How do you define "burn time"

[sourcehound]

A few years back, I bought a Vermont Castings Encore Flexburn stove. It was not my first choice, but it was the best stove I could buy on Amazon as one of my clients had given me a few thousand dollars in Amazon gift cards. First, I have to say I'm happy with it - it can keep my whole house warm even when it gets down to -15. In the Winter this stove is pretty much going all day, every day. I live on 15 acres of wooded property and have much more Oak, Ash, Black Cherry and other woods that I can process. In its specs, Vermont Castings says this stove has a 12 hour burn time and I see other stoves advertise even longer burn times.

But if I pack this stove full of perfectly cut, seasoned Oak with the catalyst hot and a glowing bed of coals, I probably could barely get 6-8 hours of actual "burn time" where there's flames in the stove. Yet it will easily stay fairly hot for 10-12 hours, but at a slowly declining rate. So if I stabilize the burn at 425 surface temperature, it's fairly likely the surface temp will still be at close to 400 when I wake up 8 hours later, yet most of the wood will be gone, with just a layer of hot coals left. Also, I've had enough hot coals last 18 hours to light another fire without kindling,

So what is "burn time" - is it the time from when you load the stove for a long burn until the surface temp drops to the point where you would reload it again? Or is it when the wood is gone and the flame is out?

 

[Todd]

Many different definitions of burn time. I think most manufactures think of burn time as down to a coal bed able to rekindle a new fire. I see pretty much the same as you, flame for half the burn then coals for the other half. I’ve been able to reload splits on top of coals and have it take off as long as 16 hours but the stove is only making meaningful heat for half that.

 

[Woody Stover]

I’ve been able to reload splits on top of coals and have it take off as long as 16 hours but the stove is only making meaningful heat for half that.

Yep, I also consider the coaling stage as part of the burn. I can open the air a bit on the coals and keep the stovetop 300-350, which still heats the house in most weather here. Now, you Cheezers probably can't get away with that as often as I can.. 😏

 

[begreen]

Todd has it right. Burn time is a somewhat ambiguous marketing term. The period of meaningful heat is more helpful and even this definition has to be factored with the heat demand due to the heat loss of the building. Our stove can easily stay above 250º for 12 or more hours. I am still burning down a large bed of hot coals at 9am with a stove temp of 320º, 12.5 hrs. after the fire was lit last night. The house is at 70º but this is with a calm outdoor temp of 41º. On a windy 25º night, the period of meaningful heat could drop down to 8 hrs. because I'd be pushing the stove harder for more heat. So marketing could say the T6 has a burn time of 14 or 15 hrs and be technically correct, but that has little practical value except under ideal conditions of mild outdoor temps when minimum BTUs from the stove are sufficient.

 

[TomMcDonald]

Agree with the above, but will add that in my experience inserts have a shorter useful burn time and require reloading earlier than their freestanding equivalents.

 

[peakbagger]

In my experience burn time is equivalent to how a fisherman measures his fish and subsequently how it grows when discussed

 

[Woodsplitter67]

To me personally.. burn time is usable heat.. that is a thick layer of coals and the stove no less then 325 degrees.. My stove can hover around 175/200 degrees with the air cut all the way back and the bypass closed for like 6 hours and I can easily do a relight on the coals left.. I dont consider that apart of the burn time

IN your stove its important to pack the stove tightly to get the maximum amount of heat and burn time.. your an east/west top loading stove.. Your better off splitting thick for overnight burns and splitting square and rectangle to pack the box.. you should have very little to no space between the splits.. With a load of oak/hickory I got 16 hours ot of a burn

 

[mdocod]

Ooooo! I like that VC Encore Flexburn. I was actually very interested in their slightly larger Defiant stove for our home. Such a beautiful stove! Nice!

I would also define burn time as how long the stove can go between reloads on coals that are still active enough to set new wood ablaze without too much drama/smoke. It sounds like you're seeing cycles as long as 18 hours. That sounds fantastic to me. Jealous of your Wisconsin Oak! My Grandparents lived their lives in Wisconsin and I have fond memories of the north woods.

On the ponderosa junk that we burn around here in the semi-arid dessert that is front range Colorado, flames are usually done in ~2-3 hours, in the ~3-4 hour range there's still some wood gases coming out of the bigger pieces but not enough to keep an active flame. This is where the cat in these types of flex/hybrid stoves comes into play to pick up the slop. After ~4-5 hours it's a heap of coals in the shape of the logs that were originally loaded. Between 5-8 hours the charcoal lumps just steadily shrink as the carbon burn phase progresses and the stove steadily cools. As long as the stove started with a pretty big load I'm able to reload after 8 hours on decent bed of coals consistently.

If I squeeze some thicker chunks into the stove and really get them packed in tight with other pieces, the active flames will run out to ~3-4 hours and the coals will make it out to a usable relight in the 10-12 hour range. Hitting the 12 hour mark is rare but it's happened a few times. Oak is about 60% denser than ponderosa, and you're getting about 60% longer burn-time. Makes sense to me!

Stove surface temps fall below 150F sometime between 12-16 hours depending on the fuel load. I would call this the functional "heatlife" of the stove on this fuel.

When the weather is milder, like in the 20s for nighttime lows, 40's for daytime highs, letting the stove run 7-8+ hour burn cycles works great, and if its sunny out there's no need for a morning reload the sun will heat the house. When it's colder the reloads get closer together. When it's down around or below 0F I try to keep active flames in the stove continuously when I'm awake and around to do so so that's a smaller load every 3 hours or so.

I need to get a load of hardwood to play with.... That would be nice for super cold nights.

 

[begreen]

I need to get a load of hardwood to play with.... That would be nice for super cold nights.

Can you get some high-altitude spruce? It is much slower growing and denser than the lowland spruce. Or maybe some tamarack?

 

[weee123]

I personally consider burn time from reload to being able to rekindle the fire with the remaining coals. Sounds like you get a great burn time in my definition!

 

[appointed EPA deviant]

Long burn brag times are worthless @ -15F
BTU's is BTU's . The cat stoves are probably scientifically rated as being more efficient but even at that, if you want your house @ a comfortable temp....like above 65F your burn times will be like an EV mile range in the same -15 scenario....seriously diminished.

 

[sourcehound]

Thanks everyone for confirming what I thought, so it does seem that my stove is working very well! Stay warm everyone!

 

[sourcehound]

Long burn brag times are worthless @ -15F
BTU's is BTU's . The cat stoves are probably scientifically rated as being more efficient but even at that, if you want your house @ a comfortable temp....like above 65F your burn times will be like an EV mile range in the same -15 scenario....seriously diminished.

No kidding! I was running the stove at full burn with the catalyst going and surface temps around 600 for nearly 36 hours until the freeze was over. I burned and entire rack of firewood that usually lasts a week!

 

[bholler]

Long burn brag times are worthless @ -15F
BTU's is BTU's . The cat stoves are probably scientifically rated as being more efficient but even at that, if you want your house @ a comfortable temp....like above 65F your burn times will be like an EV mile range in the same -15 scenario....seriously diminished.

That depends upon the BTU load of the home. For some homes including mine you are correct. For others you are dead wrong

 

[VintageGal]

"meaningful heat" I like that definition.

 

[bholler]

"meaningful heat" I like that definition.

That is my definition as well. And it varies greatly through the year from 24 down to 8 hours. Sometimes less

 

[sourcehound]

"meaningful heat" I like that definition.

I didn't really mention in my post what "meaningful heat" and burn time means to me, but I have a rock solid standard for it. I live in a farmhouse built in 1900 - it is drafty and largely uninsulated (though I added some). The house has a forced air propane furnace, and the thermostat is in the coldest part of the house (farthest from the wood stove), set to 55 degrees. When the furnace kicks on, I know that "meaningful heat" has come to an end, and of course that depends on the weather - unless it gets under 15 degrees outside, it never comes on in a 12 hour cycle, even if the fire is just coals. If it gets colder than that, I have to feed the wood stove a lot more - below zero I have to put a couple of logs in every couple of hours, or even more frequently.

 

[Woodsplitter67]

Long burn brag times are worthless @ -15F
BTU's is BTU's . The cat stoves are probably scientifically rated as being more efficient but even at that, if you want your house @ a comfortable temp....like above 65F your burn times will be like an EV mile range in the same -15 scenario....seriously diminished.

So its quite obvious you dont understand the advantages of a cat stove. Your thought process is so off its unbelievable.. If its 15 degrees out you run the stove for the amount of heat needed. The other weekend then it was 7 degrees with a windchill of -8 , my stove was ran for the heat demand needed and my house was in the 70s A cat stove has a wide range of heat output, Major advantage.. Cat stove put out a more even heat.. AKA no temperature spiking like a burn tube stove. Burn tube stoves cant be turnd down as low.. Major disadvantage, because when the heat demand is alot less the owner of a burn tube stove is sitting with a cold stove.. while the owner of the cat stove is still burning

My stove can put ot 68k BTUs.. the same size burn tube stove will put out the same BTUs.. My stove can be turned down to 11k BTUs... the same burn tube stove can only go down to 28k BTUs

For someone like me who heats primarily with wood, why wouldn't I want that advantage. The more free wood I burn the less I pay big oil.. Im not one to contribute to their record profits every year

So.. what stove are you running that has you so sour on length of burn time.. Im thinking from your posts.. you don't run a stove at all

 

[begreen]

These statements are pretty off the wall too. Lots of fallacies but I don't have the time to disassemble them all. Maybe later.

 

[Todd]

There are some good controllable non cats out there. I know mine can run pretty low at 16000 BTU and easily goes 12+ hours burn time. It actually reminds me of the same kind of soft heat My Woodstock’s put out. The PE’s with their EBT tech also has some good control.

 

[begreen]

Yes, we've been heating fine in mild weather. The stove is just one part of the equation in any heating scenario, the wood, draft, and operator all factor in as does the space being heated and its heat loss. Some pure cat stoves like the Fireview can go pretty low in output, but most cats bottom out around 10-11,000 BTUS. The non cats are higher, but not that high. Some are pretty close to the cat stove bottom end.

The big Lopi Liberty tested at 15,155 BTUs on the EPA low run. The Lopi Answer's low run was at 12,129 BTUs. Mid-size Regency 2450 clocked 14,197 BTUs and the PE Super tested at a respectable 12,518 BTUs.
But on the opposite side of the spectrum the top end for these stoves sa

 

[bholler]

Ok both cat stoves and non cats have their place. If you have a house that generally needs a lower BTU output a cat stove will be a pretty good fit. But noncats can absolutely work just fine in that situation as well. And if your BTU load is typically higher yes a cat stove will probably do the job but you will be paying for cats when you could easily do the same thing with lower maintenance costs.

 

[appointed EPA deviant]

So its quite obvious you dont understand the advantages of a cat stove. Your thought process is so off its unbelievable.. If its 15 degrees out you run the stove for the amount of heat needed. The other weekend then it was 7 degrees with a windchill of -8 , my stove was ran for the heat demand needed and my house was in the 70s A cat stove has a wide range of heat output, Major advantage.. Cat stove put out a more even heat.. AKA no temperature spiking like a burn tube stove. Burn tube stoves cant be turnd down as low.. Major disadvantage, because when the heat demand is alot less the owner of a burn tube stove is sitting with a cold stove.. while the owner of the cat stove is still burning

My stove can put ot 68k BTUs.. the same size burn tube stove will put out the same BTUs.. My stove can be turned down to 11k BTUs... the same burn tube stove can only go down to 28k BTUs

For someone like me who heats primarily with wood, why wouldn't I want that advantage. The more free wood I burn the less I pay big oil.. Im not one to contribute to their record profits every year

So.. what stove are you running that has you so sour on length of burn time.. Im thinking from your posts.. you don't run a stove at all

Nice little attack but you didn't disagree with me. I said the cat stoves are scientifically more efficient..... by maybe what? 10-20% tops?
Obviously everyones dwelling is a unique situation. It seems many of the members on here that are cat stove owners are in the perfect temperate climate for them where stringing out the BTU's works. Easy peasy. Big deal. My custom "tube" stove furnace is easy to burn and coast with. Heating with wood is a part time job. Mine ducts to the entire house or only part as needed. I don't mind a restart or 2 when the temps are like the warm temperate east or west coast.
The temp I mentioned was - ( minus) 15.....NOT + (plus) 15....30 degree dif there. I think everyone understood my thought process.
Unless you think a that cat stove somehow extracts more BTUs out of a given load of cordwood we have no disagreement. Stringing out BTUs don't mean squat if the coldest person in the house thinks its too cold. When you live where the temp can be below zero with a serious wind for weeks on end ain't no time to brag about burn times.....too busy haulin and stokin'. Enjoy what you got. I know i do.

 

[bholler]

Unless you think a that cat stove somehow extracts more BTUs out of a given load of cordwood we have no disagreement. Stringing out BTUs don't mean squat if the coldest person in the house thinks its too cold. When you live where the temp can be below zero with a serious wind for weeks on end ain't no time to brag about burn times.....too busy haulin and stokin'. Enjoy what you got. I know i do.

In general yes cat stoves are more efficient meaning they do extract more BTUs out of each piece of wood. But in reality the efficiencies are pretty close. So there isn't a big difference there at all. The real difference is in being able to run at much lower temps with more even heat output over a longer period of time while still burning cleanly. If that fits your homes needs a cat stove is probably something you should consider. But yes they can be opened up and put out allot of heat when needed as well.

This forum really has a fairly good variety of cat and noncat users and some of us that have used both. I have and there are some things I prefer about the cat stoves some things I prefer about the tube stoves.

I just don't understand why you are bashing cat stoves the way you are. If you don't want one no one is making you buy one

 

[Woodsplitter67]

Nice little attack but you didn't disagree with me. I said the cat stoves are scientifically more efficient..... by maybe what? 10-20% tops?
Obviously everyones dwelling is a unique situation. It seems many of the members on here that are cat stove owners are in the perfect temperate climate for them where stringing out the BTU's works. Easy peasy. Big deal. My custom "tube" stove furnace is easy to burn and coast with. Heating with wood is a part time job. Mine ducts to the entire house or only part as needed. I don't mind a restart or 2 when the temps are like the warm temperate east or west coast.
The temp I mentioned was - ( minus) 15.....NOT + (plus) 15....30 degree dif there. I think everyone understood my thought process.
Unless you think a that cat stove somehow extracts more BTUs out of a given load of cordwood we have no disagreement. Stringing out BTUs don't mean squat if the coldest person in the house thinks its too cold. When you live where the temp can be below zero with a serious wind for weeks on end ain't no time to brag about burn times.....too busy haulin and stokin'. Enjoy what you got. I know i do.

Its not an attack, and your still not getting it.. The efficiency of the stove is what its manufactured to.. If a stove is rated for 80% then that is what it is, that's not going to change unless one is altering the stove.. My example is quite obvious.. It doesn't matter if its 7 or -15 degrees.. nobody is going to run the stove on low.. the stove is run based on heat demand. The example of me running my stove in my home is a great example.. My home is 2x6 construction, open floor concept, heat travels freely throughout the home. My stove is sized perfectly for my home and its 70 degrees inside and everyone comfortable when its 7 degrees out, my stove is not struggling to keep up and is running at the efficiency it was designed for at the time of purchase.. If my home was in a colder climate Id have to size my stove up. Again your not getting that the advantage of the cat stove is to be able turn it down during mild weather.
Iv seen you posts regarding cat stoves.. Your upset that many here including myself aren't slaves to the stove. Your issue is exactly what you posted in your response to me.. Your to tied up with your stove.. "hauling and stoking". Thats an issue with you and your setup.. Your custom made ( AKA A home built) stove is on the low efficiency side, you home probably isn't holding heat very well either.. so it sucks to be you I guess. Because your tied up with your heat needs. This doesn't mean you need to bash others or a specific type of a stove, that found away to heat with wood and not have to be so wrapped up in it.
If your struggling and it sounds that way, there is alot of information here as well as really smart people.. enjoy.. do some research and reading... help yourself out.. life doesn't have to be that hard..