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¾" fir, ¾" plywood, ¾" floating floor. How to get the heat through.

This floor sandwich approaches R-3 and I'm wondering if it's possible to heat the space by either using good quality plates ala Radiant Engineering or possibly UltraFin. The rooms are not difficult to heat (~25 BTU's/sq.ft.) and there is another part of the house where tubing will be in the slab. I see a two temperature system.

Has anyone done something like this?
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

Two btu per sq ft for degree difference for a slab


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    I guess something like warmboard is out? An extra 3/4" (plus weight) and a threshold.
    Or of course radiant ceiling.
    In my house I have a couple zones-underside tubing in plates, 3/4" ply, pad & carpet, max water 130 (which it never gets to with outdoor reset) and never had a problem
    Part of one zone runs in wetbed for laundry room. Took a couple of tries with my heat gun to balance the manifold but works great.
    I'm sure constant circulation would help.
  • hot_rod
    hot_rod Member Posts: 22,100
    The RadPad shows 145 SWT to provide 25 but/ft with R-3.

    Radiant Engineering had some design data on their website.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited January 2016
    25 btu/hr sqft seems high for a radiant application. Thoughts on doing a combination of maybe some radiant wall along with floor or adding in some panel rads or radiant panel baseboard to work in conjunction with the radiant floor and required water temps? Kinda more of condtioned flooring/radiant application
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Gordy
    Gordy Member Posts: 9,546
    Ceilings.....wood floors are a little more foot friendly than tile floors.
  • tim smith
    tim smith Member Posts: 2,752
    I have been stuck with that scenario a few times, used extruded plates, think my max req temp here in Seattle was 140 at 20 outside. Not ideal temps but due to average odt being 47 I was still in condensing temps 95% of the time. What's your od design Alan?
  • Our outdoor design temperature is 36°F the last time I checked.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab