2 reason-one--I am from Indiana, and 2--the humidity is very hard to keep up there in the winter. The bulb should absolutely not be in cage. A 40 gallon should be OK through the winter or until he outgrows it, but the downsides of aquariums is that they see their reflections and they are prone to getting too hot and too humid causing upper respiratory issues. You should use specific UVB such as the highly reommened ZooMed Reptisun 5.0-and remember UVB does not pass through glass or plastic of any kind. Do you have a pic of the setup? What part of IN?