Combined thermal and compressed air storage systems are provided that utilize an exhaustless heater, such as a thermal storage unit, to provide power with enhanced efficiency. Compressed air is heated by the thermal storage unit prior to entering a turbine, which powers an electrical generator. In various embodiments, ambient air temperature, turbine exhaust or other types of waste heat are used to preheat the compressed air prior to the compressed air entering the thermal storage unit, thereby further increasing system efficiency.