Air conditioners circulate conditioned air through a system of supply and return ducts. Supply ducts and registers carry cooled air from the air conditioner to the home. This cooled air becomes warmer as it circulates through the home; then it flows back to the central air conditioner through return ducts and registers. Air conditioners help to dehumidify and cool the incoming air, but in extremely humid climates or in cases where the air conditioner is oversized, it may not control humidity properly. Running a dehumidifier in your air-conditioned home will reduce the humidity level in the home. However, this process will increase your energy use, both for the dehumidifier itself and because the air conditioner will require more energy to cool your house. The proper sized air conditioner will eliminate this problem.
Some information obtained from the U.S. Dept of energy web site. eere.energy.gov/