what is the big differenece

[dr.drew]

Well I went looking for a wood stove today, and the sales person showed me two kinds of stoves. One that had a non catalytic system, and the other one did . I am not sure if there is a big difference.

 

[tickbitty]

There are tons of debates on this here. Just do a search and you will see it comes up a lot, here's one of the recent ones
https://www.hearth.com/talk/threads/46794/
I think both or either kind has it's advantages and no matter which kind people here prefer, I think most respect that there are great cat or non cat stoves. Now mention which stoves you are looking at specifically and folks are sure to weigh in.

 

[Pagey]

The difference is in how they burn the volatile gases released during the primary combustion of the wood. A catalytic stoves uses a ceramic honeycomb treated with special metals that cause the volatile gases released by burning wood to combust at around 500F. A non-cat stove uses preheated secondary combustion air to cause the smoke to combust at around 1,100F. Most non-cat stoves use a series of burn tubes and a refractory baffle in the top of the stove to introduce preheated combustion air to reburn the smoke.

Each have their advantages and disadvantages. Cat stoves are known for their long burn times and perhaps somewhat more even heating cycles. Cats have to have the ceramic honeycomb replaced after several years of use, but baffle components in non-cat stoves degrade due to the high heat, so that may be a wash. Cat stoves MIGHT technically need a little drier wood to perform their best. Some claim that cats have a bigger learning curve for learning/ease of operation, but others say it isn't so.

Both are proven technologies, so go with what works best for YOUR home.

Read about halfway down this page: (broken link removed to http://www.woodheat.org/technology/woodstoves.htm)

 

[ControlFreak]

Well I went looking for a wood stove today, and the sales person showed me two kinds of stoves. One that had a non catalytic system, and the other one did . I am not sure if there is a big difference.

Dr. Drew:
There is a huge difference. Relative to cat vs non-cat, just keep this in mind: A cat stove is a much more complex stove to operate, because you will be responsible to identify the proper time to close the bypass damper to direct the exhaust through the cat, and for ensuring that the cat stays lit. Also the final combustion takes place behind "closed doors" in the catalytic element rather than in the main firebox. That is, if you run the stove on its lowest setting, you will have little or no fire in the main firebox while the catalytic combustor burns up all the smoke. This means that the fire that you observe through the glass will be more active with a non cat stove. The glass with a cat stove will tend to get covered in creosote, while a non cat will tend to have clean glass. Given that you are a new wood burner, get the non cat stove. I consider the cat stoves to be for those who have advanced knowledge of wood burning and are willing to go through the extra effort required to make them run well.
Dan

 

[John_M]

dr.drew, check out this helpful and informative link: (broken link removed to http://www.chimneysweeponline.com/hocats.htm)

Good luck,

John_M

 

[Backwoods Savage]

Dr. Drew:
There is a huge difference. Relative to cat vs non-cat, just keep this in mind: A cat stove is a much more complex stove to operate, because you will be responsible to identify the proper time to close the bypass damper to direct the exhaust through the cat, and for ensuring that the cat stays lit. Also the final combustion takes place behind "closed doors" in the catalytic element rather than in the main firebox. That is, if you run the stove on its lowest setting, you will have little or no fire in the main firebox while the catalytic combustor burns up all the smoke. This means that the fire that you observe through the glass will be more active with a non cat stove. The glass with a cat stove will tend to get covered in creosote, while a non cat will tend to have clean glass. Given that you are a new wood burner, get the non cat stove. I consider the cat stoves to be for those who have advanced knowledge of wood burning and are willing to go through the extra effort required to make them run well.
Dan

Wow!! I can tell Dan has heard some stories....that just are not true. Sorry Dan, with all due respect, I have to disagree pretty strongly with your information as I see this sort of thing every now and then. Most usually by someone who sells stoves without cats.



When we were in the market for a new stove a couple years ago I too had heard stories about those danged cat stoves and without even checking further, we had our minds made up to stay away from those things. However, long story short is that we ended up actually buying a cat stove.....and have not been a bit sorry for it. In fact, if I were to buy another stove today it would look at another cat stove.


1. Cat stove is complex to operate. Right... They are so complex that a child or even my wife can easily overcome this so-called complexity. Please allow me to explain:

Whenever you load any stove with wood and get the fire going, you have the draft set on full, no matter what kind of stove you have. Before you open the firebox door, you open the draft full.

Actually, most times you already have that draft on full open to finish off the last load you put in. So, when we go to load our stove, it really amounts to moving one lever from the up position to the down position. Excuse me, is this complex?

After loading the stove, one leaves the draft open to insure the wood gets started burning good before partially closing the draft. Now let's add the complexity of a cat stove. When turning down the draft, you at the same time move that little lever (which is right next to the draft lever on ours) from down to up. Excuse me, is this complex?



2. Ensure the cat stays lit? I've never heard of that one! Once that little lever gets moved from the down to the up position, it does not get touched again until it is time to reload the stove.


"Also the final combustion takes place behind "closed doors" in the catalytic element rather than in the main firebox. That is, if you run the stove on its lowest setting, you will have little or no fire in the main firebox while the catalytic combustor burns up all the smoke. This means that the fire that you observe through the glass will be more active with a non cat stove."

You are correct in that the final combustion takes place in the cat, but no closed doors. If you run the stove on its lowest setting, that does not necessarily mean you won't have fire in the main firebox. On the contrary, that can be when you get the best flame! Sometimes you will not get flame on a low setting for sure, but that need not be. If you want to watch flame, there is no problem at all. We have our stove both ways. I can dial down to not get any flame....but that will not stay that way for long as the secondary combustion does kick in and give a beautiful rolling flame. Or I can set the draft so there is a good flame in the firebox for viewing and extra heat. The nice thing is I have a choice in which way I want it to burn.




Now this one really gets me.....

3. "The glass with a cat stove will tend to get covered in creosote, while a non cat will tend to have clean glass."

Whoa! I'm not sure how you got this information but I can assure you it is entirely untrue. In fact, with a cat stove your glass will probably stay cleaner!

Our glass did turn black once. That is when the stove was new and we were doing the burn-in. After a good fire it cleaned itself and we have not gotten any black or creosote on our glass. None. Zilch. Nada.




4. "Given that you are a new wood burner, get the non cat stove. I consider the cat stoves to be for those who have advanced knowledge of wood burning and are willing to go through the extra effort required to make them run well."

That advanced knowledge boils down to turning that little lever one direction or the other. No other "extra effort" is required, except for cleaning the cat occasionally.

So here is one extra step with the cat stove. Usually twice during the winter we'll have a warm day or two. Yesterday was our warm day (44 degrees for high) so we almost let the stove go out. Good time to check the cat. Here is what I did:

Open the top door of the stove. With gloves on, reach in and lift out the cat. (one handed). Take cat outside and with an old paint brush lightly brush off white fly ash. Set cat back in stove, close lid. Time required? I was a little slow yesterday and it took me around 3 minutes if I remember right. Usually only 2. Hard to to? No. My wife can do it and so could a child. After closing the lid, a couple pieces of kindling got the fire going without the help of a match.

More in next post as apparently I've used up the space allowed.

 

[BrowningBAR]

The difference is in how they burn the volatile gases released during the primary combustion of the wood. A catalytic stoves uses a ceramic honeycomb treated with special metals that cause the volatile gases released by burning wood to combust at around 500F. A non-cat stove uses preheated secondary combustion air to cause the smoke to combust at around 1,100F. Most non-cat stoves use a series of burn tubes and a refractory baffle in the top of the stove to introduce preheated combustion air to reburn the smoke.

Each have their advantages and disadvantages. Cat stoves are known for their long burn times and perhaps somewhat more even heating cycles. Cats have to have the ceramic honeycomb replaced after several years of use, but baffle components in non-cat stoves degrade due to the high heat, so that may be a wash. Cat stoves MIGHT technically need a little drier wood to perform their best. Some claim that cats have a bigger learning curve for learning/ease of operation, but others say it isn't so.

Both are proven technologies, so go with what works best for YOUR home.

Read about halfway down this page: (broken link removed to http://www.woodheat.org/technology/woodstoves.htm)

Pretty straight forward response. I agree.

 

[Backwoods Savage]

In short, there is a lot of bad information out there. That may have happened because there were a few stoves that used cats years back that did not work good. So perhaps that has gotten into the minds of some and they haven't yet opened their eyes or ears again.

Probably the biggest reason though is most stove sellers have passed on this information, especially the sellers who do not carry cat stoves. It seems natural to those folks that if there is something they don't sell, they tend to put it down and say bad things about them. This is the most disgusting way of selling anything...but it happens. Actually, through our years we've found that very few salesmen in stove shops know what they are even talking about. Wood sellers seem to know even less.


Now let me add two other pieces of information:

1. The cat has to be replaced every so often. True. It is part of maintenance. All stoves have maintenance and replacing the cat is no more than what others do on replacing parts of their stoves. How long will they last? That all depends. If indeed you try to burn poor fuel, it will either ruin the cat or make its life shorter. Yet I've heard of folks using the same cat for 20 years. That is $100 spread over 20 years or $2 per year.

2. This is touching on that dirty glass just a little. If indeed one has dirty glass and as Dan stated, creosote on the glass, then he will definitely have all sorts of creosote in the chimney; much more than on the glass.

We have run our present cat stove for almost 2 1/2 years and it is our only scource of heat. If we had creosote on our glass then we would have been cleaning our chimney monthly at the least. However, I cleaned our chimney after 2 years of burning. What did it get? Somewhere around a cup full of soot and no creosote. So, instead of spending dollars on chimney cleaning or cleaning it myself many times, I did it only after 2 years.....because it simply did not need cleaning. I do believe this is because of having that catalyst simply because with our old stove, burning the same type of wood we used to clean the chimney 3 or 4 times every year because it needed it.



One final point: When we bought our present stove we were not entirely convinced it was enough stove to keep us warm. We used to burn around 6 full cords of wood per year and a couple years even more. In the two full winters we have had this stove we have burned exactly half the amount of wood we used to. In other words, what we used to burn in one year we now need two years to burn that amount of wood.....and... we stay much warmer in the house with this cat stove.


Sorry about the long posts but I get a little worked up when false information is given to new wood burners. Hopefully with this post I can help a few. I am not stating that a cat stove is the only way to go because it is not. There are many good stoves on the market. Just do not make decisions based on false information.

Good luck to all.

Keep smiling!
Dennis