I swear a few years back I when I was looking at gassers I found a calculator that allowed you to plug in your max boiler output, size of storage, max and minimum temps of storage, and design heat loss of your home. Once you plugged all of this in, it would tell you how much wood you'd have to burn for how long to get however many hours of heat out of your system. I think it was actually a manufacturer's website, but I'll be damned if I could find it now. I'm starting to look seriously at the Empyre Elite 100 with the electric backup for my remodel and I want to play around with the numbers to see how much storage it would take to get the least amount of fires per week. One of the selling points to the wife on this has to be why it will be more convenient than our current setup of a forced air furnace with add on wood furnace.