Tunnel Earth Tubes

The earth tubes from the tunnel (dead-end tunnel, now a pantry/wine cellar) are underground and insulated. 

covered and seeded earth tubes

same area from another angle

They only need two things more - the grates/screening/filter over the exterior and interior ends, and the house to be covered with dirt and the PAHS umbrella. Oh, a minor thing - there is a wire in the tube which needs to be replaced with parachute cord.  This cord is used to pull a cleaning rag thru the tube on a regular schedule.