[Strawbale] PEX, Concrete Slab, Fear of Death (by contractor)

[Shody Ryon]

--- Dion Hollenbeck <hollen at woodsprite.com> wrote:

<snip>
> Faster response, yes, but would not store as much
> heat, either, 
> compared to concrete.  The concrete continues to
> radiate heat for a 
> longer period of time after the hydronic pump shuts
> off.
<snip>
Thanks for the info. I think heating costs could be
reduced with a 2x6 or larger wood floor. I am trying
to remember the R value of ...

http://www.rvalue.net/

# House Insulation R value of Blown in Cellulose
Insulation is 3.70 per inch

# House Insulation R value of Fiberglass Insulation is
3.14 per inch

# House Insulation R value of Expanded Polystyrene is
4.00 per inch

The house insulation r value of insulating boards are:

    Expanded polystyrene     4.00 per inch
    Extruded polystyrene     5.00 per inch
    Polyisocyanurate &
    Polyurethane              6-7 per inch

... 2x6 is about R 17, but I have heard there may be
high tech R 19 for 2x6 vs about R 8 or 10 if your
concrete has 2" of that type of insulation.

There maybe a tax credit or special loan offer in my
area for 45% higher than code required insulation, so
I have a high motivation to install super insulation
correctly. They told me that it has to be installed
correctly and the offer will only be extended if it
really works.

As for the slab holding more heat than a wood floor, I
agree that is should. If your system works well, that
is great, I would consider heat storage out side the
living space so that higher than living space temps
could be stored and brought into the living space by
thermostat. Anyhow, I am sure you are familiar with
this concept which may bring a degree of complexity
beyond what you wish to deal with. For those
interested solar heated water could be stored in a
separate insulated envelope from the living space,
Though I question how much work that would be. I tend
to think it might be worth while, storing it in Laren
Corie's thermal attic, which he may recommend built to
operate by heating water bottles that do not circulate
water, the system would heat air instead, unless the
system was off grid and needed to use very small
amounts of electricity. The air circulation system
would also use very small amounts of electricity, but
a water system would use a lot less, as I understand
it.

The roof sounds great. I think I would build it a
little differently. I would use a metal roof to
harvest rain water and have an air space between the
metal and the insulation envelope to collect day time
solar heated air or night time energy radiated cold
air to transfer heat or cool to the thermal storage in
the thermal attic.


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