Copper Radiant

Brad White_119

Copper still has a following for above-slab applications. There was a posting here some months ago of an astounding in-floor (grooved in plywood) job; I forget who posted it but it was absolute artistry.


I would say previously to recent copper price increases, and especially with the current situation, cost was and is a definite factor. Threading PEX or PAP into joists I would submit is faster than either coiled soft-temper copper or hard-temper tubing, with or without plates.

Flexibility, connections to manifolds, minimal "hot work" in and around wooden structures also has to be a factor.

Labor has to be less, not to mention the safety aspects.

You are correct on conductivity of course but the overall value of the PEX's is reinforced on every project in real-time economic models.

Worth bringing up! What I love about The Wall is that the old edict, "because it was always done that way", is continually challenged.

My $0.02

Brad

brucewo1b

Copper Radiant

I have a question. We all know copper was abandoned as a tubling material for in slab radiant heat.Goodbye and good riddance. But what about underfloor applications? Why isn't it advocated for between the joists installs. With conductivity vastly superior to Pex,copper seems a natural for floor cavity hydronics.No more expensive noist aluminum transfer plates.No more fighting hostile plastic tubing through endless joist bays.When you add up all the costs,copper is NOT a lot more expensaive than Pex.It has a PROVEN longevity in contact with air.More heat at lower water temperature.
Am I missing something here?

hr

expansion movement

is another issue. I'd still bet pex in good transfer plates would out perform bare copper tube in a joist bay. Especially if there is no conduction contact involved with the copper installation.

I did install a copper in nT-Fin in a shop ceiling, exposed. Yes, it does make some ticking sound as predicted, but the owner was willing to try it anyways. I used PAP for the loop ends for expansion movement. The heat output is almost instant.

I've thought about trying that coated copper for an in slab radiant. The thin plastic coat would handle the electrolsis and external corrosion and you would get the superior heat transfer.

Price and workability keep me from going down that road.

hot rod

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Gordy_2

Gordy_2

Gordy_2

Gordy_2

Ken_40

Copper has NOT

been abandoned for concrete radiant!

It is still by far the highest performer of any commonly available material. Since most radiant installs are "high end" to begin with, why not go the extra mile and use it anywhere a radiant application is sugested? No proprietary fittings, no oxygen barrier worries. Easy to repair or adapt to any situation, roughly 1,000 times the thermal output in many applications, just harder to install and a tad more expensive per foot, but given its thermal properties, jobs require far less L.F. of copper (and wider spacing) than plastics...

Ask the customer. "Would you prefer plastic tubing - or copper"? Guess what they'll say almost every time?

We stil service a large number of Levittown radiant slab homes with copper tube radiant in place. That's over 55 years of being buried in concrete and still functioning perfectly well.

Show me a plastic radiant job that can equal that!

Gordy

Pex vs Copper

Do a search for thread pex versus copper. I did the kitchen floor in copper before the jump in price.

Gordy

jp_2

maybe not?!

sure copper out performs pex in conduction BUT, the tubing is not the only part of the conducting system.

just like "weakest link in the chain", the slowest heat conducting material will be the 'weakest link'. I'd guess the plywood on the floor, or hardwood, carpeting, etc...

corvettes go no faster in traffic than the Yugo in front of it.

Brad White_9

That's right, Gordy

Yours was the posting I mentioned above. Outstanding and I bet, toasty.

Unknown

Copper is a lot more work, and especially these days a lot more material cost, for not a lot more benefit. It is technically better at heat transfer. However, the resistance of PEX to heat transfer is not much of a limiting factor here compared to all the other factors at work.

Gordy

Works beautiful Brad. I actually decided to hook it up to a little 2.5 gal ariston electric water heater with a laing pump. Makes a nice floor warming package. To bad electric rates are .09 a kilowatt costs about 20 bucks a month to run. But I can actually make my wife say her feet are too hot...mission accomplished.
The kitchen, and rest of the house is heated via ceiling radiant, and floor radiant in the basement. I will tie the floor warming loops in the kitchen to the rest of the system eventually when a mod/con choice is made.

Gordy

Gordy

Depends

It all depends on where you decide to put that tubing of any kind. Imbedded is best.

Al Corelli

Copper Radiant Job

You should have installed lexan floors. That install was beautiful!

Gordy

Thanks Al

Throw in some rope lights your idea would make a heck of a dance floor.

Seriously I don't think copper for a underfloor plate or staple up install is the answer over pex, labor or material. In that type of application conductivity is severely lost unless you use plates with the copper noise to follow.

I have the chase copper and brass pamphlets from my ceiling radiant with photos of the ole boys installing those big rolls of soft copper overhead. Those boys earned their money.

Gordy

brucewo1b

Science and the Market

Seems to me a little science needs to be thrown at this issue,something along the lines of the Kansas study on pex and plates.With copper's radiant efficiencies so much higher than plastic,I question the need for plates with CU.Lose the plates and copper installs become cheaper than pex.
Say it ain't so,Joe.

Gordy_2

DUDE

It aint so, have you priced copper lately?? Science is applied to this topic its called conduction, or contact area of the tubing to transfer the heat where it needs to go. In an under floor application you need all the conduction you can muster to keep your water temps as low as possible.

Type L copper tubing 3.14 lf.

1/2" barrior pex .35 lf.

Extruded plates 4"x 48" 7.48

ScottMP

Gordy

Could you post those pictures again Please,I missed them.

As always Ken opens my eyes to another side of our work. I agree that the labor install and the price of copper may make this type of install less compeditive. But when Ken says that its 1,000 times the conductivity, I am sure there's some science behind his statement.

Scott

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Gordy_2

Geek squad has my desktop for over haul I will see if I can find them on my backups tonight. I love copper but china has made the price out there.

Ken_40

DUDE...

True, PEX is cheaper than C by a large percentage but:

1) A PEX ell is 12 times as much as a C ell.

2) A PEX coupling has the restrictive value of ~ 30' of PEX vs. a C coupling has NO restriictive value, and is again; 1/12th the cost.

3) PEX manifolds and ZV's are far more costly than a simple tee, and reducing tees in plastic? Fawgettabowdit!

4) You need roughly twice as much PEX as as copper for equal outputs AND higher temps for PEX than C too!

5) Sunlight damage, voided warrantees? No problem with C

6) No one ever sued a C manufacturer into bancruptcy over a bad run of leak-prone radiant tube (Heatway).

7) C does not "kink" as easily as PEX

8) No uncoiler required.

9) C has no "high limit damage potential.

I suggest the cost of materials debate is a draw. The labor (as long as you are lucky enough to never have a PEX kink) would certainly favor PEX.

Guess which material I used in my own just completed house?

Couderay

copper

Copper is the only way to go for me.I have it installed in basement floor and it works great. Used type L in 60' coils one B-tank,sill-foss and away I went. Had a swedge-a-matic to make joints a definate time saver. But yes the price of copper sure puts a kink in pricing.

Couderay

copper

Copper is the only way to go for me.I have it installed in basement floor and it works great. Used type L in 60' coils one B-tank,sill-foss and away I went. Had a swedge-a-matic to make joints a definate time saver. But yes the price of copper sure puts a kink in pricing.

Gordy_2

You Got Me Ken !

Figuring in the accessories does add up, tooling up to do does also. But how many more elbows, and 45's, t's are you going to use with Cu than pex.

Hey I love copper, and totally agree with the statements made about the fact that its more conductive getting the heat out of the water, but you need to keep the conductive train going when transfering it to the room, Not waste it through a poor conductive install as suspended tube like mentioned initially in this thread.

Why take the gains in a better heat transfer material, and do a suspended application still run higher than needed water temps. than a sleeper or embedded install. You lose what you are trying to gain over pex except maybe a little lower temp in the pex verses Cu suspended tube application.

I would think that from a proffesional installers aspect pex would be easier, and keep the company more competitive in costs.

Heck I did my kitchen floor with Cu in keeping it with tradition of my copper radiant ceilings in my 50's home.

The value of my own radiant system sky rocketed, if
I were to reproduce the copper radiant in my home it would cost 20000.00 in tube, and pipe alone 4500 plus lf. of various pipe sizes at say 4.50 a lf. That translates to 57000 lf. of pex enough to do 12.5 houses like mine.

Heyy I have had my arguments with copper verses the pex lovers, but the cost of copper now can make one see the light when on a budget of any sorts....Thanks China.

Gordy

hotsacks

Perpexed

The subfloor is not the only limiting factor in conduction.The rate of conduction is also in play.IOW,any tubing in contact with the plywood will eventually heat the ply between the joists.The expensive transfer plates speed the rate of conduction.Since copper is many,many times faster in conduction than plastic,the plates may become unnecessary.
OR
Maybe the cart's been out before the horse the past twenty or thirty years.Maybe the ultimate radiant hybrid would be copper tubing in Pex plates (send me a check Wirsbo).It'd sure be quiet.
All the arguments about copper being a slow install and dangerous because of soldering are archaic.Anyone working with copper in quantity is using Ridgid-Viega joints.Talk about fast.

Ken_40

Gordy,

s possible

Ken_40

Other than soft \"rubber-like\" tubing...

Under-floor-staple-up - without plates, has been deemed "woefully inadequate" as a practical solution to legitimate designs.

Neither copper nor PEX have enough contact area to provide enough conduction for any application. Likewise, convective tube arrays underfloor are even less appropriate, even with those extruded "wing" attachments meant to heat the air quickly.

I am sure a few remaining unknowing contractors attempt designs based on convective radiant systems. Their legal problems and performance failures are the fodder lawyers lick their chops over.

Neither copper nor synthetics seem to solve the convective design flaws. Some oif us learned it the hard way (:-o)

If one cannot bury the tube in a highly conductive medium, plates were and still are the answer - with the possible excpetion of soft rubber-like tube, the redeeming feature therof being: it does not have a "point" of contact, but rather ~ 1/4" "area" of contact.

The slight variation of contact area makes all the diference in the world - with regard to performance!