I just moved my daughters snake to a plastic bin since we couldn't get the humidity over 40% using just a heat lamp. I picked up some heat tape, thermometer/hygro and dimming switch for the setup. I have the sensor inside under the green carpet on the hot side and the therm on the cool side. The humidity is now up near 70%, hot side at 92 degrees but the cool side is only 75 degrees. The plastic tub is sitting on a dresser currently. I would like to have the warm side about 90 and cool side about 80 but I cant get the cool side up without turning up the heat pad which would be too much for the snake. I see others with their bins on wooden shelves that is covering the back and sides. Am I loosing too much heat by not having the sides and back covered/insulated?

Thanks!