Check the door seals. A loose seal allows cool air to seep out.This is not only an enery waster but it makes your fridge work a lot harder than necessary. First make sure the seals are free of food residue. (Clean them about twice a year, using a toothbrush and a solution of baking soda and water.) Then try the dollar-bill test: Close the bill in the door so that half is in and half is out. If it slips out easily, you may need to have the door seals checked by a pro.
Keep the coils clean. When the condenser coils (see following page for more on parts) are covered with dust, the refrigerator can’t run efficiently. Twice a year, pull the machine from the wall to reveal the coils in back (or snap off the grille, if the coils are on the bottom front), unplug the refrigerator, and vacuum using the brush attachment.
Set the right temperature. Keep the fridge between 37 and 40 degrees Fahrenheit and the freezer at 0 degrees.
Fill it up (even if you never cook and only have takeout). Refrigerators need “thermal mass” (a.k.a. lots of stuff) to maintain low temperatures. Cool foods and drinks help absorb warm air that streams in when you open the door. If you’re the eat-out type or your fridge is too big for your needs, store a few jugs of water in there.
Be prepared. If your power goes out, keep the doors closed and use foods from the pantry. An unopened refrigerator will keep food safe for about four hours; a freezer will maintain its temperature for about 48 hours if full and 24 hours if half-full.