Check your fridge for a power-saver switch. If you don't notice condensation after you switch it off, you might not need the feature.

Photo courtesy of U.S. CPSC

Refrigerators are the top-consuming kitchen appliance in U.S. households, and separate freezers are next on the list [source: DOE]. The approximate energy range is 30-200 kWh/month [source: Hawaiian Electric].

That's the thing about energy ratings for any particular appliance: The range is vast. Lots of people still have fridges from the 1980s (or even earlier), which means they're still using in the thousands of kWh every year. If you have a brand new high-efficiency unit, your consumption could be more like 400 kWh/year. And then there are all the other factors: model size, freezer orientation (bottom freezers are more efficient), temperature settings, device placement, refrigeration habits and any available energy-saving modes (more on these in a moment).

Regardless of which model you have, there are steps you can take to reduce its energy use (although if your refrigerator/freezer is more than 15 years old, the most important change is to buy a new one if you can afford it, since efficiency values have increased so dramatically):

  • Check for a power-saver switch: Some refrigerators have in-door heaters to reduce external condensation. If you see a "power saver" switch, turn it off. If you don't notice condensation afterward, you don't need to use that feature.
  • Check the thermostat: For refrigerators, 36 to 38 degrees F (2.2 to 3.3 degrees C) is ideal; for freezers, it's 0 to 5 degrees F (-17.8 to -15 degrees C) [source: ACEEE].
  • Defrost: More than 0.25 inch (0.64 cm) of frost buildup hurts efficiency.
  • Check the seals: Close the door on a piece of paper. It should be held firmly in place. If not, replace the seal.
  • Use good refrigeration habits: Label food so you can quickly find what you're looking for; cool hot food before refrigerating or freezing it; and know what you want before you open the door.

Up next: Low humidity, high watts.