A heat panel over head is better because it will heat the air....WOW!!!!
Science lesson, heat rises.
A heat pad placed on the floor will also heat the air EXCEPT it will heat the floor more efficiently. Air is an insulator. To heat through the air to a solid material is called convection. To heat from a solid material to another solid material is called conduction. Think about how we choose to heat most of our food. Both sources are used (convection ovens and frying pans/conduction)
Belly heat or radiant heat is better because it is more efficient. In a cold room it is better because it will heat bottom up where an animal like a snake will be most likely. Arboreal snakes tend to benefit from things like radiant heat panels.
two arguments arise.
One: reptiles tend to sense heat from their backs and not their bellies.
Two: malfunctioning belly heat and cause harm.
A well placed thermostat removes BOTH risks/arguments
Flexwatt should not be sealed AND it should not be operated above 95 degrees (PER MANUFACTURER INSTRUCTIONS)