No heat pad under the cage. From what you've written so far it sounds as if you've gotten some poor husbandry information. Be aware that much of what someone at Petco told you (or sold you) may be wrong. There is much better information in the veiled caresheet and husbandry articles located under the Resources tab at the top of the forum. I suspect you'll see there are other changes you should make to keep your nice little guy healthy. Keeping the bottom of that cage clean is going to be a hassle; looks like you have to remove everything in order to change/clean the carpet. Your cham won't appreciate the disruption as he gets older and more territorial.