A few additional comments regarding non catalytic woodstoves: http://www.epa.gov/ttn/chief/ap42/ch01/related/woodstove.pdf (From page 9) "Based on commercial marketing surveys there are an estimated 9.3 million cordwood stoves in use in the United States. From HPA surveys of manufacturers it is estimated that about 0.6 million of these are certified, non-catalytic cordwood stoves and about 0.4 million are certified catalytic cordwood stoves (i.e., there are about 8.3 million old conventional cordwood stoves and about 1.0 million certified cordwood stoves in use in the United States). From http://www.burningclean.com/ "Q. “Once I have preheated my chimney, how should I operate the stove?” A. Although all wood stoves require preheating during startup and reloading, their operation afterwards varies somewhat. Wood stoves using catalytic combustors require the monitoring of temperatures and air supply to ensure the catalyst engages at appropriate times in the combustion cycle. Generally, catalytic stoves require lower combustion temperatures in the firebox to burn cleanly. At 500-1000 degrees F., the catalyst ignites, burning the volatile gases and particulates. Non-catalytic stoves attain much higher temperatures in the combustion path before the gases and particulates burn. Always refer to your wood stove manufacturer’s operation manual and follow the instructions for your particular make and model." http://www.woodstove.com/pages/combustortips.html "Q. What about non-catalytic stoves? How do they compare with catalytic stoves? A. There are a number of good non-catalytic stoves on the market, and some of them achieve clean burning that is almost as good as the clean burn that you’ll get with a catalyst. Our only reservation about these stoves is the way they are built. To meet the EPA standards and achieve truly clean burning, the non-catalytic stoves have to burn regularly at temperatures of about 1,000 degrees - i.e. the temperature that gasses and particles in the smoke will burn without a catalyst. In other words, non-catalytic stoves have to operate with very hot firebox temperatures to meet the EPA standards - much hotter than catalytic stoves. Rather than recommend specific models of non-catalytic stoves made by competitors, we offer this advice: If you are considering a purchase of one of these stoves, look carefully at the firebox and the way the inside of the stove is constructed, keeping in mind that all materials and any moving parts are subject to very high heat. If any of the materials seem to be lightweight or insubstantial, steer clear and keep looking. You will want to invest in a stove that is durable, and able to withstand high heat and heat cycling. The catalytic combustor in your stove will have to be replaced every 4-5 years. Its replacement cost (about $100) is a small price to pay for the increased efficiency, clean-burning, and peace-of-mind it offers. And, it’s much easier to replace a catalyst than a warped firebox. " http://www.mastersweep.com/OPT.HTM "Unless yours is a very primitive model, you'll find a baffle plate of some kind near the top of your stove. It's between the fire chamber and the flue outlet. This is where the secondary burn occurs. This is where your stove creates a HUGE percentage of the heat it delivers to you! When the secondary gasses are ignited, the internal temperature of the stove may go from 450 degree's to 1600 degree's! That is a HUGE performance increase! But, it DOES NOT mean the wood will burn up faster! Such high temperatures create a powerful vacuum inside your stove. You only need a very small intake hole, (e.g. 1/2 inch in diameter) to provide oxygen. That small intake port provides a high pressure, but very small stream of oxygen which enables you to burn your stove very hot, for a long time. By controlling the amount of oxygen that enters the stove, you prohibit the stove from burning the wood too fast. Even though it is burning much hotter, you can actually burn the wood you do use for a longer period. The amount of secondary combustion that occurs varies widely from model to model. Largely due to advances in heat extraction technology over the years. A twelve-year-old baffled airtight stove can be presumed to operate at about 40% efficiency, while many of today's EPA approved wood stoves exceed 80% efficiency. The main difference between the older wood stoves and today's wood stoves is in the upper baffle chamber, where newer techniques have been incorporated to re-burn and use the secondary exhaust gases." "*This article was paraphrased from a correspondence with Tom Oyen "The Chimney Sweep Inc." You can visit Tom's site at: http://www.nas.com/~chimneysweep We acknowledge Tom's contribution with gratitude." Frankly, I think the situation is ripe for a class action lawsuit against manufacturers of non catalytic stoves who A) Fail to adequately define (from a cause and effect viewpoint) what constitutes overfiring of the stove and B) Fails to provide the consumer with an adequate means to monitor the operation of the stove which will effectively identify operation close to or into overfire condition. All it will take is a few scientists, some representative stoves and chimneys, data aquisition equipment for a few hundred hours and the opinion of an expert metallurgist to create a body of evidence that will demonstrate the inadequacy of existing instructions from the stove manufacturers. Relatively speaking, non catalytic stoves are in their infancy in the marketplace, as demonstrated by the EPA report. It is entirely possible that the manufacturers are well aware of the inadequacy of their user instructions, but resist changing them since the change may be seen as recognition of their inadequacy. Unfortunately, all it will take is a sufficient number of failed stoves before a trial lawyer identifies a "business opportunity".