A Sub-Zero refrigerator uses a two compressor design that improves the quality of food stored in both the refrigeration and freezer compartments. By using two compressors, a Sub-Zero refrigerator can reportedly increase the lifetime of fresh foods stored in it by 40 to 50 percent.
A Sub-Zero refrigerator is typically fitted with a patented air-filtration system that removes ethylene gas from the air inside it. This gas is generally emitted by certain fruits, such as apples and melons, and causes other fruits and vegetables to wilt and discolor faster. The door that is fitted in the front of a Sub-Zero refrigerator is also designed with extra heavy insulation and magnetic gaskets, creating a vacuum inside it within 15 seconds of closing.