Cat vs non cat

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shockman

Member
Sep 7, 2013
25
Kamloops
I have an old fisher stove ( gramma bear) I think 🤔 heating a 1000 sq ft cabin. It is still in good shape but wondering about replacing it with a newer stove if I was convinced that I would use at least 30% less wood. That being the case I’m wondering what the difference is between catalytic and non catalytic stoves. Drolet stoves are very accessible to me but I I see that they say non cat. Are cats more efficient? And if so by how much.
Marc
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
I have an old fisher stove ( gramma bear) I think 🤔 heating a 1000 sq ft cabin. It is still in good shape but wondering about replacing it with a newer stove if I was convinced that I would use at least 30% less wood. That being the case I’m wondering what the difference is between catalytic and non catalytic stoves. Drolet stoves are very accessible to me but I I see that they say non cat. Are cats more efficient? And if so by how much.
Marc
Is this for heating a full time residence or a cabin you only use occasionally?
 

shockman

Member
Sep 7, 2013
25
Kamloops
A cabin I heat all winter to buy for construction lots of glass windows facing south 12 to 13 feet cathedral roof in Maine area 8 foot ceilings in back third
 

shockman

Member
Sep 7, 2013
25
Kamloops
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EbS-P

Minister of Fire
Jan 19, 2019
3,553
SE North Carolina
How much wood are you burning a season? Are you there to keep it burning all night or do you relight every morning?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
How much wood are you burning a season? Are you there to keep it burning all night or do you relight every morning?
That big old fisher can burn overnight easily. Not cleanly but it certainly can.
 

shockman

Member
Sep 7, 2013
25
Kamloops
No problem getting 8hr burn but have to fill properly and preferably good dry fir and really chock it down so lots of creasote. Going through probably 5-6 cords which is not a lot but novelty of getting wood is wearing off with age. 😂
 

shockman

Member
Sep 7, 2013
25
Kamloops
I have lots of experience hitting with Wood just don’t have any experience with the newer stoves that are supposed to be so great and efficient. What I have now is just fine however I do need to replace the insulated section that goes through the roof and seem to have a lot of trouble finding an 8inch inside 10 inch outside pipe and if I thought I would go through a lot less would I would spring for a new one but I would sure be disappointed if it did not impress me
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
No problem getting 8hr burn but have to fill properly and preferably good dry fir and really chock it down so lots of creasote. Going through probably 5-6 cords which is not a lot but novelty of getting wood is wearing off with age. 😂
5 to 6 cords is a whole lot for 1000 SQ ft. Even with high ceilings. You can absolutely save allot of wood. I was just trying to figure out whether the low and slow heat from a cat stove would be a better fit or more heat from a noncat
 

shockman

Member
Sep 7, 2013
25
Kamloops
I guess that is what I am asking are the catalytic stoves much more efficient than the non-cat. other than the odd time that we come out when the cabin is cold I am sure a slow burn would be fine once cabin is heated up
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
I guess that is what I am asking are the catalytic stoves much more efficient than the non-cat. other than the odd time that we come out when the cabin is cold I am sure a slow burn would be fine once cabin is heated up
No they are not that much more efficient. But was the house overheated with the Fisher running for 8 hours a load?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
I have lots of experience hitting with Wood just don’t have any experience with the newer stoves that are supposed to be so great and efficient. What I have now is just fine however I do need to replace the insulated section that goes through the roof and seem to have a lot of trouble finding an 8inch inside 10 inch outside pipe and if I thought I would go through a lot less would I would spring for a new one but I would sure be disappointed if it did not impress me
For most new stoves you won't want an 8" vent so if it needs replaced you will most likely be going with 6"
 

shockman

Member
Sep 7, 2013
25
Kamloops
I guess other than the 7 to 10 days of actual cold weather that we might get in our location yes cabin is probably overheated windows are always left open once building is heated
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
I guess other than the 7 to 10 days of actual cold weather that we might get in our location yes cabin is probably overheated windows are always left open once building is heated
Then yes a cat stove is probably a good fit
 

shockman

Member
Sep 7, 2013
25
Kamloops
Would you recommend the same size firebox as my Fischer. And would you throw out a number for extra dollar cost for a cat versus non-cat
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
Would you recommend the same size firebox as my Fischer. And would you throw out a number for extra dollar cost for a cat versus non-cat
There are really only a few stoves anywhere near the size of that Fisher. The blaze king king, the regency 5200, and the big buck stove I don't remember the model. They all have cats so no non cat option there. But I do think you could go with just a large stove instead of extra large
 

stoveliker

Minister of Fire
Nov 17, 2019
6,285
Long Island NY
Note that if you buy a stove that can get you the 26% tax credit, that credit will also apply to the chimney if you have to replace that.
 
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Highbeam

Minister of Fire
Dec 28, 2006
20,015
Mt. Rainier Foothills, WA
Would you recommend the same size firebox as my Fischer. And would you throw out a number for extra dollar cost for a cat versus non-cat

While the cat stove is usually just several points more efficient than a noncat while burning, the significant wood savings occur not because of that efficiency but because you will have more control over the stove output and won't have to waste wood burning with the windows open, you are able to just turn it down to not get that hot which saves wood but won't show up on an efficiency test. You are also able to keep the house warm vs. cycles of warm up and cool down.

I moved from a modern noncat to a modern cat stove at the same home and like most others that have done it realized a significant wood savings and increase in comfort. I went from burning 5 cords per year to 4 cords per year. Obviously, your results may vary but that's a 20% reduction.

Every 10,000 hours I need to replace the catalysts which costs about 200$. That's a drawback but the 200$ is easily paid many times over for in wood savings.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
While the cat stove is usually just several points more efficient than a noncat while burning, the significant wood savings occur not because of that efficiency but because you will have more control over the stove output and won't have to waste wood burning with the windows open, you are able to just turn it down to not get that hot which saves wood but won't show up on an efficiency test. You are also able to keep the house warm vs. cycles of warm up and cool down.

I moved from a modern noncat to a modern cat stove at the same home and like most others that have done it realized a significant wood savings and increase in comfort. I went from burning 5 cords per year to 4 cords per year. Obviously, your results may vary but that's a 20% reduction.

Every 10,000 hours I need to replace the catalysts which costs about 200$. That's a drawback but the 200$ is easily paid many times over for in wood savings.
Yes some people save wood switching from a modern non cat to a modern cat stove but pretty much only if the noncat was pretty drastically oversized for the home of your climate has really long shoulder seasons. I for example switched from a pretty much perfectly sized noncat to a similar sized cat and saw absolutely no savings at all. Now there is certainly a benifit of more even heat output. But I never opened my windows during the heating season. And honestly few do if their stove is sized and run properly.
 
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peakbagger

Minister of Fire
Jul 11, 2008
7,693
Northern NH
IMO, cat stoves in general have better "turn down" compared to non cat. With current stove technology to burn clean either requires a hot flame usually with staged primary and secondary heated air and with no moving parts that is tough to begin with and making it happen over a broad operating range is even tougher, A cat lowers the combustion temperature of the gases so they burn clean easier. In theory that means better turn down. The problem with small space is the a stove sized for the coldest night of the year will drive the owner out during normal winter nights and spring and fall. Ideally havign a big stove for winter and a small stove for fall and spring would be ideal but having turn down is the next best thing.
 

kennyp2339

Minister of Fire
Feb 16, 2014
6,706
07462
I'd check out woodstock stoves (mainly the hybrids) you might be able to get the best a both worlds here.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
30,256
central pa
Regency makes some nice hybrids as well. Their pro line are good perfomers
 

stoveliker

Minister of Fire
Nov 17, 2019
6,285
Long Island NY
I think the savings have not much to do with cat or noncat.
It has to do with having a hugely (50%?) inefficient stove and going to a much more efficient stove (75%?).
Not with a 1 or 3 % difference between different types of (modern) stoves. (And I believe that the ultimate record holder in efficiency, regardless of stove size, is in fact a non-cat? Forgot which one.)

I think Peakbagger hits the nail on the head: what BTU needs do you have - at the various times of the year, and what stove can best meet them. You may have to compromise sometimes (i.e. a sweater on or a window cracked) depending on what the stove you choose can do, but minimizing such compromises is what is best to do. That's why bholler asked for how the old stove did - as it's then (a bit, roughly, guesstimated) known how many BTUs you need.


Another way to meet the compromise is to have a (modern, efficient) stove that can't turn down well, and add a minisplit for the shoulder season lower need for heat.