A refrigeration system contains many subsystems for different purposes and insulation is an important subsystem in the refrigeration system. Refrigerator maintains lower temperature in refrigerated space as compared to the surrounding, as there is a temperature gradient between ambient air and refrigerated space heat will flow from high temperature to low temperature and as refrigerated space is maintained at low temperature, the heat will rush in from the environment to refrigerated space.

Hence in order to completely stop this heat flow from environmental air to refrigerated space insulating material is provided around the refrigerated space in the refrigerator, this insulation reduces the heat in-rush of heat. As insulation is important subsystem it should be efficient as if insulation is not efficient heat will rush into the refrigerated space and refrigerator has work to remove this rushed heat into the refrigerated space.

This result into more compressor work for same load, this phenomenon decreases the COP of refrigerator. .