Kitty Litter is not "the same thing" nor does it "do the same thing".
Funny thing is that not only does kitty litter not work in humis, it doesn't work as kitty litter. That's why it's discontinued.
(It sizzles when cats pee on it and most refuse to use it.)
I've done tons of tests on all sorts of humidifying media and all the results have been posted at Club Stogie in the past.
It takes more than 9 times the volume and 9 times the surface area for kitty litter to even begin to compare to the efficacy of Mark's or Dave's beads.
It takes more than 17 times the volume and 17 times the surface area for the kitty litter to compete with my HCM beads.
The kitty litter costs about 15 bucks for 7 lbs. That's about $35.00 for 17 pounds. Shipping on 17 pounds is definately going to be at least 10 bucks.
A pound of my beads runs $45.00 shipped and they come in their own permanent bags.
So for the same price, you can either use 17 pounds of kitty litter or 1 pound of my beads.
You'll also have to arrange the kitty litter to bear enough surface area to be effective. You could use 2-8 ounce bags of my beads, or 34-8 oz. bags of kitty litter.
So I guess, if you want to generalize, silica gel kitty litter does do the same thing.
I've tried it, tested it, and found it worthless to me for the way I do things.
I use 5-8oz. bags of my beads in my winadors. I can't fit 42 bags of kitty litter in there.
Hope this helps you understand what "does the same thing" really means.
Good luck with whatever direction you choose!!!
Scott