A refrigerator works best when it’s kept in good condition. Check the door seals. If they’re cracked or you feel cold air leaking out, they should be replaced.
Out with the old, in with the new
Your refrigerator uses the most energy of any appliance in your home if you consider that it runs 24 hours, seven days a week. According to ACEEE, there are 126 million refrigerators and 38 million freezers using 200 billion kWh a year.
Unless you cook a lot, more efficient cooking appliances won’t save you more energy. With stoves and ovens, efficiency often comes down to practicing efficient cooking habits. However, these appliances have long lives so it's worth considering efficiency when shopping for a new one.