A humidifier/dehumidifier device is disclosed herein. The humidifier and dehumidifier both, respectively, evaporate water from and condense water into a shared (same) water storage container. The device is fitted with an air intake and at least one air outtake. In embodiments of the technology, one or more of the air intakes receives air from outdoors. One or both of an indoor and/or the outdoor intake is used to receive air based on a determination that an indoor and outdoor humidity and temperature is most efficient to achieve a desired indoor humidity or temperature.