Midnight Noises
As insulation technology improves, foam thickness decreases. Because the insulation has become so thin, many newer refrigerators make noises that old units didn't. Sounds you hear when the house gets quiet can include humming, knocking and clicking. While your refrigerator might sound sick, these sounds are usually normal. While a malfunctioning fridge might make a strange noise, the sound is usually accompanied by other more tell-tale symptoms, such as cooling failure and interior condensation or ice buildup.