Perfect advice from Spaniard. You can heat multiple racks and cages so long as it doesn't exceed the wattage that can be handled and that all the heating elements and cages are identical.

i.e. you DO NOT want to run a rack that has 4" flexwatt and another that has 11" flexwatt off one thermostat. But you could run two identical racks with 4" flexwatt off one t-stat or several identical cages off of one.

If you do want to run different cages/heating elements, then you need to get more t-stats or get a herpstat II (can run two) or herpstat Pro (can run 4).

I have the Herpstat Pro and I have one probe running bp rack, one running two identical cornsnake racks, one running cornsnake yearling/hatchling rack, and the last one running bp incubator. So I can control these four different set ups with one unit.