Heat pad under Sterlite???

I did the DIY sterlite critter cage, and I have a basking light on the cage but I'm having a problem keeping the temperature high enough. I was wondering if I would be able to put a Human heating pad under the plastic and not have any worries? The tank is also on the ground/carpet would this be a problem? Or what would be a better remedy to raise the temp. Thanks.

Yeah they do but you need to make sure that there is space between the tank and the mat for the air to circulate around the mat and the container.

I just wanna add if your heating pad has settings such as hi med low or 1-5 or 1-3 or some such I wouldn't go over medium because heating pads get hot enough to burn past medium- just a thought. :) Air space would be good - just use those little feet from walmart (I got the thickest I could find)... It would probably be best if you could find a piece of plywood or something to put underneath.. I don't know how flammable carpet is or anything though so others may know more. :)

I have human heat pads directly under the sterlites I'm keeping my 3 newest BPs in. The pads are under 1/2 of the container, but because the pads are so large, a good portion of the pad is not covered by the container, which I think may help diminish any danger of overheating. I have about an inch of aspen as substrate, and with the heat pads on low, the temps stay perfect with no need for a lamp. Since I don't use a lamp, the humidity stays perfect as well. I was hesitant about putting the heat pads directly on the wood surface of the table I have the containers on, so I put down a piece of plastic pegboard to help with air circulation. So far, its working great.

Addendum (after reading Jonah's reply): if you are not using loose substrate like aspen or bark, and are using something like newspaper, take Jonah's advice and use the tall rubber feet on your sterlite. I use short ones on one side of the sterlites to even out the container since 1/2 of it is propped up by the heat pad.