Air mass isolation system
In an exemplary configuration, an air container is placed in a vacant portion of a structure and substantially prevents convection between an air mass in that portion and an adjacent air mass of an occupied portion of the structure. By thus isolating the air masses, the air container restricts heat transfer between them and advantageously allows the occupied portion's air mass to heat up and cool down without requiring substantial heating and cooling (at least initially) of the vacant portion's air mass. Other methods and structures with different advantageous features are also described.