Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Water temps and costs different types of rad floor

Solarbair1Solarbair1 Member Posts: 3
I am trying to make a table which will list required water supply temps and cost for slab, thin slab, staple up and some of the other popular radiant floor structures (assume same floor covering and heat load).  I want to be able to give people a good general idea of what radiant floor system to use. Anybody know a good source for this kind of info? Have client building new house who wants radiant 2nd floor (wood framing, cold climate).  How do I choose between warmboard, gypcrete, subray, raupanel, staple-up etc?  Need to know costs and water temps, we want them both to be low. Any tips appreciated


  • CMadatMeCMadatMe Member Posts: 3,066
    Pretty Close to Impossible

    Every structure has a different heat loss and your water temps are going to be based on the loss and square footage of floor and covering r-value. 

    I could design the same structure for radiant many different ways and come up with many different prices. It is all dependent on what the consumer wants. While tubing, plates, loop lengths and manifolds can be budgeted based on square footage in order to qualify a customer for the radiant material only, how would you budget the boiler, control and zoning side?

    There are some of us who after many years of installs and design work could  come up with a budget number based on experience in different jobs but I only use it to qualify customers so I don't waste my time breaking out the loss and design.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Solarbair1Solarbair1 Member Posts: 3
    Water temps and costs different types of rad floor

    Thanks for your reply Chris.  My goal here is to get a general idea of the costs and water temps involved with different radiant floor systems.  I agree it is difficult but if we assume the same heat load on the room (20 BTU per sq ft) and the same finish flooring R value (R-1) insulate per standard practices (similarly in each case) we should be able to get an idea of the water temperatures required and be able to estimate materials and labor.  Of course there will be some variance in individual cases but if and when I complete this project I will make it available to others for their general education.  I'm sure you can commiserate with me when I say that not all sources of information agree.  Warmboard thinks their system has the lowest water temps and so does Ruapanel.  Different heat loss programs spit out different water temps, etc.  This is a problem in our industry and many others which have to deal with the real world.  We do what we can.
  • Mark EathertonMark Eatherton Member Posts: 5,843
    Tough Question....

    and you may not be aware of it, but we don't openly discuss pricing here because of differences in labor cost, overhead costs and regional costs. The best I can do is to give you guidance as it pertains to WarmBoard compared to Gypcrete.

    A lot of G.C.s only look at the component cost per square foot and don't take into consideration other costs associated with a given method. The cost of WB is approximately 3 times as much as the per square foot cost of Gyp alone. But, and there is a but in every crowd, ain't there, you must look at ALL of the cost associated with the installation of Gypcrete or equal. Second sole plate, increased elevation and required framing adjustments, deeper TJI on long spans due to additional dead load, the incremental cost of the Gyp itself and on and on, to say nothing of the additional water temperature operating costs.

    It has been my experience that the WB will cost more than a gyp pour initially, but that true overall cost differential is quickly recovered in energy savings, performance and delivered comfort.

    If the customer wants to use RFH on upper framed floors with low temp heat sources (GSHP, Solar Thermal), WB is not an option, but a requirement. If I am to deliver guaranteed comfort, then I need to be able to dictate the emitter, not the GC, not the Architect and not the H.O.

    One problem this industry has to learn to over come is the over use of warm floors. Granted, they are comfy and neat (warm and fuzzy?), and appropriate in certain settings (bathrooms) but they are not the only way to deliver true radiant comfort. Once you have retrained yourself to sell "radiant comfort" and not just radiant floors, your job becomes easier, and the delivered cost of the "comfort systems" you are purveying comes down.

    Radiant ceilings, for example.

    In most cases, it is only necessary to do the exterior 4 to 6 foot band, not every square foot of ceiling space.

    The system, when properly controlled through ODR, delivers excellent comfort, with low temperatures of operation.

    The consumer can cover the floor with Bear Rugs if they want, without affecting your delivery system.

    The floors are NOT cold. If anything, they are slightly warm, but rarely cold. And if they are cold, its an indication of other issues (infiltration).

    From a retrofit consideration, it is easier to do ceilings than it is floors. No door cutting, counter top raising, stair tread adjustments etc.

    I could go on, but hopefully you get the gist. Get out of the radiant floor heating business, and into the radiant comfort business. And don't forget, in order to deliver full spectrum comfort, you ARE going to have to move some air, and if you don't do it within the walls of your company, partner up with a good company that does, and make money off of their services.


    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • CMadatMeCMadatMe Member Posts: 3,066
    Water Temp and Outputs

    I agree that you get different numbers from whomever's program you use. Ultimately it's the comfort of the customer that is the end result. Heat losses and radiant design programs are great in the aspect of limitations and a starting point for a project. It's then up to you to tweak out. Every person lives differently and every person has their own comfort level. I think ME hits the nail on the head in his post below. It's the comfort business.

    I tell everyone that when you quote a radiant/comfort job you should have built into your price an x amount for going and visting an installed system throughout it's first full heating season to make approprite comfort adjustments. It is impossible to think that you set it and forget it if you truly are selling comfort systems.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Solarbair1Solarbair1 Member Posts: 3
    Water temps gypcrete, warmboard, slab

    ME thank you for your response.  We can just skip talking about prices if you want I can find those from the manufacturer.  You seem to be a warmboard advocate.  Given a heat load of 20 BTU per sq. ft. and the same finish floor covering what would you say the required water temps will be for gypcrete, warmboard, fined staple-up and in slab respectively.  Assume all reasonably insulated.  If you have a program or source for your information and you don't mind disclosing, I would like to check it out. 

    I hope you can see what I'm trying to get at: the inherent efficiency of these different heating systems, in both BTU's and dollars.  Everyone cares about dollars and with low temp heat sources like GSHP and solar thermal coming on strong the required operating temp influences efficiency more than ever.

    I feel that it would be a service to our industry to put together a cost and efficiency comparison like I'm talking about here.  That's what I'm about, when I come across an issue I feel I should, as a heating professional, understand, I try to put together an article. 

    I like what you said about radiant ceilings.  That is another issue I would like to explore.  Thanks again for your input.  
  • Barry E. LaDukeBarry E. LaDuke Member Posts: 16
    edited May 2014
    Water temp chart sources

    May 2014: Due to the passage of time, my career change, and a couple of computer upgrades, I no longer have access to the calculator I used to product the file mentioned below. My apologies.

    For temperature comparisons, Warmboard has a very effective infrared comparison on their web site.

    For side-by-side cost comparisons between the various infloor methods, I'm afraid I can no longer maintain the inputs for that calculator, so I've retired it.

    ----- original post below ------

    I have a PDF file of nearly 4Mb (that I don't think will post here because of its size) that contains water temperature charts for several floor heating methods, including Warmboard, thin slab at 1 1/2" with various tube spacing, Quik Trak, Thermalboard, Joist Track, staple-up, RauPanel, and a separate file for Ecowarm (new entry and didn't get into my original analysis). Disclaimer: I sell Ecowarm. Disclaimer 2: I used to sell Warmboard.

    My sources were the manufacturer's specs and Wirsbo's Design Manual.

    I did what you were asking for, but haven't taken the time to put all the data into one graphic yet. But with your own sweat equity, you can plot the temps for yourself by looking up the ones you're interested in.

    The cost data will be a little harder to come by. I've done cost comparisons of the various floor heating methods for nearly 10 years and the number of variables is staggering depending on how many methods/products you want to compare.

    For cost data, I found it best to pick two, then compare the methods side-by-side. Get the devil's advocate position from the devil himself, meaning talk to the reps to get their side of the story regarding the cost factors of their competitor. Then do the same with the other devil. You should get pretty close to apples-to-apples that way.

    It's not what happens to you. It's how you handle what happens to you that makes the difference. - Zig Ziglar
  • NRT_RobNRT_Rob Member Posts: 1,013
    good luck

    I had to build a shop and pile in monitoring equipment so could begin really testing this stuff. won't really be able to until next winter. oddly enough I don't think any MFGs will pay me to actually test their stuff either... I don't think most of them really want to know.

    the only stuff in existence right now with published figures that actually were tested out, as far as I know, are slabs. Everything else is modelled or guesstimated but nothing is tested, not really, and certainly not in any kind of apples to apples way. the "testing" you see from rehau was deeply flawed in its conclusions, but you could look at their raw data and get some useful stuff out of it... the data (notably floor surface temps) seemed decent.

    otherwise, best you can do is accept mfg data when it is sane, and ignore it when it is not. unless you too want to build a testing facility.

    Now accepting donations for the first round of winter testing ;)
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
  • Barry E. LaDukeBarry E. LaDuke Member Posts: 16
    What products do you have? Need?

    So, who's at least provided product (panels, tracks, etc)? I don't think you'll have much trouble getting participation from most manufacturers unless they already know their numbers are inflated.

    Launstein floors didn't have much trouble gathering product for their hardwood testing lab. Maybe you should partner with them and bring your hydronic expertise to their lab and get the data from the infrastructure they already have in place. Including hardwood floor covering!
    It's not what happens to you. It's how you handle what happens to you that makes the difference. - Zig Ziglar
  • NRT_RobNRT_Rob Member Posts: 1,013
    haven't thought about it too much yet

    we're doing radiant cooling and ceiling cooling light plate vs graftex first, and we're busy getting our system all hooked up and spic and span.

    the very first test will be the warmboard base system we have installed. Beyond that, I'll send out a few emails to panel MFGs to offer an opportunity to get in line early. Otherwise it will simply be whatever we find interesting, cheap, etc...
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!