I've been heating our house since 1982 with a larger "Wood Saver" wood stove. For those not familiar with the brand (and very few people would be), it was made by one of the many small wood stove builders that were making stoves at the time. It is basically a copy of one of the larger Fisher stoves...very well made, made of 1/4 " steel, excellent welds, very heavy cast iron door, lined with firebrick, and still in great shape and air tight after all these years. We're heating about a 1700 sq. ft. older (no, ancient) farm house with it (stove is in the cellar). Now I know that the newer EPA certified stoves burn cleaner and burn more efficiently. My question is, would replacing my stove with a new model actually save much wood. On the surface, it appears to be a no-brainer. If you increase the burning efficiency, you get more heat out of the wood, so less wood needed. I've seen claims that the increase in efficiency will save you up to 1/3 less wood. But I'm not convinced. Anyone who's burned wood for a while knows it's not cut and dry, like burning oil. With an oil furnace, you have a set orifice size and you cycle it on and off, so it's relatively easy to calculate efficiencies. With a wood stove, it's burning all the time. Sometimes you burn less wood, sometimes you smolder the fire some, sometimes you burn it almost full bore depending on how much heat the house needs. So are these newer stoves efficiencies calculated at a full burn? What happens when you have to burn them cooler? Are they still efficient then? I'd especially like to hear from anyone who has replaced an older airtight stove in good working condition with one of the newer stoves (in the same house and same place in the house). Is your new stove using any less wood? How about the smoke? Is it really noticeably less? I'd also like to hear from any engineers or engineer minded people who know about how these burning efficiencies are calculated. Does burn efficiency that is advertised for the new stoves really translate into heating efficiency? (A fireplace burns pretty efficiently, but heats very inefficiently). I cut my firewood off of our own property, so it's harder to justify the cost of a new one. But...if it were to save me 1/3 of the 6 to 6 1/2 full cords I use, and burn cleaner...maybe. I'm just doubting that switching would save me anywhere near that. Any thoughts appreciated.