What's your definition of "burn time" - I found how to actually achieve mine

Me :lol: I go by full load until its time to load again... Like if I load at 10pm and wake at 6am and load up, thats an 8hr burn time. I can get 8-10 hours with hardwood.

If i fall down on the stove and get burned, thats burn time

Hanko, where the old avatar... It cracked me up!

I think of burn time as the period between when the stove is loaded and when you have enough good coals to get the next load off and running without the need for kindling. For me, this is typically 8 hours, reloading at 250-300*. I don't like to think of a definition of burn time that includes a fairly cold stove, offering no appreciable heat to the home, and rummaging around in mainly ash trying to find enough small coals to get the kindling going. Now, this last part is nice - I can let my stove go for probably 12 hours and sift enough coals to get the kindling going, and that's good. But.....to me 'burn time' is the time when 'real' heat is entering the home. Cheers!

Like NH Wood said, I define burn time from the moment I re-load the stove. I typically re-load around 300* and get approx 4 good hours of burning from the Heritage and approx 3 from the Jotul. Today my wife left at 830 and I got home at 415. Stovetop temp was 150* and the Heritage was easy to re-lit but the house was cool, Jotul was cold for hours.

burntime said:

Hanko, where the old avatar... It cracked me up!

Click to expand...

dunno, I forgot, which one

joefrompa said:

Hi all,

First question is simply: How do you define "burn time"? What is the end result that is your end limit of the "burn"?

Also, I wanted to share my own burn time notes.

I've been burning pine, ash, and ironwood. For the most part, when it's 20 degrees outside and windy I'm loading the firebox about 1/2-2/3rds full and then re-loading every hour or so to maintain really solid heat output. My firebox has a max burn time of 8-10 hours according to Lopi.

Anyway, at the end of the evening I've been getting the firebox nice and hot (450-550 stove top) but mostly burnt down, then shoving it full of medium splits stacked densely but allowing some air movement. Then I shut down the air about 70% (shutting it down further will kill the fire on this model).

Normally, after about 7.5 hours and if I had a good 1.5-3" ash bed, I'd come downstairs to a completely dark firebox. Stove top temp would be 150-175 degrees. After sifting through the ashes, I'd find a good amount of coals which I could simply throw a few smaller splits on and within 10 minutes they'd be blazing.

...

After watching my in-laws, who put a solid 8" thick un-split log onto their coals at the end of the night, I tried something similar this morning. I put a really massive chunk in.

8 hours later, my wife came home and found red glowing coals outside of the ashes. No need to sift. Stove top temp of around 200-225.

Is that what is considered "burn time" - when after 8 hours, you still have visible glowing coals?

Joe

Click to expand...

Joe, the first thing I have to question is why do you add wood every hour? The outside temperature only in the 20's is not that cold to begin with but a half or 2/3 load you should not be adding wood every hour! I wonder how you are setting your draft? It sounds like you have it fully open to need wood that soon.

On the large unsplit log your in-laws used, that is fine. You will get longer burn times with it. For overnight fires we quite often will use one unsplit log in the rear bottom or else a large split there. Then fill from there.

Another thing I question is how you load for night when you state that you, "stacked densely but allowing some air movement." What air movement are you trying to create? For sure you need a little room on top and at the ends but other than that, just shove the splits in tightly. You'll get longer burns and more heat.

What is burn time. I consider it from the time you load the stove until it needs wood again. Sure, one can get long burn times by saying they can stir up some hot coals from the ashes but that to me is not a true burn time. If it were then I could claim well over 24 hours burn time! Not so. The stove certainly has not given heat that whole time unless you consider a 100 degree stove giving heat. That won't heat your home very well.

As for manufacturers claims on burn times, that is under very controlled conditions and they were probably using kiln dried wood to get those burn times. So take those with a grain of salt.

Burn time for me is approximately 6 hours for sufficient coals to put medium splits on, 8 hours to have coals to light some kindling. I run an old VC Vigilant (pre EPA) that throws a lot of heat consistently.

Burn time and time of usable heat are different. For burn time in my Endeavor which has the same firebox as yours I believe will go 11-12 hours easy with enough coals for an easy restart. Probably has a stove top temp of around 200 which isn't providing heat to the room. My longest span is while I'm working which is from 7am-6-7pm. I load with full size splits when I get home without any issue.

Burn time and usable heat are the same in my thinking. I reload on something that looks like this. Yes, I could probably squeak out another 4-8 hours and still light off of the coals, but the house temp would go down. So, my definition of burn time is full load to reload time on top of a maintainable coal bed, one that stays hot and doesn't grow. This time of year it is 12 hours, 24 in more moderate temps.

I haven't really "timed" it or anything, but I just fill the stove roughly every 12-14hrs and there are coals like in the pic above.

Around these parts, the high in the day is in the 50's, and the low at night in the mid 30's. I can only put 2 or 3, 6" pieces of split hickory on when we leave for work, (7am), and have 2 or 3 glowing logs left when we get home around 6pm. I only heat approx 600 sq ft of our DW with the Magnolia. It doesnt shut all the way down when the damper is in the lowest setting so, if I put any more than the 2 or 3 pieces of wood in it, the inside temp of our house gets up to mid 90s and we have to open windows to maintain lower 80s.

Random thoughts . . .

Like Backwoods I am wondering why you are re-loading every hour or so . . . I would go nuts if I was loading that often . . . to say nothing about the huge build up of coals that I would have in the firebox . . . and that's not even getting into the whole efficiency of the thing . . . I mean to say if it's wicked cold outside (talking single digits or sub-zero) I will be loading more frequently and may end up with more coals . . . but I'm talking reloading every 3-4 hours vs. my normal reload time of 4-5 hours if it's just plain cold vs. my overnight or overday "burn time" of 5-7 hours.

On the flip side, sounds like both you and the in-laws are doing OK to go 7 1/2 or 8 hours . . . of the two the in-laws may be doing a bit better . . . providing they are not suffocating the fire just to preserve the coals . . . in my own opinion I consider "burn time" like NH Woods . . . the time from when I reload to the time when I throw on some small splits on to the coals and get things going again . . . with one amendment . . . AND the stove is still putting out 200-300 degrees F of heat.

Of course defining a burn time really varies according to the person . . . there is no single definition . . . we all have our own opinion on what that definition should be . . . and as Dennis mentioned you really need to take what the manufacturers say with a grain of salt.

Funny how this debate keeps popping up eh?

My definition seems to match the currently popular one. Burn time is the time from one reload to the next. The length of time varies considerably depending on so many factors including the outside temp, what wood I'm using, etc. I don't believe my definition has any bearing on what marketers of stoves call "burn time" - if anyone can get a straight answer from the stove makers on their definition it may be interesting to learn but likely not all that useful since at best you could use that info to compare stoves from same manufacturer.

So my overnight burn time is determined largely on what time I wake up - independent of the condition of the stove.

As to overnight burns technique to maximize heat output, I do save up my 'best' wood for overnight burns. This year it is black birch which I split myself so I have lots of nice rectangular pieces (they stack in the stove so nicely!). I load up whenever the last time of the day is required (sometimes I try to push this later but less so as time goes on, I'm just too lazy).

Last night I fed the stove 6 pieces at 8pm. This is on a nice hot bed of coals. I set the air a bit lower than during the day - last night was between .5 and .75. My peak temperature on top (according to the foil high-water mark) was just a tad under 650*. This morning at 6am I had a bed of coals that looked much like the one in the picture shared by SolarAndWind (after I spread them out). Stove top temp was above 250 but I don't recall what exactly it was. I fed the stove and the pieces were burning before I could finish filling the firebox. Temps outside were 25f at 8p, 17f at 6a (I don't know the low for the night). Inside I lost 4* which is fairly normal for cold nights.

Daytime today the stove will likely get one more load before bed, perhaps 2 since it is colder outside and we have to make up that lost 4*. So my 'normal' high burn pattern gets 3-4 loads/24hrs or about 6-8hrs average. Obviously when it is warmer outside I load less frequently (longer burn time). I much prefer the more frequent loads as I like to have the new load burning well before I close the door to minimize smoke up the stack. Raking a small handful of coals together to get a stove burning again is a pain and makes too much smoke as it starts up (in my opinion) so I'd almost rather build a top down fire and us a piece of a SC to get it going in that case...

Last night I loaded up mine about 90% full at 8:30 PM, by the time I went to bed 10:00 the stove top was 600°. I woke up at 7:00 AM and the stove top was 250° with a small bed of coals. I put a small load in there to get the house from 67 up to a nice 72. Now that the sun is shining I will let the fire go until sunset and I will d1 o another small fire until 8:30 or 9:00. Last night it got down to around 5°, when it is warmer outside I can load it to 70% and still have enough coals to start it back up in the morning.

All I have is lodgepole pine. The burn time is about 2 hours less than with my old first generation cat stove that did not put out nearly as much heat.

Burn times are when you feel you need to reload to keep the house at the temp you like.

I loaded last night at 8P, when I get home about 2p today there would still be coals for a restart, evan though I did not load this morning. I want to clean the ash out of the insert.

Does this mean my insert has 18 hour burn times. I dont think so.....

Lanning said:

Burn times are when you feel you need to reload to keep the house at the temp you like.

I loaded last night at 8P, when I get home about 2p today there would still be coals for a restart, evan though I did not load this morning. I want to clean the ash out of the insert.

Does this mean my insert has 18 hour burn times. I dont think so.....

Click to expand...

Well, if you are happy with your house temps then it seems it meets the definition you gave, but I would say that for YOUR home with the outside temps what they are today and your temp preference you had an 18hr burn time.

A 'legal' or even 'generally accepted' definition of burn time doesn't exist. I don't believe that one could assign such a value to a particular make/model of stove that would be meaningful as there are far too many variables that come into play that are dependent on the particular install. As other discussions point out - the flue/chimney system is a major part of the install and will affect how it burns. Whatever definition of burn time you go with you would get different values in different installations.

With that said - these discussions are helpful particularly for folks to see what practical experiences are out there in a variety of installs. Perhaps those looking to buy can get a better feel of what to expect from different stoves and those of us who are burning can perhaps see if they are getting comparable results to others with same stoves - perhaps identify ways to burn better.

[/quote]Another thing I question is how you load for night when you state that you, "stacked densely but allowing some air movement." What air movement are you trying to create? For sure you need a little room on top and at the ends but other than that, just shove the splits in tightly. You'll get longer burns and more heat.[/quote]

I trust backwoods as he seems the residant "old timer." I mean that in a good way. I am loading in a log cabin style and am only getting 4ish hour burn times with elm. Is stacking wood tightly a common practice? Sorry to piggyback joefrompa.

I define MY burntime as USEABLE heat. For me, anything below 400 stovetop is not very useable in my uninsulated leaky house. For me to keep warm using the woodstove as primary heat, stovetop has to be above 500. I try to cruise around 600-650. You say you stack "log cabin style"...im assuming this means one row of splits north/south and the next east/west, etc etc? Is this on reload or from a cold start? If it is on cold start, thats fine, but on a reload, I would suggest as other have to load tightly in a north/south direction. This has yielded me the longest and hottest burn times.

As far as overnight burning for me, If I drop a full load of hardwood in around 10pm, let it settle down a bit, I can wake up at 7-8am and still have useable coals for a relight. At that point, the stove has been sitting around 200-275 for quite a while so for me, that is too cold to use as a only source of heat. But, the oil furnace kicks on in the am to take the chill off and then I reload, get her kickin again and the furnace doesnt run again all day.

These are just my experiences...

mrfjsf said:

I define MY burntime as USEABLE heat. For me, anything below 400 stovetop is not very useable in my uninsulated leaky house. For me to keep warm using the woodstove as primary heat, stovetop has to be above 500. I try to cruise around 600-650. You say you stack "log cabin style"...im assuming this means one row of splits north/south and the next east/west, etc etc? Is this on reload or from a cold start? If it is on cold start, thats fine, but on a reload, I would suggest as other have to load tightly in a north/south direction. This has yielded me the longest and hottest burn times.

As far as overnight burning for me, If I drop a full load of hardwood in around 10pm, let it settle down a bit, I can wake up at 7-8am and still have useable coals for a relight. At that point, the stove has been sitting around 200-275 for quite a while so for me, that is too cold to use as a only source of heat. But, the oil furnace kicks on in the am to take the chill off and then I reload, get her kickin again and the furnace doesnt run again all day.

These are just my experiences...

Click to expand...

You are correct on my definition of log cabin. Using the stack tight method how long does it take to close down the air controls. This all sounds fine, but I don't want to get up a 5am just to slowly close my air down before work.

SolarAndWood said:

This time of year it is 12 hours, 24 in more moderate temps.

Click to expand...

You know, you Blaze King owners are really starting to get under my skin. :coolgrin:

Battenkiller said:

SolarAndWood said:

This time of year it is 12 hours, 24 in more moderate temps.

Click to expand...

You know, you Blaze King owners are really starting to get under my skin. :coolgrin:

Click to expand...

My humblest apologies.