Catalytic burn times

[Moose032]

I have been burning a Quadrafire 3100 for about 4 years now since I bought my home but the stove seems to be a bit undersized for my home, which was more evident this year with the winter we’ve had in PA, so I’d like to upgrade to a blaze king princess this year. I have done a lot of research on here about the difference between catalytic and reburn stoves similar to what I have now and it seems like there is a lot of conflicting information in what I’ve read about the burn times at a higher output.

A lot of what I have read says that the burn times and wood consumption of the two stove types will be very similar at a high output but also at the same time a lot of people say they only need to reload every 12 hours with a princess in single digit temperatures. This is pretty drastically different from what I’ve experienced with my reburn stove which typically only has about 3-4 hours of good heat in each load and would need to be loaded 5-6 times per day in single digit temperatures. Can I actually expect good heat output from a catalytic stove like a princess 8 or more hours into a burn at a higher output or is it really going to be more similar to a reburn stove where I’m getting 3-5 hours of heating followed by coaling and cooling off up to 12 hours?

 

[begreen]

Burn times are subjective and relative to several variables. Two same sized homes could have very different insulation levels, sealing, window exposure, stove location, external temperature, wind exposure, and the wood could vary as well as the way the stove is operated. That said, the colder it is outside, usually the greater the heat loss of the house. The output demand on the stove is going to be higher to keep up with the heat loss.

We're in an old farmhouse with too many windows. In milder weather we reload on a 10-12 hr cycle. That will drop to 8 hrs when it's cold out.

 

[Moose032]

Burn times are subjective and relative to several variables. Two same sized homes could have very different insulation levels, sealing, window exposure, stove location, external temperature, wind exposure, and the wood could vary as well as the way the stove is operated. That said, the colder it is outside, usually the greater the heat loss of the house. The output demand on the stove is going to be higher to keep up with the heat loss.

We're in an old farmhouse with too many windows. In milder weather we reload on a 10-12 hr cycle. That will drop to 8 hrs when it's cold out.

Thank you for your explanation. Assuming that you’re needing to burn at a higher output due to the conditions you’ve described, I would still personally consider that to be a pretty good amount of time between reloads. This is where I’m getting a little bit confused because that tells me that the catalytic stoves do perform quite a bit better even at higher outputs (assuming you do have a catalytic stoves), despite a lot of people saying they are about the same in really cold weather.

 

[begreen]

bholler has run both in his setup and can offer a better comparison. A cat stove in our house means this.

 

[stoveliker]

One could estimate the BTUs you put in your stove (volume of dry wood), multiply with the ( <1) stove efficiency, and have the BTUs out in your room. Then divide that by the reloading time in your current stove. That gets an estimate of BTU per hour needed in your place

Then see how long you can go using a 3 cu ft firebox.
This suggests that when you need significant heat (i.e. you're not running low), you'd gain 50% of time between reloads (from 2 cu ft to 3 cu ft).


In the end it's fuel amount in, and its output spread over a certain number of hours.
Efficiency of modern stoves is not that different when not running near extremes (low or high).

 

[bholler]

Thank you for your explanation. Assuming that you’re needing to burn at a higher output due to the conditions you’ve described, I would still personally consider that to be a pretty good amount of time between reloads. This is where I’m getting a little bit confused because that tells me that the catalytic stoves do perform quite a bit better even at higher outputs (assuming you do have a catalytic stoves), despite a lot of people saying they are about the same in really cold weather.

The quad 3100 is a medium sized stove at 2 cubic feet. So I have a feeling it is undersized for the job. Have you checked all the gaskets the door latch adjustment etc? What pipe temps are you running at? Because those are very short burn times. Now as far as comparison goes I have never used a medium tube stove mine have all been right around 3 cubic feet. Going from.a tube stove to the princess there were some benifits but overall I havnt been terribly impressed. The bk is absolutely fantastic for mild weather. It burns low and slow for a long time. But when it drops to 20s outside which is most of my winter it is running on 8 hour cycles just like the tube stoves were. So for most of the winter I personally dont see a ton of benefit. It will vary greatly based upon climate and btu load of your house.

 

[John Lehet]

I've been using the number 6600 BTU/pound of wood, which takes into account the water in the wood (assuming teens% moisture) and my stove (Progress Hybrid) as 82% efficient.

I also find I have never gotten long burn times in my house with my chimney. My old Jotul, a tube/baffle secondary burn stove definitely worked best when burning hard, and it had a small firebox. It was one log after another. Didn't hold a fire overnight. Ran the mini split overnight and the room was cold first thing.

The Progress Hybrid is cat+secondary flames. With my wood and my chimney it will make pretty short work of say a 15 pound load of wood. I'll put 20 to 30 pounds of wood in for the overnight, and I never stay up late to see how long it flames. This stove I guess would burn at a low rate and smolder with a small load of wood, but with a big load of wood on coals, it will burn with secondaries no matter how I shut it down, usually. I try to burn it with secondaries because it seems to be designed for that. So relatively short duration of flaming, BUT the stove is massive soapstone, and it holds heat and coals very well, keeps heating for a long time between loading. 20 or 30 pounds of wood for the overnight will give me a deep bed of glowing coals and a room that is 72 or 73 even at below 0F.

 

[Moose032]

The quad 3100 is a medium sized stove at 2 cubic feet. So I have a feeling it is undersized for the job. Have you checked all the gaskets the door latch adjustment etc? What pipe temps are you running at? Because those are very short burn times. Now as far as comparison goes I have never used a medium tube stove mine have all been right around 3 cubic feet. Going from.a tube stove to the princess there were some benifits but overall I havnt been terribly impressed. The bk is absolutely fantastic for mild weather. It burns low and slow for a long time. But when it drops to 20s outside which is most of my winter it is running on 8 hour cycles just like the tube stoves were. So for most of the winter I personally dont see a ton of benefit. It will vary greatly based upon climate and btu load of your house.

I think the stove, which was installed a few owners ago, was sized based on my living area which is around 1500 sf but this is a log home with a 1000 sf footprint with 20 ft vaulted ceilings over half and a second story with vaulted ceilings over the other half so in reality it’s probably over 2000 sf of heating space so I think I need something closer to around 3 cf. I’ve tested the seal on the gasket with the dollar bill and it seems to be tight. I typically need to run the stove at around 400-550 flue temperature on the single wall pipe that goes straight through the ceiling to get good heat output to maintain or increase temperature but I’ve never had an issue with things getting too warm in the house. Most of the time if it’s pretty cold out my mini split will be kicking on while the stove still has flames.

One thing that also doesn’t help with the burn times is that the small firebox makes it tough to pack much wood in once you have a good bed of hot coals.

 

[John Lehet]

My Jotul was just like that. The space was often in the 60s and a fair bit of mini split use, especially at night.
The Progress Hybrid, it's super warm 24/7, and the only question is how long to coast on coals between fires. It's usually 4-8 hours between adding wood.

 

[begreen]

My Jotul was just like that. The space was often in the 60s and a fair bit of mini split use, especially at night.
The Progress Hybrid, it's super warm 24/7, and the only question is how long to coast on coals between fires. It's usually 4-8 hours between adding wood.

We coast on coals too. A big stone stove and a castiron-clad steel stove have a lot of additional thermal mass. These are heavy stoves, This contributes to a flywheel effect that goes a long way toward keeping room temp steady even as the fire dies down.

 

[Moose032]

It sounds like maybe I should give a second thought to some larger stoves that are either cast iron or soapstone to radiate heat a little longer after the fire dies down.

 

[John Lehet]

I hear it comes down to firebox size. This Progress Hybrid I have is my first stove since the old smoke dragon days that has a big firebox. In the case of this stove almost every aspect of the design is pretty unique and brilliant. But it might also be that any stove with a big firebox would do the trick.

 

[bholler]

I think the stove, which was installed a few owners ago, was sized based on my living area which is around 1500 sf but this is a log home with a 1000 sf footprint with 20 ft vaulted ceilings over half and a second story with vaulted ceilings over the other half so in reality it’s probably over 2000 sf of heating space so I think I need something closer to around 3 cf. I’ve tested the seal on the gasket with the dollar bill and it seems to be tight. I typically need to run the stove at around 400-550 flue temperature on the single wall pipe that goes straight through the ceiling to get good heat output to maintain or increase temperature but I’ve never had an issue with things getting too warm in the house. Most of the time if it’s pretty cold out my mini split will be kicking on while the stove still has flames.

One thing that also doesn’t help with the burn times is that the small firebox makes it tough to pack much wood in once you have a good bed of hot coals.

At that you are sending all of your heat out the chimney a d over firing the stove. Try shutting it back more the pipe temp will probably drop and stove top temp climb

 

[Moose032]

At that you are sending all of your heat out the chimney a d over firing the stove. Try shutting it back more the pipe temp will probably drop and stove top temp climb

400 on the stove pipe has always seemed to be about the optimum temperature for longest burns and heat output on my stove. Much higher than that can be difficult to keep the fire under control and below that doesn’t seem to put out much heat or keep a good secondary burn. My wood is pretty dry too. I honestly don’t test it too often but I’m usually about two years ahead on cutting and splitting.

 

[bholler]

400 on the stove pipe has always seemed to be about the optimum temperature for longest burns and heat output on my stove. Much higher than that can be difficult to keep the fire under control and below that doesn’t seem to put out much heat or keep a good secondary burn. My wood is pretty dry too. I honestly don’t test it too often but I’m usually about two years ahead on cutting and splitting.

400 is about the max I have ever run my pipe surface temp at. I shoot for 250 to 300. How tall is your chimney overall?

 

[begreen]

Ideally the flue temp on a non-cat should be roughly close to the stove top temp, maybe a bit higher. Surface temps on singlewall are about half the flue gas temp so a 400º surface temp is like 800º internally. Close down the air more and shoot for the 250-300º range on the flue thermometer like bholler notes. That should correspond to an increase in stovetop temp and more heat in the room.