In order to remain healthy and thrive, ball pythons have very specific temperature requirements ... they need a temperature range that goes from 82-84 degrees on one side of their enclosure to 92-94 degrees on the other ... they use the different temperatures to regulate physiological functions in different ways (digestion, immune systems, respiration, etc) ... If you want your ball python to be healthy, you cannot "guess" at these temps ... The best way to make sure you have to correct temps is to measure them often with a $9.00 digital thermometer available at any store that sells household products (Target, Wal-Mart, K-Mart, etc are some examples) ... Once you have an handle on exactly what the temps in the enclosure are, you can then use a combination of direct and indirect heating elements to get them where they need to be for your animals welfare. One of the easiest and "hands free" way of providing the proper temps for your animal is with a thermostat ... but even without one, it is quite simple to get the temps where they need to be with a little research and effort.
Hope this helps.
-adam