1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)

Catalyst vs Non Catalyst

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by ecolbeck, Jan 15, 2012.

  1. ecolbeck

    ecolbeck New Member

    Joined:
    Aug 25, 2008
    Messages:
    17
    Loc:
    Shelburne MA
    Greetings,
    I know that this topic has been discussed at length already and I am hoping that someone can point me towards and answer to this question. Non-cat stoves are designed to operate at high temperatures (to facilitate clean burning) with the help of an insulated firebox. Therefore, more heat must necessarily be going up the chimney and less out into the room. How then, can they be considered as efficient (in terms of actual heat output into the room) as catalytic stoves? I must say, that having used both a Jotul F12 and an F400, they are both great stoves, but I prefer the latter for ease of use and fire display.

    Thank you

    Helpful Sponsor Ads!





  2. HotCoals

    HotCoals Minister of Fire

    Joined:
    Oct 27, 2010
    Messages:
    3,357
    Loc:
    Rochester,Ny.
    Seems like you already answered your own question.
    Less air in..less air out.
    Some try to run a tube stove like a cat stove with varying results.
  3. ecolbeck

    ecolbeck New Member

    Joined:
    Aug 25, 2008
    Messages:
    17
    Loc:
    Shelburne MA
    Not sure what air has to do with it..... Not sure either how to run a secondary air stove like a cat stove....
    Mostly I was curious how proponents of secondary air stoves would answer my question. The point of a wood stove is to transmit heat into a room. An insulated firebox, while increasing overall efficiency, works against the principle of heat transfer.
  4. afptl

    afptl Member

    Joined:
    Dec 16, 2010
    Messages:
    135
    Loc:
    Northern KY
    Put me down as a Non cat fan. Experience has been the teacher on that one!
  5. SolarAndWood

    SolarAndWood Minister of Fire

    Joined:
    Feb 3, 2008
    Messages:
    6,770
    Loc:
    Syracuse NY
    That's not exactly right. Cat stoves can burn much lower than a non-cat of similar size and still burn clean. At high burn, the non-cat arguably has the edge on efficiency but they are pretty close. I also think the the non-cat does much better with less than perfectly dry wood than a cat stove. I bought a big cat stove so I could heat solely with wood from September to May without overheating the house and still have enough ooomph to keep the house warm in January. If that wasn't my sole goal, I would probably have a non-cat as they are a lot more entertaining to watch burn.
  6. SolarAndWood

    SolarAndWood Minister of Fire

    Joined:
    Feb 3, 2008
    Messages:
    6,770
    Loc:
    Syracuse NY
    If it hadn't been for a member here from the Yukon, I would have done the same because of a similar experience with two stoves from the same manufacturer as you. There are much better cat stoves out there that make fantastic 24/7 heaters if you are committed to having dry wood.
  7. HotCoals

    HotCoals Minister of Fire

    Joined:
    Oct 27, 2010
    Messages:
    3,357
    Loc:
    Rochester,Ny.
    Well now a days you can buy both in one stove.
    Progress Hybird.
    Check out the thread on it.
    Might just be the cats meow.
  8. ecolbeck

    ecolbeck New Member

    Joined:
    Aug 25, 2008
    Messages:
    17
    Loc:
    Shelburne MA
    Solar and Wood,
    I agree with what you said, however, I don't think that you refuted my point that "more heat goes up the chimney" with a non-cat stove. We have to discern the difference between "burning efficiency," the ability to efficiently turn wood into heat, and "heating efficiency," the ability to throw that heat into a room. How much does an insulated firebox on a non cat stove inhibit the latter?
  9. Hogwildz

    Hogwildz Minister of Fire

    Joined:
    Nov 3, 2006
    Messages:
    7,088
    Loc:
    Next to nuke plant Berwick, PA.
    Not sure how you arrived at your info, but non cat stoves do not need to be run at high temps for a clean burn(guess that depends on what "high" temps is to you). And I am not familiar with any that have an insulated firebox? I run mine at complete low air setting, so the least amount of air in = the least amount of heat up chimney. The more air you let in, then yes more up the chimney. That goes for any stove. You can always run less fuel for less heat also.
    Steel is steel, takes and transfers the heat similar between with a non cat as a cat. Can one brand or type release heat slightly better or differently? I am sure they can. According to BK owners, their stoves release heat more evenly with less of a curve. May be true to some extent, I look more to the temp rise or fall within the house itself. Which is usually steady for most the time, but as with any stove, as the fuel supply diminishes, the steel cools and the house will cool in time also. The debate is that cat stoves have longer burn times. This seems to be the case per reports from owners on the site here. Having a larger firebox also helps with burn times. As seems does the thermostat. Now you can't smolder wood in a non cat as you can in a cat, and burn cleanly, and that may be a benefit of the cat over non cat, as the cat burns the smoldering smoke/gases as it passes through, again hence the longer burn times. But at the expense of the low BTU's put out to extend burn time, I would not benefit from that here except for possibly in the shoulder season. I know whether a cat or non cat, 350 degree stove top temps, ain't heating this big place. May during the shoulder season, but not on the colder winter days and nights. When the temp drops the difference in the two diminishes. Size of firebox and type of wood burned makes a very big difference in the amount of heat and length of heat put out.
  10. rdust

    rdust Minister of Fire

    Joined:
    Feb 9, 2009
    Messages:
    3,866
    Loc:
    Michigan

    Who is testing the efficiency of these stoves? Brotherbart posted in a thread on the Progress that he wasn't aware of the EPA labs testing this and no one answered him. So I guess I wonder if the EPA is testing it or an independent.
  11. SolarAndWood

    SolarAndWood Minister of Fire

    Joined:
    Feb 3, 2008
    Messages:
    6,770
    Loc:
    Syracuse NY
    The BK has two rows of firebrick on the bottom and one half way up around the sides. I have the Ultra that also has side panels on the sides and back. I assume you have seen the marketing ploy where you can put your hand in the pipe while its running. Guaranteed you wouldn't be able to do that at high burn without losing some flesh. One of the permanent heating solutions I have considered is two Kings side by side so that I can always be running them in the sweet spot. Now, if you don't have a high heat load, that might not be an issue for you anyway. From what I have read here, I push the stove a lot harder than most.
  12. SolarAndWood

    SolarAndWood Minister of Fire

    Joined:
    Feb 3, 2008
    Messages:
    6,770
    Loc:
    Syracuse NY
    Especially when its cold, the wind is blowin and you have a high heat load. Moisture content also becomes a real big factor. My stove puts out half with less than ideal wood than perfectly dry.
  13. HotCoals

    HotCoals Minister of Fire

    Joined:
    Oct 27, 2010
    Messages:
    3,357
    Loc:
    Rochester,Ny.
    You have it right imo..all of it.
    If I can add to your post

    My box is so big I only load half as much as smaller stoves...that saves from firing the stove higher to get to temps half as much.
    The box on the BKK can hold a ton of ashes that can be burned for hours on high.
    I been burning coals(ash wood)) down for 3 hours now and my house is really warm..76f in the next room and it's like 10f out..no wind.
    I truly believe most of the magic is the size of this thing and a properly sized very effective cat.
  14. Hogwildz

    Hogwildz Minister of Fire

    Joined:
    Nov 3, 2006
    Messages:
    7,088
    Loc:
    Next to nuke plant Berwick, PA.
    Not being nitpicky, but think you meant the King can hold a ton of "coals"?
    I do like how deep the firebox is.
  15. ecolbeck

    ecolbeck New Member

    Joined:
    Aug 25, 2008
    Messages:
    17
    Loc:
    Shelburne MA
    Hogwildz,
    Check out this link (not the best).

    http://www.woodstoveinsertsblog.com...serts-and-catalytic-vs-non-catalytic-burners/

    It describes non cat fireboxes as insulated. I have seen this many places. I have three thermometers on my stove set up (don't ask why). On is on the stack, one is on the stove top (per manufacturers instructions) and on is on the side. the side of the stove is VERY slow to heat up and never comes close to matching the temps on the stove top. I used the same setup on my former stove (cat stove) and not surprisingly the reverse was true, the side thermometer (near the cat) far exceeded the temps on the stove top.
  16. HotCoals

    HotCoals Minister of Fire

    Joined:
    Oct 27, 2010
    Messages:
    3,357
    Loc:
    Rochester,Ny.
    Yep..no clue why I typed ashes. Other then my fingers getting ahead of my brain..it happens..lol.
    Probably I was thinking burning the coals to ashes but left most of it out.
  17. Hogwildz

    Hogwildz Minister of Fire

    Joined:
    Nov 3, 2006
    Messages:
    7,088
    Loc:
    Next to nuke plant Berwick, PA.
    They should have worded it better, but what your reading as insulation, I believe is the brick lining inside the firebox, and both cat & non-cats have this. Older pre EPA stoves, some had bricks, some did not.
    Non cat stove and cat stoves.....neither are insulated.

    Edit: Some baffles are insulated such as mine, but the firebox itself is not.
    Easy way to show my point, which you can do, as I have enough times...is pick a few non cat makers, and look at their parts lists in the manual. The only insulation you will find is for baffles &/or maybe rails. Not the firebox. Yes your question and reasoning of why would they insulate the firebox as it would impede heat transfer. Your correct, it would, thus the firebox not being insinuated.
  18. ecolbeck

    ecolbeck New Member

    Joined:
    Aug 25, 2008
    Messages:
    17
    Loc:
    Shelburne MA
    The brick lining is acting as an insulator. Try these links from for info on insulated fireboxes:

    http://hearth.com/econtent/index.php/articles/choosing_and_using_wstove
    http://woodheat.org/how-epa-certified-stoves-work.html

    also this info quoted from Morso.com

    "How much ash should be left in the stove?

    Keep a 1" thick layer of insulating ash. The ash layer insulates the bottom of the stove in the same way as the fire bricks or vermiculite board on the sides of the stove. This ensures a high combustion temperature which contributes to a cleaner more efficient burn."
  19. HotCoals

    HotCoals Minister of Fire

    Joined:
    Oct 27, 2010
    Messages:
    3,357
    Loc:
    Rochester,Ny.
    The BKK has heat shields spaced out a inch or so on the sides and the back,above the firebrick.
    Seems strange but there maybe to protect the outer shell?
  20. Hogwildz

    Hogwildz Minister of Fire

    Joined:
    Nov 3, 2006
    Messages:
    7,088
    Loc:
    Next to nuke plant Berwick, PA.
    You can post as many articles as you wish. There is NO insulation surrounding a fire box, cat or non cat, period. There is brick in both cat & Non cat, which lines the bottom and about 1/2 or lower portion of the walls and back of the firebox. This both helps to insulate to some degree to keep a more steady temp inside the firebox, and to transfer that heat to the steel shell. I don't care what that article says. The stoves I have do not have an insulated firebox as the way your thinking. There is no insulation wrapped around, under or on top of the firebox.

    BOTH cats & non cats use firebrick. BOTH cats & non cats suggest 1" layer of ash on the bottom both to help keep the inside of the firebox at a steadier warmer temp. Again BOTH cat & non cats have this, so what is your point? You originally stated that the non cats had an insulated firebox as opposed to the cats. Both have bricks & both suggest ash in the bottom. No differential there.

    "Firebox insulation or lining that keeps temperatures high" This is the bricks, and yes they
    insulate to a degree....and both type stoves have them.

    Research is one thing, but you are way over analyzing this one.
  21. ecolbeck

    ecolbeck New Member

    Joined:
    Aug 25, 2008
    Messages:
    17
    Loc:
    Shelburne MA
    Quote: "You can post as many articles as you wish."

    Just trying to further the discussion.....

    Quote: "There is NO insulation surrounding a fire box, cat or non cat, period."

    Then why is it mentioned in the articles?

    Quote: " This both helps to insulate to some degree to keep a more steady temp inside the firebox, and to transfer that heat to the steel shell. "


    Bricks cannot simultaneously insulate AND transfer heat. Its a contradiction in terms.

    The fact that both stove types have firebricks doesn't mean that non cat stoves don't have insulated fireboxes.
  22. Hogwildz

    Hogwildz Minister of Fire

    Joined:
    Nov 3, 2006
    Messages:
    7,088
    Loc:
    Next to nuke plant Berwick, PA.
    NEITHER CAT, NOR NON CAT STOVES HAVE ANY INSULATION AROUND THE FIREBOX, PEROIOD!
    The only insulation you are referring to is FIREBRICK! BOTH STOVES USE IT! BOTH STOVES MANUFACTURERS SUGGEST ASH ON BOTTOM!

    Yes the brick holds temp, and transfers heat to the steel shell also. How hard can that be top realize? Not contradictory, fact! They don't "Insulate" as your thinking. They absorb and retain heat to help keep the firebox temp and help buffer the steel shell from direct exposure to very high firebox temps. Some stoves even use heat shields on the top of the stove inner, such as my Summit and other PE stoves, and many others, and some like Hot Coals has a shield above the brick. The bricks release the heat at a slower rate than the steel does, therefore helping keep firebox temps up. The heat does transfer to the steel shell. Put your hand against the side of a stove when it is hot, down around the bottoms of the sides where the brick are, and tell me how much those bricks are "insulating" the heat from the steel. I suggest having some burn cream and aloe hand, cause your going to need it!

    My insert is set into a brick fireplace, the bricks from the fireplace absorb and retain the heat, and also transfer to the home. Even after the fire is out or cooling down, the bricks release heat for a very long while. Masonry heaters are built for this purpose on a MUCH larger scale and MUCH better heat retention & release. Helps keep the area around the stove warm while burning, yet releases it to the area around it long after the fire is out. Similar to the bricks inside the stove.

    Here is the one link you sent, look at the pics of the non cat and cat. The only difference is the non has 1 air control. The cat has an air control and a bypass. The non cat has a secondary burn system, the cat has a cat. BOTH have firebrick. So even if you want to consider that insulation, then both the non cat & cat are "Insulated". Other than the firebricks, there is NO INSULATION on either type stove! If there was insulation on a cat or non cat, why would they not show it on the pic?
    Now go search the hell out of the internet or photoshop some insulation into a cutout view of a stove and post it here, then I still won't will accept your view of "insulation".

    http://woodheat.org/how-epa-certified-stoves-work.html
  23. HotCoals

    HotCoals Minister of Fire

    Joined:
    Oct 27, 2010
    Messages:
    3,357
    Loc:
    Rochester,Ny.
    Think of the fire bricks as a "buffer" if you will.
    They absorb high temps when you first light the stove off then latter equalize somewhat to the inside stove temps.
    In doing so they help protect the shell from warping and to keep the shell temps down some.
    They also help to radiate heat back to the fire for a better..cleaner burn.

    I think some stoves have insulating board above the burn tubes...and some have a insulating blanket also.
    Maybe that's what you're reading about..dunno.
  24. n3pro

    n3pro Minister of Fire

    Joined:
    Aug 24, 2008
    Messages:
    553
    Loc:
    Enola, PA (near Harrisburg the unknown Capitol.
    That's how I see it too. My stove is basically a steel stove inside a cast iron shell. Similarly, the steel heats up much faster then the cast iron, but the cast iron will stay hotter longer then the steel. When my stove is heating up the steel can reach 650 while the cast iron is 300, then when the steel part drops to 300, the cast iron can be 400.

    Same way with the firebrick IMO.
  25. HotCoals

    HotCoals Minister of Fire

    Joined:
    Oct 27, 2010
    Messages:
    3,357
    Loc:
    Rochester,Ny.
    I sure like the looks of some of those cast iron stoves!
    Mine aint purty. lol

Share This Page