Originally Posted by padlin
I have heard of, but not tried, running the A/C and the heat at the same time for this purpose.
As Bob and Carl explained, sometimes you need to remove moisture even after enough heat has been removed. Since a dehumidifier works by cooling air to the point that the water comes out by condensation, then dumping the heat right back into the air, running the A/C plus heat does essentially the same thing. A dehumidifier is much more efficient, because it puts the heat taken out of the air back, while running A/C and a heater means throwing the heat taken out of the air away, and using more energy to replace it.