Underground PEX

[all night moe]

Wondering what the current per ft price is?
Looking for 1 1/4'' closed cell foam type. Logstar rebranded.

I need to hold off on adding stoves to this house and feeding the furnace in the basement is a lot of extra work. Wood pile is processed on opposite side of house. OWB to the rescue. I need to put a pad in now and run the pex this spring. Pop up a shed over the boiler, with some room to keep a couple cord inside. Get that done over the summer and I'll only have a boiler to obtain, and it's controls, by fall.

Tried doing a couple on line searches and couldn't find any pricing. Trying to get a rough idea on a spread list.
I'm heating a large semi drafty house with two DHW heaters, that I'm sure I'm going to heat as well.

 

[sloeffle]

$13 - $14 a foot seems to be the going rate these days for 1" from Heatmaster ( Rhinoflex ). I'd expect 1 1/4" to a little more. Call some local Heatmaster or CB dealers in your area to get an idea of what it's going to cost. As I understand it, it's all pretty much the same stuff.

I'm probably going to take on a very similar project this summer too.

 

[brenndatomu]

$13 - $14 a foot seems to be the going rate these days for 1" from Heatmaster ( Rhinoflex ). I'd expect 1 1/4" to a little more. Call some local Heatmaster or CB dealers in your area to get an idea of what it's going to cost. As I understand it, it's all pretty much the same stuff.

I'm probably going to take on a very similar project this summer too.

I think what my folks just bought was about the same price between 1" and 1.25"...the dealer screwed up and brought 1" the first time, had to order a roll of 1.25" for them then...I believe the price was the same, other than maybe extra shipping since the dealer didn't stock 1.25"
And beware that the brands that are smooth on the outside (like Logstor) are much stiffer and hard to work with than brands that have "ripples" on the outside (like Rhinoflex) the smooth ones will have a little larger minimum bend radius too.

Logstor

Rhinoflex

HeatMaster RhinoFlex Foam Insulated Underground pex pipe

Pex Tubing

www.rsiboilers.com

 

[Medic21]

$17 a foot for the 1 1/4”

 

[hedge wood]

I did close cell spray foam in the trench back in 2009 but I needed to run four lines 450 Ft. It still seems to be working great and never have any snow melt on the line.

 

[salecker]

I did foam in trench as well
I ran 4 lines as i could not get any pex over 1" so i have 2 for hot going to the load and 2 return for cold.
I figured if any of the lines did get a leak i could get by with one line and a bigger pump.

 

[all night moe]

Luckily my 150' run is a straight shot. The only bend will be to the boiler.

Now to decide if I'm making my own or crippling my funds. I'm thinking of doing corrugated drain pipe and spray foam. Just have to figure out how to keep spacing between and around the lines. The other way is to run the pex in the trench, hold them up and let the foam flow?

 

[Medic21]

Luckily my 150' run is a straight shot. The only bend will be to the boiler.

Now to decide if I'm making my own or crippling my funds. I'm thinking of doing corrugated drain pipe and spray foam. Just have to figure out how to keep spacing between and around the lines. The other way is to run the pex in the trench, hold them up and let the foam flow?

When I priced it, cost of PEX and cost of spray foaming to make my own vs buying a lifetime warranty pipe wasn’t enough of a difference to not have the warranty for replacement.

I think I would have saved $150 if I remember right and I used 1 1/4” Thermopex which is ID and the largest on the market at the time.

 

[all night moe]

Currently can't get past the sticker shock .....

I may be able to get the foam fairly cheap.

 

[all night moe]

The Rinoflex at 1-1/4 is order 500' roll only. At $14/ft .....

 

[Medic21]

The Rinoflex at 1-1/4 is order 500' roll only. At $14/ft .....

Thermopex comes in 100’ rolls or if you can find someone that sticks it what you need.

Closed cell spray foam is expensive as it’s not the normal for what they would spray your house with. If it’s not closed cell it will take water on.

 

[Medic21]

The Rinoflex at 1-1/4 is order 500' roll only. At $14/ft .....

The kits Lowes and others sell will do about 50 feet for around $800. Another $400 for 1 1/4” pex 100 foot roll from supply house and your at $1200 for 50’ without plastic or digging a trench yet. At $19 a foot it’s cheaper to use Thermopex and you get a lifetime warranty that has someone else doing the work if it fails. Thermopex can be tranches in a lot cheaper than digging a 1’ wide trench.

I can go on and on to why it’s better in the long run to buy a closed cell premade pipe vs make your own. Back when there was only on player in the market it may have been beneficial to make it. Today, you can find a dealer that stocks it and buy what you need.

 

[all night moe]

I'm assuming i need the 1 1/4'' following the "better to go bigger than not to to have enough flow. "

I'm at 4500sq ft with 4 baths and two hot water heaters. 2nd DHW heater is small and just for the kitchen.

 

[brenndatomu]

Our local dealer claims he installs 1" on everything with no issues...

 

[sloeffle]

I'm assuming i need the 1 1/4'' following the "better to go bigger than not to to have enough flow. "

With the distance you are going and the heat load you are expecting I'd get the largest diameter pipe I could stomach buying personally. Lots of threads on the net of folks who put too small of pipe in the ground and have to replace or add more piping later down the road.

 

[Medic21]

I'm assuming i need the 1 1/4'' following the "better to go bigger than not to to have enough flow. "

I'm at 4500sq ft with 4 baths and two hot water heaters. 2nd DHW heater is small and just for the kitchen.

Gpm requirements are roughly BTU/delta T x 500.

Never let your return water drip below 140 due to it creating condensation.

I have 100,000 air exchanger, 30,000 garage heater, 5x12 plate exchanger at around 40,000.

If everything is pulling at once I have a load of 170,000 btu. Delta t of 25 degrees at those times and my requirement is roughly 14gpm.

Next would be to figure head pressure of the system and pump size. Velocity of the water matters and 1” pex would not supply the BTUs I needed to maintain the delta t of 25 max. If I took away the garage heater it would have been right at the edge.

What size is your furnace now, how far is the run, how many elbows, plate or tube for hot water, etc. there are many factors in pipe and circulator sizing.

 

[Medic21]

Our local dealer claims he installs 1" on everything with no issues...

1” with low head and under 140,000btu will work. It will fall under a 15-58 pump very easily. But, at 11gpm it is the very top edge of what 1” pex is capable of. 4500 sq feet is going to roughly need 200,000 btu in a colder climate. 1” won’t even come close to that.

 

[Medic21]

I went with a primary/secondary loop system. There are three pumps now, one for the hot water exchanger, furnace, and one for the garage. Even with the larger pex it would have not worked to go series, by the time it got to my garage it would have been 140 degree water if I was making hot water and heating the house before. This mixes used water back into unused 180 degree water before the next tee.

 

[Medic21]

My domestic hot water dropped to 145 on the return while doing laundry but the return stayed at 145 with my supply at 170 while it was heating the house. Without the secondary loop I would have been supplying the furnace with 145 degree water and returning 135 degree water back to the boiler.

It took awhile for me to make sense and I worked with quite a few professionals to design this.

 

[brenndatomu]

View attachment 292558View attachment 292559
I went with a primary/secondary loop system. There are three pumps now, one for the hot water exchanger, furnace, and one for the garage. Even with the larger pex it would have not worked to go series, by the time it got to my garage it would have been 140 degree water if I was making hot water and heating the house before. This mixes used water back into unused 180 degree water before the next tee.

That's about $5k worth of copper there, at today's prices!

 

[Medic21]

That's about $5k worth of copper there, at today's prices!

😂😂😂🤣

I have about 200’ of 1” and 30’ of 1 1/2”. I got very lucky with a friend that owns a HVAC/Plumbing business. He sold me the copper at wholesale costs. He made his money on the 4 pumps though lol. Cost me twice what I could have bought them for online.

$1200 for all the copper three years ago.

 

[Medic21]

And for the OP I’ll add this. When spending upwards of $15k for a system why would you want to find cheap on the one piece of the system that is 1) the part that heat loss will kill efficiency and, 2) the absolute hardest and most labor intensive to replace?

Skimping on the underground lines is the difference between being happy with the system and questioning every life choice you’ve ever made cutting wood every weekend to stay ahead.

 

[Medic21]

Underground lines - not the place to skimp!

This is a sticky inspired by Tenman, who suggested it as a topic to address one of the most critical components in a boiler system, namely the underground line set for those installations where the boiler and / or storage is in a different building from where the heat load is. Not all installs...

www.hearth.com

It’s been covered and hashed out here and many places. A lot of mistakes out there to learn from.

 

[all night moe]

What size is your furnace now, how far is the run, how many elbows, plate or tube for hot water, etc. there are many factors in pipe and circulator sizing.

I don't currently have an OWB. I am using a add on wood furnace rated for 200 BTUs. It shares the existing duct work for the hot air oil fired furnace that has not fired in over a decade. I plan to convert to hydronic heat, with radiant floor on the first level, and cast rads on the second level. I will run feed lines to the attic and feed the second floor with legs from each rad. This house has been 65-70% remodeled on the interior, making it much easier to feed rads from the attic.

At this point I'm planing ahead of my schedule. Concrete pad, underground lines, then shed by June / July. I will be adding the boiler in the fall. The boiler shed will sit right where I process my firewood. It takes far to much of my time to process the wood, season it, then move it to the opposite side of the house where the bilco doors are to feed the indoor wood furnace. Not to mention this hot air duct system dates to the 50s and sucks. Total run from OWB to house is just under 150'. That is with a little length to spare, so I think my measurements were 141' including a couple feet into foundation and into shed.

I hope I'm painting a clear picture here.

After reading through the sticky thread, I have decided on the manufactured foam lines. I'll eat the cost up front once. 1-1/4" is my best bet.

 

[all night moe]

And for the OP I’ll add this. When spending upwards of $15k for a system why would you want to find cheap on the one piece of the system that is 1) the part that heat loss will kill efficiency and, 2) the absolute hardest and most labor intensive to replace?

Skimping on the underground lines is the difference between being happy with the system and questioning every life choice you’ve ever made cutting wood every weekend to stay ahead.

Underground lines - not the place to skimp!

This is a sticky inspired by Tenman, who suggested it as a topic to address one of the most critical components in a boiler system, namely the underground line set for those installations where the boiler and / or storage is in a different building from where the heat load is. Not all installs...

www.hearth.com

It’s been covered and hashed out here and many places. A lot of mistakes out there to learn from.

I just typed my last post before yours posted.
I couldn't agree more. I'm over the sticker shock after thoroughly thinking things through.