This paper discusses the operating experience of two ice storage systems in Wisconsin. Both systems were designed and sized for winter heating loads. The Reedsburg Center, on-line since 1978, has the lowest energy usage of all facilities in the Wisconsin VTAE system. The Oshkosh facility was completed in 1982. Both systems have performed well in furnishing low-cost stored energy. They have proved that an ice-maker heat pump (IMHP) system will operate effectively, under various levels of operational care, even though the building system may not be operated at optimum design. The IMHP system’s heating and cooling storage lends itself to effective energy savings without complex control and monitoring. However, as is true of all energy storage systems, optimum energy savings are obtained through either a good operator or a properly conceived computer control program.