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Discussion Forum

Radiant floor heating

Ry | Posted in Energy, Heating & Insulation on April 1, 2005 04:48am

Hi everyone. I’m in Kenmore Washington, near Seattle, and am looking into installing radiant floor heating throughout the house. We’re replacing most of the floor in the house, so we’ll probably go with something like the Warmboard which replaces the subfloor. I do have a concern though. Today we were at a store looking at windows and stuff, and one of the sales people there has a family member in the heating business. She told me that he was converting a lot of people back to forced air heating due to problems with freezing up with the radiant floor heating. She didn’t know exactly what the problem was, or if this was with all types of radiant floors, or maybe just one type, such as the staple up variety. But what I’ve read so far, and heard, has been positive about radiant floor heating, and this is the first negative I’ve heard. Can anyone shed some light on this for me?

Thanks,

Ryan

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Replies

  1. tmaxxx | Apr 01, 2005 05:37am | #1

    Hi Ryan

    i would say that from past experience nothing compares to heated floors.  they work great and i have never heard of it freezing before.  i would guess that it was installed wrong.  if thats what you want then have it engineered by an engineer, not the contractor and make sure the installer is certifed at doing that type of flooring.  the other option which is much easier and you dont have to replace the sub floor is electric heating pads.  check out this link

    http://www.nuheat.com/

    i have put in several and they rule.  there are several companies that do this type of heating.

    cheers.

    Tmaxxx

    Urban Workshop Ltd

    Vancouver B.C.

     Now when i nod my head, you hit it.

  2. User avater
    CloudHidden | Apr 01, 2005 05:43am | #2

    RFH freezing in an interior space? On its face it sounds ridiculous. I guess I could imagine an extreme scenario where the power was out for days in a poorly insulated building in sub-zero weather, but any normal circumstances, can't see it happening, be/c after all, the water is heated...

  3. BrianWI | Apr 01, 2005 06:17am | #3

    any hot water systems i ever worked on the water isnt all water. glycol and glysterine type stuff went in to make it hyperwater (as is how it was described to me, and the additive is from memory lol) wich heats and cools easier,less expansion makes 10x better contact with fixtures and heat chamber, AND DOES NOT FREEZE. i dunno if they put it in residential but im sure they could.

    1. User avater
      RBean | Apr 01, 2005 07:53am | #4

      "...converting a lot of people back to forced air heating due to problems with freezing up with the radiant floor heating."<!----><!---->

      Water freezes because it dropped below the freezing temperature - so what on earth would cause that?<!---->

      One or more of the following could cause it:<!---->

      Poor building efficiency: The builder failed to insulate, vapor barrier and seal the trimmer and header joist…happens more than we like to admit…have seen it with thermography many times – usually with the home owner there with the builder standing next to her – always a pleasant meeting - lots of red faces and stammering.

      Let’s make the assumption that the builder did his job…then a;<!---->

      Failure in the fuel source: Could happen regardless of the heating system.  Two identical houses – one heated with radiant – the other with air – turn off the fuel – which home’s plumbing systems freezes first?  Think about it.  Radiant heats mass – air does not.<!---->

      Also if it was a fuel failure the control systems if they were properly done would have kept the water moving since everything would have been calling for heat…moving water does not freeze like stagnant water.  Again the plumbing system would have failed first.  If the house was getting cold and the controls did not open flow valves and power on the circulators...shame on the control contractor.<!---->

      Failure in the mechanical equipment. Could happen regardless of the heating system.  Same answer - Two identical houses – one heated with radiant – the other with air – turn off the pump or fan – which home’s plumbing systems freezes first?  Think about it.  Radiant heats mass – air does not.<!---->

      You never ever hear anyone say that it takes a long time to heat up a home with a furnace – but you always hear about how it takes longer to bring a home up to temperature with radiant  Anyways the reverse is true…what heats up fast also cools fast - so radiant is the better choice as far as freezing goes.  If there are any concerns glycol is a choice but only if you have to…it has greater density and less heat capacity so the flow rates have to go up.  Its all in the design – like the previous post – get a qualified designer.<!---->

      The guy making the switch based on freezing may have ulterior motives…a great big red flag.  Get another quote from other reputable firms.<!---->

      Here’s a link to some pics of installs by some Top Dogs and a few by the starving wolf pack... http://www.healthyheating.com/blog/index.php?cat=4 One of the good guys shown is from <!----><!----><!---->Seattle<!----><!---->.  Check his credentials with any manufacturer, distributor or association.  Even if you don't award him the contract he'll set the benchmark for your system.  But you won't go wrong working with him.

      As far as electrical radiant goes…ALWAYS ask the manufacture what their floor systems EMF rating is.  I have limited knowledge at this point but am in the process of researching it for our clients but at this time it appears anything over 0.5 mG per day is not safe.  Some American manufacturers use a patented two wire cancellation technique and have very low EMF – others do not.  Some claim zero EMF...I suppose its possible but then I'd like to see the testing methods used. 

      Also any product made to an ISO Standard does not mean its safe.  You can manufacturer the highest quality concrete life jackets and still get ISO certification. As far as CSA/UL...several years ago a number of electric ceiling manufacturers (most in Canada) had their CSA/UL numbers pulled because of fire hazards. The point is if you have any doubts about electric radiant do your home work on the web. Deal with reputable firms.  A starting point for American citizens is contact the Radiant Panel Association for a list of names to do your due diligence on.  In Canada contact CIPH, HRAI, AHAC or RHWHA of BC.

      As a side bar for the readers considering web purchases on all radiant products - if the vendor doesn't have a business address that you can physically drive to when your mad as hell - then that's a red flag - why would any distribution company not want to publish their address?   It may be nothing to worry about but it’s better to know and be safe before hand than ignorant and sorry afterwards.

      Just looking out for our bosses - they're called consumers.

      Keep smiling.

      RBean

      http://www.healthyheating.com

      http://www.healthyheating.com/blog

       

       

      Edited 4/1/2005 12:55 am ET by RB

      Edited 4/1/2005 12:57 am ET by RB

      Edited 4/1/2005 1:43 am ET by RB

      1. Ry | Apr 03, 2005 06:20am | #5

        Thanks everyone for your info!

        Ryan

    2. User avater
      Nuke | Apr 04, 2005 02:42am | #8

      glycol and glysterine ...

      I would imagine the intent here is to a) lower the freezing point below water's natural 32ºF (0ºC) freezing point, and b) to elevate the boiling from above water's natural boiling temp of 212ºF (100ºC).

      BTW, do radiant floor heating systems based on heating of a liquid (that is then transported throughout an area) really have to be water at all if they are a closed system?

      1. User avater
        RBean | Apr 04, 2005 04:20am | #9

        If there were a safer, cheaper, more readily available fluid with similar or better qualities including specific heat, density and viscosity...then we should be using it.

        Perhaps some day nanofluids will be the norm - who knows?

         

         RBean

        http://www.healthyheating.com

        http://www.healthyheating.com/blog

         

         

        1. pvaman | Apr 04, 2005 05:14am | #10

          RB

          Do you consider an open system a bad thing? I'm going to be building a new house w/a basement. I'd like to use radiant heat just in the basement -- to make sure we a nice warm basement. I was considering just having the tubing layed in the concrete floor and one day in the future complete the install. I was considering making provisions to hook it directly to the house hot water supply. Bad idea?

          1. User avater
            CloudHidden | Apr 04, 2005 05:48am | #11

            The tube I had (Wirsbo) wasn't approved for potable water.

          2. User avater
            RBean | Apr 04, 2005 06:03am | #12

            ahh - the mother of all debates!

            When I was the first chairman of the Foothills Conference we had a "forum" on open vs closed (boiler vs water heaters)...it go so out of hand we almost called the police.

            You can go to our site to participate in the ongoing - never ending - lingusitic lashings but lets just say for me, being held accountable as a professional - I wouldn't recommend combing heating with the potable systems.  I would run the tank hot, put a mixing valve on the domestic for scald protetction and seperate the radiant with a heat exchanger. Why?  Because the higher temp is need to drive the heat exchanger for the radiant, kills any bugs in the tank and improves the available quantity of mixed temperature for fixtures.  There are small pre assembled "mini" boiler rooms in a box made just for this application. Danfoss is one of them.

            Remember to vapor barrier and insulate the slab with high density rigid insulation.RBean

            http://www.healthyheating.com

            http://www.healthyheating.com/blog

             

             

          3. pvaman | Apr 05, 2005 02:21am | #16

            RB:

            Well, nothing like a hot debateable topic ;)

            Can you help me find this unit on Danfoss web site. I looked at almost everything on their site (http://www.danfoss.com) but never really found any heating units. I did find some nice heat exchangers. BTW there is no natural gas where i'm out so whatever i use will need to be electric.

          4. Arvid | Apr 04, 2005 01:59pm | #13

            Bob,
            My wife and I did exactly what you're talking about. Before our basement floor was poured we laid 2" ridged foam over the ground and up the walls tapered to the wall about ½" below the future floor line. Laid rebar and grids, then attached 300' loops of ½" Wirsbo PEX to the grid. Brought the lines up to a manifold on the wall making sure to protect the lines at the future floor level by running each through electrical conduct at that spot. The cement contractor didn't pour until the end of October (one reason we now do everything ourselves). The basement sat open during a northern Michigan winter. Next summer we framed the basement and put on the 1st floor subflooring and covered the whole thing with tarp. When we got some water, gas and electricity in the basement we set up a cheap water heater and heated the floor. We drew hot water from this system for one utility wash tub in the basement. So it was an open system of sorts. After a while the water got pretty funky. But it heated the space well. After we had radiant heating pipes in the 1st and second floor we put in a real water heater and did the open system right using the designs provided in the Installation Manual from the Radiant Floor Company in Vermont. http://www.radiantcompany.com Just call them at their toll free number and ask for the manual if you can't order it on line. I think its free. They are very friendly Vermont people. We eventually used their system but got much of our parts locally. We have had our open system operating for several years and have no problem with the domestic water. Here are some books we found informative on radiant heating: "Hydraulic Radiant Heating" by Dan Holohan. If you can only afford one book get this one. If you can afford two get his other book "How Come?". They are both fun to read. You can purchase them both on line at http://www.HeatingHelp.com
            Good luck, Arvid

          5. pvaman | Apr 05, 2005 02:27am | #17

            Arvid:

            thanks. I've seen all the advertisements from the company you're referring to. Sounds like you did quite a bit of study yourself. What did you finally end up with as your heat source and did you keep it an open system? After all ... you mention the water tasting 'funky' <-- makes one kind of nervous.

            How much work was involved in putting the tubing down. I've read a little (very little) and i get the feeling that this is much more work that it seems! I just curious why/what's involved. That said, most stuff in life is harder than it appears so it doesn't surprise me.

          6. Arvid | Apr 05, 2005 04:29pm | #18

            Bob,
            We chose the Polaris high efficiency water heater sold by the Radiant Foor Company as the heat source. They will walk you through the process of designing the system. The few times I had questions they were only a phone call away. We have an open system throughout the building. Pipes are laid in thick slab in the basement floor, staple up under the first floor, thin slab on the second floor and an additional zone in the ceiling of one north facing room with lots of windows. The open system brings fresh cold water into the system every time you turn on a hot water faucet in the house. Seems strange but it works. Keeps the water in the system fresh and we have no problem with funky water. Our first temporary set up for the basement slab did not do this (didn’t know what we we’re doing then). If you are only talking about doing your basement slab you can do it yourself. It’ll go easier with two. My wife and I laid ours aferwork and on the weekends. Things to remember from the start: level out the dirt so when you lay the rigid foam insulation you can walk on it without cracking it. Lay polysheeting over the ground. Cut out the foam board from over the cement pads that will support the rest of the house. Figure out where the finished floor level will be and bring some foam board up the side walls, beveled to about ½ below that line. Lay your rebar or have your cement contractor do that. You can attach your pipes to the rebar with plastic bag ties. Don’t worry about how deep the pipe should be, as long as it stays with the rebar it’ll work. Figure out how much pipe you will need to cover the basement floor. We tried to keep them 12" on center, but 6" on center under the bathroom and two foot from the walls. We have a walk out with patio windows and along that wall we ran the pipe 6" on center for about 3 foot in. Keep the runs (or loops) the same length, as much as possible, within 10-15% variance. One local contractor laid a single run of 1600 ft. Don’t make that mistake. With ½ PEX don’t go over 300 ft. Divide the total length you’ll need by 300 and you’ll see what size of manifold you’ll need. If you want you could make it yourself but your local plumbing supplier or Radiant Company can get one the right size for you. We put ours on the wall near where the heater would be. Protect the pipes by running them through short pieces of electrical conduit where they will exit the concrete under your manifold. Connect the pipes to the manifold and hook up a air pump top it with an air gauge attached. Charge the system with air to a fair pressure and see if holds. We left ours on until a few weeks after the pour. If there’s a leak, find it and you can replace that loop or just cut the pipe at that spot and put in a connector. I drove a nail through a pipe in the thin slab on the 2nd floor and it was a breeze to fix. Have a few connectors on hand just in case the cement contractor damages a pipe during the pour. Last word is ... put the pipes in the floor even if you may not use them. Its cheap and you can’t do it later.
            ArvidEdited 4/5/2005 9:33 am ET by ArvidEdited 4/5/2005 9:38 am ET by Arvid

            Edited 4/5/2005 10:16 am ET by Arvid

          7. User avater
            RBean | Apr 05, 2005 05:26pm | #19

            You have to go the Canadian website which is http://www.Dafoss.ca or call the factory at 403.236.9560 and ask for a Brian Wheeldon.

            The other guys which have packaged control systems is Uponor Wirsbo, Watts Radiant or CPI.

             

             

             RBean

            http://www.healthyheating.com

            http://www.healthyheating.com/blog

             

             

          8. pvaman | Apr 06, 2005 04:22am | #22

            Arvid..thanks much. I really appreciate the detail/time. I'm a little unclear on what you've done with foam once it leaves the bottom of the foundation. Is it run up the side of the poured basement walls....between the basement floor (side) and the basement wall? Normally there's some kind of expansion joint there right, so is this in addition to that? Also it sounds like you stopped it just below the surface. Also, why beveled?

             

          9. Arvid | Apr 06, 2005 03:54pm | #25

            Bob,
            Like me, you over think these things. This is really a no-brainer. There may be better and less better ways to do it. But there probably isn't much you can do wrong if you just get the pipes in the cement. I've never seen an expansion joint where the wall and floor meet. Our cement contractor didn't put one in either. You could probably skip that insulation without much loss if the outside of your foundation is insulated. Don't know the reason for tapering the foam against the poured basement wall. I was just following the directions, I believe from a FHB article. It sounded like a good idea.
            Arvid

          10. User avater
            slimjim | Apr 04, 2005 02:19pm | #14

            RB said it.

            Bottom line on open systems

             If you happen to own a radiant heat supply company, you are pushing these open systems, and its a paradigm shift for you.

            If you are a hydronics installer, you will tend to think it's a bad idea.

            I bet nearly 100% of the open systems that are installed are DIY.

            Also it cant be done where I live inspector (and code?) wise.

          11. frenchy | Apr 05, 2005 07:54pm | #20

            Bob,

             sure that would work.. start small and upgrade when you are ready.. check your local building codes regarding the use of radiant floor water being used in the whole house.. it's ok in some locations and not in others..

             You can get clever and do some cross plumbing to get around the issue if it's not legal.  Use one water heater as your domestic hot water and another as your flooring heat source.  Then you can cross  plumb to use one as a backup to the other.

                

          12. User avater
            RBean | Apr 06, 2005 02:24am | #21

            A fellow industry writer who done a lot of work on this topic has allowed me to make available his 12 page report...will work on it this week and get it ready by the weekend. Stay tunedRBean

            http://www.healthyheating.com

            http://www.healthyheating.com/blog

             

             

          13. pvaman | Apr 06, 2005 04:26am | #24

            Frenchy -- thanks. it it's against code here (i need to find out) then a small water heater would be dedicated to it. Seems like the major chore is doing a heat loss calculation and determinging the layout -- pipe lengths, pipe diameter, and pipe seperation.

          14. TRice | Apr 07, 2005 03:51pm | #27

            I can't speak for other manufacturer's distributors, but if you were to buy Wirsbo directly from the supply house, they might run the loads and do the layout for you.

            I do this for my customers, whether they be plumbers, heating contractors, or DIYers. The price of the materials WILL reflect the amount of work required on my part, as you should expect from anyone else.

          15. pvaman | Apr 08, 2005 01:40am | #28

            Timbo

            I may ask...i'm happy to pay for that.

          16. TRice | Apr 08, 2005 06:48pm | #29

            BTW,

            I have been designing, commisioning, installing, troublehooting and selling HVAC equipment and systems for most of the last 20 years, and I have to concur with the consensus, that radiant floor heating systems freezing is a rare occurence and indicative of either severe incompetence or of a series of other significant failures.

            In other words, it is hard to beat the comfort and efficiency of a properly done RFH system. Go for it. 

  4. User avater
    slimjim | Apr 03, 2005 03:54pm | #6

    "due to problems with radiant heat freezing"

    That made me chuckle!

     The only scenario I can think of is a development (I know one) that routinely gets their power substation (or whatever you call it) knocked out in  winter storms. Since they're kind of in the boonies, they're the last to get it fixed.

    So everybody got back up generators.

    As was said already, its easy to do a glycol mix.

    Go back and ask the sales person how on earth do they do those snowmelting systems if the tubing freezes?

    1. Ry | Apr 03, 2005 07:44pm | #7

      Yeah, I was quite skeptical when she told me. But since I have no experience with radiant floors, nor do I know anyone with them, so I had to ask the question. Sounds like if there was a problem it was more of installation error or poor product choice than it being a bad product. The antifreeze is a good idea, but near Seattle it rarely gets cold enough to worry about needing it. Thanks for your info.

      Ryan

  5. User avater
    Mongo | Apr 04, 2005 04:28pm | #15

    Regarding open vs closed radiant systems...go closed. Keep the heat separate from the domestic.

    Regarding RFH freezing...normally a design flaw or a build flaw.

    When the PEX is run, it's normally held back about 12" from the rim board. If it's run closer, problems could occur.

    I've only seen one RFH run freeze, and that was with a system that ran under a bumpout. The area under the bumpout was open to free air, and the loop that heated the joist bays that made up the bumpout froze. Even with that loop frozen the other nine loops that heated the first floor ran fine.

    Solution? Opened up the bottom of the bumpout to find FG insulation, above the FG was 1/2" foil-faced polyiso with inadequate insulation against the rim joist. That's great for inside the envelope, but not outside. I pulled the FG and instead installed three layers of 2" polyiso up against the tubing and against the rim, and reset the FG under the polyiso. No problems since.

    If you live in a severe climate where you don't have backup power to run the heating in case of an extended power outage, then you could add an anti-freeze to the RFH system. Adding glycol is fairly common in residential, but it's not required in a well-designed system.

    I'll armchair quarterback and say that replacing RFH with forced air is about the silliest thing I've ever heard. Kind of like running out of gas and deciding to replace your car with a mule-pulled covered wagon.

  6. UBuildIt | Apr 06, 2005 04:23am | #23

    ((little wave))

    Welcome, I'm Kirkland!

    -christi

     

    Let the beauty of what you love be what you do. ~ Rumi

  7. weiserbNYC | Apr 07, 2005 05:07am | #26

    I installed Nuheat in additon to the existing steam radiator. I am very pleased with it. The floor is kept warm regardless of weather the whole house heat is running or not . It is a nice touch even in the warmer months!

  8. Ridechignik1 | Apr 10, 2005 09:45pm | #30

    Ryan,

    I am a builder and engineer in Northern Wyoming.  I have been reading through the responses to your question and I am compelled to give you some suggestions on the design of a radiant floor heating system.  One thing that I have noticed when ever this discussion comes up is the complete lack of any kind of accurate knowledge anyone who thinks they know something actually posseses.  Radiant heating, If designed and installed correctly is by far the most comfortable, and energy efficient system available. I have installed these systems in this area with un-paralelled success (it gets much colder here than in the Seattle area). As far as freezing the system, you should never use water as a medium for transfer of heat energy in a radiant system.  In the systems I design I always specify the use of propolene glycol (RV antifreeze).  This is a non toxic antifreeze with a specific gravity very similar to water and a very low freeze point.  I also always use Kitec PEX-AL-PEX tubing by IPEX.  It is a cross link polyethlene type tubing with a very important difference from other products like Wirsbo.  It is a thin aluminum tubing sandwitched between two layers of cross linked polyethelene.  The aluminim provides three major advantages over straight polyethelene tubing.  First it creates an oxygen permeation barrier so oxygen is not infiltrating the system.  This will speed the corrosion of many boilers, hot water heaters, heat exchangers, etc.  Second when installing the tubing the aluminum helps hold the shape of bends and helps keep the tube where you want it.  And third, it makes this stuff extremely collapse resistant and tough.  This is very important when a crew of concrete muckers are beating it with shovels during the heat of a concrete pour.  Where other systems would be rendered in-operable by a careless concrete worker this stuff is still there.  Ipex also makes excellent control panels and most of the other components for use with this tubing.  Many heating contractors will try to sell you a circulation pump for use with each zone and thousands of dollars worth of equipment you don't need.  Check out thier self contained control manifolds.  Very slick.  Visit thier website at http://www.ipexinc.com for the facts.  They also have very good information on design and intallation that will crush all of in inaccuate information and wives tales you have been exposed to on this subject.

    Good luck,

    Casey Jones

     

    1. User avater
      RBean | Apr 10, 2005 11:51pm | #31

      There is a very interesting history between then Wirsbo, now Uponor Wirsbo, Unicor of Germany and Kitec Ltd. Both Unicor and Kitec applied for patents on the multi layer pipe (MLP) in and around 1993.  As far as public records go - Unicor (Which, like Wirsbo is owned by Uponor) bought Kitec’s rights several years ago. Other than Unicor there are only three other companies which may legally manufacturer the product they are IPEX, SKS and Metzerplas.  Uponor Wirsbo in addition to their PEX offering, sell the MLP in NA under the Multicor brand name.  

      <!----><!----> <!---->

      So Wirsbo or IPEX offer either PEX or PEX-AL-PEX (brand names Multicor or Kitec) and either has pro’s and con’s depending on application. They both keep the water on the inside, come with oxygen barriers and have temperature and pressure characteristics which are more than adequate for residential radiant and snow ice melting systems.  

      .

      The global relationships between radiant pipe manufacturers gets even better when you throw in Rehau, Velta (Velta Wirsbo) and Tour and Andersson - Probably the first four major players in European Radiant Plastics going back to the 60’s. 

      <!----> <!---->

      Another story for another day...RBean

      http://www.healthyheating.com

      http://www.healthyheating.com/blog

       

       

  9. Frandn | Apr 11, 2005 04:16am | #32

    We had Radiantec http://www.radiantec,com of Lyndonville Vermont design our heating in the floor system. It is installed in the basement, garage and under the floor of the living area. The Polaris water heater provides all of the hot water for our needs including the heating. The only challange that we experienced was when the hot surface igniter in the water heater failed (middle of winter) and it took five days to obtain a new one. The basic reason for the delay was the lack of availibility in this area. I ended up ordering the ignitor from Radiantec and received it right away. Lesson learned--- always keep a spare ignitor!

    The house is insulated concrete forms from the footing to the roof and the temperature only dropped to 50 degrees without heat for five days. This system is the greatest. Oh by the way, we installed this heating system ourselves and never had any issues. Radiantec has a solar system that will work with our installation and we plan to purchase this addition this summer. If you have any questions, don't hesitate to e-mail.

     

    Fran

    1. frenchy | Apr 11, 2005 05:39pm | #34

      FNADO,

        Let me state that is been the experance I heard from everybody who uses radiantec, they provide what you need to do the job, the cost is reasonable and they will be extremely helpfull. 

      1. pvaman | Apr 12, 2005 06:39am | #35

        frenchy

        I'm a home owner/builder and am planning on laying the tubing in the basement and finishing this later once i finish the basement. (just background info)

        I'm considering Radiantec but if you read some of the other forums (http://www.heatinghelp.com the wall for one) you'll see some pretty vicious posts about radiantec. The main source from what i can tell = support adn standing behind their heat analysis but to be honest i haven't really studied the topic much.

        1. ruffmike | Apr 12, 2005 04:18pm | #36

          Without choosing sides, here is my experience.

          I used an online supplier for a radiant system, first floor in slab and second floor staple up. About 5 k for it all incluing a co-heater boiler. The supplier was suposed to layout my loops off a print I sent them, but never did.

          System is installed and heating the house. we are happy with that.

          There is however a problem with the controller on the domestic side, when radiant is on. I found this out myself through a series of phone calls, posts and contractor visits. The manufacturer said they would replace controller but I am getting a cold shoulder from the area rep- over100 mi. away.

          I am close to getting this resolved, but here are my feelings now-

          I wish I had used a local contractor, that could provide support and would have used a boiler that is known locally. My boiler is made in Canada, sold in New York distributed out of Seattle and installed in my area by one contractor 100 miles away (and I suspect they don't install many).

          When I called contractors to "fix" my problem they were unfamiliar with my brand although these boilers all operate in similar fashions.

           The manufacturer and their reps don't really want anything to do with a do-it yourself type. Their stuff is supposed to be installed by approved contractors.

          Just my experience, in a short form.

          1. N30X1D3 | Jun 07, 2006 08:16am | #37

            I spent a summer working for a concrete construction firm that specialized in Insulated Concrete Forms and Radiant Floor Heating. And this is the little advice I can give you.
            1. Insulate below the slab. There is no sense in wasting your energy bill to heat 300,000 lbs of dirt heat sink below your house. Also I'd be worried about foundation issues forming because of uneven ground temperatures causing weird expansion and contraction under your slab. (I'm just being cautious; I make no claims at expertise in the thermodynamic properties of dirt)2. Use the insulation below the slab to fix the heating lines in place and keep your runs straight and even. We used giant plastic staples (they seemed to be meant for this) over the pipes and into the foam; we had zero problems with the pipes moving on us.3. Use closed cell insulation. You don't want concrete filling the cells and killing your R value, do you?4. Spray in closed cell foam is not recommended. Unless a very skilled person operates the sprayer it tends to be uneven. Laying a slab on an uneven surface usually makes it much more difficult to maintain level concrete. An unleveled slab can lead to some pretty nasty problems when doing the framing (like needing to cut every stud to a different length to keep the roof level. Also sprayed in foam doesn't leave any space for moisture to leach into the ground when the slab is drying. It could be the concrete we used, but this made for some very weird drying/curing times.5. Test pressurize the lines and make sure they stay pressurized for a few days before the pour. This makes sure that if the concrete contractor slices a line with a #2 spade shovel you can hold him/her responsible. Also keep them pressurized while you pour as that should increase their strength (keeps them from collapsing under the weight of the cement) and they will cause bubbles in the cement if you break one (makes sure you can fix it before it’s too late).6. I would recommend the use of a pumper truck to move the concrete while pouring the slab if you can't get the truck in close enough to pour very close to where you want it. Often if the truck doesn’t get close enough contractors resort to wheelbarrows and the newest guy on the crew to move the cement to where it needs to be. I know first hand that these wheelbarrows can be a couple hundred pounds when filled with cement. You don't 400lbs of cement on 3 square inches of wheel rolling across your new heating lines. (If you must use wheel barrows, lay down temporary paths for them using plywood scraps to more evenly distribute the weight just make sure to pick them up before you get concrete on them)7. Make sure that the workers know and understand the vulnerabilities of the tubing. If they are dumber than a box of rocks and won't understand anything else, tell them that the lines are pressurized with a toxic gas and that they could get very sick or die if they break them. I know first hand that is a statement any one can understand. Especially, if bubbles, the slightly slow but friendly giant of a man we had moving wheelbarrows of cement, could understand it.

    2. kazm | May 02, 2008 06:05am | #38

      How has your Radiantec system held up? Was reading your post today and wondered if your thoughts had changed. We are considering using Radiantec for a project this summer.

      1. FCOH | May 03, 2008 06:02am | #39

        I feel I have to throw my .02 in here.

        I have installed two hydronic radiant systems both designed by Northeast Radiant Technology.  One in my house and one in a clients house.  More than happy with both.  I am a carpenter by trade so I had many questions during the installations and they were more than happy to take the time to guide me through what I needed.  First class guys.

        NRTradiant.com is their website

        One mistake I did make was staining my oak floor while the system was running.  I have very faint stripes darker where the tubes are and lighter in between them.  99% of people would never notice but just a bit of wisdom from my experience.

        Matt

  10. EuroBuddy | Apr 11, 2005 11:10am | #33

    Dear Ryan.

     

    I am an east coaster living in Austria.  Just finishing up a renovation of an American size house here where we installed about 1500sq feet of Radiant heat.  First, it is standard practice to run Anti Freeze in radiant heat flooring.  Always use water while tuning the system up etc.  When everything is complete and tested, then drain the water and pump in the Glycol.

    We also had an insteresting experience when it came to wood flooring and Radiant heat.  I spent about 1 year inquiring here and there about how to address the issue of laying wood floor over radiant heat flooring.  The subfloors are all fine concrete.  Finally, one of the very high quality flooring companies came back with what I thought was the finest answer.   They also were willing to stand behind their word.  The company was Admonter,  http://www.stia.com .  They advised to use a special glue and to glue the tongue and groove floor down to the subfloor.  The glue the recommended is a construction glue that I can only describe as going on like peanut butter and finishing like rubber cement.  It has a rubbery finish that gives a very nice solid but dampening effect.  The glue, from what they say has very good heat transfer through to the wood.  We laid it down with a 4mm toothed putty knife like used for tile laying.  The floor looks and feels great!  We have the same flooring in the bedrooms but layed floating.  It simply does not have the same feel.

    Anyway, I can do nothing but recommend the radiat heating.  The comfort is excellent, the efficiency valuable, and no radiators or duct work.  Also to consider which is really growing here as well is radiant heating in the walls.  In many cases in the US this would be far easier to install than in the floor.

    Ok,  all the best

    Bruce

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