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[Airgap]

No one here believes that dirt makes a good insulator, do they?

In other words. Would any of you think it's a good idea to bury your heating lines in the ground with no insulation at all?

[jackel440]

maybe if it were dry all the time.
The problem is the ground water heat sinks with the tubing and sucks all your heat away.That is the whole reason for burying it in some sort of tube.You have to have a thermal barrier from the tubing and ground moisture.
 Oh yeah and your crazy!

[Airgap]

The reason I mention it is. My wife's uncle has found a guy to build him an OWB. He started digging this weekend, and buried a couple of 1" pex lines in black plastic drain with no insulation....

To which I said, Oh that's how he's doing it so cheap....The uncle said, "He said the ground would insulate it". I said If you run it under your driveway, you won't have to worry about snow. How's that for insulation?.....

[oldchenowth]

I would say that dirt can be insulating to some extent if buried deep enough below frost line.  But any ground water is going to suck the heat right out of the lines but less so with the air gap than direct burial.  I would think you would have to bury so deep it won't be cost effective, might as well save the work and insulate the pex. 

[RSI]

No one here believes that dirt makes a good insulator, do they?

In other words. Would any of you think it's a good idea to bury your heating lines in the ground with no insulation at all?

I don't know about everyone here but I sure wouldn't recommend it. It depends on the dirt but most will conduct heat real well especially if it is wet or damp.

[yoderheating]

I know guys who have used no insulation and then later went back and ran insulated lines several years later. The ones I know cut wood consumption in half when using the insulated line.

[RSI]

I know guys who have used no insulation and then later went back and ran insulated lines several years later. The ones I know cut wood consumption in half when using the insulated line.

Only half? Lol
I would have expected more.

[yoderheating]

 I expect different situations would be different. I do know that one of them had a strip in his yard when no snow would stick no matter how cold it was.

[willieG]

taken from the net......

What is the R-value of soil?
The resistance of soil to heat flow (R-value) varies a great deal, depending on the type of soil and the moisture content. In general, soil is not a good insulator.
For a fine-grained soil with 20 percent moisture content, the R-value is about 1 per foot, roughly the same as concrete.

Because of this low R-value, it is important to insulate foundations, including slabs-on-grade, crawl space walls and full basements. Insulating the first few feet below grade is the most critical area, but we recommend full-depth insulation.

typical closed cell foam like in the underground pipes is about R5 per inch

[Daped01]

I'm pretty sure this is how my dads boiler is run.  Its abou 100' from the house, and all winter long there is a small trench in the snow where its all melting....right where the lines are run.  in the spring, this path is the first to be soft and spongey when the rest of the ground is still frozen.



might have something to do with why the stove is a wood hog as well eh?

[Airgap]

Thanks to all.

Preventing heat loss is the most important thing with an OWB. It's a terrible waste of energy not running insulated lines.

I'm going to try to get my wife's uncle to change out the lines while the ditch is still open. Hopefully he will listen...

[gmviso]

Well the dirt below the frost line is gonna be a constant 50 to 55 degrees which is warmer than the winter air. But if you run 180 degree water in pipes buried directly in it, the dirt is gonna try to suck all that heat out of the water.

When you add the 4" pipe around them, if you could also suspend your water lines without them touching the wall of the 4" pipe maybe that wouldn't be too bad. That is kinda what wrapping them in insulation is doing.

But if they just lay on the bottom of the 4" pipe then they are still going to lose their heat to the earth pretty fast.

Just my 2 cents

[willieG]

air that is in the pipe (if the ends are closed off and no drafts can get in) has a R value of about 1 per inch. i t would be much higher if you could consider it really "dead" but you can not. also you would have to use some sort of spacer to keep your pipes in the middle of the underground pipe

spend your money wisely and insulate your pipes as  best you can afford.