The ideal temperature for a freezer in terms of energy costs is between zero and 5 degrees Fahrenheit. This temperature range ensures the safety of the food while minimizing electricity costs.
Another way to reduce the energy costs of the freezer is to check its placement in the kitchen. It is best to place the freezer away from direct sunlight, the stove or a heating vent. All of these can increase the temperature in the air immediately surrounding the freezer and force it to work harder to maintain the designated temperature, thereby increasing the electricity bill.
Additionally, it is important to double-check the seal on the freezer. If a gasket is allowing cold air to escape, the machine consumes more energy attempting to maintain the desired temperature. One way to test the seal is by placing a dollar bill in the door of the freezer. If the bill can be easily removed, then it is likely the seal should be replaced.
Another way to ensure the freezer is operating at optimal energy efficiency is through defrosting it at least twice each year, unless it is a frost-free model. Large amounts of ice in the freezer increase the amount of energy used by the machine.