I do have an air conditioner (well, an air-source heat pump), but it doesn't adequately remove enough moisture before the indoors gets too cold. It's possible this is not properly sized, but I cannot change it because I rent.

In my case I did some tests, and the additional power usage of the dehumidifier is way more than offset by the power savings I realize by running the air conditioner less frequently. This only works because the dehumidifier enables me to be comfortable at a higher indoor temperature.