Choosing the Right Underground Insulated Pex Pipe
for your Outdoor Wood Furnace


Underground Insulated Pex Pipe
Pre-made, pre-insulated Pex Pipe

We'll be happy to assist you any
way we can, to make this the
easiest thing you have ever done!









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Pre-Insulated Pex Pipe from $4.97 a foot!


Shaver Outdoor Wood Burning Furnace Outdoor Wood Burning Furnace


ALL types of heating supplies are also available, such as all components
for in floor radiant heat systems, baseboard heating, unit heaters,
heat exchangers, plate exchangers, air handlers, pools, hot tubs
and complete installation kits for everything. Call for pricing!


This is the Easiest System for Self-Installers!

Simply drop it in the ditch and cover with dirt!

Also available with the electrical wire already installed!

pre-insulated pex pipe for outdoors underground

Pre-insulated. Pre-made Pex pipe for outdoors - underground.

Figure that you will just save just $1 a foot, on average, if you insulate it yourself.

$6.00 a foot for 2 Pex pipes insulated  in a 4" pipe.

$7.50 a foot for 4 Pex pipes insulated in a 4" pipe.

Shaver Furnace customers get a 17%-20% discount, making the per-insulated Pex pipe as low as $4.97 a foot/2 lines, $5.97 a foot/3 lines, $6.67 a foot/4 lines



Pre-insulated underground Pex pipe

Pre insulated Pex Pipe for outdoors - underground

What's nice is that you have 4 Pex lines for heating your home and domestic hot water tank too.
This also gives you a fill or supply line for your outdoor furnace. The 4 Pex pipes are
surrounded by insulation - FOUR WRAPS of insulation with a black tile pipe around that.
That is 33% more insulation than triple wrap pipe!
Total Heat loss is only 2-3 degrees F MAX per 100 foot run!

We also have insulated pipe with as little as 0.6
 degrees F per 100 foot run!

Underground insulated Pex pipe for outdoors

For best results and less heat loss (less wood burnt)
always bury Pre-insulated Pex pipe underground, below the Frost Line.

Pre-insulated Pex pipe wrapped four times with insualtion

2 x 1"

All pipe is wrapped FOUR times with insulation as opposed to being only wrapped 2 and 3 times by rur competition - and many use Chinese (junk) Pex!


Insulated Pex pipe for outdoors  
2 x 1" and 2 x 3/4"

(before discount)

Pre-insulated Pex pipe for outdoors. Made to be put underground. Totally insulated with  FOUR wraps insulation.

Our competitors are only wrapped 2 and three times and many use Chinese Pex!

$5.95/foot  (before discount)


Choosing the Right Underground Insulated Pex Pipe
for Your Outdoor Wood Furnace

    There are many options available when it comes to installing the underground pipe for your outdoor wood furnace. Sectional or seamless, foam or foil wrapped, the right underground piping can make a huge difference in how effective your outdoor wood furnace operates.

    It wasn’t too long ago that insulating underground pipe was timely,  difficult and very expensive. To save on cost most homeowners turned to 10 foot sections of insulated 4 inch PVC pipe that had already been available on the market for other specialty plumbing needs. The outside of each pipe was insulated and wrapped with a plastic bag material. Long pieces of Pex pipe were fed through these sections of 4 inch pipes. After threading each section, the pipes would be glued to make them water-tight. The job was awkward, difficult and labor-intense. If the pipe would fill with water, it would cause major heat losses and ruining any advantage of an outdoor wood furnace.

   Other sectional pipes have also come onto the market but they all have the same basic flaw; seams underground. The flexible foam variety not only lack adequate insulation value but are susceptible to water penetration through each and every joint underground.

    Modern underground pipe lines for outdoor wood furnaces have many advantages; namely, there are no seams buried underground. Even within this seamless category there are disadvantages with some.

    Most manufacturers wisely use Pex pipe in their construction. Foam filled varieties may seem to be the best alternative but a deeper investigation proves that foam isn’t the answer.

The insulation itself should also be carefully considered.  Piping used for supplying heat from a hot water source, such as an outdoor wood furnace, loses heat in 3 ways: Convection, Radiation and Conduction.  

is air moving across a surface similar to a radiator or heat exchanger. Convection doesn’t apply when outside air is sealed off, such as in insulated Pex pipe.  R-value, a measure of convection, means little when convection is absent. 

    Radiation is heat moving from hot to cold, Remember high school physics? 

 About Heat Loss/Gain

Click on image for a larger image.

    Radiant heat loss is the most relevant when speaking of underground insulated pipe.  We’ll return to this shortly. 
    Conduction: heat transferred away by the materials surrounding it. Conduction, related to convection and radiation has to do with how heat moves through materials like air, foam or plastic, is best controlled by wisely choosing the proper materials for insulation.  


Click on image for a larger image.
   Foam filled underground pipe use urethane-based foams that limit heat loss based strictly on R-value, trying to limit how much heat is lost to convection.  Foams only limit radiant heat loss by absorbing heat in a slightly limited way and is subject to cracking when rolled up for shipping and then un-rolled at the installation site - because it is so thick and rigid. 

    The best choice for underground lines is a pipe incorporates foil wrapped insulation.  The foil wrapping retains over 97% of the radiant energy back into the pipe, virtually eliminating heat loss.  Foil wrap must be contained.  Strong, flexible corrugated pipe provides a shell of protection for the foil wrap and also creates a space of dead air that serves as a conductive break.  Having the correct corrugated pipe is important, too stiff and it will crack when bent or compressed, too thin and it may be pierced by rocks or other sharp objects in the ground.  After installation this type of underground pipe, expanding foam should be used on each end to seal the air space, eliminating heat loss by convection. 

Use the blue colored can foam; made for doors and windows. When everything is installed and in it's final resting place, tape a cut piece of cardboard securely to both ends of the outer corrugated pipe. Make a small hole the size of the spray nozzle and add foam into each end. Do not add too much. Remember that some expansion will occur. Allow at least 5 hrs. dry time before removing the cardboard. 

Trench for Pre-Insulated Pex Pipe


Insulated Pex pipe installed and ready to cover up with dirt!

This looks like good dirt here; with no big rocks in it. Avoid dropping rocks on the pipe, so that do not damage it. holes in the outer casing will result in water in the pipe, which dramatically increases heat loss!

outdoor wood furnace concrete pad dimensions

 Recommended Dimensions for Concrete Pad

 You only need to put the pipe at exact 45 degree angle, 
if you are making your own insulated Pex and using PVC pipeare you are on aed - 
OR you get cab pre-made insulated Pex from us!




1. Installation kit (includes 2 shut-off valves, a drain and 2 SharkBite fittings) at $71.99 ea.
2. Hot water kit (includes a thermostat, pump flange
    and fittings to attach everything; top and bottom) $72.99
3. Heat exchanger for ductwork  U.S. made: $175 and up (U.S. made-Lifetime Warranty)
4a. SharkBite style fittings for the water to air heat exchanger) $26.21 pr. (elbows), $18.18 pr. (straight)
4b. Fittings for a plate heat exchanger (needed for boilers and snow - ice melt systems)
1 1/4 to 1' reducer couplings $7.56, 3/4 SharkBite style fittings, 1" SharkBite style fittings 11.50/pr
5. Pump for the H/W heater  $90 (3 -speed & 3-yr. warranty)
6. 4 Line Pre-made insulated Pex pipe for $7.99/ft. for a 4" black corrugated pipe with two
    1" Pex pipes and two 3/4" Pex pipes - U.S. made.

Our parts supplier offers a 17% discount to Shaver furnace customers, making the price of the Pex pipe only $6.67/ft. 

3 Line Insulated: Pex 2 X 1" & 1 X 3/4" reg. $7.50/ft.
Discounted 20%  to $5.97/ft. 

2 Line Insulated: Pex 2 X 1" lines Reg. $6.00/ft.   Discounted 17% to $4.97/ft.

(If you only need two Pex pipes, for a garage, for example, you can use our pre-made insulated Pex pipe for $4.97 a foot (for a 4" pipe with two 1" Pex pipes - U.S. made.) Remember you still need a fill line or a way to top off the furnace, if it isn't being hooked up to a hot water heater.

These prices are plus shipping.

Note: The Pex pipe fittings we use are simple, push-on-by-hand Pex fittings




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* Some building codes may allow a homeowner to be their own contractor and do much of the work themselves. In other locales a licensed electrician and plumber may be required to do the actual hookup.
This usually doesn't preclude you from putting in the concrete pad, trench, pipe and wiring.
Check with your local Building inspector's office for information pertaining to your area.