Using basic heat transfer correlations, the distribution of heat losses in a copper electrorefining tank house has been determined. The initial study led to programs to cover refining cells at both Kennecott refineries, with potential energy savings of approximately 1 MM Btu/ ton cathode. Only partial implementation of cell covers has been possible to date at the Utah refinery due to water availability problems which developed. The same heat balance approach can be used for copper electrowinning, although results differ significantly. In the design of a leach/solvent extraction/electrowinning facility, careful consideration must be given to the heat balance to minimize cost while maximizing cathode quality.