Frost acts as an insulator and forces your fridge or freezer to work harder. Auto-defrost refrigerators take care of this problem for you but use more energy. Make sure your refrigerator and freezer doors seal airtight. Close a dollar bill or piece of paper in the door. If it pulls out easily, your refrigerator may need a door hinge adjustment or a new gasket.
Dirty coils make the refrigerator work harder and use more energy.
Get a pan ready to go and place it on the burner before you turn on the heat. And don't forget to turn the heat off when you're through using it. Use the right pan for the job. Foods will cook faster and at a lower temperature if you use pots and pans with flat bottoms and tight-fitting lids. Oversized and undersized pans waste energy.