While temperature controls vary from manufacturer to manufacturer, refrigerator and freezer compartments all have one thing in common: the optimum temperatures at which food should be stored. Refrigerators should keep foods at 3.33 to 4.44 degrees C, and freezers should keep foods at 0 to 2 degrees F. A refrigerator set too low uses more energy and can freeze fresh foods, ruining the items' taste, texture and viability. If the temperature is too high, the flavour and nutritional value of foods is reduced and some foods may develop harmful microorganisms. Frozen foods may also deteriorate faster when temperature levels are too high.
The age of your refrigerator, along with seasonal climate variations, can impact the appliance's efficiency. The best way to ensure your refrigerator and freezer are keeping their respective compartments cold enough is with an appliance thermometer. Appliance thermometers are generally inexpensive and simple to use. Most have a clip for attaching them to a rack or retention bar or come with stands for placing on shelves. Thermometers are widely available at general merchandise, speciality and grocery stores and can be used in either the refrigerator or the freezer. Place one thermometer in the refrigerator compartment and another in the freezer compartment.
Place the thermometer in a glass of water, and set it on a shelf in the refrigerator compartment before you go to bed or leave for work so the refrigerator will remain unopened for several hours. Check the temperature as soon as you open the refrigerator door. The temperature should be between 38 and 40 degrees F, but can be as low as 1.11 degrees C without being in danger of freezing your fresh foods. To check the freezer compartment, place the thermometer between already frozen items, like bags of vegetables, and leave it for several hours. Check the temperature as soon as you open the freezer compartment door. The temperature should be no higher than -15 degrees C.
The best method for adjusting the controls properly is to consult your owner's manual for the appropriate settings. If your appliance's temperatures are only off by a few degrees and you do not have a manual, adjust the controls to slightly higher or lower levels. Wait 24 hours for the appliance to complete the adjustment, and test the temperature levels a second time using the methods described above.
The way food is stored in the refrigerator and freezer compartments can affect the appliance's efficiency. If you find different areas of the compartment too warm, see if the air vents inside the compartment are blocked. Rearrange items as necessary to ensure free flow of air inside the refrigerator. Check the freezer vents too. If frost has built up in the freezer, defrost the compartment according to the manufacturer's directions and retest the temperature after 24 hours. Placing hot foods in the refrigerator will not only raise the interior temperature significantly but will make your appliance work harder. Frost in the freezer compartment may force colder air into the refrigerator, making it colder than it should be. Divide large items into smaller containers to help maintain good air circulation.