Dehumidifier work best down to 50%RH. Reducing the RH to 30% when the outside temperature is less than 50^F is best down with outside fresh air ventilation. A good bath fan exhaust 75 cubic feet of air per minute. This removes 2-3 pints of water per hour when cold dry outside replaces the damp inside air. The energy required to heat the ventilation is much less the than the dehumidifier uses. Reducing the humidity in a home requires several days of ventilation becuase of the tons of mass of the home and the humidity in the materials.
2 pints/hr X 24 hours X 30 days = 1440 pints/mo.