[Greenbuilding] Effective R Value Was: Kitty litter

[Peter/Pam Martin]

At 01:04 PM 2/2/2012, Rob Tom wrote:
<snip>
>So I'm wondering "Why not just use sawdust or woodchips for kitty litter
>instead of buying processed wood pellets for the task ?"
>
>Softwood sawdust would be naturally scented (ie pine, spruce, cedar) so
>should meet with the approval of Ms Cat.
>(I understand horses don't like a particular species of wood shavings for
>their bedding but I don't remember which).

Some cats may have an allergic reaction to Western Red Cedar, but 
other softwoods should be ok. The problem with sawdust is the cat may 
traipse it around or inhale it, but woodchips sound like a good idea, 
and I should be able to locate a source closer than the pellets, 
probably for less cost too.

For some reason the image of frost heaving cadavers got me thinking 
of effective R values (perhaps both are fantastical). What is an 
effective R value? Can one say anymore that in a particular assembly, 
at a particular time, and under particular conditions, the effective 
R value is x? Thus are statements such as "my 24" earthen wall has an 
actual R value of 6 but due to the thermal mass effect the effective 
R value is 22" mythical? Can anyone point me to the latest and 
greatest treatise, or even essay, on effective R values? Thank you. Peter