Methods and apparatus for a two chamber freezer whereby both chambers can be maintained at a substantially constant ultra-low temperature, such as within the range of about −40° C. to −80° C. Short term items may be stored in and accessed by the upper door from an upper chamber while long term items may be stored in and accessed by the lower door in the lower chamber. The upper and lower chambers are thermodynamically independent of each other thereby reducing the power usage of the freezer.