Timber Frame Radiant.........hb

heatboy

This project has been going for almost a year now. It has been one of the most challenging projects we have ever done. 100% radiant, Vitodens and 7 tons of Unico cooling with 2 tons of Mitsubishi as an extra. These timber frame homes are designed for radiant/Unico. I can't imagine trying to get conventional ductwork in here.

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Paul Rohrs

Great work....

Very nice work. Thanks for sending me the info on the wiring gutter you use. Top Shelp Work as usual.

I have been doing hydronics a while now. I requested to speak to the Viessman people as it pertains to selling their product line (wholesale). They were going to come down from Wisconsin (nearest manf. rep I guess) to interview me and see if we were a "fit". They never showed and haven't heard from them. They sent me a catalog which I poured over.

I have seen specs on the Vitodens, but have yet to see one installed in our neck of the woods. Can you tell me the....say...top 10 features that you like about it that separates it from all others including the MunchkinPinnacle? I would be in your debt. I am looking for a constructive conversation to build on, especially with the fine work you do.

regards,

PR

S Ebels

I'm curious HB

Why the plates and sleepers instead of Climate panel or the like? 5/16" tube design considerations?

heatboy

How about........... : - )

Superior heat transfer. Less money out of my clients pocket. Lower water temperature. Less money out of my client's pocket. Twice the loop length, which means smaller manifold stations. Less money out of my clients pocket. Smaller pumps due to less head loss. Less money out of my client's pocket. No messy silicone, which makes for lousy heat transfer. Less money out of my client's pocket. I don't have to pay to ship plywood all over the country. Less money out of my client's pocket.

hb



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kevin coppinger_4

I wondered the same thing....

my guess is that he couldn't get the btu's he needed with the loop lengths on such small tube...the 1/2" bought that output..ifin I had to guess....kpc

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kevin coppinger_4

what does that give ....

you for an overall height....do you have to cut the plywood to snug up against the plates? Who's tube? ty, kpc

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heatboy

It raises floor height...........

7/8" of an inch, Kevin. I have the plywood run right up to the tube for better heat transfer from the bottom since the entire plate is covered. If the plywood is relieved 2" on both sides, the floor height is 3/4", the thickness of the plywood.

I'm by no means running down products like Wirsbo Quik Trac. It's just on large projects this is a much better application. For small retrofit work, you may only be able to give up a half inch of height so Quik Trak makes sense in those situations. Also, using Quik Trac means the builder doesn't have to be involved with the installation. I haven't had this as an issue yet and the builders I have worked with have been very helpful.

All in all though, the extruded plates do a better job, IMHO. We can compare these systems to gyp, but that's another thread.

hb

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heatboy

They work for me!

Probably the most important quality of the Vitodens is it construction and the materials it is constructed of. While there seems to be this consensus that condensing boilers will only last 10 years, I’m banking on the fact that the Vitodens will last twice that long and be just as efficient as it is right out of the box. Just pick up the heat exchanger (with two hands, it’s so heavy!) and you’ll immediately notice the way it’s finished and the tolerances are amazingly close. Saying stainless steel is akin to saying plastic. There are many, many grades. I got a chance to see the robotic welding of the stainless steel in the Vertomat and indirects while I was in France a few years ago visiting Viessmann.

The control system is typical Viessmann fare. Well thought out and is capable of more things than I can do with it. Once the upgrade to the Vitotronic series happens, it will be even better. The logic flows very well during set-up and can be matched to practically any heating system that can be dreamed up. I love just tinkering with the settings to fine-tune the operation. Very cool.

The Matrix Burner is as close to non-polluting as fossil fuels can be with current technology. When the burner modulates up and down it is so smooth you hardly notice since the whole thing is virtually silent.

On the smaller units, the 24 and the 32, the variable speed pump ramps up and down just like the burner to maintain proper flow and Delta T across the heat exchanger. This is also controlled from the computer on the boiler.

The venting is remarkable in the way it monitors itself and modulate the speed of the exhaust fan according to the pressure it sees. If the vent gets blocked, the whole system will throttle down to prevent CO from building, making this a much safer boiler than anything else I’ve worked with.

The Munckin/Pinnacle are fine boilers as I’m sure the Ultra from WM is, although I haven’t seen one yet. I know the Vitodens and I can guarantee this is head and shoulders above the pack. Viessmann gets a premium for the equipment, but they back them up with cutting edge technology and product quality unparalleled by anything else. I feel it is the best value for my clients and their needs. That’s why I offer them.

hb


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hr

Why not

use the U fin on top. I like to have the aluminum close to the flooring and be able to get to the pex easily. More of a Warmboard approch.

Lot's of drug crazed flooring subs in this area! Something about a pex tube that attracts their nail guns

This was a timber frame job also.

Are those the new ThinFins?

hot rod

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heatboy

That's a good idea.

I haven't asked any of the builders to relieve the plywood. Do you router the bends, hr? What you have pictured is a far better option than Warmboard since tube spacing can be anything other than the 12" Warmboard gives. Well over half of the loops I install are 9" or less, which is why I have never given Warmboard a serious look. That, plus the framers have to be involved.

hb

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hr

Looks like

your spacing was pretty tight. I give the carpenters a drawing or description of what I need. They built and installed the strips and routered ends. I thought the routered ends were over kill. But, hey, these were the TRIM carpenters

With a hardwood on top the ends could be squared off like Dan Peel shows at the RPA board. I agree the PAP is the best tube for this to minimize expansion movement and keep loop ends stable.

Dale has a cool new CNC router table and I think he will offer the plywood return bends. Watts Radiant has them available also in a very nice Baltic Birch lamanet.

If "perfect heat transfer" is your goal, Dale can now fab these aluminum "hot slots" for your end bends.

Very nice work on that TF by the way. That's magazine cover material. Send it to the timber frame association.

hot rod

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Dave_22

Dumb question???

Ever try to mount these plates upside down?? So the largest portion of the plate is towards the finished flooring? Or is that the way the U fin works? Seems that if you could do it, you'd get even better transfer. But then again, I stare at my woodstove and try to think how to get better transfer.. What is WRONG with me!!!!!!!

Ted_5

Hey, Heat Boy

Look at HeatLink. Jerry Katz and HeatLink have designed an above the floor dry system complete with the return bends and you use 1/2" tube and your own plywood and plates. It's looks like the picture Hot Rob had. Check it out!

Ted

P.S. This is one I did about 3 yrs ago.

heatboy

More striping?

I like the plates like this and then the filler panels be installed. As far as heat transfer, I don't see a big difference. Some, yes. Let's remember that 3/4 plywood has almost the same R as 1.5" of gyp. The extruded plates do a much better job of pulling the heat of the water and distributing it. I have no documentation other than thousands of feet of this application, but water temperatures are at least as low as they would be with gyp. That's not to say I don't like gypcrete projects. We have two of them totaling 15K sqaure feet going right now. Every project differs from the last so that's why we all do so many different styles of radiant. There are advantages and disadvantages to each style.

hb

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hr

Actually the

more R value you have above the tube the wider and more even the temperature spread. Same with a slab. Tube at the bottom of a 6" slab will have a more consistent temperature spread (between the tubes) at the surface than tube held up at the top. Same with transfer plates, and saucers with additional wood layers.

But there is a trade off, that being supply temperature required, and response time.

All things being equal, hb's example would show a more even floor surface temperature, than my installation with the plates directly below the finished floor.

His will cost a few more degrees and a bit longer to reach surface temperature, as 3/4" softwood presents a R-0.8.

Radiant Engineering has modeled and tested a bunch of different R-value floor coverings to show this, also. Intended to show BTU output at various temperatures and coverings, the isotherms also show the spread between the tubes.

Siggy has modeled it in slabs in his column "How Deep is Too Deep"

As hb mentioned, decide which is the most desireable for your application, there is always trade off and pros and cons to consider.

Meeting the accurately calculated load with reasonable floor surface temperatures is paramount. How you accomplish it and to what degree of ultimate surface temperature you desire, may be secondary Maybe not, you decide.

hot rod

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Dan Foley

A/C?

Nice looking job, HB. Flag and I need to make the trek up to PA and check out some of your fine craftsmanship. Any pics of the Unico system for us HVAC guys?

-DF

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heatboy

Response time.

I always wonder what this phrase means. Radiant and response time are, for the most part, mutuallly exclusive. Even low mass radiant will take eons (g) to respond when compared to a forced air system. I'm not sure if that is what we use as a model when we say "response time". There is a definite difference between high and low mass radiant. Again, I'm not sure how much that matters.

I live on the East Coast where we have a 20°F (+ or -) swing in temperatures during a day's cycle. So here, it seems response time matters little, especially once you bring full reset into play. Out West, where there are pretty large swings over the same 24 hrs., a low mass system may or may not make more sense. But aren't there a lot of slab homes out there? Ultimately, it comes down to the structure's construction. Quality construction practices should minimize the difference needed in response time, I think?

So I ask, is response time as relavent as the people who promote low mass radiant say it is? Or is it more to sell their widgets? We come back to every project being different. How can an Internet company know all of this? I'm sure they are brighter than I am, but the crystal ball they use is no shinier than mine, I'd bet.

hb

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Mike Kraft_2

Tubing with U-fin

I have not had the privilege as of yet to install on top other than a staple down with gyp.The U-Fin application always gave me the appearance of a real tube challenge.If you could can you give a brief synopsis of install procedure:).BTW that is quite an install.What thickness was the stresskin panels?

cheese

hr

Maybe acceleration

would be more accurate. I imagine it's in the numbers as the time to raise one square foot of gypcrete from 68° to 83° under certain loads.

When I did those infared photos last year this became real obvious when compairing various "dry" methods.

By far the King of acceleration was type M copper tube in ThermoFin. The tube and plate became hot in a minute ot two!

The difference is calculatable, measurable, visual (with IR cameras) and certainly "feelable" if that's a word to any bare footed radiant afficionado

As you said, hb, this may or may not be importanrt depending on climate, owners expectation, surfaces, horoscopes, etc

I feel those wide, frequent temperature swing climates would benefit most from a dragster, as opposed to a 10 wheeler!

I think bathroom floors and tile shower walls are prime candiates for quick accelerating radiant. This would allow the use of setback, or intermitant use better than a slab or any high or medium mass (gypcrete) installation.

hot rod

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Capt.Dan

great job

This is one of the cleaness install jobs I have seen to date. I can't find, or have overlooked, what you used for the aluminum plates, could you provide me with any info. Thanks, CaptDan

ScottMP

Sweet Job HB

Very nice. I wish we had one of these lined up.

I am sure you had this well planned.

Now I have to go back and reread all the post

Scott

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heatboy

I say the same.........

when I see one of your projects. "I wish I had a project like that to do." I had more than a couple sleepness nights figuring how to fit it all in this home.

An interesting side note. "Harold's Chimney" is done by an older gentlemen who is actually a metal sculpturist. To build this chimney, he wandered around the mountain that's part of the owner's property and hand picked each stone then painstakingly squared it with a stone hammer and grinder so it would fit perfectly. It took him more than a few months to find and finish it. It will be THE conversation piece of the building.

hb

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heatboy

Thanks, Dan.

These heat transfer plates are made by Radiant Engineering in the bustling metropolis of Bozeman, Montana. Or, as refered to by those of us who know him, "Dale's Country" ;-)

hb

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Terry Alsberg

12\" spacing

I have never quite understood the obsession with spacing. Spacing and conductivity go hand in hand. All things being equal if the conductivity of a panel doubles so can the spacing. The only thing that close spacing really accomplishes except driving up cost, is the reduction in stripping. Warmboard is so conductive that the temperature variation (stripping) across our tube pattern is less than 3? in tile areas and is only 1? in carpeted areas. Close spacing is a legacy of the bad old days when we had panels that were low in conductivity.

heatboy

Ah, the bad old days!

It sounds like you are trying to pick a fight, Mr. Alsberg. Since I have no idea who you are, I can only imagine you are affiliated with Warmboard products in some aspect. Why else would you condemn my installation practices? I did not say anything derogatory about your product. I said it doesn’t fit what I try and accomplish. All things being equal, closer tube spacing lowers water temperature, which is paramount when wood floors are involved. Even you would agree that Warmboard with 8” centers would yield lower water temperatures than 12” centers. 10° or 15° lower water temperature can make a big difference when condensing boiler are used as the heat source.

I can’t argue the point about your claims of temperature drop of 3°F from tube to tube with your product. I am very skeptical, I admit. With the 4” wide ThermoFin plates, there is no drop in temperature from the center to the edge, which is 2”. But if Dale Pickard, who knows more about heat transfer than most anyone I know, told me that by using transfer plates that are 8” wide there would be no appreciable temperature drop across the plate, I wouldn’t believe that either. Warmboard is certainly no more efficient than ThermoFin when it comes to heat transfer. Pile enough “resistance” on top of any radiant panel, you will flatten out the discharge curve.

If you are not looking for a fight, I apologize for saying so.

hb


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hr

Picture proof

Don't think Terry was picking a fight, hb. Here is a side by side WB and ThermoFin.

Notice a couple things. On the WB you can see where I routered across the aluminum.

On the ThermoFin, notice where I forgot to screw the ends of the plates where I crimped the pex. The importance of conductive transfer power becomes pretty obvious.

Not a lot of difference betweeen WB 12" and T-fin 8" as far as spread between the tubes.

The back half of these panels have carpet, no pad. You can actually see the carpet fibers getting warm! The front, closest to you are plain 3/4 Advantec.

hot rod

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Dale Pickard

Heat transfer in floors

It's ok HeatBoy,

I know Terry and I'm quite sure that he is making disparaging remarks about gypsum and concrete and their relatively low conductivity and response and not about you or your methods, including your use of ThermoFin. He's into low mass systems. I have a great deal of respect for him and am very appreciative of the effort involved in bringing an excellent product like Warmboard to the market. Through his own unique position and creative talent, Terry came by his original and innovative ideas completely independently. There is only one guy like him for every thousand or more imitators.

A few points,

I'm no heat transfer guru. HT is a very complex subject and I'd like to think that I'm a little aware of what I don't know, which is a lot. I'm an ok industrial designer who, with perseverance, stumbles into some good ideas now and then. The ThermoFin extrusions incorporate some very basic heat transfer theory with a physical design that is governed by practical concerns, application issues and economics as much or more than heat transfer. Definitely not rocket science.

Decreasing the tube spacing is a perfectly valid, and very effective means of increasing surface temperature uniformity while decreasing floor supply temperatures. At Radiant Engineering, we have designed and installed LOTS of radiant floors of all kinds. aircraft hangers with tube spaced at 24" to trophy homes with ThermoFins on 6" intervals. We've done lots of thin pours of lightweight aggregates as well as gypsum. We don't have any problems with gypsum systems but in 20 years of doing this work, we have never installed tubing without some heat transfer.

Tube spacing, diameter and layout are all important variables that can be adjusted and manipulated in the design of specific systems to achieve particular ends, some of which are more related to hydraulic design issues than floor heat transfer.

For a simple example of this, here at Rad-Engine, we design every floor we do in CAD. (before CAD, we did it on paper) This lets us measure, balance and optimize loop lengths in design. We have developed design methods that allow us to closely balance loop lengths in some designs. Conventional radiant floor designs using concrete or gypsum as well as our ThermoFin systems are not very restrained to any particular tube diameter, spacing or layout. We think it is important in design to manipulate these variables to achieve an optimum design that is appropriate for the application, matches the plans etc. (I think that is kind of a non-statement as in duh! I think this is what we are all trying to achieve)

I don't dismiss gypsum or concrete applications. We developed our dry systems for reasons that have a market and application all their own. The advantages of the collection of dry systems on the market are well noted by others. Those who use these systems, like HeatBoy know why they do it. From a performance standpoint, I use our collective, substantial and very successful empirical experience with these high mass systems to benchmark performance goals. I don't dismiss these "castable" systems from a performance standpoint, the conductivity of concrete may be low, but we use it in 1.5" and 4" thicknesses, and that makes a difference.

Aluminum of course, is much more conductive, which lets us move more heat laterally for a given thickness and DT. The cross sectional area, measured by the gauge or thickness of the plate, the conductivity of the plate, the FIT of the plate to the tube, the width of the plate and the tube spacing and diameter can be manipulated, within economic and practical limits, to achieve particular design goals. Again, some of those goals are hydronic and are related to flow, pressure drop, pipe and pump size etc. (more non statements)

On quoted DT's across plate or across floor. DT's have to be quoted as a function of output to be meaningful. i.e. DT mean tube surface to floor surface @ 30 btu/ft2 gross floor area.
When you throw a rug on the floor, you increase the temperature uniformity of the floor surface but at a lower output; you also increase mean surface temperature as it approaches the tube wall temperature, right? The floor not under the throw rug is releasing more heat at a lower mean surface temperature.

I make a point of emphasizing mean surface temperature because real world systems of different kinds access the actual floor surface area to varying degrees. Because the heat in the tubing is constrained to a cylindrical shape with a constant surface area, overall heat transfer is strongly related to heat "distribution" from the tube surface to the actual available floor surface. In below the floor applications, a feature of the ThermoFin C is that the design allows the extrusions to be physically located near the rim joist, rather than ended prematurely so the tube can exit the end of the extrusion rather than being brought out of the snap channel. This more effectively utilizes more of the available floor area, at the perimeter of the room where the heat loss is greatest.
The Warmboard clearly has an advantage in this regard. It's width and more complete coverage, (wider plate) allows it to take advantage of all of the floor area.

The reason heat transfer at the tube wall is critical is because the surface area available for heat transfer, by any means, (conduction, convection, radiation), is slight in comparison with the floor surface area. All of the heat that is ultimately released at the floor surface has to come through the limited area available at the outside tube wall. This makes the outside tube wall a significant bottleneck or controlling resistance.

The ThermoFin extrusions work by increasing the surface area of the tube and extending it's physical location laterally, so as to make effective contact with as much of the floor surface as possible. In order to do this it is crucial that the thermal resistance at the boundary of the extrusion to the tube wall be held to a minimum. The extrusion must grip the tubing strongly so as to eliminate air spaces between the tube and the extrusion. Even very small air spaces make very large differences in heat transfer.

I have measured temperature drops of as much as 20 deg dt created by air spaces as small as .015". The magnitude of the dt dependis on the absolute rate of heat flux through the system; dt increases as output increases. Air spaces here make the performance of the plate "mushy", like air in your brake lines.

It's also important that the plates be thick enough so that they can maintain a minimum dt across the plate at rated (high) heat output. As the heat flux through the plate increases, the dt across the plate increases. As the transfer abilities of the plate are exceeded, it "cools" from the edges to the center, where the tube is.

I'd like to comment on the controversy surrounding the position of the heat transfer plate in the floor sandwich.
It is common-sense-like to think that the heat output rate and/or responsiveness of the radiant floor to the room will be increased when the tube and the conductor plate is closer to the floor surface. In some systems, like the Rehau plate system, or the new Roth styro/aluminum panel this will be more or less true. In the case of my ThermoFin U product, (installed with plate / channel facing up) and in the case of the Warmboard, I think that this is much less true.

In both cases, the underside of the plate is in good contact with the sleeper panels, or in the case of the Warmboard, bonded to the substrate. While plywood is not concrete, there is some substantial thermal mass in a typical wooden flooring assembly. The aluminum alone, which is denser and holds more heat than concrete, adds a great deal of thermal mass to the floor. When the system has been off for some time, the floor mass comes to an equilibrium temperature with the room; when the system has been on for some time the mass of the floor is at equilibrium with the heating system, and the room.

On start up, as the mass in the floor heating system is brought to an operating temperature, the plate moves heat into everything it is in contact with, upward at a rate no greater than heat is moved downward. If the floor is well insulated underneath, with a constant water temperature, the floor will reach an equilibrium at which mass of the floor is charged, losses downward from the plate are limited and all of the heat loss from the plate into the floor system is lost up, where the load is. The mass of the floor is the same whether the conductor plate is above or below the sleepers.

The sleepers and the subfloor have to be charged before more heat is moved to the load. Thicker heat transfer plates do help responsiveness because the plates are not overwhelmed, (moving heat down as well as up) as the floor temperature is ramped up to equilibrium.

The Rehau extrusion and the Roth insulated aluminum panels are different in that there is a thermal break between the plate and the sub-floor. The plate has only the mass above it to heat, (immediately), which it can do more quickly. We recommend that the ThermoFinU be installed this way in walls and ceiling applications, ie long ThermoFins mounted across the framing supported by foam (3/4" foil faced iso-cyanurate) sleepers. The heating system needs to be thermally isolated from any exterior building framing. We have used the ThermoFin U to retrofit concrete floors by Hilti nailing wooden sleepers through 1/2" foil faced iso-cyanurate foam placed on top of the slab. Again, the heating system needs to be thermally isolated from floor slab.

Having said all this, I don't think that "responsiveness" is really important. We are strong advocates of reset controls and constant circulation. We don't think that radiant floor panels should be operated like forced air systems.

Also, to some extent, when a building is under load, especially strong load, I think that it is the "charging" of the thermal mass in the building that is partially responsible for the reputation of "extreme" comfort that radiant floor heating enjoys. All radiant floors radiate to walls and ceilings and glass and store heat in their mass. This is very different than forced air systems or hot water systems that move heat by moving air and have little access to the thermal mass of the building. I think that radiant floors are much more effective and useful, and appreciated in cold climates. In warm climates, the ability to move heat into the mass of the building is less desirable and the pre-dominant cooling loads result from the removal of moisture from the air.
We usually recommend that the ThermoFin U be installed with the channel and the conductor plate facing down, as HeatBoy has shown. The reason is that this installation is much easier to install. The FinTube can be placed first, on an open subfloor. The 8' long extrusions allow for a clean layout with tube runs that are parallel to each other. This makes the job of the carpenter much easier as she is able to simply measure and cut sleepers to fit between the FinTubes. They don't have to create the tube layout in wood. It is easier to make the serpentine tube loops with the continuous lengths of tubing than it is to create a long continuous slot in plywood especially for the carpenter. More importantly, installing it this way, channel and plate below the sleepers, produces a flat dry nailing surface, which is especially friendly to finish flooring installers who don't have to fasten through the aluminum plates.

If the U Fin is installed the other way, channel and plate facing up, as Hot Rod shows, the installation is more difficult because the carpentry and the woodwork has to be done before the tubing is installed and less of the resulting surface is flat dry wood.

Finally, I think that Hot Rod's IR photos are worth thousands of words. You can see how the ThermoFins, (conductors mounted below the plywood) do an excellent job of extending the tube wall. And you can see that very little heat is transferred between them.
The Warmboard (conductor on top facing the IR camera) is not as effective over the 4" surrounding the tube as the ThermoFin, but it does move heat further laterally and produces a more uniform surface. I believe that Hot Rod was pumping fairly hot, 140F, water through them so I know that the output was very high, probably as much as 50 btu/ft2. These systems can be very effective, so heat adequate for most buildings can usually be provided at much lower water temperatures.

I haven't posted on the Wall for awhile but I think that I just made up for it.

Dale

jerry scharf

why I want response time

Heatboy,

(sorry, I'm way behind on my wall reading)

I'm not looking for fast heat rise, it's the ability not to overshoot that's my concern. The more mass that's heated, the slower it is to disipate it's heat when you want it to stop. The thing that I'm running into is glass windows that have shading. When the sun track passes the shade, suddenly the heat gain is fast and you don't want any extra heat in the system.

It's a situation that may not exist in your building, but if you have it, metal on top seems an important part of the design to me.

just my $.02

jerry

heatboy

Yeah, what Dale said! ;-)

Thanks, Dale. I'm sure Terry wasn't trying to pick a fight. But it did bring YOU back to The Wall, which can only be a good thing for everyone here interested in radiant.

Heat transfer is the most important and least understood principle in radiant floor heating. Your statement about never doing radiant without a heat transfer medium is dead on. I never have and never will do radiant without some sort of conductive medium, whether it be concrete, gypsum or extruded plates. To do otherwise, is a disservice to my clients.

Dale, thanks for helping me all these years do a better job of understanding heat transfer and it's importance in all aspects of radiant.

hb

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