Abstract A review of vacuum processing in a multiple-chamber vs. single-chamber vacuum furnace and the advantages and disadvantages of both design concepts will be presented. Cycle calculations will be shown to illustrate the differences in the floor-to-floor time, heating energy required to process and cooling power to quench a normalized load. Additionally, the presentation will discuss the differences in residual atmosphere for a given vacuum level for the two furnace concepts. Differences in operation and maintenance between the two concepts and appropriate processes to run in each will also be discussed.