I'm from UK and keep my lights outside the tank for the reasons stated above. My snakes seem to be able to climb into every nook n cranny of their tanks so I would never have the bulbs inside. My leos tank has a guarded bulb inside but they have a 'tall' viv and nothing anywhere near the bulb so that they could climb near it. If you have a heat mat, you shouldn't need any other source of heating unless you are having probs keeping the temps up.