I'd advise against using the carpet. I started out with that for my lizard, thinking it'd be easy to clean, cushion the impact of a fall, and all the other crap they'd like you to believe. It's more hassle than anything. You need to wash it anytime your snake makes a mess, meaning you'll need at least two pieces for the cage (one to use while the other is in the wash). You might even need 3 if your snake likes to poop right after you clean, which they WILL do. I'm convinced my snakes' main goal in life is to poop in a freshly cleaned cageAlso, if you decide to go with an UTH, they do not transmit heat very well and you may struggle with both heat and humidity. If I could do it again, I'd save myself the 40 bucks and buy a $2 roll of paper towels if you want to go with a non-particulate substrate.