The reliable way to check refrigerator temperature is an appliance thermometer in a glass of water on the middle shelf, read after several hours; the U.S. Food and Drug Administration recommends 40°F or below for the fridge and 0°F for the freezer. Run the test when food spoils early, milk tastes off, or anything freezes in the fresh-food section, and any time you change the settings.
Time: about 10 minutes of work over one day · Difficulty: Easy · You'll need: one or two appliance thermometers, a glass of water
Before you start
- •Don't rely on the number on the control dial or display. Many controls use a 1 to 9 scale or show a target rather than the actual temperature.
- •Avoid opening the doors often during the test, since every opening lets warm air in.
- •Give the fridge time to recover if you just loaded groceries or it was recently off.
Steps
Step 1 — Get a proper thermometer
Use an appliance thermometer made for refrigerators and freezers. Kitchen meat thermometers aren't designed to sit in a fridge for hours.
Step 2 — Place it in the fridge
Set the thermometer in a glass of water on the middle shelf, toward the center. The water reflects the temperature your food actually sits at, rather than brief swings in air temperature.
Step 3 — Place one in the freezer
Put a second thermometer between frozen packages in the freezer. If you have only one, test the fridge first and the freezer the next day.
Step 4 — Wait, then read
Leave the thermometers for at least five to eight hours, or overnight, and read them first thing before anyone opens the doors.
Step 5 — Adjust in small steps
If the fridge reads above 40°F, turn the control one step colder. If food is freezing in the fresh-food section, go one step warmer. Make only one small change at a time.
Step 6 — Recheck after a day
Controls take time to settle. Read the thermometer again 24 hours after any change before adjusting further.
Didn't fix it?
If the fridge won't reach 40°F at its coldest setting, or swings widely from day to day, look for air leaks first; see how to test a refrigerator door seal. Warm temperatures with a clean, unblocked unit, a freezer that's fine while the fridge is warm, or frost on the back wall of the freezer can point to fan, defrost or control problems. Those need a refrigerator repair technician.
How often to do this
Check once a season, after a power outage, and whenever you notice food spoiling sooner than it should. Leaving a thermometer in the fridge full time is an easy habit.
From Kevin: I'd guess most homeowners have never measured their fridge's actual temperature. Two thermometers and one morning will tell you more than staring at the dial ever will.
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