Ive got a seperate room in the house just for my snakes. I have shut off the AC vent during the summer and am running a space hearter in there for their heat. I have this room regulated between 80-90 degrees. Now in the wenter when I kick on the heat I will open the vent back up and turn down the space heater. I do not have any heat under any of the tubs. I have 13 snakes in there and havent had any problems so far with them. I do not use a humidifier in the room, I dont know if you would really need one since you are going to put them in tubs. Maybe someone else on here could chime in and give their ideas. This is just what I do and works for me.