Catalytic vs Secondary Burn Technology Advantages?

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I can only speak of what I know and I have a Woodstock for 5 yrs original cat....zero problems and is a seriously well constructed piece of furniture almost. all I do for my cat is brush off fly ash occasionaly and that is all. the cat is 125.00 and looks like ill get a 6th season out of it burning 24/7. burn times are overrated for me cause I burn hot

 

[BeatCJ]

The thing that interests me is the hybrid stove uses both technologies so you would think it would class leading in the amount of emissions it releases but there are others that are marginally better. Why is that? In general, it seems like the secondary burn stoves produce on average more effluent... any insite?

I believe that in making a hybrid, you have to make compromises. I do think there are advantages, too. The way I read it, it doesn't use both approaches at once, but one or the other, based on combustion temps. Not that interested to really delve into it.

I don't think you should choose solely on emissions, but it's a factor. I would guess that there is no way a secondary burn stove CAN achieve the lower emission levels a catalytic stove can reach. Both types of EPA certified stoves are such an improvement over a non technological wood burning box that even a secondary burning stove is acceptable to the rule makers. While I'm glad the EPA allows for differences, I'm somewhat surprised that they allowed for different approaches. If they were as onerous as people claim, they would have set a level and said achieve this, or don't manufacture a stove.

 

[Chris-PA]

While I'm glad the EPA allows for differences, I'm somewhat surprised that they allowed for different approaches. If they were as onerous as people claim, they would have set a level and said achieve this, or don't manufacture a stove.

As far as I know they have done exactly that - there is a test that is described in detail, and specific output limits one must meet. How that is achieved is not part of the regulation. It is a performance test.

 

[BeatCJ]

Hmmm, maybe it's Washington State then, but I was pretty sure there is one standard for catalytic stoves and a higher allowable level for secondary burn stoves.

OK, from EPA Burnwise: http://www.epa.gov/burnwise/woodstoves.html

Emission Limits for Wood Stoves
The internal design of wood stoves has changed entirely since the EPA issued standards of performance for new wood stoves in 1988. EPA's mandatory smoke emission limit for wood stoves is 7.5 grams of smoke per hour (g/h) for non-catalytic stoves and 4.1 g/h for catalytic stoves. (Wood stoves offered for sale in the state of Washington must meet a limit of 4.5 g/h for non-catalytic stoves and 2.5 g/h for catalytic stoves.)

 

[Idahonative]

This is why a consumer shopping for a new "high efficient" wood stove needs to understand what high efficiency means. Efficiency in the real world is how well a stove burns, extracts, and delivers heat to your home (aka HEATING EFFICIENCY). I believe the EPA ratings are only a measure of how cleanly a stove burns (low emissions), not how well it heats. Consumers are easily confused when talking about efficiency and there are companies out there that exploit that to sell stoves.

This is one of the reasons why I questioned the Woodstock Ideal Steel. It makes no sense to me how a stove can have a large firebox and "record 82% EPA tested efficiency", but yet only have average burn times of 10-14 hrs. It's being marketed as a super efficient stove which it is from an emissions standpoint (1 gr/hr). But from a standpoint of giving the consumer the most possible heat out of a given amount of wood, it's performance is just average. Does this make it a bad stove? ABSOLUTELY NOT and no one should take offense to that statement. I just believe that potential buyers should understand exactly what they are purchasing...and I shouldn't be attacked for that.

Here's the bottom line no matter if you burn a cat, non cat, secondary, or hybrid stove: The hotter your flue temps, the lower your stoves heating efficiency will be in the real world. If the heat energy is going up the stack, it's not going into your home. A magnet thermometer, placed on a single wall pipe, 5 inches above the stove top will tell you a lot about your stoves heating efficiency (for double wall use probe).

http://www.condar.com/Stovepipe_Thermometers.html

During normal operation, ours usually runs 150-200 degrees. There is nothing at all wrong with a stove that runs higher than that. It just means a lot of your heat energy is being wasted. Manufacturers can market their stoves pretty much however they want, no matter how misleading it may be. They are in business to sell stoves and make a profit. A flue thermometer is a low cost reliable way for consumers to monitor, first hand, the heating efficiency of their stove.

 

[Idahonative]

Not sure why I was thinking about it this morning but I think I've figured out why some on this site are so sensitive about my Woodstock stove comments. It's the companies SIX MONTH RISK FREE IN HOME TRIAL, MONEY BACK GUARANTEE.

Think about it. The company has all these stoves out there and the customers have a six month period in which they can return them for a refund. If people like me post things that could be considered negative, it's a huge threat to the company. They simply can't have many customers decide to return their stoves. It would bankrupt the company.

Woodstock advertises their return policy to be, "by far the best guarantee in the stove industry!". Once again, misleading. Yes, it is unique to the industry but it is nothing more than creative marketing. Because their ONE YEAR, PARTS ONLY warranty on the firebox is one of, if not the poorest in the industry. The THREE YEAR warranty on the cat might be closer to average.

I believe the company is using people to get on these forums to help sell stoves. It's a great strategy but it can be a double edged sword. They can use people like BrianK but forums are great informational tools and eventually, facts about any stove will come out (good and bad). BrianK, didn't Woodstock select you to test their latest hybrid as well?

I don't wish anything bad on Woodstock but I believe a person should be able to get on this forum and discuss things like stove efficiencies and warranty without getting beat up. I'm not an expert but if there are areas of concern, there should be no crime in discussing them.

 

[1project2many]

Not sure why I was thinking about it this morning but I think I've figured out why some on this site are so sensitive about my Woodstock stove comments.

I don't care about Woodstock. I'm just wondering why you continue to talk badly about the stove. You seem to worship at the shrine of Blaze King and talk about other brands as if they are created by Satan himself. Why? You may not realize it but to an observer you aren't discussing warranties and efficiencies. You're attempting to influence the readers' opinions in a negative way about other brands of stove. It's not just "Here's why I like mine" and "Here's what I didn't like about the other brand." You are in another place. Your message is "That brand is bad because I don't like the warranty. That brand is bad because they can't get the efficiency. That brand is bad, bad, bad. When I attempted to discuss the warranty including potential valid reasons why it might not match your expectations, there was no acknowledgment of validity, no realization that your interpretation might not be correct. Instead you tried to imply that I was somehow in league with another member and together we'd undertaken an attempt to subvert your message to the masses, probably under the auspices of the Devil's Own stove maker. Was that a discussion or a persecution? Was it even necessary?

There is no crime in discussion. There is no problem with disliking a product. What you're doing is different.

 

[Idahonative]

I don't care about Woodstock. I'm just wondering why you continue to talk badly about the stove. You seem to worship at the shrine of Blaze King and talk about other brands as if they are created by Satan himself. Why? You may not realize it but to an observer you aren't discussing warranties and efficiencies. You're attempting to influence the readers' opinions in a negative way about other brands of stove. It's not just "Here's why I like mine" and "Here's what I didn't like about the other brand." You are in another place. Your message is "That brand is bad because I don't like the warranty. That brand is bad because they can't get the efficiency. That brand is bad, bad, bad. When I attempted to discuss the warranty including potential valid reasons why it might not match your expectations, there was no acknowledgment of validity, no realization that your interpretation might not be correct. Instead you tried to imply that I was somehow in league with another member and together we'd undertaken an attempt to subvert your message to the masses, probably under the auspices of the Devil's Own stove maker. Was that a discussion or a persecution? Was it even necessary?

There is no crime in discussion. There is no problem with disliking a product. What you're doing is different.

Well I respectfully disagree. Go back and read my posts. I talk about things that other people, shopping for a new stove, might find relevant. I will agree that there is the added dimension in my discussions concerning Woodstock's marketing. To me, they are misleading and that bothers me. Am I on a mission to inform others...possibly. The nice thing about this forum is I am free to talk about what I feel is important. You and everyone else on here have the same luxury.

 

[Chris-PA]

This is why a consumer shopping for a new "high efficient" wood stove needs to understand what high efficiency means. Efficiency in the real world is how well a stove burns, extracts, and delivers heat to your home (aka HEATING EFFICIENCY). I believe the EPA ratings are only a measure of how cleanly a stove burns (low emissions), not how well it heats. Consumers are easily confused when talking about efficiency and there are companies out there that exploit that to sell stoves.

Efficiency is calculated as a ratio of two numbers - "how well a stove burns" is a vague term and not a definition of efficiency. The EPA tests the mass of particulates emitted by the stove wile burning a set load of wood.

Because the energy is stored in the wood mostly in the form of carbon bonds with other elements, and the particulates are mostly carbon molecules, then particulates also represent energy not extracted from the wood. Therefore the particulate test can be used to calculate the efficiency of energy extraction from the wood. "How well it heats" is also a vague term, but one could say that if you extract more energy from the load of wood then you got more heat.

However, none of that has anything to do with the rate of heat output, either peak or average, as you would also need to know the time it took to calculate that.

I believe the biggest confusion about modern stoves has to do with manufacturer published, unverified numbers on BTU/hr output rates. Even if the peak output numbers are correct, the secondary burn stoves make big peak output rates but cannot maintain that continuously, so people are fooled into thinking the stove is big enough when it isn't.

 

[Idahonative]

Efficiency is calculated as a ratio of two numbers - "how well a stove burns" is a vague term and not a definition of efficiency. The EPA tests the mass of particulates emitted by the stove wile burning a set load of wood.

Because the energy is stored in the wood mostly in the form of carbon bonds with other elements, and the particulates are mostly carbon molecules, then particulates also represent energy not extracted from the wood. Therefore the particulate test can be used to calculate the efficiency of energy extraction from the wood. "How well it heats" is also a vague term, but one could say that if you extract more energy from the load of wood then you got more heat.

However, none of that has anything to do with the rate of heat output, either peak or average, as you would also need to know the time it took to calculate that.

I believe the biggest confusion about modern stoves has to do with manufacturer published, unverified numbers on BTU/hr output rates. Even if the peak output numbers are correct, the secondary burn stoves make big peak output rates but cannot maintain that continuously, so people are fooled into thinking the stove is big enough when it isn't.

Kinda took what I said out of context didn't you Chris? You are right, "how well a stove burns" is a vague term but that's not really what I said is it. I said, "how well a stove burns, extracts, and delivers heat to your home." BIG difference because what you quoted is referring only to the burn and what I stated is referring to the heating efficiency of the stove. And I never said "how well a stove burns" was the definition of efficiency so please don't insinuate that I did. But hey, your buddy BrianK likes it so I guess it's not all bad

The "real world" efficiency of a wood stove is not hard to understand contrary to what many will have us believe. You have X amount of wood (fuel), capable of creating X amount of heat and there will be X amount of loss up the flue. You are right when you say, "the particulate test can be used to calculate the efficiency of energy extraction from the wood." But that has NOTHING to do with getting that heat transferred from the inside of the stove to the inside of the house. You are referring to efficiency like the EPA where only the particulate emitted is measured (and energy released calculated). I am only talking about heating efficiency which is how much heat energy is actually transferred to the inside of the home.

I stand by what I've stated in this thread. Woodstock is pushing the Ideal Steel as a super efficient stove and in the real world, it is not. Potential buyers should be aware that efficiency in that context has little to do with the amount of time the stove will actually heat their home. Don't you find it interesting that the Ideal Steel has a 3.2 cf firebox but yet most owners are reporting real world burn times of 10-14 hours? While owners of the Blaze King products with a smaller firebox (2.75 & 2.85 cf) are reporting TWO TIMES that amount. That is not an insignificant difference...that is HUGE. And to be clear, when I say burn times I mean burn times that actually heat the home. I know BrianK and others will get on here and debate that until the cows come home but it's difficult to debate facts. How in the world can there be such a big difference? Two words: HEATING EFFICIENCY.

 

[Chris-PA]

Kinda took what I said out of context didn't you Chris? You are right, "how well a stove burns" is a vague term but that's not really what I said is it. I said, "how well a stove burns, extracts, and delivers heat to your home." BIG difference because what you quoted is referring only to the burn and what I stated is referring to the heating efficiency of the stove. And I never said "how well a stove burns" was the definition of efficiency so please don't insinuate that I did. But hey, your buddy BrianK likes it so I guess it's not all bad

The "real world" efficiency of a wood stove is not hard to understand contrary to what many will have us believe. You have X amount of wood (fuel), capable of creating X amount of heat and there will be X amount of loss up the flue. You are right when you say, "the particulate test can be used to calculate the efficiency of energy extraction from the wood." But that has NOTHING to do with getting that heat transferred from the inside of the stove to the inside of the house. You are referring to efficiency like the EPA where only the particulate emitted is measured (and energy released calculated). I am only talking about heating efficiency which is how much heat energy is actually transferred to the inside of the home.

I stand by what I've stated in this thread. Woodstock is pushing the Ideal Steel as a super efficient stove and in the real world, it is not. Potential buyers should be aware that efficiency in that context has little to do with the amount of time the stove will actually heat their home. Don't you find it interesting that the Ideal Steel has a 3.2 cf firebox but yet most owners are reporting real world burn times of 10-14 hours? While owners of the Blaze King products with a smaller firebox (2.75 & 2.85 cf) are reporting TWO TIMES that amount. That is not an insignificant difference...that is HUGE. And to be clear, when I say burn times I mean burn times that actually heat the home. I know BrianK and others will get on here and debate that until the cows come home but it's difficult to debate facts. How in the world can there be such a big difference? Two words: HEATING EFFICIENCY.

I have zero interest in your Blaze King vs. Woodstock crusade, rather I find it tedious. My interest is in trying to cut through the confusion that surrounds stove operation, much of it caused by ill-used, incorrect and meaningless terminology.

The energy is stored in the wood in the form of carbon bonds. When you break those bonds you release the energy. There are only two places then energy can go - through the walls of the stove and into the living space through thermal conduction, convection and radiation, or up the flue (stack loss). Any modern stove of similar design will have a stack loss that is determined primarily by the size of the air inlet, which is adjustable. So if your theory is that one stove has a greater stack loss than another stove of similar design, then it must have a larger air inlet that can not be adjusted out (which would be easy to verify).

You are defining heating efficiency as the percentage of heat extracted from wood minus the stack loss. The amount of particulates (carbon bonds not broken) is a good measure of total energy extracted from the wood load, and the stack loss will be very similar between two stoves of similar type, so in fact two stoves that have similar particulate emissions will also have similar heating efficiency.

This whole heating efficiency and stack loss canard is the same argument WS was using to try explain where the heat went with secondary burn stove and why it didn't heat his home, but it didn't wash there either. The problem is not efficiency, it is the rate of heat output. When calculating the "heating efficiency" there is absolutely no time term involved, it is only about the magnitude of energy you get - even if you could make a stove that took a week to extract 99.99% of the energy of a load of wood and all of it entered the living space, you would still freeze to death because that is a very low rate of heat energy output.

If you are comparing two stoves of similar particulate emissions ratings, but one has a bigger firebox and holds more wood, then they will both have similar heating efficiencies, but one will have a higher heat output rate.

 

[BrianK]

 

[Ambull01]

View attachment 403269

Nice. I'm more and more impressed with England's Stove Works! An A+ rating selling in a big box store to what I assume would be less than knowledgeable wood burners.

 

[Chris-PA]

LOL - I've been very happy with my US Stoves Magnolia for at least 7 years now.

 

[zogger]

Red Mountain Majic Automatic No 122...still kicking out the therms after generations....cabin still warm just on a thin layer of coals from wood I chucked in earlier this morning, dog water bowls outside still frozen solid, I just checked. Not too many hours burn time with it, but...starts fast, throws heat like crazy with a few sticks and then some splits, and useable heat from a cold start literally within minutes, like 4-5.

Notice auxiliary toploading spiffyness, will fit a decent fat ugly for sure, drop one in at night, crank the air closed, let the door cracks feed it, stays warm, decent coals to restart it in the morning. In any sort of house with modern insulation it would be even better, this cabin is one leaky SOB.

 

[Ambull01]

Red Mountain Majic Automatic No 122...still kicking out the therms after generations....cabin still warm just on a thin layer of coals from wood I chucked in earlier this morning, dog water bowls outside still frozen solid, I just checked. Not too many hours burn time with it, but...starts fast, throws heat like crazy with a few sticks and then some splits, and useable heat from a cold start literally within minutes, like 4-5.

Notice auxiliary toploading spiffyness, will fit a decent fat ugly for sure, drop one in at night, crank the air closed, let the door cracks feed it, stays warm, decent coals to restart it in the morning. In any sort of house with modern insulation it would be even better, this cabin is one leaky SOB.

I thought that was a toilet for a second. Would be a nice warm seat.

 

[Marshy]

 

[Chris-PA]

I thought that was a toilet for a second. Would be a nice warm seat.

Me too, especially after the description: "will fit a decent fat ugly for sure, drop one in at night, crank the air closed...."

 

[Ambull01]

Me too, especially after the description: "will fit a decent fat ugly for sure, drop one in at night, crank the air closed...."

lmao. Needed that laugh.

 

[Idahonative]

You are defining heating efficiency as the percentage of heat extracted from wood minus the stack loss. The amount of particulates (carbon bonds not broken) is a good measure of total energy extracted from the wood load, and the stack loss will be very similar between two stoves of similar type, so in fact two stoves that have similar particulate emissions will also have similar heating efficiency.

Ok, I'm going to tell you straight up, I think that is complete BS. The Ideal Steel and Blaze King Ashford 30 have similar particulate emissions but the Ashford 30 will heat a home TWO TIMES as long on the same wood. Same thing with the Chinook 30 and the Sirocco 30. Heck, the Princess produces more than twice the particulate emissions as the Ideal Steel and the same can be said for it as well. All of these models hold LESS FUEL than the Ideal Steel.

People can debate this all day long but it doesn't change the facts. Explain that to me Chris. And I'm being completely serious. If I'm wrong about heating efficiency, then please explain to me how this is possible.