Homeowners know that freezers are made to freeze the items you put into them. This is less well known: most of the work that your freezer does each day is to cool down the air that flows into the freezer every time you open the door. In Phoenix and Scottsdale, Arizona, we look for high appliance energy efficiency ratings when we purchase new appliances, but do not always know how to help out that energy efficient freezer once we get home.
Since cold air escapes and warm air flows in each time you open your freezer, it stands to reason that the less room there is for air, the less work your freezer must do – leading to a more energy efficient freezer. Your freezer will operate most efficiently if it is full or near full with slight gaps at the sides and top. Not everyone keeps enough frozen food on hand to fill the freezer. But there are little tricks you can play to fill the space and boost the appliance energy efficiency.
Sealable plastic bags filled with water are a great start. They will not only fill the space, but you will always have ice blocks handy for coolers or parties. The one downside is that the bags can freeze in odd shapes, so it can be helpful to initially freeze them in loaf pans or other structured items to contain the shape.
Reusable plastic food containers filled with water work well. And since they are a standard shape made for stacking, you will have an easy job of removing or reorganizing the blocks to make needed food space. The containers could also be left empty.
Packing peanuts in plastic bags can easily fill a freezer that is mostly empty. They are easy to obtain and will fit to almost any shape without freezing solid.
Newspaper that is either crumpled or folded can also fill the freezer space efficiently and affordably. Take care not to over-pack the freezer, and to leave a small gap at the sides and top.
Plastic milk jugs filled with water are another popular choice. While they are easily obtained, they can be less friendly for rearranging.