So it is basically a small heater and fan. It would cost about $8 per month to run.
Most find a bucket of Damp Rid works to remove extra humidity over the winter.
I use a 9" fan on low which creates enough air movement to avoid humidity problems. It uses 20watts and cost $20
I usually leave it on during the week in the summer since it gets wetter with regular use between the weekend and once during the week usually.
In the winter, I put it on a timer so it only runs about 6 hrs per day.
1991 MariStar 240sc, 454, tower, WetSounds, Krypt and Rockford Fosgate