Welcome to the club Tennis.
The building code folks don't seem to have any idea about energy
management. or they have an invested interest in the energy suppliers.
A local builder here tried to get a permit for a $250,000 earth sheltered
home but the building code folks called it a basement and code clearly says
you cant occupy a basement. You should see the tizzy that a geodesic dome
puts the building code folks in. Solar heat, forget it here, it is an
eyesore to the building code folks and is not allowed. God forbid if you
try to put up a wind generator. A greenhouse must have a 3.5 foot deep
foundation, my house foundation only goes down 2 feet. I put 4 inches of
foam on the greenhouse foundation walls while they weren't looking and
didn't tell them. I also used a few other tricks that don't show after I
finshed construction that saves energy.