I personally don't hold with covering up air flow to increase humidity. Yes it works, just like a plastic bag over your head increases humidity, does it sound like a good idea? How much ventilation is needed I can't say open tops don't vent out as well as you might think either.

Yes room humidifiers work super well I currently use this method.

Variation one,

You need a larger amount of water mass. Misting is useless as it is a small amount of water and dries quickly. I used to do this with open top tanks. Place a drip tray (the thing that goes under a plant) or low plastic container on the bare floor of the cool side. I would cover it with substrate (coco coir aka eco earth) about 2 or 3 inches deep banked toward the warm side (only 1/8 -1/4 deep over the warm side uth) and then poke a hole down to the tray and fill the tray with water. It will evaporate and has humid air rises humidify the lower end of the tank. It keeps the surface where the snake is dry and yet adds lots of humidity into the hides. simple, effective.

Variation two,
http://ball-pythons.net/forums/showt...arium-Solution

This takes a bit more effort but in the end is a far better solution. It solves the open top and as hi/low vents are far more efficient it remains well vented, while reducing heat loss and humidity loss. I have a few now and a number of commercial PVCx enclosures and feel that the differences are so slight it doesn't matter much. It also helps with ambient temps if you install a fluorescent light and blue led night lights.