from the info i have read the humidity should be higher, low humidity leads to upper respitory infection, it dries out their lungs, i try to keep mine at a minimum of 50%, and usually 65%. it is not an easy task!! constant misting but watching for inbetween dry outs, i run a room evaporative humidifier plus a cool mist humidifier into the fan of the evaporative one. i have cool mist humidifiers with PVC piping it to the top of all my cages. 1 humidifier takes care of 2 enclosures. i have cages side by side so i hang a clear plastic on open sides except the top and front. in the winter i have 1 warm mist humidifier in the room also.
i notice all my cham's open their mouths when they are basking especially after they drink water, they are regulating temps.