Love the Curtis. Is that made by Curtis Wright? The old factory still stands in Buffalo.
Howie has a different thread about his snow melter. He has something like two low temp gas boilers connected in parallel with each producing 150k BTU or there abouts. His driveway, sidewalk, and back yard are plumbed with tubing under concrete or pavers to circulate the warm water through on demand. I'm too lazy to find the thread for reference here but I just saw it a couple days ago. Nice set up, if you can afford all the concrete. I'd also have to think you need to keep it above freezing simply to keep the lines from freezing and breaking inside the concrete.
Actually 3 condensing boilers at 140,000 BTUH each, piped together in a primary loop, primary/secondary system, 12 zones of heat, thermal storage, instantaneous DHW, 2 zones with 6 loops each of snow melting! That's a little more precise Jim, but there's a lot more to it!

It's propolylene-glycol anti-freeze, not water. No freezing issues.
Here's the link for it:
http://www.cvoharley.com/smf/index.php?topic=11910.msg185333#msg185333Hoist!
