Has anyone used these "bend your own" plates from this place, or otherwise bent your own staple up plates from flat sheet stock? How hard or easy is it to get good contact between the tube and plate?

As an alternative, who are some of the better suppliers for staple up plates, particularly in lengths at least 24" or more and roughly 6" width. I've found some 16" and 19" plates but not much for longer ones. Any suggestions?

It's not easy making a quality plate. Don't bother trying to make your own lightweight plates with that rig. The contact you get will be minimal at best on the tube plus the aggravation of cutting & bending. Are you sure that lightweight plates are even acceptable for your application? Radiant Engineering makes a heavy extruded aluminum plate that is the very best bar none. The tube can be installed from either the top (ThermoFin C) or the bottom (ThermoFin U) I get them shipped out in 8 foot lengths "typically" the same day. They're the kind of plates that radiant professionals use under hardwood flooring to increase output & lower water temperatures. The fit is very precise. They're mostly sold to other OEMs such as Viega which then re-labels them but you can buy them direct. http://www.radiantengineering.com/index.html Bend your own? The HORROR!!!

Thanks for the comments.

I've been trying to find info on the ThermoFin plates, but it doesn't exist on the web that I can find! Every page of their website is under construction except the home page and contact page. Their web site is currently worthless except for their address and phone numbers.

The 2 panels on Viega's web site are the same then, correct? They show their ClimateTrak available at 8' but the heat transfer plate, which is what I need, is only 19" long. Does Radiant Engineering sell the U style directly at longer lengths? I'm planning on doing a ceiling install so I need the U style. What other brand names are they sold under? Looks like Uponor's Joist Trak is one of them also, but they list the length at 4'. Can you give me a link that shows the details of the ThermoFin panels if these aren't the same as ThermoFin?

Would you be willing to PM me with some information about the pricing Radiant Engineering sells their panels? I'm working with my HVAC contractor nephew and he's giving me all the prices as he gets them from his suppliers. His prices, w/o markup, are what I'm working with for my house project.

Any idea how ThermoFin prices compare to Rehau's Raupanel? If I can't get U style plates at a low enough price it looks like Roth panels or the Beka USA capillary mats may end up being the most economical route after all, and I thought they were pricey! 1 x stringers to support the plates start adding up pretty fast.

By the way, thin panels should work OK for me as they will be sandwiched between 1 x stringers and the ceiling sheet rock. NRT.Rob posted a photo over on the Radnet forum showing me how he does ceilings using thin plates.

A cheaper, easier, faster solution is to  use the finest reflective foil insulation MicroFoil, has 1 inch flanges on each side.  You can set depth.  Comes in widths of 16/24/ whatever your joist box is.    See picture on here

Relying on reflective insulation to do the job of a plate is ridiculous, and I will not sugar coat that. If you're going to advertise, please do it responsibly. You might use it in addition to a plate, but not instead of. Radiant energy cannot even compare to the power of direct conduction. Conduction is and always will be king until physics changes.

Rehau makes a very nice 5" x 24" lightweight plate. 19/1000ths. For staple up the extruded aluminum plates are much, much better though. We use the Rehau lightweights for standwiches and ceilings, Radiant engineering's Thinfin C and U for staple up and heavy sandwich applications.

Yeah I know; Radiant Engineering’s website is STILL down. I hope Dale gets it back up again sometime soon. It’s been down for a while now! They do sell their U Finn plates in 8’ lengths as I’ve still got a few of them around here from our last job that I’m currently making a solar collector with. Just give them a call. They’re very helpful. The two Plates Viega offers are NOT the same. Their “Climate Trak” is re-branded ThermoFin C or ThinFin C (not exactly sure). If you’re worried about the cost of the 1”stringers (we use 3/4” strapping) extruded plates are definitely not for you. Viega’s “Heat Transfer Plates” are probably what you’d want for the ceiling application as you describe, but they’re just 19” long. Trust me: you wouldn’t want to work with an 8’ lightweight plate anyway so I’d go with Rehau’s 24” lightweights as Rob describes. It’ll be very easy to work with. We’ve done some ceiling radiant Rob’s way. A good system if the floor isn’t too cold;-) Although it may be “cheaper, easier & faster” I feel that it’s irresponsible for anyone to suggest the use a reflective foil to eliminate heat transfer plates. That’s just inappropriate marketing IMO. Instead use REAL fiberglass insulation or foam. This is the most important detail. It’s all about the insulation.

HaHaHa you should see what some of the hacks(plumbers) up here in Colorado call 'Radiant Floor'. I couldn't really believe it. Yup, 'Staple Up'. One installation that I witnessed looked like the horizontal cables of a suspension bridge! They used 3/8" Pex that literally hung from staple to staple. If there was any contact with the subfloor, it was only at the staple locations. This was absolutely the poorest excuse, both in installation technique and no doubt efficiency, that I've ever seen.

And this company, gasp, had started a 'Hydronic Division'.

The only reason for my comment about the cost of 1 x stringers is what starts out to be a "not too badly priced" system, i.e., light weight plates, soon becomes not quite as economical when you add in the cost of "cheap lumber"! I'm beginning to get the picture there ain't nothin' cheap about hydronic heating! You know, Roth panels may not be so expensive after all! I'll have to see if I can buy the straight panels only, not the entire bundle they like to sell.

I finally found the Rehau lightweight panels in their catalog. I agree, they look like what I'll want to use. Now, all I need is to get a price for them. One distributor my HVAC contractor nephew buys from is his "last resort" supplier. Prompt, friendly service is not a strong point! He needs to get an account established with the other local distributor before we can pricing from them. They are enthusiastic about hydronic radiant heating, and even interested in working with me for the radiant cooling. Night and day difference from the other Rehau distributor, and from the Zurn and Uponor distributors!

Gary, what do you mean exactly by 3/4" strapping, and how do you use it?

I talked to a plasterer today about plastering over the Beka capillary tubes. Ouch, a budgeting number he gave me was about $4/sf. Add that to $4/sf for the Beka mats and I'd be looking at around $8/sf to use the mats like they do in Europe. Tells me that Beka may be facing an uphill battle in getting their mats established in the American market. But then commercial installations may be altogether different story, economically. I may revisit the plan I once had for using Beka mats glued to the upper side of the sheetrock using joint compound. The biggest problem there is getting back to the eaves of the house to get the tubing laid down good, and that's where it's most critical!

Thanks for the comments.

Gary works with us on some projects; we spec 1x3 strapping in ceilings, which is dirt cheap. They are actually 3/4" thick.

PC: actually if you aren't going to use plates, you want to suspend the tube off of the subfloor to avoid heat striping. Touching the subfloor in that case results in so little actual contact that it doesn't really help much, so they use a convective circuit around the pipes to transfer heat (pipes should be 1" below subfloor). edit: that is a situation where reflective foil might help, if you trust it to stay reflective long term when facing upwards. I don't.

Rob & Gary,

I didn't realize such a stick existed! Talked to my lumber guy this morning and asked him about strapping. They don't stock it, but can get it. The main issue with strapping, apparently there is no quality control over it's production. I guess that's one reason it's cheap! So what's been your experience on the cull rate when you buy a package of the stuff? What % in a typical package would not be the correct thickness or straight enough to put on the ceiling, 10%, 25%, 50%? I asked the lumber guy how much would I have to buy to get 9000 ft of usable strapping, 12,000 ft? He said that would be a good guess! Agree? Even if 1/3 of it is firewood, the price sounds like it would be attractive.

I am not sure. Strapping is used in most every home here in maine as drywall screw surface, so whatever the cull rate is it's not prohibitive.

Strapping is just your standard 1x3 material. It's hard to believe your lumber yard doesn't carry it. Maybe the term strapping is confusing them. Just ask them for 1x3s. You won't have any more waste from 1x3s than you do any other lumber.

Bending system looks a little suspect. If you want to bend your own find a seamless gutter contractor in your area. They can adjust the first die and remove the remaining dies to extrude plates that fit your pipe perfectly. The machine will also shear the material to the length you need.

Not sure that this will be any cheaper than buying plates. With the cost of shipping it might be. You can also specify the gauge to match your heat transfer requirements.

The idea of talking to a gutter guy crossed my mind but I just assumed they have special shaped rollers and so wouldn't be able to roll what I want. I may talk to one just to find out what can be done. Blue Ridge Company has 5" wide plates for 1/2" tubing for about $0.72 per running foot plus shipping. Seems like a pretty good price to me.

Has anyone considered buying an inexpensive "bead rolling" machine and getting or making a proper die for it.  They sell for as little as $150 and will easily bend .019 aluminum.  I looked into a few suppliers and the aluminum is available in 667' rolls (about 125 lbs each) if using 8" wide stock.

On the job site you could then just roll out the lengths you needed as you worked.

If there is any interest maybe a group purchase could be put together to get custom dies made and also for a good source for the rolls of aluminum.  If there is enough demand I am sure that lighter rolls could also be gotten.

The cost of making them yourself runs half of what they sell the premade short strips for not counting the labor savings with the longer pieces.

That sounds like a good idea any further info on it?===The bead rolling machine

you want an "omega" groove in a plate more than a 'U' groove. bead rollers would result in poor quality plates as far as tubing contact goes.

Better than nothing though, sure.

there is no real labor savings in long pieces of lightweight plate. they are just more cumbersome to handle.

I am new to this Green Talk Forum and I missed this thread from/since last year. Let’s see if I can contribute my 2 cents worth.

I am very familiar with the BEKA USA capillary tubes for radiant heating AND cooling in the same installation. Just switch the tap water temperature from warm to cold and you go from radiant heating to radiant cooling. I you want to cool the water further below freezing (with glycol) you can get a freezer (a Penguin’s cage in the Berlin Zoo –Germany –) and in between if you want a wine cellar (at 56-58°F year round) or any other temperature for medical, commercial, industrial goals, etc. The system and the techniques are the same and any installer that familiarizes him/herself with the system now has few new lines of business opened at once. The system is extremely easy and safe to install and very fast that saves you labor big time. If the installation is small, yes it may be a little bit more expensive but this is the “Cadillac” and 21 century HVAC system. You should pay more for comfort and a healthier system. As soon as you are in 2-3000 ft2 or more the total system may not cost you more putting all construction costs on the table. If you go to an even bigger installation the system may not only be “for free” but may leave up to 15% savings in construction upfront moneys.

The system installed as BEKA USA recommends, welded to itself all by fusion, running water between 60 and 95°F, should last over 100 years. There is no possibility of condensation because of the BEKA USA system. If you get condensation it will be for some other reason. It comes with a fool proof shut off as you are even close to reaching the dew point, whatever it may be at that moment.

Some comments said that it may be a little expensive ($4 for the mats and $4 for plastering – although you do not “have” to plaster) you have to add the piping to take the water from/to the control panel and the control panel itself. If money is your main concern then all DIY is the way to go because you are going to forget your time and labor as part of the costs anyway. The BEKA USA system can also be DIY but you cannot manufacture the mats themselves and have the over 20 million ft2 installed worldwide behind you to warrantee/guarantee the system.

Six months ago $4 per ft2 gave you change back but today, thanks to the Dollar/Euro and Oil price situation you won’t get any change back.
There are many other advantages and solutions to other problems mentioned here but I don’t want to burden you with details you may not be interested in. Let me now if you have specific questions or doubts and I’ll try my best to respond.

www.bekausa.com

I have seen a contractor that used standard 6" aluminum flashing which he stapled to the subfloor on either side of the tube sanwiching the tube between the flashing and the subfloor. There was hardwood flooring above, and the max water temp was set for 150 deg. the system worked and the owner had no complaints.
I am sure that they saved a bunch of money doing it this way.

that's a wildly high water temperature by today's standards. I'm sure it was cheap to put in, but that leaves almost no wiggle room if your "calcs" are off, and you'll never get high efficiency heat sources to operate at peak efficiencies at 150 degrees.

dmaceld said:
 I've been trying to find info on the ThermoFin plates, but  it doesn't exist on the web that I can find! Every page of  their website is under construction except the home page  and contact page. Their web site is currently worthless  except for their address and phone numbers."

I've been a technical sales associate at Radiant Engineering since January. I'm working on our new awesome website every day, and I put up a temporary website last week. The temp site has all of our ThermoFin info and brochures, as well as a request information form for specific questions and for brochure and sample requests. Comments and suggestions would be appreciated. Thanks! www.radiantengineering.com

Not sure what all the fuss is about re bending your own plates (fins I call them).

1. Buy a roll of aluminum flashing like that used for roofing
2. Cut pieces of it to the length you wish to work with. 36" worked well for me.
3. Use a router table and a cove bit to put a groove in the edge of a 4' piece of 4x4 lumber. Groove to be 1/16 deeper and wider than the pipe you are working with.
4. Determine spacing of pipe on the fin, either centered or 2 across. Mark all the pieces of flashing.
5. Using a 4' long scrap of the pipe, lay first piece of flashing on top of it and line up the marks.
6. Center the 4x4 groove on the flashing with these marks and use a hand sledge to hammer the flashing around the pipe and into the groove. Work back and forth along the length to ensure good bend around the pipe.

This is a bit of work to accomplish, but is far more economical than the cost of commercial made fins.

There you have it!

Mechanical design, material specification, production method and required tools, figure in "a bit of work" for man hours plus economics 101...fantastic!

Of course the output would be questionable and less than half of a proper ThermoFin, which is a "heavy" extruded aluminum heat transfer panel designed by a real engineer with real world experience. We don't leave home without them.

I can’t imagine any engineer ever getting involved with plates. It seems like the only folks who get involved with plates are the folks who sell them or install them. There must be good money to be had selling and installing plates to clueless customers who must have HR heating no matter how much it costs.

Let's see. Siggy is an engineer. And he goes over, even advocates, the use of aluminum plates in "THE BOOK" you are so fond of regurgitating. I refer you to a link, here:

thttp://static.squarespace.com/static/50de4c94e4b0a05702aac0fb/t/511a6e48e4b0735b6626ef38/1360686664633/PlatelessInRadiantville.pdfhe pdf

Imagine.

I am beginning to suspect you are a shill for the forced air industry.

"Let's see. Siggy is an engineer. And he goes over, even advocates, the use of aluminum plates in "THE BOOK" you are so fond of regurgitating"

Too Funny, I love it!!

No, John doesn’t like plates either. He just explains that plates are necessary if you place PEX below wood in order to get any significant heat transfer. He then provides the data and method to show how lousy plate systems perform compared to slab systems. I reckon John felt the need to do this because there are apparently folks who place PEX below wood without any plates at all and run supply temps in excess of 120F. I agree, it is hilarious…provided you are not the one who paid a premium for this level of heating performance!

here is a cost break down of a 1,000 square foot RHT floor panel system (our sandwich type system)
pipe needed on 8" pattern 1,500 '
turn bundles needed 2
Omega heat transfer plates 6 units 200'= 1,200'
5 outlet manifold
8 sheets of 3/4 plywood ripped to 6"
Values
pipe 1,500x.26' $390.00
Heat plates $810.00
RHT floor panel turns 2 units $300.00
RHT manifold SS $167.00
3/4 ply estimate $35.00 sheet x 8 $280.00
miss nails/staples $50.00
Total $1,997.00
OK, so we have less tha 2 dollars a square foot for a surface sandwich system, average install time 500 square feet per day 2 men. A 1,000 square foot square optimizes the install, real world is more involved. My point, cost is not so great, delivered water temps with this system can be 100 degrees or less, very efficient. Easy to apply in new or retro fit, has benefits that slabs do not, building floor is not stiff, diaphragm,the installer can take 1/2 the building commission it and come back for the rest later, on and on.. Read; I also like slabs, never said I did not.I am pointing out that the sandwich site built system has its place as a valid option. Dan

Okay, so the cost of just this sandwich built HR emitter [i.e., NOT including cost of the heat source, circulator(s), distribution plumbing and control system] might be $2,000 uninstalled and $3,000 to $4,000 installed. The cost of the equivalent concrete slab HR emitter might be $390 uninstalled (i.e., just the cost of the PEX if you are already pouring a slab for other reasons) and $600 to $800 installed. Delivered water temps with a slab HR emitter can be 85F or less. I will leave it to actual person considering their HR emitter options to ascertain whether the cost and performance differences between these options is significant to them.

I never said that a plate system was not an option. I just said that a plate system was a more expensive, lower performance HR floor heating option as compared to the slab option. I also said that it is the folks who sell plate system components and design/install these systems who largely market and advocate these plate systems. We don’t design/install plate systems, period. If we get a potential customer requesting a plate system, we just refer them elsewhere and wish them well with their project. Again, our focus is working with customers pursuing energy efficient new construction and NOT with remodeling old buildings where a sandwich built HR emitter may very well be the best option if you have a customer that insists on having HR floor heating and who doesn’t care about the cost (e.g., is opposed to going with a lower cost, higher performance, more versatile mini split cooling/heating system option).

So,
Math is your friend, yes mine to.
A carpenter and helper can install 500 feet a day average with a lay out (printed map of the pipe).
Assume they run $50.00 per hour for the pair, 8 hours / $400.00/ $800.00 installs 1,000 square feet
On a slab if you are stapling to the foam 2 men 2,500 square feet per day, tying to wire mat or rebar less like 1,000 square feet.
Do not forget the insulation at $1.00+ a square foot, typically only required in a heated slab (at least in the fine state of Washington).
No doubt slab is less cost, better heat mass but we have multi million dollar multi story homes where the solution for a slab on every floor is not a option.
Our systems can preform perfectly in these applications at very low delivered water temps similar to slab.
Same is true for the modest 2 story home.
Some homes will only have a slab in the basement.
It is not wise to rule out so many great options with hydronic heat, ceilings, walls, topping pours, radiators, sandwich and more.
This is one of the greatest things about water based heat. zoning, versatility, invisible.
So, as I said, I like slabs have some in my house, as well as topping pours.
Have no issues with heat pumps have one going in a house I am building currently(air movement, filtering, heat & cool), same house has a radiant floor 1 1/2" concrete topping (just cant get away from the stuff), and 5,000 watt PV system to off set the utility.
All good .
All about options, solutions and more.
Dan

Hey Dan;
One question on your numbers: How do you get to 8 sheets? I get a number more like 23.

Also, a couple of comments:

I used OSB, much cheaper, and added construction adhesive to avoid those squeaks. As far as cost both systems require a manifold, so that is a wash, as is most of the tubing, the slab might let you run slightly cooler, but you are still going to need the pitch to avoid striping.

Anyway, I did one of your RHT systems DIY, it is working great.

True Dave, the $167 manifold should NOT have been included in the comparison...good catch! I also wondered how Dan got 8 sheets and thought perhaps 31 sheets (i.e., 1000 square feet divided by 32 square feet per sheet) minus the area occupied by the PEX would have been required. However, I am not familiar with this RHT system at all and I just trusted and used all of Dan's numbers as he provided them for the comparison. If 23 sheets is the right number, that would further increase the sandwich built HR emitter cost by $525 (i.e., 23 – 8 or 15 additional sheets times $35/sheet).

Dan, I thought you said “500 square feet per day 2 men”. So it would take 2 men 2 days to accomplish 1000 square feet. So 2 men x 2 days x 8 hours/day x $50/hour is $1,600 in labor for the sandwich built HR emitter install. So total installed cost for the sandwich built HR emitter is $1,997 + $1,600 - $167 or $3,430 total (or perhaps $3,430 + $525 or $3,955 total if 23 sheets are required). Agreed, it’s all about options and to each their own...and we also like the fact that HR heating can be easily zoned, is invisible, is quiet, and is draft free too!

Posted By sailawayrb on 31 Jul 2014 01:26 AM

Dan, I thought you said “500 square feet per day 2 men”. So it would take 2 men 2 days to accomplish 1000 square feet. So 2 men x 2 days x 8 hours/day x $50/hour is $1,600 in labor...

He said it was $50/hr for the pair, not per each worker.  That would be 16 hours x $50/hr = $800.

Good catch Arkie6, I now see where Dan also said that too. I normally think of an hourly rate as being per person and NOT the rate for the number of people accomplishing the work. Okay, so Dan is thinking that the average hourly rate for this carpentry team is $25/hour. So 2 men x 2 days x 8 hours/day x $25/hour =$800. So total installed cost for the sandwich built HR emitter is $1,997 + $800 - $167 or $2,630 total (or perhaps $2,630 + $525 or $3,155 total if 23 sheets are required).

Amazing how much she has to say about something she has never done, and would never do!

Perhaps she read about it, in "The Book"? Or had tea with "John" where he imparted his decades of real-world experience in a instant?

If you don't agree with her, you are a hack, a fraud, unlicensed moron and worse; your customers are ignorant, gullible, and most egregiously; effete!

Correct my error on ply
Should be 216 ft2 gap and peri tier turns
784 ft2 ply or 24.5 sheets
Keep in mind this is a square room model
This area would install fast a day perhaps 2workers
In a home with odd rooms hall ways... 500 ft2 day is a good time value
Dan

Correct my error on ply
Should be 216 ft2 gap and peri tier turns
784 ft2 ply or 24.5 sheets
Keep in mind this is a square room model
This area would install fast a day perhaps 2workers
In a home with odd rooms hall ways... 500 ft2 day is a good time value
Dan

Amazing how much you have to say Badger about stuff that you do and clearly know little about! I never said if you don't agree with me any of that and if any of that truly applies to you, there is little I can do about it anyhow. You are free to operate and treat your customers as you please.

Thanks Dan for clearing up the sheet count issue.

As I recall, plates spaced for ~100% coverage have nearly the same heat transfer as a thick slab (with the same covering). A thin slab should be less, although tube spacing has an effect. And the low thermal mass (faster response) and lower weight have different values in different situations. Just to be provocative - Siggy makes it clear that he doesn't like high mass emitters. Even worse is trying to combine them with direct gain passive solar (read the link).

For the record my RHT system set me back ~$1.54/ft^2, with my wife and I supplying the labor. This was inclusive of manifolds and tubing. I will note that we installed it during the crash, so materials were cheaper than now. Dan's suggestion of $2/ft^2 before labor is probably sound.

In my area I think it would be at best difficult to get a slab poured, I know of flatwork that is going begging. Most of the experienced trades headed to the Dakotas to roughneck during the crash, and construction around here has seen significant recovery.

As to why I went with the low mass system the house is ICF with a CCSF roof, so fairly well insulated. I was concerned that a high mass emitter would complicate the control strategy. The low mass emitter gave me a type one loop that I could compensate by varying water temperature, with the 95 degree water I'm running slightly overdamped with a bang-bang control, so very comfortable with no overshoots. My GSHP is also running very efficiently with the moderately low water temperature. I also find that my legs get tired when I'm on a concrete floor all day, just less impact on wood. Anyway, these were my reasons, someone else could easily have different priorities and come up with different trade offs.

“Just to be provocative - Siggy makes it clear that he doesn't like high mass emitters.” Not sure where you drew that conclusion Jonr. Yes, we all know that YOU don’t like high mass emitters as you are like a parrot on this! John’s company, Appropriate Designs, has mostly done HR high mass emitters. However, his company doesn’t currently do integrated HR and passive solar heating using high reactive high mass collectors/emitters like we do. BTW, John is officially releasing his new book titled Heating with Renewable Energy in a couple months. This new book provides design/install info on solar collectors, air-to-water heat pumps, geothermal water-to-water heat pumps, and wood-fueled boilers.  I give it two thumbs up.

Dave, typically even simple outdoor reset control can handle HR high mass emitters without any issues. This becomes even more true the more you stabilize the indoor temp by well-insulating it from the varying outdoor temp…to the point that outdoor reset control may not even be needed. Yes, if you have significant solar heat gain, you will likely need a more sophisticated control system to ensure that you maintain a comfortable indoor temp without any overshoots. I always avoid standing on floors all day (I much prefer sitting with carpet under my feet…), but I would agree that standing on wood all day would be preferable to standing on concrete all day. However, I prefer the much lower cost and lower maintenance of well-finished concrete (or tiled concrete), especially since we have cats and dogs. So maybe $2/SF for the uninstalled RHT system and maybe $0.39/SF for the uninstalled slab system…so maybe about a cost factor of 5 for our DIY community.

Not all people want/like concrete stained floors. Don't forget your rigid insulation cost, adds significantly to that .39 cent a foot. Think $1.00 ft2 for 2" rigid pink.
Some like the diaphragm wood provides, the response time and some like the choice of wood (cherry, oak, ...)
Do not write off the future options realized with a platform crawl space that can not be accomplished with a slab such as wire changes, additional plumbing and the like. How about a rat slab and mechanic dolly to zip around under your platform !! Living large..
To many folks a few more dollars spent to have the type of floors that may serve them for the next decade is not the issue, where living on a stone floor could be.
Some old wise person must have said "It is a good idea to not assume another persons budget or aesthetic requirements substituting your own".
Its all about options here, hydronic heat systems can provide a huge collection of options.
I already said I like insulated slabs as well..

Dave thanks for the input on your system,

Dan

FWIW if you are going from a standard wood framed floor with some sort of HR emitter on top or underneath, to a concrete floor, there is a gigantic up-charge for both labor and materials that is far in excess of the $1.61, if you are pouring a slab anyway its foolish to not lay in the pex, even if you don' use it right away

hell a concrete floor makes $8/sf for warm board look cheap

from what i've been able to find You are looking at $15 to $20/sf for something like amdeck (the foam alone is over $5,)

Precisely, if you are doing new construction that will have a slab, we recommend placing the PEX even if you don’t plan to use it right away. I can’t imagine anyone NOT putting any insulation under a slab in most zones these days, even if the slab is not heated and code minimums allow it. Folks who build to code minimums are not exactly energy efficient building role models and I wonder why they would even hang out on a green building forum. The real question is whether the slab insulation needs to be increased from what was originally planned given that the slab will now be heated. That is easily answered by running the free DIY HR floor heating design software on our website. Of course, you have to ask this same question for the RHT system too. In fact, if the RHT system is installed on a floor having an unheated crawl space below it, more insulation will be required for the RHT system than for the slab system, everything else being the same. So I view the insulation as a push or maybe a small additional cost bump to the RHT system..

Speaking of rats, there have been cases where they have damaged PEX in above/below-floor systems. That can't happen if the PEX is embedded in the concrete...ideally in the middle of the slab!

Not to throw rocks, but that $0.39/ft^2 is about the cost of the raw concrete for a thin slab, if you want it colored, stained, stamped, or otherwise finished the cost of the mix is insignificant. Finishing a large area of concrete is also beyond the ability of most DIYers, things just move to fast. I will not try more than about 40 ft^2 at a time, a large area is really a job for a crew. On the other hand I was able to start and stop the RHT install as needed, no time critical operations there.

As far as there being no other additional costs I would also note that IIRC a thin slab is on the order of 18 lb/ft^2. That is not an insignificant uptick in dead weight, and in many cases would require additional support.

As far as insulation, I did install it. Prior to install the crawl was running a couple of degrees warmer than the house above in the winter. Not to efficient, but I am only one guy and everything doesn't happen at once. The difference is that I used fiberglass with an air barrier. With the ICF shell there was not a large temperature drop to the crawl, so the convection loss of fiberglass is of little concern, and I got the fiberglass in R30 for about a third of the cost of R10 of foam. I did use better insulation in those areas that experience a larger delta T, but that is just good engineering.

As far as control systems when I did my research there was not anything that really fit. Things may have changed by now, but at this point I am uninterested. At some point the wife and I are thinking about building up an Arduino based controller with a web interface so that we can better track the system, as well as add features such as outdoor reset (where did that name come from anyway, for us control system types it is just feed forward), it is kind of a hobby thing.

Anyway, as always, my tradeoffs may not be your tradeoffs, just have fun with it.

True Dave, the $0.39/SF is just the DIY cost of placing the PEX and does NOT include any cost associated with creating the slab or finishing the concrete floor. Again, this scenario is based on doing a slab anyhow for new construction…just like already having an existing wooden subfloor for the RHT. We didn’t include the cost of finishing the RHT floor with hardwood or tile (which would provide much better heat transfer), so it would NOT be appropriate to include the cost of finishing the concrete floor for this cost comparison either. In both cases, you have to finish the floor anyhow and there will be increased cost for both which will depend on how you finish them. We only included the costs of getting the slab or the existing wooden subfloor to be a HR emitter. I will say that it costs less to hire out finishing a concrete floor as compared to hiring out hardwood floor or tile floor installations. I will also say that it costs less to create a slab-on-grade floor than to create a wooden subfloor. I agree, pouring slabs for buildings and finishing concrete floors is NOT a DIY project! However, placing PEX before the concrete pour is an easy DIY project...and likely easier than building the RHT system.

Arduino based controllers are educational, fun, and useful for hobbies. However, we wouldn’t recommend using them as the HVAC control system for a building. We use Programmable Logic Controllers (PLCs) to control our more sophisticated integrated HR and passive solar heating projects:

http://www.greenbuildingtalk.com/Forums/tabid/53/aff/14/aft/82183/afv/topic/Default.aspx

Sail way far away,
By your logic the insistence of coming back to the .39 cent value you are overlooking multi story houses and all the other right reasons for the diversity in application of hydronic based systems.
Seemingly refusing all but the slab as smart. Remember I said I like slabs, acid wash, even stained been there done that.
If I hold the line as you prescribe and push the idea of saving every possible cent on the building process I can see myself living in a slab on grade cinder block (paint optional) flat shed roof with role composite roofing building with plywood counters and no dimmer switches. Not that there is a problem with that but...
I like options, Wood siding, architectural shingles, granite counters, real wood flooring, wood windows, Washington wines.
I guess said another way is where do you recommend your clients spend all the saved $$ forfeiting the things they want?
Why would you refuse to assist designing all the great alternate systems as you have said earlier in the blog? I don't get it? Client aesthetic requirements input.
What am I to assume?
Dan

Dan, people are free to buy and sell whatever makes them happy. The last time I checked, we still had a free country based on the pursuit of happiness.

It is true that we turn away a lot of customers because our residential business focus is on affordable, modestly sized, single-story, highly energy efficient, new building construction. It is also true that we prefer educated, intelligent customers who have spent some time researching what they really need and can afford as opposed to simply buying whatever they want with no consideration given to the cost (both dollars and environmental impact).  So I suppose you could say that we have reached a point where we only work with customers to accomplish projects that both us and our customers are highly interested in accomplishing and that makes both us and our customers happy. How many general contractors or HVAC companies do you know that also design, fabricate, and construct hydroelectric turbines and hydraulic ram pumps?

We have never sacrificed our green building beliefs or integrity just to generate more revenue. So we reserve the right to turn away customers who have plans that simply don’t interest us or don't align with our green building beliefs. So Dan I would say that you could rightly assume that we, our customers, and our DIY community are very happy with how we operate our business. You are certainly free to live in a multi-story mega mansion and cater your business operation to that market niche if that makes you happy. Bottom line, you are free to spend your dollars however you choose and so is everyone else...and you are free to operate your business however you choose.

Supersilious. It is the first thing that popped into my mind. Who but Catherine the Great stills speaks in the third person?

Recount again your personal credentials and lets leave our Dads out of it for a minute.

Why are you slogging around in this particular thread, about a topic you have no interest in?

You have plugged your company a couple of times and poked fun or derided all the competition (you insist you don't have). Why not give it a break and leave the subject, to which you you obviously can't contribute, to those who can?

Whatever Badger... We will leave it to the educated and intelligent reader to sort out substance and facts from BS and hate mongering...

Sail way far away please,
I still am confused with your green building design concept / client selection limiting process.
It is easy to understand that a multi story residence (2 or more) is the optimum choice when placed next to the single story slab on grade for the truly ecologically green build client. Be it 1,600 ft2, 2,400 ft2 or more.
Building foot print is minimized reducing; Lot size in urban design, all the related products to support a larger foot print are minimized. Drainage, back fill and related heavy equipment time, soil movement and foundation labor, concrete requirement. Keep in mind for green concrete very energy consuming in both manufacturing of and transportation next to sustainable wood product. Mid platform insulation is minimized, plumbing is stacked, electrical consolidated.
Roof Square footage is halved, cost of related framing, sheathing, oil based roof products halved.
Exposed exterior surface area of the building is reduced saving energy as well as insulation requirement.
The list of green and or cost effective building design goes on.

I have trouble with your logic "we turn away a lot of customers because our residential business focus is on affordable, modestly sized, single-story, highly energy efficient, new building construction. It is also true that we prefer educated, intelligent customers who have spent some time researching what they really need and can afford as opposed to simply buying whatever they want with no consideration given to the cost (both dollars and environmental impact)."
Are multi story home owners less intelligent?
What is a modestly sized building?
Dan

True Dan, there is a cost savings for multi-story construction largely because you can minimize the foundation and roof footprint for a given SF building. The electrical and plumbing is about a push if the layout is efficient. There is more cost for multi-story construction for the additional floor and stair well construction. There is more cost for multi-story construction if you want HR floor heating on all the floors. So you can’t really generalize and say multi-story is always significantly more cost effective. Furthermore, some folks can’t deal with stairs. So like you said Dan, having options is a good thing. However, if you are building in an urban area and have a small lot size relative to the house size that you want to build, you don’t have any option except to build multi-story. There are many reasons why people might find themselves in this situation, so I wouldn’t characterize them as being less intelligent. Nevertheless, we don’t get involved with multi-story tract home construction. Our focus is as previously stated.