A refrigerator uses basic refrigeration principles to extract the heat from air. Refrigerant circulates between an evaporator and a condenser in a closed system that provides continual cooling.

The refrigerator box is heavily insulated so that very little heat is absorbed from the outside air and little cold air escapes. Most refrigerator/freezers introduce chilled air into the freezer section; from there, the cold air can pass into the refrigerator. Controls regulate how much cold air may pass.

Today, most refrigerators are frost-free. They have automatic defrosting systems so that you don’t have to take everything out of your refrigerator to melt built-up ice in the freezer. An automatic defrost system includes a timer, a limit switch, and a heater, which melts away frost.

Refrigerator failure is usually caused by the unit’s electrical controls, such as the timer or temperature control.

The ideal temperature for a freezer compartment is between -5 and 5 degrees F., and the ideal temperature for the refrigerator section is between 36 and 38 degrees F.