What is the purpose of filling empty spaces in the refrigerator and freezer with water bottles and ice packs?

The purpose of filling empty spaces in the refrigerator and freezer with water bottles and ice packs is primarily to maintain a consistent temperature. When the refrigerator or freezer is full, it is better able to retain cold air, reducing temperature fluctuations that can occur when the appliance is opened frequently. The water bottles and ice packs act as thermal mass, helping to stabilize the temperature inside the appliance. This is particularly important during power outages or when the door is opened, as it minimizes the warming effect when the cold air escapes.

While reducing energy consumption can be a secondary effect of maintaining a consistent temperature, and bulkiness or aesthetics might play a role in some contexts, the critical function served by adding these items is the stabilization of the internal environment to ensure food safety and quality.