Experience with catalytic wood stoves

[m7040]

Considering updating our wood stove to a Vermont Casting or Woodstock soapstone stove using catalytic combustion. Using an older non catalytic Jotul stove at the moment and it works fine but uses a lot wood and is not quite big enough on cold days. So we would consider upgrading to a larger and latest design wood stove. The Jotul is easy to operate and will burn anything we put in it but has to be tended to often to keep it going. Was wondering about your experience with medium size Vermont Casting or Woodstock stoves. Precautions to protect the catalytic converter, start ups, maintaining the fire, extended burns during the night, ash removal, savings in wood burned compared to older stoves, any other comments you would care to share with us?

 

[jpolcyn]

I can not speak of the brand you are talking about but i run a catalytic stove in my home. So i will give you my experiences.

1. you need a thermostat on the stove because cataytic will only work once stove is over 450deg.

2. Replacing the honeycomb is EXPENSIVE.

I have since quit using the catalytic as i have found it to be easier and see no real difference in just using a damper in the pipe.

They say they are more efficient but i just do not see it.

 

[CobyRupert]

Following thread.
My understanding is a catalyst stove burns more of the wood gases that would otherwise go up the chimney.
Does this create lease creosote in the chimney?
Does it extract more heat and make stove more efficient so you burn less wood? (Above commenter says not really… but if you’re burning gas that would otherwise be wasted..?)
Does it make exhaust cooler? That is, is more heat extracted, or does stove have to be so hot for catalyst to operate that it’s hard to tell?

 

[ponytug]

Following thread.
My understanding is a catalyst stove burns more of the wood gases that would otherwise go up the chimney.
Does this create lease creosote in the chimney?
Does it extract more heat and make stove more efficient so you burn less wood? (Above commenter says not really… but if you’re burning gas that would otherwise be wasted..?)
Does it make exhaust cooler? That is, is more heat extracted, or does stove have to be so hot for catalyst to operate that it’s hard to tell?

The idea, stress on idea, is that the catalyst is able to burn (oxidize) more of the combustion gases, so what goes up your chimney has less unturned organic, aka creosote, in it. That makes it more efficient (more heat from the wood) and cleaner burning. However, until the catalyst is up to temperature, it is just a normal, double combustion stove. As @jpolcyn points out, you need to get the catalyst to temperature and keep it there, and not overheat heat it by over fueling the stove at full draft. So, it takes a tiny bit more attention to look after one, but once you get the feel for it, it is easy, I think.

Some other brands use straight metal catalysts, which are somewhat cheaper to replace. We looked at getting a Princess until our homeowners' insurer nixed the idea, as it had to be dealer installed, and no dealer was willing to travel to where we are. Classic catch22.

All the best,

Peter

 

[joeyd]

I have a Woodstock Soapstone stove and I love it for the warmth and looks. The catalytic converters seem to be the wave of the future with all the hoo-haw over climate change. I foresee a ban on non catalytic stoves if things continue on.
You can burn with or without the converter, the stove has to be hot enough to re-burn the gasses. The temp required to switch over may vary with manufacturers but I can switch over at 250 degrees external which I think is 500 internal. (I switch at 275). Often we will have a small fire just to take the dampness out of the house on rainy days and never use the converter. We burn just under 3 cords a winter so I cannot really tell you if it saves wood or not. I burn a mix of hard and soft wood from my property so it is always varies year to year how much we go through.
I replace the ceramic converter with a stainless steel one and it was not very costly around $150. I do not have to worry about the ceramic coating now.
As far as creosote build up I think that has more to do with volume burned and fuel moisture. Intuitively I think the less carbon in your smoke the less build up but the more you burn you get the picture. Woodstock has a great web site that answers many of your questions.

 

[Doughknob]

I have had stoves and furnaces, but never one with a catalyst. However, I have always understood that the catalyst was mainly for "emissions reduction." The main purpose of a catalyst stove is Not to provide for a user burning less wood.

As others have said, it "MAY" add a little more heat per log, but not noticeable. I do think Vermont Castings make quality stoves.

I have heated my whole houses with wood for 23 years and find that it does indeed take a lot of wood to do so all winter. I go through, on average, 3 cords per season.

 

[Snobdds]

On my Blaze King, the catalyst works good. It burns the smoke, which has a lot of energy still left in it.

The key is to burn very seasoned wood. If your always burning marginal quality wood and not very seasoned wood, you will struggle with it. I have reburn tubes on the stove at my cabin, and it too works good. The wood quality can be a little bit less picky.

I get longer burn times with the catalytic stove. I have yet to replace the catalyst on the stove and it's at least 7 year old now.

The biggest problem for me and my elevation is oxygen. These new stoves are tight and are not made for 6,000+ ft elevation and the lack of oxygen. I always have to keep the doors open to get a hot burn.

 

[arizona98tj]

I find it interesting, such as in this thread, concerning the amount of wood used during a heating season. Rarely does anyone ever comment on the status of their house. How many square feet, how much insulation, the quality of the windows, wall thickness, how many cold days (ie., -30F to -40F), quality of wood, etc. Yet, people state they burn XX cords of wood per heating season but is it the stove's fault or is it the house. You can put a top dollar high-efficiency stove in a poorly built house and still burn just as much wood.

For example: I live in a 6 year old house that was built for Northern Minnesota. That means 6" walls, good insulation, good windows, etc. We see many sub -30F days during the heating season. We get great solar gain from our southern windows assuming it is not cloudy. I can't begin to run our wood stove all day long as it would get far too hot. I burn 1.5 to 2 cords of mixed (poplar and oak) per season to keep our 1100 sq ft house warm. The wood is stored in a wood shed and is typically 2 or 3 years seasoned before it sees our stove. Our wood stove is as old as the house.

I'm not trying to stir the pot here but it seems that some of the very important things that are important to the discussion are often left out.

 

[Snobdds]

I find it interesting, such as in this thread, concerning the amount of wood used during a heating season. Rarely does anyone ever comment on the status of their house. How many square feet, how much insulation, the quality of the windows, wall thickness, how many cold days (ie., -30F to -40F), quality of wood, etc. Yet, people state they burn XX cords of wood per heating season but is it the stove's fault or is it the house. You can put a top dollar high-efficiency stove in a poorly built house and still burn just as much wood.

For example: I live in a 6 year old house that was built for Northern Minnesota. That means 6" walls, good insulation, good windows, etc. We see many sub -30F days during the heating season. We get great solar gain from our southern windows assuming it is not cloudy. I can't begin to run our wood stove all day long as it would get far too hot. I burn 1.5 to 2 cords of mixed (poplar and oak) per season to keep our 1100 sq ft house warm. The wood is stored in a wood shed and is typically 2 or 3 years seasoned before it sees our stove. Our wood stove is as old as the house.

I'm not trying to stir the pot here but it seems that some of the very important things that are important to the discussion are often left out.

Well, it would only subtract from the conversation to get bogged down in details. It's easier to just assume a house has adequate insulation for it's climate.

 

[deserteagle71]

Google "Blaze King wood stoves", that will provide you with answers to most of your questions regarding operation of a catalytic convertor stove.

My house came with an "Earth" brand wood stove - non catalytic convertor. It was very pretty - but like yours, had to be tended constantly and didn't put out that much heat. So in 1995 I bought a Blaze King - only because that's what the local hardware store carried. LOVED the stove - it proved to be a great investment. But a couple years ago I had to go to a pellet stove, only because firewood is almost impossible to get where I live in northern Nevada. I was having to drive 250 miles (one way) to Oregon for firewood and then even that source dried up.

As I said, I loved using the stove (used it for 24 years) - I much preferred using it compared to my current pellet stove. After two years with the pellet stove I still can't get used to having the sounds of fans running constantly. Yes, it takes electricity to run a pellet stove - so when the power goes out, unless you have a generator you have no heat. The Blaze King was totally silent and put out constant heat - unlike the pellet stove which turns on and off via thermostat.

Using a catalytic convertor stove is not that much different than using a regular stove. You build a hot fire to let the heat and fumes ignite the catalyst. Then you turn down the air control depending on how much heat you want the stove to put out. The important thing to remember with a catalytic convertor stove is that you can't be burning all your unwanted trash in the stove as certain things will plug up/destroy the catalytic convertor. Wood or clean paper only! These stoves put out essentially no visible smoke once the catalytic convertor ignites. Very little creosote buildup in the stovepipe - I cleaned my chimney only twice a year just to be on the safe side - because the creosote is also burned by the catalytic convertor. Ash depends more on the type of wood you burn - I burned mostly juniper (cedar) because that's what grows wild around here - and had to empty ashes only about once a month. On the other hand, if I burned elm that produced a lot of ash I'd have to empty ashes every couple weeks. The catalytic convertor will have to be replaced at some point. I changed mine after 18 years.
This is my Blaze King, a year before I replaced it with the pellet stove:

This is a photo of the catalytic convertor glowing up inside the top of the stove (hard to see and photograph!):

There is a thermometer in the top of the stove. Note that it is pointing at 1300 degrees. You'll see no flames in the stove once the catalytic convertor is lit and you turn down the control. The catalytic convertor will be providing all the heat as it burns the vaporizing wood fumes.

Can't speak for other stoves - but with the Blaze King I would build up a good hot bed of coals, then shove in a large piece of wood and turn down the control. That would last a good 12 hours of keeping my big house at 70+ degrees. Blaze King claims up to 40 hours of heat on one loading of wood if the control is turned down to low heat. This is a shot of my firewood at the time - logs ~ 18" in diameter split in half, 16-18" long, fit in the door of the stove easily.

Bottom line is this. If I could find an affordable, accessible supply of firewood I would yank my pellet stove and put the Blaze King back in. I'm nearly 80 years old now and had wood heat all my life except for the past two years with a pellet stove. The Blaze King is by far the best, the most efficient wood stove I've ever used. Not saying other brands aren't as good - no experience with other catalytic convertor stoves so I can't comment on them.

 

[jigs_n_fixtures]

I have an old Blaze King, I replaced the catalyst when I bought the house 17-years ago. I cant remember how much it cost. I was at one of the stores in town looking at replacing it, and teh store had sold he one in the house to the previous owner.

They came out and replaced the catalyst and three of the bricks. What they told me was to get it burning with the door setting on the bumpers which come out before the catalyst gets hot enough, and you switch over. Load it full, and leave it alone.

Mine has a bimetal thermostat on teh inlet air, and self dampens. It gets too hot the damper closes, too cold the damper opens. I figured out that it could be plumbed for ducted intake air, so I installed a duct through the outside wall, and it gets all of the combustion air from there, instead of sucking cold air into the house.

The trick with the catalyst stoves is get them burning and don’t open the door, until it burns down. Every time you open the door you cool off the catalyst. Open the door too often and you will coat the catalyst to the point it quits reacting. One of the guys who used to work for me said that he, his Dad, and his Sister all bought them at the same time. He read the instructions and would pack his full of wood get it up to temp, then shut the door until it completed the burn. His Dad and Sister would half load theirs, then open it every hour or so, and throw more wood in. He had the same catalyst in his that it had come with about nine seasons before. He had replaced them for his Dad and Sister several times each.

Mine is in the upstairs at my place about heating about 1300-sf. If I stoke it up before I go to bed at about 2200, and turn it down for the night, it is still hot when I get up around 0730. I restoke it and get the front of the house warmed up for breakfast, and then turn it back down before I leave for the day. I let it burn out Saturday mornings, because the air inlet is at the back bottom, and I need to get the ash out to keep it clear. Is it generating more heat per amount of wood, than a regular stove? I can’t say. It does do a good job of keeping a regulated heat, without getting too hot, and then too cold, and I get fairly long, (8 to 12-hrs), burns out of it. The outside combustion air ducting, and the thermostatic damper make a large difference in my mind on how well it works.

Mine is about twice as big as Blaze King recommended. But the Gal I bought the place from wanted one that was really big. When I was getting ready to close I’d tell people at work, what I was buying, and they would all ask me if I knew she was crazy. So, she frequently did things out of the norm.

She painted the entire downstairs in life size salmon and steelhead.

 

[Ken45101]

I don't have a cat stove but I remember why I made that choice:
1) more finicky on startup
2) eventually you have to replace the cat element ($$$)

Instead we bought the Pacific Engineering Summit model, an "EPA approved" stove.

Clean burning? YES! I visually watched the very top of the chimney and it never seemed to need cleaning. Finally after 7 years I called a chimney sweep. He took the cap off, looked down the chimney and told me there wasn't enough to warrant cleaning but I had him do it anyway. After another 5-7 years I had our roof replaced and asked the roofer to check it while he had the chimney apart Same response, very clean chimney!

I feel I made the right decision.

Ken

 

[Larry Caldwell]

I don't have a cat stove but I remember why I made that choice:
1) more finicky on startup
2) eventually you have to replace the cat element ($$$)

Instead we bought the Pacific Engineering Summit model, an "EPA approved" stove.

Clean burning? YES! I visually watched the very top of the chimney and it never seemed to need cleaning. Finally after 7 years I called a chimney sweep. He took the cap off, looked down the chimney and told me there wasn't enough to warrant cleaning but I had him do it anyway. After another 5-7 years I had our roof replaced and asked the roofer to check it while he had the chimney apart Same response, very clean chimney!

I feel I made the right decision.

Ken

Catalytic stoves are rare around here. I don't know of anyone who sells them. The EPA certified stoves with reburn chambers own the market, probably because they work. They have a lower initial cost and don't require expensive maintenance.

 

[ericm979]

My non catalyst EPA stove burns very clean with no visible smoke once it's going. Down wind you can barely even smell it. The drawback to the non catalyst stoves is that you can't turn them down really low for a long burn like you can with catalyst stoves. They need a certain amount of air to keep the secondary burn going. People with large Blaze Kings boast of 24 hour burn cycles. Mine's more like 6.

With an EPA stove you get more BTUs out of the wood than with an older type stove because burning the smoke makes more heat. They do like dry wood though. Some of my wood needs two years to dry before it burns well in my stove but most of the species I have only need one or just a summer.

 

[Larry Caldwell]

My non catalyst EPA stove burns very clean with no visible smoke once it's going. Down wind you can barely even smell it. The drawback to the non catalyst stoves is that you can't turn them down really low for a long burn like you can with catalyst stoves. They need a certain amount of air to keep the secondary burn going. People with large Blaze Kings boast of 24 hour burn cycles. Mine's more like 6.

With an EPA stove you get more BTUs out of the wood than with an older type stove because burning the smoke makes more heat. They do like dry wood though. Some of my wood needs two years to dry before it burns well in my stove but most of the species I have only need one or just a summer.

I have my fingers crossed. I cleaned out my wood shed and only have a few days firewood left, in a shed that holds 6 cords with room for a splitting stump. Some of the last wood is stuff I cut 20 years ago, buried in 4" of bark and dirt. It will be great to shovel out the shed.

Last winter's snowmageddon put about 4 cords of hardwood branches on the ground, which is all cut and stacked in single ricks to dry this summer. Because they were branches, over half the firewood is rounds. Rounds are great for long burning fires, because the natural geometry of the limb is fire resistant, but they are hard to dry. Splits dry much faster. I'm hoping 90 degree days with single digit humidity will get me there, but you make me nervous. Your area is pretty dry.

If you want a long burning fire, buy a big firebox. My stove will take a couple 10" x 20" hunks, which can burn hot all night and still leave a nice bed of coals in the morning.

 

[ericm979]

We get a good amount of rain- 45 inches a year is the average. We got less last year and this year. But it's in about 5 months of winter, 6 at most. The rest of the year there's no rain at all.

Madrone and Tan oak dry well enough to run in my stove over one summer. Eucalyptus (blue gum) takes two years. It's super dense and hangs on to its water.

 

[m7040]

Thanks for all the comments. The web sites for the manufacturers of stoves all describes their performance in glowing terms. The comments here are from real experiences that is a whole lot more useful.
Our 1800's farm house is part log cabin and brick and has virtually no insulation so it takes a lot wood. We use the old Jotul in the living room and have a larger wood/oil fired in the basement that can heat the house via forced air circulation. We use close to 10 cords a year to keep it comfortable. The Yukon furnace in the basement eats wood like there is no tomorrow with a large firebox. Most of the time we will only use the Jotul stove but we keep it up on high heat output which require feeding it often. It mostly burns out overnight. Seems like a catalytic wood stove would provide longer burns

 

[CalG]

A couple seasons back, we sold the Vermont Castings Reliant and replaced it with a HearthStone Castleton Model 8030 NON- catalyst.
We have been quite pleased with this Soapstone heater so far. Love the look of stone! Those Flame faireys are a pleasure to observe through the glass front. The glass stays clean with a hot burn , coats up when shut down, even with multi year dry maple.

Looking at this thread, I dug a bit deeper into stove options, comparing this 8030 with the newer 8031 Cat version.

Both stoves are spec.ed at 45,000 btu max output.

The 8030 is speced at 2.7 grams/ hour emission. the 8031 at .7 grams per hour
Efficiency for the 8031 was given as 77%, I didn't find the value for the 8030 in the literature.

BIG difference in BURN TIME

the 8030 , non- cat. 8 hours
the 8031 Cat fitted, a whopping 20 hours!

I certainly would be curious as to the heating capabilities of the cat equipped stove at such extended burn times.

Our downstairs stove is a brick lined sheet steel Fischer stove that takes wood up to 30 inches long. When that firebox is filled, It makes great heat for about ten hours, after that, it sort of "self banks" under it's own ashes and holds "warmth and coals for well over 24 hours, Close to 36. That with the air controls backed out less than 1/4 turn. When it's cold, I like this stove! Of course, wood variety and load fill have a lot to do with burn times.

As for the our experience with the HearthStone. The fire box holds three splitter run pieces of 16 inch length.
Loaded at night (10:00) It still has coals enough to get things going come morning. And the house stays 68 at worse. Too warm upstairs. (we run a ceiling fan constantly in winter. At a burn rate enough to keep the secondary air jets "lit", Burn time between refills is likely 4-5 hours tops. Sometimes I just throw a single fresh piece on a good coal bed to keep things moving. That gives a couple hours . These side seasons are the hardest. It's 46 degrees outdoors just now. The Parlor stove has a fire in the box. Glowing coals, a nice warmth on my backside. I don't think I'll load it tonight. I sleep better in cool air.

eta

Just a note of interest (to me anyway) Comparing fuel wood heat output by cord measure (volume) is pure foolishness.
Compared by WEIGHT, All wood has about the same heat content. in fact, the softwoods are bit above the hardwoods. Just make sure the fuel wood is DRY. ;-)

 

[otlski]

We had a Vermont Castings Defiant Encore for 15 years. Glad it's gone. The stove was finicky, tricky, high maintenance, and once you messed up once, the cat would partly stop functioning, eventually need to be replaced, and put a lot of creosote up the chimney in the meantime.

Essentially, you had to only engage the cat at a certain flue temperature. In the wee hours, when the stove burned most its fuel, the cat would still be engaged while you slept but be well below optimal temperature. This degraded the cat to partial functionality. Thus the soot.

One time the stove overfired. The bolted, gasketed, fitted, cast iron structural parts warped (very slightly) permanently, but enough that the stove had many small air leaks. This promoted more overfiring and put the stove outside its cat-function parameters. Had to reseal the stove several times. The stove also had bimetal air shutters which stopped working shortly into ownership.

I replaced it with a Quadrafire which uses air tube reburn instead of the cat. It is easy to run, very reliable, uses less wood, and puts out less creosote.

 

[wesmann]

I like my VC 1945. I have a catalytic monitor. Once the cat is lit I watch tHe monitor. With a well lit load the cat temp goes to about 1200. When it drops to 800 I know it’s time to add fuel. I have good coals in the morning and the top loading makes life easy.