The temperature inside refrigerators should be 1.11 degrees C to 4.44 degrees Celsius with an optimal temperature of 2.78 degrees Celsius. This helps to prolong the life of foods and prevent bacterial growth in dairy products. Most refrigerators have a thermostat without specific temperature increments. Adjusting a fridge thermostat for optimal temperature requires finding out what the actual temperature is inside the unit. The best way to do this is to purchase an appliance thermostat at a home improvement centre or appliance repair facility.
Place an appliance thermometer in a glass of water. Set the glass of water inside the centre of the refrigerator. Allow the water and thermometer to stay in the refrigerator for 24 hours to get an accurate reading of the inside temperature.
Adjust the temperature dial down one notch to the "Cooler" side of the dial if the temperature requires lowering. Some refrigerators use a push button arrow pointing down. Press the button once to lower the temperature to the next lower number on the display.
Raise the temperature if necessary by turning the dial one notch toward the "Warmer" setting or pushing the up arrow button one number higher.
Leave the water and thermostat inside the refrigerator for another 24-hour period and check the temperature. Adjust as necessary. Remove the glass once the temperature is adjusted.
Do not overcrowd the shelves. Allow room between foods to permit good air circulation.