I’ve been pricing oxygen-barrier PEX tubing for my addition project and wanted to see what people were paying out there for 1/2″ nominal oxygen-barrier PEX tubing. Even with an OEM discount through work, it’s still pretty spendy stuff for the quantity I require, especially if I want to do everything “home-run” with single supply and return distribution manifolds in the basement.
FYI, I’m planning to replace an ancient thermosiphon boiler in my existing house with a modern non-condensing boiler. I’m leaving the old cast iron rads and distribution piping in place and adding a new circulator for them, and supplying my new tubing loops via a separate circulator with a tempering valve arrangement to supply this loop. Since I need a hot water circuit for the rads anyway, there’s no benefit to going to a modulating condensing boiler in my application from what I can see. There would also seem to be little benefit on spending the extra money for aluminum spreader plates or a warm-floor type product (or DIY subfloor sandwich) for my 1st and 2nd floors because the boiler efficiency won’t go up anyway- I’ll still be using flue gas to heat water to ~ 180 F for the rads regardless how low my PEX tube water temperatures go. I’m not so fussy over heat-striping etc.- heck, if I can tolerate rads I can tolerate some hot spots in my floor.
My impression from talking with salesmen and seeing samples and reading the sales literature is that the IPEX Kitec composite PEX-Al-PEX tubing seems to be a superior product overall. Pricing matches- it’s being offered to me at roughly 30% premium to the Wirsbo HE-PEX product. The Kitec material stays bent when bent, which to me seems helpful for about 1/2 of the tubing which will be cast into the basement and garage/shop slabs. The tooling required to get started isn’t expensive- but using this stuff in a staple-up application (the other 1/2 of the tubing) I can imagine would be tough going.
The Wirsbo stuff is considerably cheaper, but has what I would consider to be a less effective oxygen barrier, and doesn’t remain bent when bent, requiring much more labour to tie it off to rebar or wire mesh during the slab installations but making the job of staple-up installation for the other half of the tubing a much easier proposition. But the tooling- man they charge a lot of money for their expander tool! It would eat a significant fraction of the savings over going with Kitec. Suppose I could buy one and sell it after the job on E-Bay, but it still irks me- seems like really bad value for money. Yes I know they offer a compression-style fitting but I’d prefer to use the more secure expanded ring method if I can.
I’m not planning to mix systems.
I know there are people here married to one or the other product, and I’ve gone through old threads using the search function to see people’s past opinions on the systems, but I would appreciate it if a few of you could freshen up your opinion on the merits of the two systems for what I’m planning to do.
Since pricing’s kind of a private competitive thing, I’ll understand if you don’t want to post your pricing here- feel free to send me an e-mail to let me know (rough idea) via my profile and I’ll tell you what I’m being offered here in Canadian dollars.
Thanks in advance for your help!
Replies
I don't think I can address all your questions, but:
Kitec definitely has a more durable O2 barrier. The Al sheathing will outperform a PEX coating. No suprise there.
That said, is the Wirsbo barrier effective enough? Most certainly.
Dual use (some slab and some staple-up)? It's much easier to run Wirsbo in a staple-up. Trying to pull the Kitec through joist holes and then "flipping" it to get the end-of-loop twist can be done, but I find the Wirsbo easier for pulling through joist holes and running as a staple-up. Probably a personal preference there based upon technique.
You're correct in that Kitec is great as there's no springback when it's bent. Set the bend and it stays. That does make it easier for top-of-floor serpentine runs or for WWM tie-offs.
Still, if doing both...in-slab and staple-up and going with just one type of PEX, I'd throw my hat towards Wirsbo.
With homerun setups your only connections are going to be at the manifold. With RFH your system will be runing at about 12psi. Compression fittings would work fine there. I'm pretty conservative and I wouldn't be distressed at having compression fittings on my manifold...which I just happen to have, for what that's worth.
Domestic water under 40-60psi? Yeah, then I'd want something different...especially if transitions are being buried in the wall.
You can always buy Wirsbo tools on eBay (or buy them new) then resell them on eBay when you're done.
Thanks all for the advice. It seems to me that this time it's a win-win situation: Wirsbo seems to be the most suitable product from the standpoint of both the staple-up installation AND the lower per-foot price. It also sounds like the Wirsbo stuff isn't all that big a deal to tie off to rebar/wire mesh. I'm a little concerned about the longevity of my rads and rad supply piping given the poorer O2 barrier, but since half of this tubing will be buried in slabs (adding yet another oxygen diffusion barrier), my concern on that one isn't too serious either.
I'm not worried so much about the per-foot cost- but man, the tubing for this job is EXPENSIVE. The tubing I require, even at my OEM discount, will cost me a significant fraction of what I spent on all the lumber for my 1st floor. So I'm not quibbling over a few bucks here. Rather, I'm doing what I do on all aspects of this project: figuring out what I need to be happy with the finished product, and then looking for the best value for the money I need to spend to get it done.
I'm going to look into their compression fittings, because the pricing of the expander tool is just nuts- even on E-Bay. I have absolutely no problems with compression fittings in general, since I'm quite familiar with them in services which make this one look like a joke. But with plastic tubing in a thermal cycling operation with a LONG lifetime, I am a little concerned about future leakage even at 12 psig. None of my terminations will be buried behind walls- I'll have a trimmed-off access panel for any place I have a connection, regardless what sort of connectors are used. In fact I think I may put an access panel and manifolds for the loops on each floor rather than building a giant octopus in the basement.
As to the condensing boiler, the point of running the rads with lower water temperatures is definitely worth considering. With a circulator, at least all sections of all rads will be full of water with similar temperature, which isn't the case with the old thermosiphon system. That will mean I can use the remaining rads at lower temperatures than they're currently running to generate the same heating duty, and I doubt they get beyond 180 F supply more than a few times a year as it stands.
I'm not trying to sway you, but just want to make sure you;ve seen all the options.
Have you looked at the manual expander tool? I agree that at $1000+, the penumatic and battery ones are priced high, but the manual one, even new, is maybe $125-$150. If you're just using one size of tubing, a single head goes for maye $60-$75 or so. For $200 you can get a brand new manual expander setup.
Then you can resell it on eBay.
Compare that to how may compression fittings you'll need and their cost.
IMHO you are splitting hairs regarding the price per foot of PEX, when you compare that cost as a percentage of the total project cost. The labor cost of installation...even if you price yourself at a lower-than-contractor DIY $ per hour.....will still be the biggest chunk. Trying to get savings there will be more worth it I think. After all is said and done, you'll forget what you paid for the PEX alot quicker than how much time/$ you spent putting it in.
I also think you are over estimating the time and trouble of tying regular PEX to re-bar versus Kitec. So what if it stays bent? I really believe the main atvantage of Kitec, with the aluminum, is it's superior ability to transfer heat.
I wanted to add this and my reply hasn;t been posted yet, so here's a new one:
I prefer Kitec for some DW use. I like the "rigidity" of the tubing in that it doesn't wander as much as Wirsbo when stapled off to framing, and it doesn't sag as much as Wirsbo when undergoing a delta-T as with a hot water system.
Something that I have been confused with, but not sure about. I have never used PEX, but would like to know so that I am prepared the first time that I use it.I know that each (or many) brands of PEX have their own connector system.But is the tubing standardized (IE, ID and OD) so that I would pick one brand of tools/connectors and use with the other brands of tubing?
Wirsbo is the main brand but the Uponor Wirsbo group produces both PEXa and holds the patents for the Pex-Al-Pex extruded and sold under IPEX's Kitec brand and the Wirsbo's Multicor brand.Just wanted to make sure apples to apples were compared when evaluating products.
RBean
web: http://www.healthyheating.com
blog: http://wonderfulwombs.typepad.com
Bill,
I know that some "generic" but good quality brass compression fittings will fit several types of tubing. I honestly don't know the manufacturer...they're several dollars a piece and they're what the supply house hands me when I ask for a certain sized brass compression fitting. Can I be any more vague?<g>
I've used those fittings on Wirsbo and to other types of tubing. They passed a pressure test on all three. For the past several years all I've used is Wirsbo. it's the more easily obtained tubing in my area. Simply better marketing/advertising.
You do have the proprietary tools that work with the proprietary fittings. As you've discovered, the tools, as well as the fittings, can be pricey. But the resale market for the tools has always been pretty stable. You should be able to sell a used tool for the price you bought it for.
Not all tubing has the same wall thickness. At least not in the past.
"Not all tubing has the same wall thickness. At least not in the past."I suspect that the kind of thing that I would use PEX are probably small specialized repair type of applications.For example my friend has a house with an addtion. The addition has a garage under part of it and the other part has was built over an old patio or garage. The joist are about 6" above a slab. They put a 2nd water heater in the new garage. It only serves washer and 1/2 bath.When she moved in the old WH as DOA and if she had not already gotten a new one I want to see if I could fish PEX from under that area and then feed it old part of the house.
I've used/use both. My problem with kitec is that when you run a wheelbarrow of concrete over it, there is a small dimple left in the pipe. Even when covered with plywood and full of air to 80psi. If you want an alternative to wirsbo,check out rehau. I like their manifolds.
All pipe needs to be tied down, it tends to float to the top.
We generally use the pexalpex to feed radiators, cast iron baseboard, etc. Awesome for that. Its a situation where you are using it's stiffness to your advantage. Would be a nightmare for radiant. Definitely doing it the hard way.
After using Wirsbo for a good while, we are now totally sold on the Mr. Pex tubing. This carries all the ASTM certs and pressure ratings as Wirsbo, except it is so much more flexible! Really, I wouldn't use anything else. There's no comparison.
BTW, most just ziptie the tubing to the wire mesh when doing a slab, fast and easy.
I would use compression type fittings, and spend the money on the expansion tool to buy a air stapler for the staple up work, we got one last year and it's a real time saver.
Also, regarding condensing boilers-consider that you don't need at 180 deg water every day of the winter do you? granted I don't know much about toronto's winters.
Having a condensing boiler makes alot of sense if you have several months of winter that aren't bitter cold, so you can run lower water temps, which costs less obviously.
Also, if you have done any sort of upgrade to insulation/airsealing, you will find that you can lower water temps year round anyway, especially given that most cast iron rads are oversized anyway for the rooms they serve.
A room needs a certain BTU output, and if you can meet that output with lower water temps, it's free money.
I bought Mr. Pex tubing for my basement slab, and it was great to work with. We took a piece and tried to hurt it, and it was tough stuff - we got it to kink, but rolling 15 yards of concrete over it with wheelbarrows didn't even scratch it. I was told that I should use some synthetic rubber stuff for staple-up, but I'm not sure I want to mix brands.
I ziptied all my tubing to the mesh as well - worked great but I used about two thousand zipties....
Hot water is being supplied by a Central Boiler outdoor wood furnace with propane backup and an Amtrol Boilermate for HW storage.
Isn't Kitec the one that was involved in all those
tract houses in Washington state with exploding
walls? PEX walls going boom in the night. Scary.
Got a link?
Here's the link to the local news story, in which the failed pipe is claimed to be Plasco:
http://www.kirotv.com/money/1954263/detail.html
edited quote from story
>>
"[I] turned on the light and all I saw was water," says Melanie Hoshino.
It was Christmas morning when Hoshino found hot water gushing from these plastic pipes in the garage of her three-year-old condo.
Hoshino: "It was actually coming out of the tubes."
Emerman: "Like the water, like there was breaks in them or something?"
Hoshino: "There was. I was definitely frantic."
But since Christmas Day she's had two more ruptures, the last one while a repairman was still on site.
"And on his way out, on the driveway, we looked back and a couple more had burst," Hoshino said.
"The time bomb isn't ticking anymore, it already went off...but the real problem is it's our lives tied up in these places," said homeowner Lex Reis.
So far, almost half of Hoshino's 57 neighbors have had similar failures.
"The water was just gushing out," said Carmen Ey.
"The pipes had broken and they'd been spewing 180 degree water in my garage all day," said Luanne Wing.
<!---->
And here's the Heatinghelp.com thread in which the failed pipe is claimed to be Kitec:
http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=22688&mc=9#Top
I'm not so sanguine about using PEX after reading this.
Thanks for the links. Been watching the one at the Wall.
Not trying to soft sell the stories, but for those reading the links, there are two different stories.
The plasco pipe may have been exposed to uv for a period of time, but to me the bigger point is that it is a combined dhw and open heating system. Not a good idea at the best of times.
The kitec story is still ongoing, and many of us are waiting for an answer.
Edited 6/20/2005 2:21 am ET by rich1
"Since I need a hot water circuit for the rads anyway, there's no benefit to going to a modulating condensing boiler in my application from what I can see. There would also seem to be little benefit on spending the extra money for aluminum spreader plates or a warm-floor type product (or DIY subfloor sandwich) for my 1st and 2nd floors because the boiler efficiency won't go up anyway- I'll still be using flue gas to heat water to ~ 180 F for the rads regardless how low my PEX tube water temperatures go."
If you run an outdoor reset setup, your supply temps can be much lower than 180 for most days of the year, even on the CI radiators. Much more comfortable besides.
Some modulating/condensing boilers have controls that allow the water temp to be set dynamically right at the boiler based upon outdoor reset (or other inputs). This can both save energy and simplify downstream controls. Also, they allow for a fixed high temp priority zone for domestic hot water.
With transfer plates, you can supply lower water temps than without (all else being equal).
Dunno csnow- I actually like to feel the radiated heat from a hot rad on a cold morning. Granted, I guess you get the same effect if you have a larger radiating surface at lower temperatures- you still feel warmer than you would in air of that temperature without the infrared shining on you.
As far as thermal efficiency is concerned, for a given boiler, what matters is the difference in temperature between the water circulating through the boiler and the exiting flue gas, right? The flue gas is the only source of heat here, and if I run the boiler circ water colder what we're talking about is milking ten or twenty degrees more sensible heat, plus maybe the heat of condensation of (part of) the combustion product water, out of each pound of flue gas that leaves the house via the stack.
If that's the case, unless I eliminate the rads or run them significantly colder, the main circuit for the rads will be running through the boiler, and that will be much hotter water than in the tempered loop for the PEX tubing circuits under the floors and in the slabs. It's a given that I need the rad water significantly hotter than my PEX tubing will need, even without transfer plates. Hence I won't be gaining any thermal efficiency benefit regardless how hot I need to run the PEX tubing in the floors to give the required heat duty to each room to overcome losses. So the aluminum heat transfer plates definitely will be a waste of money in my case, since I've already said that I don't care about heat striping etc. Good thing too- I'm already b*tching about the cost of the tubing itself- the heat transfer plates are even more expensive!
"If that's the case, unless I eliminate the rads or run them significantly colder, the main circuit for the rads will be running through the boiler, and that will be much hotter water than in the tempered loop for the PEX tubing circuits under the floors and in the slabs."
In most cases, spaces with CI radiators are over-radiated, and coupled with an oversized boiler. Think about how long your current boiler cycle is on a moderate heating day with 180 degree water. Odds are, it will be be a fairly short cycle, then the boiler will cut out, but the residual heat in the CI rads will have the space overshooting the thermostat setting significantly. Now imagine a longer cycle with 120 degree water. The temperature will stay within a narrower range, and you will be more comfortable. Lower return temps will result in better boiler heat transfer efficiency. Condensing appliances generally want to run below 135 degrees supply to stay in their sweet condensing range (lower is still better, but there is an important breakpoint around here). The high mass of a CI rad system couples very well with low mass boilers.
"Good thing too- I'm already b*tching about the cost of the tubing itself- the heat transfer plates are even more expensive!"
With transfer plates, you could potentially use less tubing.
csnow: I buy your argument. Thanks for talking me back out of the non-condensing boiler. I think I can run these rads a lot cooler than they do now with the old thermosiphon boiler, and it would be a shame to throw away a little extra thermal efficiency to save a few bucks in capital. With my varied heat load over the seasons, a modulating unit is very appealing too.
Forget about the transfer plates- as expensive as the tubing is, those plates are way moreso. The choices are either one or two passes of tubing per joist bay because I'm definitely going staple-up. One pass per joist bay isn't going to cut it even with the plates. Heated subfloor isn't an option because I'm replacing some rads which adjoin the addition, and the areas in question already have finished floors in good condition so they're staying put.
This link takes you to a thermography photo comparison of different radiant installation methods. Notice the "thermal density" or "consistency" among methods. You can actually see how your staple up will thermally perform with or without plates. Once you've looked at the photo's imagine what a single tube per joist bay will do - with or without plates.http://wonderfulwombs.typepad.com/photos/tresure_chest/picture3jpg.htmlRBean
web: http://www.healthyheating.com
blog: http://wonderfulwombs.typepad.com
csnow is giving you great advice. Think about putting thermostatic radiator valves on the rads, and using outdoor reset. As was said, with a modulating boiler, you will be simmering along, and the circ will pretty much run all the time. Think mini zones for each room. Nice even heat baby.
Seriously, ditch the wirsbo tubing. we get Mr. Pex from houseneeds.com in Vermont. Call the guy and tell him you are in the trade, (sounds like you are) and he can arrange discounts. Better tubing by a mile, and makes a hard job easier.
Outdoor reset's a definite. I'll take a look at putting thermostatic valves on the big rads that remain- I get your drift. As to the Mr. PEX tubing, it's a bit late but I thank you for the suggestion- someone else will benefit no doubt.
As to the thermography- I have visited Mr. Heatinghelp's site before and thank him for the valuable information given there. But I don't see the point of the plates for my situation still. Tubing will need to run hotter at a given length without plates than with them, but that doesn't matter in my situation since the boiler will need to run even hotter than that to make the rads useful- I'll still be running my tubing off a separate tempered loop with its own circulator. As to going with a single pass of tubing per joist bay with plates versus doing two passes per bay without, the latter's both cheaper and easier to install so it's a no brainer. From what I saw in the thermographs, the less thermally coupled the tubing was to the floor, the more uniform the heating of the floor surface was. Suspended tubing gave the most thermal uniformity in the flooring, followed by staple-up, though granted these would also give the highest water operating temperatures to obtain a given duty.
Hi. m.m It seems we're "alloys" in respect to an appreciation of radiant heating as well!, I'm sorry I can't help with pricing: the Wirsbo I bought was 1.25 ID (1000' coil) and the Kitec was 3/4" ID (2000'). Apples to Oranges so to speak. I chose the Kitec for my slab as I think that an O2 barrier on the outside of tubing (like Wirsbo) that expands and contracts within an abrasive mat'l like concrete will eventually wear off over the decades. I was also concerned that any tubing expansion during the pressurized portion of my pour (65 PSI) would result in less than intimate contact between concrete and tubing once the pressure was released & the tubing returned to size when the concrete was finished curing. I like it tight! you might say. (I feel the Kitec will expand less with the same applied pressure). I used the Wirsbo for my Supply & Return lines & had no particular complaints to report. A small caveat with the Kitec: major kinks are not as easy to fix as on the Wirsbo, they need to be cut out & spliced with 2 compression connectors vs. a simple but careful heating of the kink on the Wirsbo. I was able to avoid any connections within my slab and feel OK with the brass and O-ring compression connections at my manifolds (on both Wirsbo & Kitec) I can retighten if need be and/or replace the O-rings if leaks develop down the road. The Wirsbo connectors were dear at approx. $35 CAD ea. I seem to remember. I echo the poster who cautions against denting the Kitec: walk softly during your pour.