An article listing top cleanburning stoves: http://www.omni-test.com/publications/Wood_stoves_article.pdf
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webbie
Seasoned Moderator
The article also mentions how much wood burning has declined......53 million cords in 49 to 17 million today.......
Having just visited another EPA test lab, I am more skeptical than ever...... 2x4's and 4x4's of Fir, dried to less than 20%, with little 3/4" spacers mounted around the ends, and positioned in the firebox in an exacting way.....I guess it's the best they can do at standardization, but it certainly would be nice to have some cordwood tests- if for nothing else, just for rough comparison.
I priced out a lab setup - 50 grand......although I could probably put a relatively accurate one together for 1/2 that. Then I need a place to put it, have to buy all the stoves, and then site around for days testing them! Maybe a Hearth.com member will write me into their will.
BTW, they have had these "top" lists for years. Avalon used to have the "cleanest" years ago, although our shop never used that as a sales tool. The fact that many are tested in different labs (usually the labs owned by the manufacturer) and also tested by the same technicians that designed the stoves - well, that just adds too many variables. In one of the the OMNI reports, a "large" manufacturer even admits both designing and testing purely for the numbers as opposed to real world operation or cord wood performance.
On the other side of the fence, a top industry expert had good things to say to me recently about the new designs (VC, Harman, Avalon) - I look forward to having a bunch of members using them in the next couple years and reporting back on them.
Having just visited another EPA test lab, I am more skeptical than ever...... 2x4's and 4x4's of Fir, dried to less than 20%, with little 3/4" spacers mounted around the ends, and positioned in the firebox in an exacting way.....I guess it's the best they can do at standardization, but it certainly would be nice to have some cordwood tests- if for nothing else, just for rough comparison.
I priced out a lab setup - 50 grand......although I could probably put a relatively accurate one together for 1/2 that. Then I need a place to put it, have to buy all the stoves, and then site around for days testing them! Maybe a Hearth.com member will write me into their will.
BTW, they have had these "top" lists for years. Avalon used to have the "cleanest" years ago, although our shop never used that as a sales tool. The fact that many are tested in different labs (usually the labs owned by the manufacturer) and also tested by the same technicians that designed the stoves - well, that just adds too many variables. In one of the the OMNI reports, a "large" manufacturer even admits both designing and testing purely for the numbers as opposed to real world operation or cord wood performance.
On the other side of the fence, a top industry expert had good things to say to me recently about the new designs (VC, Harman, Avalon) - I look forward to having a bunch of members using them in the next couple years and reporting back on them.
titan
Minister of Fire
What I'd really like to see is a re-test of all those stoves after burning 10 cords of good firewood.......then we'd see some "real-world" stats.
webbie
Seasoned Moderator
One Real World test - fairly up to date since it was "Phase 2", and stoves have not changed much:
A very comprehensive study of emissions from EPA-Phase 2 certified woodstoves, as they are
operated in homes was done in Klamath Falls and Portland, Oregon in the late 1990s
In that EPA study, emission sampling was done for up two months on 16 woodstoves while consumers operated the
woodstoves conducting their “normal” heating practices. EPA devised an Automated Wood Emissions
Sampling system for this study in which flue gas was drawn off and passed through a glass filter and
then through a XAD cartridge.
Mass emissions for these stoves covered a wide range from 2 to 32 g/hr and averaged 11.1 g/hr,
which is significantly above the certification limits for Phase 2 woodstoves of 4.1 g/hr (catalytic design)
and 7.5 g/hr (non-catalytic design). A comparison of the actual PM emissions to each stove’s hang-tag
certification value is provided in this same EPA study and shows that actual in-use emissions from
certified stoves are on average 3.3 times the certification value.
End------------
The problem is that we cannot "pick and choose" data we want to believe. A cat encore was the worst performer (20 grams) in the tests above. The same report says that OWBs burn as clean as EPA stoves!
Again, the problem appears to be picking and choosing data. Elk likes to trumpet VC's new N/C number, but at the same time he is telling his town fathers to regular OWBs, which are as clean as EPA stoves! Of course, he does not mention the 20 GPH in the real world encore test, saying that is an "older model" (which is true enough, but those numbers are 8x the number on the older model hang tag).
What is needed is an independent test lab - not the same one that takes millions from the manufacturers. That is not likely to happen. How about simply this - a couple brave manufacturers who tell us what the test runs in their labs with cord wood show - just so we know!
A very comprehensive study of emissions from EPA-Phase 2 certified woodstoves, as they are
operated in homes was done in Klamath Falls and Portland, Oregon in the late 1990s
In that EPA study, emission sampling was done for up two months on 16 woodstoves while consumers operated the
woodstoves conducting their “normal” heating practices. EPA devised an Automated Wood Emissions
Sampling system for this study in which flue gas was drawn off and passed through a glass filter and
then through a XAD cartridge.
Mass emissions for these stoves covered a wide range from 2 to 32 g/hr and averaged 11.1 g/hr,
which is significantly above the certification limits for Phase 2 woodstoves of 4.1 g/hr (catalytic design)
and 7.5 g/hr (non-catalytic design). A comparison of the actual PM emissions to each stove’s hang-tag
certification value is provided in this same EPA study and shows that actual in-use emissions from
certified stoves are on average 3.3 times the certification value.
End------------
The problem is that we cannot "pick and choose" data we want to believe. A cat encore was the worst performer (20 grams) in the tests above. The same report says that OWBs burn as clean as EPA stoves!
Again, the problem appears to be picking and choosing data. Elk likes to trumpet VC's new N/C number, but at the same time he is telling his town fathers to regular OWBs, which are as clean as EPA stoves! Of course, he does not mention the 20 GPH in the real world encore test, saying that is an "older model" (which is true enough, but those numbers are 8x the number on the older model hang tag).
What is needed is an independent test lab - not the same one that takes millions from the manufacturers. That is not likely to happen. How about simply this - a couple brave manufacturers who tell us what the test runs in their labs with cord wood show - just so we know!
precaud
Minister of Fire
webbie
Seasoned Moderator
Yes, I think (for one instance) that a new Harman (and others) would make the list - and perhaps many others.
The article also would be a couple months behind that date (deadlines), so closer to two year old data.
Hey, we can massage the numbers this way - by weight, and by cubic firebox size! A formula, called "heat my barn for the most bang per buck" - I think we know which one will win!
Now excuse me while I go buy an OWB since it is now certified clean by engineers.
The article also would be a couple months behind that date (deadlines), so closer to two year old data.
Hey, we can massage the numbers this way - by weight, and by cubic firebox size! A formula, called "heat my barn for the most bang per buck" - I think we know which one will win!
Now excuse me while I go buy an OWB since it is now certified clean by engineers.
I don't have access to Hearth & Home magazine. Maybe they've updated the list since then? I'll email the author and see if there has been.
I was wondering where the PE's were myself.
I was wondering where the PE's were myself.
Klamath Falls and Portland, Oregon in the late 1990s
Craig that testing procedure was so flawed it can't be anyway near being called scientific
I lack the basic control of establishing the condition of the tested stove from the beginning then wnce the results are in it goes back to admit there were no original condition reports
Once normal maintance was done the only valid point of the report was a well maintained stove runs cleaner
Craig as I remember correctly the date of the study was the early 90" before Phase II stoves and that no stoves in the study were EPA stoves.
This has been discussed here before and that study is not germane to todays stoves lacks scientific structure, no control base, and is just about useless to index or to call any attention to.
A also believe this was about the time Omni Labs got caught cheating (Fudging results) and got de -certified.
Has any noted some major manufactures without one entry in the top ten list or honorable mention
Note this list was 2004 more stoves have been certified and would have made this list when it is updated All stoves with the horizontal burn technology similar to the Everburn, would populate this list Included would be the new non Cat Defiant the Harman Oakwood and the Lopi, shame on me for forgetting the name, top loader Leyden??
Craig that testing procedure was so flawed it can't be anyway near being called scientific
I lack the basic control of establishing the condition of the tested stove from the beginning then wnce the results are in it goes back to admit there were no original condition reports
Once normal maintance was done the only valid point of the report was a well maintained stove runs cleaner
Craig as I remember correctly the date of the study was the early 90" before Phase II stoves and that no stoves in the study were EPA stoves.
This has been discussed here before and that study is not germane to todays stoves lacks scientific structure, no control base, and is just about useless to index or to call any attention to.
A also believe this was about the time Omni Labs got caught cheating (Fudging results) and got de -certified.
Has any noted some major manufactures without one entry in the top ten list or honorable mention
Note this list was 2004 more stoves have been certified and would have made this list when it is updated All stoves with the horizontal burn technology similar to the Everburn, would populate this list Included would be the new non Cat Defiant the Harman Oakwood and the Lopi, shame on me for forgetting the name, top loader Leyden??
webbie
Seasoned Moderator
Study was 1999.
Resolute Acclaim (horizontal burn technology) was introduced in 1989. Current versions of it...by various names (I call it downdraft) are very similar.
"Long-Term Performance of EPA-Certified Phase 2 Woodstoves, Klamath Falls and 41 Portland, Oregon: 1998/1999,"
It is a far reaching to suggest that all the stoves from 1985 to 1999 were "bad" (relatively) and that, all of a sudden, the new ones finally figured things out. No doubt we see improvement, but the question is always how much of an improvement is "lab" and how much is real world.
I talked to one manufacturer who got numbers below one gram, but said that type of "tuning" would have made their stove perform worse with cordwood - so they added more air passages, which doubled the EPA GPH to about 1.6...... personally, I'd rather have a two gram stove that worked well, than a finicky one with .5 grams.
This reminds me of my cousin, who always had a car that would suck mine into one tailpipe and out the other (according to him) - last time I visited him, he had a Ford Focus, which he still claimed (because of the tires) was the quickest thing on the road.
Resolute Acclaim (horizontal burn technology) was introduced in 1989. Current versions of it...by various names (I call it downdraft) are very similar.
"Long-Term Performance of EPA-Certified Phase 2 Woodstoves, Klamath Falls and 41 Portland, Oregon: 1998/1999,"
It is a far reaching to suggest that all the stoves from 1985 to 1999 were "bad" (relatively) and that, all of a sudden, the new ones finally figured things out. No doubt we see improvement, but the question is always how much of an improvement is "lab" and how much is real world.
I talked to one manufacturer who got numbers below one gram, but said that type of "tuning" would have made their stove perform worse with cordwood - so they added more air passages, which doubled the EPA GPH to about 1.6...... personally, I'd rather have a two gram stove that worked well, than a finicky one with .5 grams.
This reminds me of my cousin, who always had a car that would suck mine into one tailpipe and out the other (according to him) - last time I visited him, he had a Ford Focus, which he still claimed (because of the tires) was the quickest thing on the road.
TMonter
Minister of Fire
The EPA in a 2000 report revisits the 1992 wood stoves (phase II) study.
The study was concerning 1992/ 1993 stoves without pre determining their current condition. Which to me is totally unscientific.
Some how I think some technology has been improved since 1992 and Find it hard to draw any conclusions to 2007 stoves
I mean the reports were probably typed in windows 3,0 on 486 processors Computers Yes technology has changed a bit by then
Auto cad was a dos based program and had to run alone outside of Windows. Complicated revisions in complex drawings took days to re-claculate
The study was concerning 1992/ 1993 stoves without pre determining their current condition. Which to me is totally unscientific.
Some how I think some technology has been improved since 1992 and Find it hard to draw any conclusions to 2007 stoves
I mean the reports were probably typed in windows 3,0 on 486 processors Computers Yes technology has changed a bit by then
Auto cad was a dos based program and had to run alone outside of Windows. Complicated revisions in complex drawings took days to re-claculate
I'm obessive about running my stove clean - I need real world testing so I know if I belong in the Woodburner's Hall of Shame or not.
For further reading on the topics of real world emissions testing, residential combustion, etc. http://www.omni-test.com/publications_search_results.php?q=stoves&anyallexact=all
If the link doesn't work type stoves in the search box.
One of the articles shows in the real world, most wood piles have an avg moisture of 26%, with most being 24%. Interesting stuff if you have the time.
For further reading on the topics of real world emissions testing, residential combustion, etc. http://www.omni-test.com/publications_search_results.php?q=stoves&anyallexact=all
If the link doesn't work type stoves in the search box.
One of the articles shows in the real world, most wood piles have an avg moisture of 26%, with most being 24%. Interesting stuff if you have the time.
TMonter
Minister of Fire
Not when you want to see how stoves perform in real-world situations. Did you read the report Elk, they did inspect the stoves during the study and note any major defects.
Except stove technology has not changed dramatically. Stoves are not computers and combustion fundamentals do not change.
One more thing the EPA should give part of their $30/stove to Craig to establish the RW Testing lab
Do you think the stove engineers and combustion engineers are still using windows 3.1 and dos Auto Cad?
I know they are using modern computers and the latest Auto cad and drawing rendering.. Variable and what ifs are calculated in seconds and minutes.
I think they might be using this technology to improve stoves. So I can't buy technology has not changed or completely buy that.
When I took mechanical drawing in college It was done with a pencil Today in auto cad not only can I change the stairs location it provides me a time difference factor a materials comparison and does all this in minutes. In home construction Stairs are critical to placement of just about every dememtion of the home
webbie
Seasoned Moderator
Where is Will Rogers when you need him?
If he was here, this is what he would say "I've looked into the box of a 1990 Avalon, and I've looked into the box of a 2005 Avalon, and By Golly, they certainly look the same to me!"
Phase II is EXACTLY the same standards as today. As to whether testing "real" stoves in the field is better than testing brand new stoves, with 4x4's and spacers - and with lab technicians stirring the coals and operating the air controls....well, I'll let our intelligent readers make the decision as to which might be more accurate!
One thing for certain - as we have all said from the start - the chimney, operator and wood provide MUCH MORE of a variable than anything else. Just like GUNS don't kill people (people kill people), stoves don't burn dirty, people burn dirty.
The C. Issod testing lab just does not have the right ring to it. We need that big donor who really want to expose the truth. Problem is twofold - first of all, there is no way to make money with the results....secondly, some manufacturers might get angry at the published reports.....sounds like a no-win situation!
Every read a boating magazine? You'll never see a bad review - because "guess who" are the advertisers in the magazine.
So perhaps someone could offer a suggestion as to how one might make money by independent testing? It would seem almost impossible to make the amount needed to keep the operation going....
If he was here, this is what he would say "I've looked into the box of a 1990 Avalon, and I've looked into the box of a 2005 Avalon, and By Golly, they certainly look the same to me!"
Phase II is EXACTLY the same standards as today. As to whether testing "real" stoves in the field is better than testing brand new stoves, with 4x4's and spacers - and with lab technicians stirring the coals and operating the air controls....well, I'll let our intelligent readers make the decision as to which might be more accurate!
One thing for certain - as we have all said from the start - the chimney, operator and wood provide MUCH MORE of a variable than anything else. Just like GUNS don't kill people (people kill people), stoves don't burn dirty, people burn dirty.
The C. Issod testing lab just does not have the right ring to it. We need that big donor who really want to expose the truth. Problem is twofold - first of all, there is no way to make money with the results....secondly, some manufacturers might get angry at the published reports.....sounds like a no-win situation!
Every read a boating magazine? You'll never see a bad review - because "guess who" are the advertisers in the magazine.
So perhaps someone could offer a suggestion as to how one might make money by independent testing? It would seem almost impossible to make the amount needed to keep the operation going....
TMonter
Minister of Fire
Stoves are simple designs. No doubt computer drawing packages make design to manufacturing quicker and changes easier, but they don't do any magic that changes the fact that stove designs haven't changed much in about 15 years. Sure small tweaks have been made, and the right software makes that easier, but that's all it is. Someone still has to hand calculate all of the combustion design parameters.
Remember Elk, I am a combustion engineer and I can tell you technology has not fundamentally changed the way things are done, it's just made them faster and easier.
webbie
Seasoned Moderator
We can easily dig up patents and stoves from 150+ years ago that show "base burning" as the new thing. The big difference then was that the designers were not forced to use 2x4's for fuel.
When I was over at TARM in the early 90's, they were using Sun machines for CAD....worked fine. Nuclear weapons and ICBM's were made with slide rules and formulas. The moon shot was done without transistors (or maybe just a few).....
OH, that reminds me - all TARMS had base (horizontal cross) burning with injected air (like an Acclaim) for decades. The difference is that the boilers had "cold" wall - with water around them, so they could not get as hot as current stoves....and therefore not as efficient.
Garbage in, Garbage out...... I have a great guitar and amp, and yet for some reason I can't really get that Clapton sound.
Another interesting "tidbit" is that many stove companies - even the 'biggest" farm out much of their R&D;and design. I was friendly with a dude (in fact, he designed the first extendaflue!), who worked for about 70% of the companies out there designing combustion systems. His clients, according to him, were all about PRICE....and him keeping his mouth shut!
Even another "inside" story - Some folks tend to think there is a crew of engineers and scientists sitting around these stove companies thinking about how they can make things better (every day).....not always true! I have seen guys in garages making parts for large public stove companies. We had a local machine shop in Medford, NJ run by one guy (the only employee) making parts for the Fusion Reactor at Princeton!
Just as with other companies, the profit motive runs the stove biz. Good enough is usually good enough, and a purple enamel, larger glass or lower price will usually increase sales more than a 10% reduction in GPH.
In the end, the problem with stoves is that they run over a wide variety of outputs. That is why a Russian type stove or a storage boiler....or pellets....are the best ways to get the cleanest burn possible.
No doubt the lower emission numbers are good news - but in the media, we are losing the battle because OWBs are in the paper and on the radio almost every day around here! Another bad rep for the industry.
When I was over at TARM in the early 90's, they were using Sun machines for CAD....worked fine. Nuclear weapons and ICBM's were made with slide rules and formulas. The moon shot was done without transistors (or maybe just a few).....
OH, that reminds me - all TARMS had base (horizontal cross) burning with injected air (like an Acclaim) for decades. The difference is that the boilers had "cold" wall - with water around them, so they could not get as hot as current stoves....and therefore not as efficient.
Garbage in, Garbage out...... I have a great guitar and amp, and yet for some reason I can't really get that Clapton sound.
Another interesting "tidbit" is that many stove companies - even the 'biggest" farm out much of their R&D;and design. I was friendly with a dude (in fact, he designed the first extendaflue!), who worked for about 70% of the companies out there designing combustion systems. His clients, according to him, were all about PRICE....and him keeping his mouth shut!
Even another "inside" story - Some folks tend to think there is a crew of engineers and scientists sitting around these stove companies thinking about how they can make things better (every day).....not always true! I have seen guys in garages making parts for large public stove companies. We had a local machine shop in Medford, NJ run by one guy (the only employee) making parts for the Fusion Reactor at Princeton!
Just as with other companies, the profit motive runs the stove biz. Good enough is usually good enough, and a purple enamel, larger glass or lower price will usually increase sales more than a 10% reduction in GPH.
In the end, the problem with stoves is that they run over a wide variety of outputs. That is why a Russian type stove or a storage boiler....or pellets....are the best ways to get the cleanest burn possible.
No doubt the lower emission numbers are good news - but in the media, we are losing the battle because OWBs are in the paper and on the radio almost every day around here! Another bad rep for the industry.
I see whatt you mean in the 60's I was the New England school boy champ in golf. I can't play any way close to that level now. I had crappy clubs compared to what we use today
My Farther was director of research Cabot Corp. Oldest brother PHD chemistry and Physice MIT. But not of this adds or has anything to do with the discussion at hand .None prove GPH worth or disclaim it I can go on with nonsense that has nothing to do with the guestion at hand. But not as good as you can, you are much more practice at it than me.
The question is is the cleanest tested stove any indication it will burn clean in the real world with Joe homeowner at the controls. ? Again name any other scientific controlled data by an independent or supervised by independent certified tech that allow comparisons?
My Farther was director of research Cabot Corp. Oldest brother PHD chemistry and Physice MIT. But not of this adds or has anything to do with the discussion at hand .None prove GPH worth or disclaim it I can go on with nonsense that has nothing to do with the guestion at hand. But not as good as you can, you are much more practice at it than me.
The question is is the cleanest tested stove any indication it will burn clean in the real world with Joe homeowner at the controls. ? Again name any other scientific controlled data by an independent or supervised by independent certified tech that allow comparisons?
Webmaster said:
Yeah. That is how all of those stoves of yesteryear with 1/4" bodies and 3/8" tops have turned into 3/16" bodies, 1/4" or 3/16" tops and a ton of bricks in them.
The old ones lasted twenty or thirty years. Be interesting to see how long these can go.
cbrodsky
Member
Getting back to Craig's point - how structured the tests are - what everyone is getting at is we really need to see a "process window" type of measurement for these stoves. We do this at work every day. You think about what problems you're going to have in the manufacturing line - then artificially induce that problem to see how the process withstands it and redevelop your process based on those findings across many different tests.
The same thing could be done for stoves. (maybe it is and the EPA just doesn't tell us?) For example, we probably all have some ideas as to which variables might affect stove emissions and burn efficiency. The EPA could start looking at a series of designed experiments varying conditions like the size of the spacers they use, the moisture content of the wood, the volume of wood loaded, the amount of ash left in the bottom of the firebox... all things that we likely fail to accurately control every day we use our stoves.
All of these parameters could still be accurately controlled in the tests to help model the behavior. In the end, the real score of interest would be which stove design holds up best as you start deviating across a variety of real world conditions.
It would cost way too much money, but even if it was an exploratory set of work on some of the leading high-volume manufacturer stoves, it would provide incredibly interesting insight that might also help educate all of us on what really makes a good stove and what should we really spend our time obsessing on when operating it since none of us are following the current test sequence.
Maybe we'd learn they're really all more or less the same in the real world and we'd have to go out and cut some wood instead of arguing about specs all day
-Colin
The same thing could be done for stoves. (maybe it is and the EPA just doesn't tell us?) For example, we probably all have some ideas as to which variables might affect stove emissions and burn efficiency. The EPA could start looking at a series of designed experiments varying conditions like the size of the spacers they use, the moisture content of the wood, the volume of wood loaded, the amount of ash left in the bottom of the firebox... all things that we likely fail to accurately control every day we use our stoves.
All of these parameters could still be accurately controlled in the tests to help model the behavior. In the end, the real score of interest would be which stove design holds up best as you start deviating across a variety of real world conditions.
It would cost way too much money, but even if it was an exploratory set of work on some of the leading high-volume manufacturer stoves, it would provide incredibly interesting insight that might also help educate all of us on what really makes a good stove and what should we really spend our time obsessing on when operating it since none of us are following the current test sequence.
Maybe we'd learn they're really all more or less the same in the real world and we'd have to go out and cut some wood instead of arguing about specs all day
-Colin
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