Abstract: Heat is supplied to the solvent bath of a vapor degreasing apparatus by a heat pump system to maintain the solvent bath in a constantly boiling state and generate a zone of solvent vapor above the bath. The solvent vapor is condensed on a cooling coil through which the heat-carrying medium of the heat pump system is being circulated, thereby transferring heat from the solvent vapors to the heat-carrying medium. Thereafter, the heat-carrying medium is compressed and discharged directly into the solvent bath while a portion of the condensed solvent vapors is diverted into the cooling coil.