The most basic Earthship Design. Quick and Inexpensive to build. Requires no mortgage., instead of tires, let's use a "HESCO Bastion" type set-up. Less labor intensive than packing tires, and the walls can be load bearing.
Rubble Trench Foundation, Radiant Heat, Adobe Wall, Straw Bale Insulation - complete entire exterior with this formula. Run hot water heating under earthen floor for winter/heat. Adobe wall can be cob.