All that air in your freezer may be costing you money. To save energy, keep your freezer tightly packed, and add bags of ice as needed to fill the empty space. Replacing the cold air with something colder than the air decreases the temperature, making your freezer run more efficiently and use less energy. Not an ice fan? Try packing the freezer full of frozen local fruit bought while in season. A cold strawberry, raspberry, or apple slice makes a great alternative to an ice cube in water, or is a great summer afternoon treat.