Thread: What type of insulation for underground pipes?

Help what to use???????????????

Trunk insulation. Foil backing on two inch fiberglass. Check Menards. Kind of like what you'd wrap a water heater in. Not weather proof by any means so I would assume you'd run it in pvc or draintile.

it needs to be closed cell foam to be very effective. Once fiberglass is full of ground water or compressed it is not much R value. It only insulates by the air in it. The insulated and plastic covered pipe with one or more pex lines inside are hard to beat for insulation value and convenience but are a bit pricey.

Pre-insulated lines best, but pricey ($13/ft. or slightly less, on avg.) or spray foam in the ditch over/under the pipe.

Originally Posted by MNGuns

Trunk insulation. Foil backing on two inch fiberglass. Check Menards. Kind of like what you'd wrap a water heater in. Not weather proof by any means so I would assume you'd run it in pvc or draintile.

Foil needs an air space to do ANYTHING. It's a radiant barrier. If it's touching, it's conducting.


Fiberglass underground? In DRAINTILE?!?!?!?

Watch all your hard work go into heating the soil!!



Closed cell foam. Period.


Or don't bother.

I have a very short run and used a product similiar to this.



I fear no heat loss..

Originally Posted by Crofter

it needs to be closed cell foam to be very effective. Once fiberglass is full of ground water or compressed it is not much R value. It only insulates by the air in it. The insulated and plastic covered pipe with one or more pex lines inside are hard to beat for insulation value and convenience but are a bit pricey.

This is correct. One the fiberglass gets wet, it is junk. SOLID drain tile is required for this method, and take care to seal the ends so as to prevent water from entering. Ideally the foamed PEX with the plastic liner is certainly best. At $13 a foot, I'll take my chances with something else. If I'm wrong, I'll burn a little more wod and try something different next year.

I don't have an outdoor burner and have never even helped install one but from all the reading I have done the most common complaint is heat loss. Going cheap on the transfer pipe doesn't sound like a good idea to me. I'm sure someone on here has the efficiency ratings for different materials. I've seen some pretty stupid setups before or at least ones that looked stupid to me.

Originally Posted by MNGuns

I have a very short run and used a product similiar to this.



I fear no heat loss..

Yes just use this works fine for me i was told when i bought it that it will work fine as long as it dont get wet. Therefore keep it in a non-perf tile and you are good to go

It doesnt have any insulation between feed and return so you lose efficiency with lower water temperature at your radiators and the return temperature is higher so you lose some efficiency at the boiler end too. If you can keep the insulation from sucking up groundwater it will work but will use more wood. If the wood is cheap not a big deal but if you are paying top dollar buying wood it likely would pay to go the better pipe.

Originally Posted by Crofter

It doesnt have any insulation between feed and return so you lose efficiency with lower water temperature at your radiators and the return temperature is higher so you lose some efficiency at the boiler end too. If you can keep the insulation from sucking up groundwater it will work but will use more wood. If the wood is cheap not a big deal but if you are paying top dollar buying wood it likely would pay to go the better pipe.

I make no claim to be an expert, but....speaking with my CB dealer who of course recommended the foamed PEX, also commented that the lines touching has minimal impact as in a simple forced air setup the temp of the return is on average 10 degrees less than the input. Perhaps with infloor or a larger setup it would be more important, but for a simple setup as is mine, I think it will do.

If you are only dropping the temperature 10 degrees the line to line loss would be quite small. Have you estimated what your cost per foot will be to stuff your own. That O tube is a bit ch to drag anything through that is not very slippery. How many feet boiler to house?

Has anyone used the product of ebay http://cgi.ebay.ca/OUTDOOR-WOOD-FURN...QQcmdZViewItem or had any dealings with this company. They call it a quad wrap product

Originally Posted by MNGuns

This is correct. One the fiberglass gets wet, it is junk. SOLID drain tile is required for this method, and take care to seal the ends so as to prevent water from entering. Ideally the foamed PEX with the plastic liner is certainly best. At $13 a foot, I'll take my chances with something else. If I'm wrong, I'll burn a little more wod and try something different next year.

Why not do it right the first time and be done with it?If what you use dose'nt work,you have that money plus the money for the good stuff added together plus tearing up the yard again and having to pay for the second excavation as well.You know that you shopped around and priced and looked at different models of boilers until you made the choice that was right for you,why would you shortchange yourself at the end of the process?

The part that gripes me is that few (if any) of the insulation suppliers quote an accurate (and independently verified) R value for their insulation.

Beware of the bubble type insulation, it is designed for blocking radiant heat transfer, not conduction. The Federal Trade Commission filed a order on one of the larger suppliers for making false claims on the performance of their product.

I'm getting ready to install a Hardy H-2, 60 feet from the house which requires 4 lines (2 for space heating, 2 for water heating). I plan on putting each line in its own 4" corrugated pipe, with ARMAFLEX insulation rated at R-5 on each pipe and then boxing the 4 pipes in a "box" of 2" foam board rated at R-10, which will give me a net insulation value of greater than R-15 when you include the air space in the 4" corrugated pipe.

Just my .02 worth.