Boilers, efficiency, on demand

Does anyone have experience with an on demand gas system for hot water and heat? It seems from the literature that the efficiency is much higher than a traditional boiler like a weil McClain CG (as much as 97% or 14% higher) and the sticker price isn’t so high on some models (Tagaki is one maker I’ve looked into).
I’d be using the system with cast iron radiators, not radiant heat.

By hegelian | 05/15/2008 11:09 PM