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Radiant Heat in home not working

KHamid Member Posts: 6
We had a Slant/Fin radiant heat system installed in our home this summer and now (October) we have turned it on for one week and it is not heating the floors (except right next to the system).

It was a new installation on old house. The old house is slab and when they installed the radiant heat tubing, there was no insulation put on the bottom or on the sides, they just poured the concrete on the top of the tubing (that was on top of the old slab with ceramic tile floor), and that's it. It is now not working, and not heating our home. Do you have any suggestions to solve the problem?

Looking forward to any replys or ideas!

Kindest - Carina


  • I work at Slant/Fin

    Give me a call, I'd like to see what we can do.

    516 484 2610 ext 456

    800 873 4346 ext 456

  • Mad Dog
    Mad Dog Member Posts: 2,595
    Slant Fin makes a nice product, but the installation is everythi

    ng....won't the contractor come back? Was he the cheapest bid? Just curiuos, hope we can help you. Mad Dog

    To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
  • KHamid
    KHamid Member Posts: 6
    remedy to our radiant problem

    We received help from Slant-Fin on our issue with our radiant problem. They suggested that we dig a four foot ditch around the house and add insulation to the perimeter. They feel that this should remedy the problem. We have not felt that the problem was in the Slant-Fin product, just in the installation (I just wanted to clarify this point).

    We were told that there are two schools of thought on radiant; one is that there should be insulation on the bottom of the slab and the other is without insulation. Without the insulation on the bottom it will take longer to heat up but will hold the heat longer at a steady temp. because you are heating the earth...I think they called it a heat-sink. But both schools of thought require the insulation on the perimeter.

    So before ot gets too cold around here we will be digging our ditch, if anyone wants to come and help with "project" they are absolutely welcome...

    Kindest - Carina
  • Steve Eayrs
    Steve Eayrs Member Posts: 424

    There really are NOT 2 schools of thought on this. You either insulate under the slab, or pay aprox. 50% more in heating bills.

    Someone at this site posted a study done in Canada, with two small houses, one with insulation under the slab, and one with none. I believe both had it around the perimeter. Aprox. 50% more to heat the one without. Temp. sensors were installed on both, and the ground was being heated up to 6' down! This is not a heat sink, but a heat loss. In order for it to be a heat sink, you need to have someway to contain the heat.

    I have personally seen the difference between insulating and non on many houses. And the non-insulated do not hold heat longer, but shorter. In fact the main complaint was too cold of floors on the outside perimeter, (about the first 2' in) of the outside walls. This is exactly where you usually want the most heat.

    Insulating around the perimeter of the house will help a lot in containing some of the heat. Heat does not than rise, it conducts. Also the higher the moisture content of the ground the better the heat will conduct....any direction. If your soil is real wet, you may want to also install better drainage (footing drains), at the same time you dig things up for insulating. If this is a slab on grade, you will want to be careful to not undermine the house footings in the process.

  • Josh M.
    Josh M. Member Posts: 360

    I would have to agree with Steve on this. I have personally been on calls like this and tried all of the quick fixes. You might find a slight change in the way your house heats by adding insulation around the perimeter but it will most likely never pay for itself. Radiant heat will heat both ways. You see hot air will rise but radiant heat heats objects and in this case it will heat the ground. That is why we can install radiant heat in ceilings and it still works.
  • Paul Mitchell
    Paul Mitchell Member Posts: 266

    if i installed this job i would be digging the ditch...how does that work?

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  • Mad Dog
    Mad Dog Member Posts: 2,595
    It may be radical, but think about chopping up the slab

    and starting from scratch...yeah I know...the tile. the carpets..blah blah...but all that unecessary heat loss will really add up in fuel bills. Mad Dog

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  • heatboy
    heatboy Member Posts: 1,468
    You know............

    there are dozens of other things that could be causing your issues. Things like air, incorrect pumping, piping or control theory. Have all of these variables been eliminated as possible sources of no heat? That's not to say lack of insulation isn't the problem, but there are many systems with no insulation that work fine.


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    The Radiant Whisperer

    "The laws of physics will outweigh the laws of ecomomics every time."
  • Michael B
    Michael B Member Posts: 179
    I second

    what Heatboy posted! Obviously the contractor who installed the system did a marginal job at best. Why not get a "second opnion" about the total health of the system before performing radical surgery on the house itself.?

    Michael Bleier
    Able Distributors
    "The Supplier Who Works With You"
  • This is an aberration of a radiant job.

    I wonder why a brand new B&G circulator could have it's windings open? Bad pump. However, that won't explain this botched radiant job though. More wrong than right:-( Saddens me to see things done so poorly.
    Insulation won't do the trick with this one guys.

    I feel really bad for these people. I'll try to remedy their situation as best I know how. This looks like a new candidate for my before and after Find A Contractor job which is how this job came to pass my way. Thanks Dan. Find A Contractor really works.

    Will the RI heating & scorched air company responsable for this heteroclite, PLEASE stand up?

    Gary Wallace AOL IM; Radiantfloors

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  • Radiant Wizard
    Radiant Wizard Member Posts: 159
    There is no fix

    There is only a compromise here. Steve's point above is a fact. Don't insulate double the btu's needed to heat the space. The question now is going to be is that boiler big enough to handle the job. You just doubled the btu's needed to heat that space by not insulating. Adding perimeter insulation may help but it's just a bandaid.
  • Earthfire
    Earthfire Member Posts: 543
    hey Gary

    what is that black hose hanging of the circulator flange and where is it going? or do I need to clean my bifocals? I think the explanation for that mess is: "Hey its only copper, I can solder!!"
    ROJOHO Member Posts: 8
    okay, so how much

    and what kind of insulation under the slab is sufficient?
  • Earthfire
    Earthfire Member Posts: 543
    it depends

    Lots of variables. Water table, ground temps, design temps desired responce time are just some. As for insulation, blue or pink rigid with a vapor barrier (at least 1 inch thick) or insultarp or a combination thereof under the slab. and I prefer 2" perimeter insulation at least 2ft. down
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