DSTAR’s SEDS software was upgraded previously in Program 11 to perform optimization of transformer size and conductor size selections to minimize first costs while respecting voltage drop and flicker constraints. Since energy efficiency is of interest to member utilities, the contributions of losses to total owning costs should also be part of the optimization of the transformer selection and secondary system design. This SEDS enhancement calculates and evaluates the costs of losses when optimizing transformer and secondary cable selections. The transformer database is expanded to include load and no-load losses (resistance of cables is already present in the database). Using the loss and resistance values, along with current flows from the particular case being simulated, total no-load and full-load system (distribution transformer and secondary cables) losses are calculated. A and B factors set by the program administrator (for each company) are used to monetize the life-cycle costs of losses on a first-cost equivalent basis. Selection of the transformers and cables are optimized on a total-owning cost basis.