It's nothing elaborate - 40 gal. aquarium with plastic grid in the bottom so the plants aren't sitting water, covered with plastic sheet turned back at the front corners to allow a bit of air circulation. There's no fan, but they don't seem to mind the lack of air circulation. They love the humidity.
The basement is cool. It ranges between 12 to 17 C. in the winter depending on how cold it is outside. In the summer I try to keep it below 24 C. I have a portable air conditioner that vents to the outside through a window which helps a lot.
When I water I let the water level just reach the bottom of the pots, leave the top open until any water sitting on the the foliage is gone, pull the plastic back over the top, and they're good for a couple of weeks.