The comfortable temperature range in any earthship is largely provided for by
the natural thermal stability of the earth itself. Many amphibians &
reptiles survive winters by burying themselves below the earth's frost line.
Below the frost line, temperatures hover at a fairly stable 55-58 degrees.
The earthship design takes advantage of this by being dug partially into
the earth, or heavily earth-bermed along the outer walls, or both.
Skylights provide the release of built up heat in warm climates, and shading
for front glazing can control the amount of solar energy coming in. The
orientation of the "U-rooms" and angle of the front-facing glass also play
key roles in how much heat is absorbed or dismissed by the dwelling. In
extremely hot climates, U-rooms may be pointed away from the midday sun.
Additional cooling can be provided for by a pipe run through the
cool underground and into the earthship for an all-natural air conditioner.