Novel air conditioning systems which provide full comfort conditioning while drawing as little as half the normal electrical power at times of peak load have already been developed. This paper describes one such system and evaluates its attractiveness as an alternative to conventional practice.As utility rates rise due to higher costs of fuel and new equipment, it is anticipated that the attractiveness of systems which use off-peak power will increase. The advantages to electrical utilities are an improved load factor because part of the demand for electrical energy is shifted from times of peak load to times of lower load and a reduced need for new peak load generation plants and transmission equipment. This constitutes a saving in operating expense and investment. These factors are reflected through the rate structures meaning reduced operating costs for the user.Air conditioning equipment with these advantages are extremely attractive to electrical utilities. Nevertheless, the decisions to specify such systems will be based on the economics of each particular application. A detailed study has therefore been made to determine the operating economies which will accrue to users of these energy storage air conditioning systems.Energy-system simulation computer programs were used to model the performance of nine hypothetical air conditioning systems on an hourly basis for an entire year. The particular building characteristics, air conditioning loads, and weather data and equipment efficiencies were chosen as a credible, specific example. The results are directly applicable only to this specific building; however, they indicate a possibility for detailed evaluation in engineering the comfort conditioning system of any building.