Burn Time Softwood vs Hardwood?

[WidowMaker]

When you get to older then most of the wood your burning, burn time or species doesn't
mean much as your up often enought to keep the fire fed ...

 

[Marc]

Care to fill in the firewood geeks among us on the difference in the two measurements? Seeing 20 different charts and no two the same makes me pull out my hair, which is falling out by itself nicely enough and doesn't really need my help.

I'm not positive, but I think he's talking about expressing the moisture content on a wet or dry basis. It's the way we express moisture content of the various cellulosic fuels we use in full scale fire testing.

It's just expressing the weight of the moisture at a given level as a percentage of the weight of the material + plus the moisture (wet), or as a percentage of just the material (dry).

Obviously dry basis moisture content tends to be a little higher than wet for the same weight of water in a given material.

 

[Fyrebug]

Here's a really good presentation by Intertek on the intricacies of burning wood and how to measure moisture content.

Good edjumacation right there...

Enjoy!

http://www.epa.gov/burnwise/workshop2011/WoodCombustion-Curkeet.pdf

 

[Doug Fir]

Thanks for the link. The document contains some very interesting and useful information.

Look at the graphs of drying times on page 34. For ponderosa pine, stacked in the summer, in Albuquerque NM, in takes about 13 days (!) to hit 15 percent moisture content. And at that point it is starting to get drier than optimal. You need to wait to split your wood if you do not want it to dry out too much before the winter. An interesting problem to have.

Doug

Here's a really good presentation by Intertek on the intricacies of burning wood and how to measure moisture content.

Good edjumacation right there...

Enjoy!

http://www.epa.gov/burnwise/workshop2011/WoodCombustion-Curkeet.pdf

 

[WidowMaker]

Very Interesting..
Thanks for the link...

 

[Marc]

Here's a really good presentation by Intertek on the intricacies of burning wood and how to measure moisture content.

Good edjumacation right there...

Enjoy!

http://www.epa.gov/burnwise/workshop2011/WoodCombustion-Curkeet.pdf

Someone should have had that checked for accuracy before publishing ... whoops

 

[EXCALIBER]

Yes I understand that hard wood is more dense and thus has more btu's, but my question was just from a standpoint of how much difference based on the different types of stoves it would actually make in real world burning. I have filled the stove to the brim with Elm (when I could find it) and set the stove on low and got better than a forty hour burn once. Usually with Elm I can get 35-40 hour burn, but that is on low with the temps not very cold say 40 day/20 night. On medium with Elm the stove goes about 24 hours when it is cold out. I will still be in the active range on my stove at this point, anything below that and I consider it to be not usable heat. I can have coals for a very long time, lets say a week or better.

Part of the reason I ask is a friend at work has an older wood stove with a well insulated house (mine is not, plus high winds in the middle of nowhere) and he is always up loading wood into his stove. The other part is I am just curious. I figured I might find a few of you who could load up the stove with soft and hard and do the same burn with the same outside temp and see where you ended up at. Thanks for all the responses, keep them coming

 

[stihly dan]

I did this test last yr. Eastern white pine loaded up 3 hrs fire,on low but temps 600. Red oak 7 hrs fire, on med temp 550. Coals for many hrs after with oak. Pine just ash.

 

[Hddnis]

Quadra-Fire 2000

Loaded with:

Pine 6-7 hour burn time.
D. Fir 8-9 hour burn time.
Maple, silver 8-9 hour burn time.
Cherry 14 hour burn time.

All I've tried so far.
I've got some walnut, apple, june berry, and locust to try someday. I'm guessing they'll be about the same as the cherry.





Mr. HE

 

[agstr]

If anyone is wondering what that firewood your burning is really worth. Here is a list sorted by pounds per cord and MBTU (million BTU per cord).. So you can take a look at what packs the biggest punch per pound.

Got to think of the wood appliance for burning also, as some approaches capture heat more efficiently and keep it from going out the chimney

 

[Yerpdog]

Got to think of the wood appliance for burning also, as some approaches capture heat more efficiently and keep it from going out the chimney

Gets pretty tricky when you try and analyze the total efficiency of the stove. There are so many types of stoves and fireplaces. There is almost no way to generalize how well wood is going to burn in any given house and in any given stove. Sometimes, surprisingly fireplaces can cool a house down by drawing in too much air. All you can really do is look at how much heat you'll get per cord or per whatever unit of size you can think of.

 

[Highbeam]

Yes I understand that hard wood is more dense and thus has more btu's, but my question was just from a standpoint of how much difference based on the different types of stoves it would actually make in real world burning. I have filled the stove to the brim with Elm (when I could find it) and set the stove on low and got better than a forty hour burn once.

No stove will burn as long as the BK cat stove, they are special in that way. Also you may notice that the #1 and #2 most efficient stoves in the world are the BK king and BK princess.

You can't really compare the BKs to anything else. I also own a BK princess ultra after spending years dumping wood into a hearthstone heritage. Burn times are vastly superior.

 

[stihly dan]

How much wood fits in a blaze king? I can't imagine burn times that long, and enough heat output to heat a house for 2 1/2 days when its cold out. The math doe's not seem to work out. Well my math anyway.

 

[EXCALIBER]

The king has 4.32 cubic foot firebox. You can get a 40 hour burn time with it, however that is on low setting. So if its fairly decent out you can run it on low to keep the house at 72ish (good for shoulder season). Now if its say 20 out you have to run it with the thermostat a little more open, thus lessoning the burn time. I would say I usually fill the stove once every day if its 0-20 degrees out. If it gets real cold I put in some Elm to really heat things up.

 

[Steve NW WI]

How much wood fits in a blaze king? I can't imagine burn times that long, and enough heat output to heat a house for 2 1/2 days when its cold out. The math doe's not seem to work out. Well my math anyway.

It's simple Dan, they're 140% efficient. Having to haul wood back up the stairs and out of the house is what keeps me from buying one.

:big_smile:

 

[EXCALIBER]

Yeah and if you had as much hot air as Steve, you wouldn't need to cut any more wood. :msp_scared: Now where would the fun be in that? They are just simply very efficient stoves, with a wider range in heating due to the cat. You simply can not get that wide range of heating ability without the cat. Is it the best stove for everyone, maybe not. I certainly have not seen anything else that I would consider to be of a better design.

It just seems to me we would never put a person on the moon, no one would buy unleaded gas as leaded is better, we won't buy anything made in China and so on. Times and technology change. Some people just cannot accept that. I guess Elvis ain't dead either right?
http://www.blazeking.com/PDF/posters/Crowining Achievement 2012 Ad.pdf

 

[Blazin]

I have a 5648 CB OWB and burn a lot of softwood (pine, poplar,hemlock, box alder), mainly in the fall and spring. I found the best lasting to be hemlock which I have a bunch of storm damaged trees to clean up on 50 acres. Even in the coldest weather I'll still throw some softwood in the mix, I definitely don't get the burn times out of softwood compared to the oak, maple, beech, elm and yellow birch I have in my pile.

 

[Whitespider]

The thought came up that many people, myself included, never have seen a real piece of hardwood.

That’s because you live in that god-forsaken place called Nebraska… the only place worse is Kansas (and certain parts of Oklahoma). I get out in Nebraska for work from time-to-time; once you drive under the archway and get west of Kearney… well, you might just as well have landed on the moon. I swear I could set the cruise control, let go of the wheel, take an hour nap, and wake up still zooming straight down the road… if it wasn’t for that god-awful wind. I’ve stood there, leaning 6-degrees into the wind so I wouldn’t blow over, watching small cars tumble down the street, and my customers will say, “What wind? Oh, this ain’t bad, yesterday the bank blew down.” Heck, I don’t even start the engine driving back to Iowa. Y’all ain’t got any trees because the wind blows all the seeds into Iowa and Missouri! And then, if for some strange reason the wind doesn’t blow, there ain’t a cloud in the sky… or a tree to make shade. I ain’t never been so sun and wind burnt as I was after working a week out there one July… except for the week I spent in the panhandle of Oklahoma.

Anyway, that was way off topic… but I just had’ta. :jester:

 

[Steve NW WI]

Spidey, if you didn't like NE, stay out of the Dakotas. Same thing, only colder. oke:

That nice warm breeze we had here the last few days turned around last night. Instead of the hot air coming out of Ioway otstir:, we're now enjoying that cold metric Cannuck wind. Wish they'd switch to Fahrenheit up there, maybe it'd be warmer!

Got two 3 gallon pails of ashes to spread on the driveway/skating rink. One more benefit of wood heat.

 

[EXCALIBER]

Nebraska's not bad, you just forgot to screw a 2x4 to one boot to compensate for the breeze.