Be extra careful with those under the tank heat pads, they have been known to burn dragons. Dragons regulate their temps from OVERHEAD heat. Please put something between your dragon and the glass that he can't move or burrow in.
Heat mats can be very dangerous for beardies as said above. I’m in a cold area and I use a Arcadia 100w ceramic heat emitter , plain black with no light- just heat. I have it on a habistat thermostat so it turns on as needed. Mine runs the majority of the day and all night due to cold temps and Marlow’s vivarium is kept perfect temp with it