Systems including a moisture pump for removing moisture from an inside environment to an outside environment. The moisture pump includes a housing defining a chamber with a heater, a heat spreader, and a desiccant for selectively adsorbing water vapor in the heating chamber when the heater is off and desorbing water vapor into the heating chamber when the heater is on. A valve assembly is also maintained by the housing transitionable between an adsorption position and desorption position. The adsorption position allows water vapor to be selectively transmitted into the heating chamber from the inside environment. The desorption position allows water vapor to be transmitted from the heating chamber for transmission into the outside environment. The adsorption and desorption ports can have asymmetric adsorption and desorption areas.