Natural refrigerants have no, or an insignificant, effect on the ozone layer and greenhouse effect. They are widely used in smaller applications, such as heating pumps, small chillers, and commercial systems.
A night setback system is used to control a heating system. A night setback system will lower the room temperature at night, which reduces heating costs. Office type buildings are not used at night, so lowering the room temperature will not cause discomfort.