The condenser coils on your refrigerator are used to transfer heat from the inside to the outside of the unit. If the coils are dirty or dusty, they make the refrigerator work harder and use more electricity.
Step by step:
Unplug the refrigerator and move it away from the wall.
Locate the condenser coils. Older refrigerators have the coil mounted on the back. Newer refrigerators often have the condenser coil at the bottom. Remove base grille, if necessary.
Vacuum the coils. Use your vacuum cleaner's hand-held soft brush attachment to clean the coils and the area around the appliance.
Clean hard-to-reach parts. Use a refrigerator brush, an inexpensive tool available at most hardware stores, to help clean hard-to-reach parts of the coil.
Move it back to its position and plug it in. Make certain there are three inches or more of space on all sides of the refrigerator to allow heat to easily escape.
Repeat. Plan to conduct this cleaning annually—or every six months if you have pets.