> That is one special house.  How does the air circulate through the tubes?
> (Same question for Cuyler's rock wall - what "pumps" the air up and down
> while cooling or heating?)

Used a couple of reversible polarity large bathroom exhaust style fans to 
move air through the rock and masonry thermal mass.   They were installed at 
crawl space level in the base of the concrete block masonry.   Used a speed 
control switch to experiment with.    Couldn't hear them either because of 
the masonry.   The crawl space under the kitchen, family room and the 
bedroom wing was used like a plenum because of conventional furnace duct 
floor grills installed in each room.    However, there was never a sense of 
"forced air".   It was simply a gentle, unnoticeable, constant motion of air 
through the building.   Two bedrooms were in a wing extend away from the 
house core, and sound transmission from room to room through the crawl space 
was not a problem.   The very large master bedroom/retreat was the second 
floor, above the kitchen, with stunning views.   Sunken living room was 
cathedral ceilinged.

No insulation below the crawlspace.   We just allowed the 53 degree earth 
temp. to be our constant friend, so it was only necessary to add 18 degrees 
in winter.   All the moving air and the naturally dry climate prevented any 
condensation and mould problems, one of the big problems that can happen 
with earth tubes.

cp in bc 

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