I am having a hard time understanding how a heat pad alone can create an ambient heat of around 80 degrees throughout the tank.

The set-up I am thinking of is one that is apx. 18-24 inches high and 2x4 feet of floor space (vision cage, reptile basics or glass aquarium for example)

Many people claim that with an under the tank heat pad (with a thermostat) one would not need to add additional overhead heat.

I can see how the pad would maintain the desired setting within a hide (the pad is under a hide on a cool side and another one is under a hide on a hot side). However, as I mentioned earlier, I am unsure how the ambient heat would be maintained.

I can see the cost benefits of not having a heat lamp over head and would like to feel confident that I can provide proper care with out one.

Having said that, it is mindful to concider that the temp of the room that the enclouser is maintained at 72 degrees in the winter and 76 in the summer (cold winters, hot summers).

What I would like from you all is some clarification. is this really possible (ideas for both PVC enclosures and glass aquarium enclosures).

Jimmy