Cob: to insulate or not

[Darel Henman]

Drew Neve wrote:
> 
> The earth is a terrible insulator so you do
> want to insulate that rear wall. 

This statement is not accurate, except in one dimension.
Earth itself, when considering its thermal characterics together show
that it has very good temperature control ability in its thermal mass. 
It will not loose heat quickly and will not absorb quickly.  It will
once heated up to a comfortable level, maintain that level and prevent
quick chilling or over heating in a house.  

> Using the rear rooms for storage does
> provide further insulation for the living areas and keep them more
> comfortable. 
This is good common sense, for the north side of a house in the northern
hemisphere.

> The advantage to being against the earth is that you are
> insulating against 40 degrees instead of -20 degrees (around here), 

Not if the earth pocket is charged up to 80 degrees in the summer.  It
would stay the temperature or down to about 65 during the end of
winter.  


>.....but the earth will absorb the heat if you don't insulate.

Not if it was charged up to the 80 degree level.  In this case it would
provide heat for the house.

Some clever people put an insulative umbrella from the outside of the
foundation and down and out away from the house for about 10 to 20 feet
to use the earth below it as a thermal storage area to float the house
at a comfortable temperature throughout winter.

This is just another way that it can be done.

Darel