That's really interesting, Joe. Are there systems like that actually in use today, or is some of this on the horizon for residential applications (i.e., prohibitively expensive at the moment)? I was struck by your mention of diminishing returns. That gets to my philosophy of heating old houses that were originally designed to be fueled with cheap coal: The house was designed to be made comfortable with existing equipment (cast iron radiators, large diameter piping, etc.). You can insulate, replace windows, drop ceilings, etc. and try to compensate by burning less oil or gas, or you can find a cheaper fuel and heat the place like it was designed to be heated. I could easily spend $40,000 or $50,000 on more insulation and new windows for my big old house, or invest $10,000 in a really good woodburning system and wind up being a lot more comfortable in the end. People say, "yes, but you're wasting wood, which is a valuable resource." But if you know anything about forest management, you know that the amount of low-grade wood left to rot in most of the forests in the Northeast is where the real waste exists. Using something that would otherwise rot in the woods is not, in my mind, wasting it. Anyone on this board knows that people routinely throw this valuable fuel away--in fact, they pay to have it removed. Burning it in an efficient, clean-burning appliance is even better. Nobody is going to argue that insulation and other energy conservation strategies are a bad thing, and I insulate my house as much as possible. But I think there's something to be said for working with what you have, which in my case is a circa 1865 farmhouse with an excellent heating system. Going to great lengths to save oil and gas, on the other hand, is well worth the effort and expense. This sounds like a rant, which it's not intended to be. Thanks for your excellent description of a smart heating control system.