? Heat Mizer Brand!

  • Outer Casing is "Forever Waterproof" 
  • Less than one degree of heat loss over 100 feet!
  • Industry Leading Warranty - Full Replacement Coverage, including LABOR!
  • Perfect Performance Record - Over 1 Million Sold and ZERO Failures
  • Experts Agree! Our proprietary design has been PERFECTED for over 30 years!
  • Best QUALITY, Best PRICE, Best VALUE!


Underground Insulated PEX Pipe

We offer two sizes of PEX, 1” which is usually used, and 1 ¼” if you need a bigger size. Some of our customers choose 1 ¼” when they're heating more than 2 buildings or if they are also heating a pool and a spa.

PEX Sizes

Never splice Insulated PEX UNDERGROUND

Spliced underground pex water pipe fails 100% of the time. We make every roll custom-made to your ordered length. We will make you the exact length you need.

If you need 137 feet, we won't force you to buy 150'. But please measure the distance required and add 10 feet for the sweep into the back of the boiler, and to go through the wall into your building at least 3 feet. Measure twice, cut once.

Why are End Caps necessary for underground insulated PEX pipe?

Another essential thing to consider aside from the pipe insulation is to keep water from entering the outer casing of the pipe. Heat Mizer Insulated PEX is creatively designed with some air space between the insulation and the outer casing to make the radiant barrier effective.

End Caps

You don't want that air space to fill with water. Water can quickly damage the insulation if it enters the pipe so you need to have a proper seal on both ends of the pipe. A simple pex pipe cap on the end of his Insulated PEX in the back of the boiler would have prevented this. Also, we want to avoid any moisture or humidity entering the insulated PEX from inside the home so we recommend using pex caps on both ends of the Insulated PEX. Our end caps create a dead air space plus keep moisture and critters out. 


Visit or Call us at (888) Log-Burn or (231) 861-8200 with any questions.