I have no idea what it is real world. The manufacture says 88% LHV rating and 82% HHV. At one point I found those testing procedure and read them. I cant recall the specifics, its just a method of testing to determine the overall heating efficiency. I will be emailing a BK rep with some IR images of my stove and I will ask him what the maximum peak output if in btu/hr and let you know. Maybe he has a graph of the stoves operating profile he will share with us. It would be very interesting to see if they have something like that. I have to believe they do. I might be proprietary though.
Woodstove Efficiency Debate
- Thread starter Marshy
- Start date
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No... I'm using all of the available fuel... I'm just using a portion of the available space for fuel.
Which is what I've been saying all along... I control the heat output by the loading technique.
I could load longer pieces of firewood to a lessor depth... or I can load shorter pieces of firewood to a greater depth... the result is the same.
Burn time is not determined by the amount of fuel... it is determined by the burning rate of the fuel.
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just read all 4 pages. i like the bias tire debate better.
in all seriousness.
if your wood isn't dry your screwed. i'm talking 8-10%.
if your not burning /using rounds in you overnite mix. your screwed.
i'm using a 1980's pre EPA stove in my 30x40 under insulated shop and keep it at 60-70* all winter long. (to keep the pipes from freezing) wood usage is under a cord a month.
in all seriousness.
if your wood isn't dry your screwed. i'm talking 8-10%.
if your not burning /using rounds in you overnite mix. your screwed.
i'm using a 1980's pre EPA stove in my 30x40 under insulated shop and keep it at 60-70* all winter long. (to keep the pipes from freezing) wood usage is under a cord a month.
Mine is a Jotul F600CB, also called the Firelight.
It also has a grate in it's floor and ashes drop through to an ash pan.
I don't have to fiddle with this stove at all.
Great heat and a great fire view. I burn mostly pine, poplar, leyland cypress, etc. In other words mostly trash wood that people do not want to buy.
We also burn a lot of rounds that can hardly fit in the side door and a few that have to be loaded via the front two doors. Our wood is wood shed dried usually for at least two years and often more.
Some of the bone dry large rounds are so large that when loaded via the front two doors and placed on an inch or two of coals that the round almost reaches the secondary tubes. These rounds burn great and quite slowly with secondary combustion happening within minutes of loading.
We exclusively use the 'top down' method of fire starting.
Maybe you caught me at a bad time, I was being 100% serious lol.
midwest_170
ArboristSite Operative
Non of that BS will matter now with trump in office and his stance on the EPA. Trump has stated he will remove 80% of the regulations put in place.
brenndatomu
Hey you woodchucks, quit chucking my wood!
I get a more complete burn then with my old school burner...and I can tell two different ways.
1. Much less (almost none) unburnt coals (or charcoal) left. I actually made a screen for my ashes with the old furnace, haven't used that since firing the new one up 3 years ago.
2. The chimney stays much cleaner. Only need to clean 1 time per year instead of 3-4 times per.
Chris-PA
Where the Wild Things Are
I burn mostly ash, but lots of white and red oak too, some cherry, walnut and hickory when one comes down. I love having tulip around for quick starting. But I'll burn any wood, including pine and sassafras.
I've said before that I load the bottom logs in the stove end on to the door, and each layer over that perpendicular to the one below (sometimes with smaller splits I have 3 layers). With a small gap between slits this allows gases to move freely through the wood load. My Magnolia can fit 20" logs end on, but only about 18-19" cross wise. I have been cutting both lengths because I can get more wood in the stove that way, but lately I'm thinking about just cutting everything to 19".
The little Hampton H200 takes 14" logs cross wise to the door, and I use an 8" block on the bottom on one side to prop up the stack. With a prop block on one side it leaves a chamber underneath of just the right size to make lighting a breeze. I block lots of those short pieces out of knots and crotches, usually with one of my little ported 40cc saws.
I also like to mix in some ash with slower burning wood to keep the temperatures up. I save those thin long splits you sometimes end up with to lay on top of the pile to help kick off secondary combustion - they're like afterburners for as long as they last.
This has turned into a great thread...
Chris... I like your idea of crisscrossing the layers in the stove.. I may give that a try. I tend to split my wood with squarish corners so I can utilize as much of the firebox as possible. But I am finding, as you probably already know, its more mass to get warmed up to finally start burning. Sometimes I find myself with not enough coals to get the new load going well without some air input from me.
Chris... I like your idea of crisscrossing the layers in the stove.. I may give that a try. I tend to split my wood with squarish corners so I can utilize as much of the firebox as possible. But I am finding, as you probably already know, its more mass to get warmed up to finally start burning. Sometimes I find myself with not enough coals to get the new load going well without some air input from me.
I mash mine full to the brim when I need the heat, it will burn and air circulation has never seemed like a problem inside the firebox with it full. The more fuel loaded the hotter it burns. I don't worry about criss crossing splits. I would throw them in with no air gaps if I could. One end/side of the wood is going to lite and burn. When the firebox gets hot enough the rest of the wood will offgas and burn in the combustor. Eventually everything is reduced to hot hot coals. Maybe the fancy stacking isn't needed in a cat stove. Last night was warm, about 34F and I filled my stove to the brim and turned the air control down to 80%. I think it could have burned nother 2-3 hours without letting the house temp drop any. Peak temp on the stove reached 788F near the cat before I tuned the fan on. The face of the stove near the door was at 810F.
That's normally how I load as well. I've still got a year or 2 using this 15" wood cut for the old stove. Not really utilizing the firebox to the fullest.
sent from a field
sent from a field
Wood-burning efficiency is affected by an enormous load of variables. Besides what stove or insert you’ve got—what is the length of flue above it? Is the flue triple-wall insulated going up through the inside of the house, or brick and clay tile directly exposed to the north wind? Is the draft wide open for a clean burn, or closed down somewhat to extend burn time? Is the wood plenty dry, or still holding some moisture? Large diameter chunks vs. small splits. Hardwood vs. less dense. Outside temperature of 44 degrees or 18 below zero. And so on and so on.
I’ve burned wood in many stoves and in several houses over the years, and every stove and situation is different.
Right now my main floor heat comes from a Hampton HI300 insert, with the blower pushing the heat into the room. Down in the basement I’ve got a Hearthstone Homestead freestanding soapstone stove. The same wood burns different in each one. The downstairs stove will burn down to nothing—no coals, just pure ash—if I don’t stoke it in time. The insert will hold coals a lot longer. Same wood in both.
Like someone said above, in real cold temps if you keep pushing wood into the insert before it has time to fully burn the coals they build up and become a nuisance. To reduce a giant bed of coals I rake them to the front and crack the door to get the venturi effect.
But all in all I like both my units. The glass doors alone are worth the price of admission. At beer time in the evening—Jeez, it comes early this time of year—I like no other light in the room but the fire. It’s pretty near hypnotic, way better than TV for my viewing pleasure.
I’ve burned wood in many stoves and in several houses over the years, and every stove and situation is different.
Right now my main floor heat comes from a Hampton HI300 insert, with the blower pushing the heat into the room. Down in the basement I’ve got a Hearthstone Homestead freestanding soapstone stove. The same wood burns different in each one. The downstairs stove will burn down to nothing—no coals, just pure ash—if I don’t stoke it in time. The insert will hold coals a lot longer. Same wood in both.
Like someone said above, in real cold temps if you keep pushing wood into the insert before it has time to fully burn the coals they build up and become a nuisance. To reduce a giant bed of coals I rake them to the front and crack the door to get the venturi effect.
But all in all I like both my units. The glass doors alone are worth the price of admission. At beer time in the evening—Jeez, it comes early this time of year—I like no other light in the room but the fire. It’s pretty near hypnotic, way better than TV for my viewing pleasure.
Chris-PA
Where the Wild Things Are
LOL, it's not all that fancy....
I don't have a cat stove but I think it would work very differently. Really all you need is to keep it smoldering - you don't have to keep the firebox temperatures up in the same way? I'd probably load it differently
Oh, and another thing. Outside a grocery store in town the other day, I passed by the stack of plastic-wrapped bundles for sale. Around here it's all pine or some other conifer--$4.00 or whatever they charge, for a poor bit of fire that won't last.
The bundles in this stack caught my eye because they were lined with condensation on the inside. Adding insult to injury.
The bundles in this stack caught my eye because they were lined with condensation on the inside. Adding insult to injury.
Maybe on low but my stove burns quite hot. You look at the videos for BK and they show you how its operating with no flames an all that but with it turned up to high its roaring with flames. Once its reduced to coals its just one bid blue flame dancing over the coals.
Chris-PA
Where the Wild Things Are
OK - I just have no experience with them, and like I said I don't know that I'd load them the same way I do my secondary combustion stoves.
I've yet to read where anyone else tried stacking the wood as I do, and I'd be curious what their results would be.
I'd loose too much room in the firebox. The coal bed in the BK King is 8" deep and is nearly full to the top of the firebricks at all times. Coals will last for days in that deep of a bed. My stove burns 24/7 and with that much coal its duck and chuck until its loaded.
brenndatomu
Hey you woodchucks, quit chucking my wood!
I do that when I want a fast and hot fire, like in the spring and fall. The only difference is since all of my burners have long and narrow fireboxes I have to stack the wood in more of an X shape rather than full on perpendicular. It does work great for a nice hot fire when you don't need 8-10 hours of intense heat.
