An electrocaloric element for a heat transfer system includes an electrocaloric material of a copolymer of (i) vinylidene fluoride, (ii) an addition polymerization monomer selected from tetrafluoroethylene, trifluoroethylene, vinyl fluoride, or combinations thereof, and (iii) a halogenated addition polymerization monomer larger than vinylidene fluoride. It is also provided that: (a) the monomer (ii) includes an addition polymerization monomer smaller than trifluoroethylene, (b) at least one of the addition polymerization monomers (ii) or (iii) is a chiral monomer, and the copolymer includes syndiotactic ordered segments of chiral monomer units, and/or (c) at least one of the addition polymerization monomers (ii) or (iii) comprises chlorine, and the copolymer includes an ordered distribution of monomer units comprising chlorine along the copolymer polymer backbone.