A system for controlling a refrigeration system, the system comprising: a cooled compartment including a door; at least one heat source (15, 19, 30, 32) selectively activated to provide heat; at least one sensor for detecting a temperature and a relative humidity of ambient air that surrounds the cooled compartment; a controller in communication with the at least one heat source (15, 19, 30, 32) and the at least one sensor; a compressor in communication with the controller, wherein the compressor is cycled on and off based on a temperature of the cooled compartment; and an evaporator and an evaporator fan, wherein the evaporator fan is in communication with the controller the controller including logic for: calculating a dew point temperature based on the temperature and the relative humidity of the ambient air; selecting a region of operation based on at least one of the dew point temperature and the relative humidity of the ambient air, wherein the region of operation is representative of ambient conditions that surround the cooled compartment; and determining if the at least one heat source (15, 19, 30, 32) is activated based on the region of operation, characterized in that the evaporator fan is activated and de-activated based on operation of the compressor and the region of operation; the cooled compartment includes a sensor for determining an open and a closed status of the door, and wherein the sensor is in communication with the controller, wherein the controller further includes control logic for adjusting a time interval between defrost cycles of the refrigeration system with predetermined factors for extending or reducing the time intervals between the defrost cycles based on the times of opening and closing of the door and the region of operation wherein the controller delays de-activation of the evaporator fan once the compressor is off based on the region of operation. a cooled compartment including a door; at least one heat source (15, 19, 30, 32) selectively activated to provide heat; at least one sensor for detecting a temperature and a relative humidity of ambient air that surrounds the cooled compartment; a controller in communication with the at least one heat source (15, 19, 30, 32) and the at least one sensor; a compressor in communication with the controller, wherein the compressor is cycled on and off based on a temperature of the cooled compartment; and an evaporator and an evaporator fan, wherein the evaporator fan is in communication with the controller the controller including logic for: calculating a dew point temperature based on the temperature and the relative humidity of the ambient air; selecting a region of operation based on at least one of the dew point temperature and the relative humidity of the ambient air, wherein the region of operation is representative of ambient conditions that surround the cooled compartment; and determining if the at least one heat source (15, 19, 30, 32) is activated based on the region of operation, characterized in that the evaporator fan is activated and de-activated based on operation of the compressor and the region of operation; the cooled compartment includes a sensor for determining an open and a closed status of the door, and wherein the sensor is in communication with the controller, wherein the controller further includes control logic for adjusting a time interval between defrost cycles of the refrigeration system with predetermined factors for extending or reducing the time intervals between the defrost cycles based on the times of opening and closing of the door and the region of operation wherein the controller delays de-activation of the evaporator fan once the compressor is off based on the region of operation. calculating a dew point temperature based on the temperature and the relative humidity of the ambient air; selecting a region of operation based on at least one of the dew point temperature and the relative humidity of the ambient air, wherein the region of operation is representative of ambient conditions that surround the cooled compartment; and determining if the at least one heat source (15, 19, 30, 32) is activated based on the region of operation, characterized in that the evaporator fan is activated and de-activated based on operation of the compressor and the region of operation; the cooled compartment includes a sensor for determining an open and a closed status of the door, and wherein the sensor is in communication with the controller, wherein the controller further includes control logic for adjusting a time interval between defrost cycles of the refrigeration system with predetermined factors for extending or reducing the time intervals between the defrost cycles based on the times of opening and closing of the door and the region of operation wherein the controller delays de-activation of the evaporator fan once the compressor is off based on the region of operation.