Uncovered liquids evaporate in the refrigerator causing higher power use. Mark freezer storage items to minimize open-door time. If practical, consolidate freezer or refrigerator storage so that you can turn off the spare unit. If spare refrigerators or freezers can be disconnected for only a few months per year, significant savings will result. Dormant storage will not damage a healthy unit.
Full freezers use less power.
If it is not convenient to maintain freezers full of food, store ice to fill empty space and improve freezer efficiency. Used plastic soda bottles work best. Be sure to sterilize the bottles before using them and leave about one-inch of dead air at the top of the bottle when filling. The ice storage will double as hurricane water and can provide ice for your cooler if you plan an outing. Many units have electric heating elements built into the walls to drive away condensed moisture and to keep vinyl gaskets supple.