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Considering hydronically heating tub walls

Gordan Member Posts: 891
I'm remodeling my master bath and putting in a nice tiled-in soaking tub, and it occurred to me that I could hydronically heat it to a) keep the water in the tub warm longer as well as increase comfort while the tub is in use, and b) as an ancillary benefit, get some extra heat into the bathroom while the tub is not in use. The tub is an acrylic one, with relatively straight walls which would allow me to epoxy joist trak to them. Water temp should never exceed 130 F as that's my design supply water temp, so I don't think that, combined with a quarter-inch of fiber-reinforced acrylic and the fact that the tub will be filled with water while in use, there's any concern with discomfort, let alone scalding.

Two questions: is this just a bad idea? And should I be concerned about the tub material itself?


  • Dave H_2
    Dave H_2 Member Posts: 545
    Heated tub

    I would just put the tube in the area itself under the tub deck. Lay it on the floor, it will heat up the air pocket around the tub. Not worth the extra effort to get it on the tub walls. Its a trapped air cavity.

    Now I do know if you were to quik-trak the deck, that would be nice, don't insulate below and that will also heat the walls of the tub

    Dave H.
    Dave H
  • pipeking
    pipeking Member Posts: 252
    wouldn't work sorry.

    a nice hot bath is a little more then 100*. and radient runs at 120, thers just not enogh btu's. but the bathroom is 1 of the most comfy places for radient.
  • Gordan
    Gordan Member Posts: 891
    Wouldn't work for what?

    I'm not looking to heat the water, just keep it warm longer... Maybe I wasn't clear about this, sorry.
  • Gordan
    Gordan Member Posts: 891
    You know, I like that idea.

    There won't be a deck per se, but the area under the tub lip will be tiled. I guess I could use that as a radiant wall. I can still use joist trak... it's better than quick trak. I'll spray paint the back of it to make it radiate on that side as well.

    But now you've got me thinking... (Uh-oh.) I could throw a short length of fin-tube in there, as well, and even put a little quiet DC fan on it to really get things toasty around the tub, and it should be nice and gentle and even. Hmmmm...
  • SWEI
    SWEI Member Posts: 7,356
    my insulation guru

    with 30+ years of experience and a couple of patents tells me that filling the void around a tub completely with dense-packed cellulose does wonders for both tub heat retention and also gets rid of that cheap-sounding thump you get when you step into a polymer tub.
  • Zman
    Zman Member Posts: 7,542
    I like..

    I like the idea of heating the tub. I think I would do the tile on the front and deck as well. Joisttrack should work just fine. It is always a challenge to heat that area and there is usually a window to boot. Did my first radiant wall last year it works great.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
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