Disclosed herein is a method for producing heating in a high temperature heat pump having a heat exchanger. The method comprises extracting heat from a working fluid, thereby producing a cooled working fluid wherein said working fluid comprises at least one alkyl perfluoroalkene ether. Also disclosed is a method of raising the maximum feasible condenser operating temperature in a high temperature heat pump apparatus. The method comprises charging the high temperature heat pump with a working fluid comprising at least one alkyl perfluoroalkene ether. Also disclosed is a high temperature heat pump apparatus. The apparatus contains a working fluid comprising at least one alkyl perfluoroalkene ether. Also disclosed is a composition comprising at least one alkyl perfluoroalkene ether, and specialized additives or lubricants for use in a high temperature heat pump.