Each building rests on a concrete slab with no insulation beneath so as not to separate the structure from the surrounding mass of earth. The rigid insulation extends over the earth eight feet beyond the back wall of the buildings. The walls below the ground are wrapped in a sealant, water proof rubber membrane and four inch insulation. That is, units are designed to be affected by the immediate environment under changing climatic conditions without the advantages of a heat sink, heat exchange system, pre-heaters or solar collectors. Because of their southern orientation, the structures receive maximum sun exposure through the clear windows by day.
Heat is absorbed in the concrete floor mass through the red quarry tile.
The heat, then, slowly radiates throughout an apartment and is retained in the space when the specially-designed linen drapes are closed by night. The drapes are lined with a highly reflective metalized polyester fabric that deflects infra-red rays, thus minimizing winter heat loss through the windows to the outside as well as summer heat gain through the windows to the inside. The roof insulation, extending beneath the ground beyond the north wall, helps to maintain a constant year round earth temperature near the buildings of about 55 degrees Fahrenheit. Increased energy efficiency in a two-level structure because of the compact space. The reduction of summer solar heat gain through the roofs.