said by Bob:+1
Get a hygrometer so you can adjust the humidity properly.
The digital models are usually around $20 or less at a hardware store.
Start with the control knob on the dehumidifier around the middle of the range and see how it looks in 48 hours. Each new setting may take 24 or 48 hours to give a reasonably true reading to the hygrometer.
At a price of around $0.24 cents per KWh (taxes and fees included) where I work, the boss pays around $1.00 per day to keep a circa mid 1700s - 28' by 35' cellar dry to 50%, according to my power usage device. (They do have an early 1900s concrete floor though, as opposed to a dirt floor that was popular in the mid 1700s.)
$1 a day is based upon a one year data recording of usage. Before I came along, they used to run it 24/7 with the control knob set to full dry. They were paying around $200 per month as opposed to $30. Silly folk.