What would not extending all interior walls to the ceiling in the home do for heating and cooling purposes? I've seen how this is done in earth home designs, figured it was because they use earthtubes to heat and cool instead of forced induction. Wondering if it would still be more efficient even with forced induction?

It makes for weird sound transference in the house, and in an air tight house with a fairly open design, would probably not be necessary, as the heat from space to space tends to be very even, even more so with radiant heat.

-Rosalinda

it would still be more efficient even with forced induction?

Enclosed spaces need ventilation. They either make their own air circulation within the envelope, or you can make one, but there is still the issue of bringing fresh air in.