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using radiators with heatpump

wmaring Member Posts: 1
I have a wtw heat pump and pex under my subfloor with a hardwood floating floor. I'm not getting heat through the floor and cork underlay(checked with flir camera). thinking of adding base board radiators and using 130 degree water. will the radiators work at that temp? ...that or take up the floor and remove underlayment, but not sure that will help.


  • Dave H_2
    Dave H_2 Member Posts: 560
    We just did a webinar on this several weeks ago on how to design low temp hydronics. You can watch it here

    So the answer is yes you can use low temperature but Do the Math based upon your emitters.

    However, radiant floor heating with 130F should be working. There are some things to check, is the insulation in properly and sealed against the rim joists?
    Was there a design performed with the heatloss of the room(s)?
    Are you using heat transfer plates or just the tubing itself?

    Dave H.
    Dave H
  • Jamie Hall
    Jamie Hall Member Posts: 23,656
    The radiators will be warm at that water temperature -- but they won't put out much heat. Less than half as much as you would get with normal hot water heat.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 22,486
    Do you know the heat load of the rooms that are under-performing? There are cases where the floor radiant alone will not cover the load, floor coverings, lots of built in etc.

    Here is some info on rad output and low temperature systems in general.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • neilc
    neilc Member Posts: 2,716
    silly question, but,
    you sure you have flow thru all your loops?
    nothing airbound?
    known to beat dead horses
  • bburd
    bburd Member Posts: 935
    “Cork underlay”?  Cork is an excellent insulator.