The use of 1,1,1,2-tetrafluoroethane for increasing the miscibility of 2,3,3,3-tetrafluoropropene with a lubricating oil, and in particular with a polyalkylene glycol oil. Further included are heat-transfer compositions and also equipment and processes using these compositions. Also, a kit including a heat-transfer fluid including 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane, and a lubricant oil including a polyalkylene glycol, for use in a heat-transfer installation including a vapor compression circuit.