My brothers house stays pretty cold in the winter time. He has his three snakes (2 balls and a rtb) in vision tanks. He stacked the three of them. He ran heat cable up and down the back of all three. Then he covered the back and the two sides with the foil bubble wrap insulation. He has the UTHs one one thermostat and the cable on another thermostat. Works like a charm! You can feel the heat coming from the front in the winter time, when the house is 60 or below and the snake tanks are 80ish!