Clean… yes.
Efficient… not so much.
Going from an old smoke dragon last year to an EPA certified (non-cat) firebox this year, I’ve noticed as temperatures drop so does the efficiency. During warmer periods this EPA box uses far less wood than the old box, but during colder periods it uses at least as much, if not more wood than the old box… and when it gets down-right arctic out it definitely uses more wood, a lot more! Overall, my total wood consumption hasn’t really changed… but we’re not as warm inside during extreme cold. And, the longer the cold weather lasts the worse the disparity gets.
Now some of y’all have argued that my problem is a bad install, or bad draft, or my modifications, or I’m using a firebox too small, or whatever. But none of that made any sense to me; the firebox is damn close to the same size as the old smoke dragon, and installed/modified in the same fashion… there just had to be more to it than that. I’ve experimented and tried dozens of things to improve performance, the best result has been to leave the intake air wide open and control the fire with a flue damper… better, but far from perfect. I’ve contended that the EPA design was simply a poor design, and in some ways I still think that… but the real problem is the EPA and how they require testing.
The EPA requires testing to be done under conditions they believe would result in the highest emissions rate (i.e. warmish weather) using a 15 foot stack height (measured from the floor the stove is sitting on). And the stove must perform, without the fire going out, while remaining within regulations, at minimum draft setting using dimensional lumber rather than cordwood. Well, that’s far from “real world” for many of us… my firebox is in the basement, resulting in an overall chimney height approaching 40 feet. What happens is, as the temperatures drop and the wind increases, the “heating efficiency” of my EPA box falls below that of the old smoke dragon… yet, because of design, the “combustion efficiency” remains. In other words, compared to the old smoke dragon much more of my heat is exiting the flue, which explains the excessive coaling and why the flue damper works best for me. Simply, the EPA regulations are all about combustion efficiency (emissions)… they have nothing to do with heating efficiency. In reality, in my home, during extreme cold, an old smoke dragon will use less wood and be a far more efficient “heater”… and yes, produce more emissions. During warmer weather the EPA box would be a better choice, but that ain’t when I need the heat the most.
Now, y’all can argue with me if ya’ want… but I’ve studied this at length. The other day I came across this article written in the 2006 WETT newsletter that not only confirmed what I was suspecting… but does a darn good job of explaining it. He calls it the “
Florida Bungalow Syndrome"…
Florida Bungalow Syndrome
…and it also explains very well why some of us have problems similar to mine, while others of us don’t. Basically, the closer conditions are to test conditions the better these EPA stoves will work, but as conditions move away from test conditions the worse they will work… and the degradation in performance ain’t linear. If my fire box was sitting on the main floor of a single story, ranch-style home, in a slightly less cold and windy area of the country I’d likely be singing its praises… but living where I do, in the type home I do, I’ll never get close to the performance I need when January rolls around. It-is-what-it-is… it’s all about having the correct tool for the task at hand.
addendum; Sorry, I'm not meaning to hijack this thread, upon hindsight I should have started a new thread with it.
Which I've done, find it here...
http://www.arboristsite.com/firewood-heating-wood-burning-equipment/230141.htm#post4182465
