Dehumidifiers of all types work by pulling moisture from the air. As water vapor is removed from the air, liquid moisture in wet materials evaporates to compensate for this loss. The Institute of Inspection, Cleaning, and Restoration Certification recommends that enough dehumidification is available to provide a constant relative humidity at or below 60%.

Refrigerant dehumidifiers draw air over cooling coils, lowering air temperature and causing condensation of water vapor. This water is pumped into a sink, toilet, barrel, or outdoors if possible.

Refrigerant dehumidifiers perform better than desiccant dehumidifiers, but only work in temperatures between 32^oF and about 80^oF.