Refrigerators have coils that cool circulating refrigerants when air passes over their surface. But over time they get dirty and block airflow, causing the compressor motor to run longer to cool things down, and causing your electric bill to soar. Instead, remove the bottom grille in front, and vacuum the coils with a crevice tool. To reach way in back, tape a cardboard tube from a roll of paper towels onto the end. Do it every month and watch energy bills come down.