I don't beleive a UTH can get hot to put out 451oF, but you can figure out how much heat they can by doing the math of how many watts the UTH uses. I've forgotten the formula, it was in my high school physics and i paid less attention then I should have.
I found a neat little conversion thingy on the web and i'm not sure if it's giving me the information i want but basicly it says your 16 watt UTH (such as the 10.5X11" exoterra UTH) puts out 54.6 BTU (I could be totaly wrong on this, it's been a while since i've had to think about this stuff and back then i didn't want to think about it). now i'm not sure how much temperature that will put out as i think that's variable on where you're starting at, but i'm sure some one with good physics skills can figure it out.
