Abstract: An environmentally conditioned enclosure adapted for human habitation and construction methods relating to same. A foundation comprised of thermally insulative material provides support for a shelter erected thereon, and dividably defines a separate geothermal heat exchange region isolated from surrounding ground. The foundation is located within a trench which must be excavated around the separate geothermal region. A geothermal heat exchanger buried within this separate region receives fluids circulated between it and the shelter. By locating the geothermal heat exchanger apparatus in an underground region separate from surrounding ground, an enhanced time lag between variations in outside surface temperature and variations in underground temperatures is achieved. The shelter is preferably secured to the foundation by a liquid anchor received within a channel provided in the foundation.