Under normal circumstances, a refrigerator's compressor typically runs more than 50 percent of the time. Compressors in some energy-efficient refrigerators run 80 to 90 percent of the time. Run times vary based on the specific refrigerator's size and model.
A refrigerator's normal run time varies based on a variety of factors, including outside temperature, amount of food in the refrigerator and frequency of door openings. Refrigerators located in very hot or humid climates may run almost all the time. Opening the refrigerator door or placing hot foods inside the refrigerator also causes run times to increase. Keeping the refrigerator and freezer at least three-fourths full helps the unit retain coldness and reduce run time.