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under the floor

Fawn Member Posts: 1

I have a new building that is unfinished.  It is two=stories the ground floor is 36x36 with a full 4' frost wall.  I will be doing radiant heat in both floors.  The upper floor is 28x36.  I am looking for a gas heater to warm with option for solar later.

My question(s) are as follows;

what should I look for in a gas water heater for domestic and radiant.  Some in slab some under approx 1 1/2", of sub-floor between the rafters?

Is it practical to heat under 2" of floor/ what size tubing?

My intention was to use spray-foam insoltion under the upper floor,,,What is the best insolation as the ground floor is not heated as of yet?

Thank you,

Oleta in Maine


  • NRT_Rob
    NRT_Rob Member Posts: 1,013

    are all answered with heat load calculations. the answer is usually "yes you can" but the devil is always in the details.

    These days here in maine though I would seriously question propane as a choice, unless you are in a larger area that has nat gas there *may* be better options. electric boilers are cheap to put in and not that much more to run. Heat pumps are more to put in but MUCH cheaper to run. again, load calcs can advise this decision.

    you won't need anything more than 1/2" pipe.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
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