Creosote - Softwood versus Hardwood

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toddnic

Minister of Fire
Jul 13, 2013
782
North Carolina
We just finished our third season heating with wood. This year was our first year burning pine and hemlock in the shoulder season and hardwood during the colder months. I regularly clean the stove and chimney at the end of each season and have been measuring the amount of creosote each year. During the first two years heating with wood, I had approximately 1/2 gallon of creosote at the end of each season burning approximately 3 cords of wood each season. This season I burned about 1 cord of softwood and 2 cords of hardwood and had approximately 2/3rds gallon of creosote. Wondering if this increase is normal burning a mixture of softwood and hardwood?

The moisture content in the wood (hardwood and softwood) was fairly consistent with the prior years between 19% and 24% in that we live in a very moist climate. It was somewhat surprising to have an additional 50% more creosote than previous years. I'm still not overly concerned in that the creosote buildup was minimal as compared to the old "smoke dragon" of the 1990's but I thought that it was worth sharing my experience this year while burning a mixture of softwood and hardwood. FYI, I am planning on burning softwood next year in the shoulder season. I wonder if there will be any difference from this year? Beyond moisture content and the type of wood being burnt, what are the other factors that would cause creosote buildup?
 
Dry soft woods should produce no more creosote than dry hardwoods. I have a feeling the increase had more to do with the mild winter than the change to partial softwood. In mild winters the stoves dont get burnt as hard and spend more time shut down so buildup increases. Your wood is also a little wet which is contributing to the problem as well. Is that 19 to 24 on a fresh split face?
 
Dry soft woods should produce no more creosote than dry hardwoods. I have a feeling the increase had more to do with the mild winter than the change to partial softwood. In mild winters the stoves dont get burnt as hard and spend more time shut down so buildup increases. Your wood is also a little wet which is contributing to the problem as well. Is that 19 to 24 on a fresh split face?
The moisture content is on a fresh split. It is difficult to get below 20% moisture in the western NC mountains. We had over 60 inches of rain last year. Thankfully I'm about 3 years ahead on wood now and have it stacked off the ground as well as having the 2016/2017 firewood covered.
 
Thankfully I'm about 3 years ahead on wood now and have it stacked off the ground as well as having the 2016/2017 firewood covered.
If it rains that much it should all be covered. Wood dries allot quicker if you keep water off of it. In some climates you can easily get away without top covering but in wet climates it is a must. And there really is no down side to top covering anyway
 
I agree with bholler. Way more cold starts and way less 24x7 burning. I have not gotten to mine yet but expect more. If mine is a lot more, I will blame playing with a damper this past season too!
 
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The only native pine in my county is short leaf. No matter how seasoned you get it, it is still a major creosote producer. A well seasoned split of short leaf almost looks crystallized due to the high content of resins and oils. You can light it with a match like super cedars and the smoke it produces is the color of the smoke produced by a burning tire. Some of the introduced species such as loblolly will season out well and produce no more creosote than any other seasoned wood. A mild winter could definitely be the source of your extra creosote but what kind of pine you were burning could account for it as well.


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+1 on top covering your wood. I live in the WNC as well and I have issues with moisture content. By keeping it top covered, my wood averages about 18%. I have some wood as low as 14%. I use tarps and cardboard boxes...cover the stacks w/ cardboard and put the tarps over that. Keeps the tarps from getting snagged and ripped by the wind as much. Wish I would have discovered that secret a while ago because I have some holey & leaky tarps now. Just have to get some wax coated boxes I guess... ;)
I also make sure I have some space between the pallet rows. Enough really to squeeze through, but none more than 2 feet. Helps with the air flow through the stacks.
Something to try...
 
I live in the NC mountains, I am 30 miles west of Asheville. Yes, it is rainy, rainy.

I am attempting to deal with the problem with this little woodshed I built last year.

IMG_0940_zpspf0rxlen.jpg

It is 8x12. Sets right out in the sun all day. Metal roof absorbs a lot of solar heat. You get some ventilation, if you open the door.
Preliminary results are promising I will let y'all know this fall how well my solar powered wood roaster works.
Gonna load another load of black walnut in a week, along with a half pickup load of red oak.
 
You guys in NC get lots of rain, but you also get lots of nice clear, sunny days. I lived in Greenville, SC and we had tons of rain, but man did the sun shine. Not like here in the cloud belt of the NE.
 
Following along with the burning with restricted air logic - most softwoods seem to offgas more vigorously and coal less than hardwoods. Not only is there the shoulder season burning habit differences to consider, but presumably a greater need to close down the air to keep the house at the desired temperature when burning softwoods. I try to use my larger splits when I want a slower burn.
 
For shoulder season burning we burn hot still, maybe not as hot as 24/7 burning, but enough to get good secondary combustion. If the temps are mild outside then we just the stove go out and let the mass of the stove continue to heat the house for many hours. Burning softwood like this, creosote has never been an issue.
 
For shoulder season burning we burn hot still, maybe not as hot as 24/7 burning, but enough to get good secondary combustion. If the temps are mild outside then we just the stove go out and let the mass of the stove continue to heat the house for many hours. Burning softwood like this, creosote has never been an issue.

Ditto.
 
For shoulder season burning we burn hot still, maybe not as hot as 24/7 burning, but enough to get good secondary combustion
This - if you don't have secondary combustion your burning too low, if your using soft woods that off gas to fast in your stove to get good secondary lite off and make it too hot in the room then load less.
 
For shoulder season burning we burn hot still, maybe not as hot as 24/7 burning, but enough to get good secondary combustion. If the temps are mild outside then we just the stove go out and let the mass of the stove continue to heat the house for many hours. Burning softwood like this, creosote has never been an issue.
Yes it absolutely can be done right with little to no extra buildup but on average we see more buildup in chimneys when we have mild winters.
 
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On average, what percentage of the chimneys cleaned have older, pre-EPA stoves connected to them in this region?
 
On average, what percentage of the chimneys cleaned have older, pre-EPA stoves connected to them in this region?
I would say roughly 20 to 25% of the chimneys we work on. But we see more buildup in many chimneys with modern stoves as well. Like I said it absolutely can be done right but what can be done and what is done are many times very different.
 
Yes, a new stove can be run poorly and smolder or forced to burned partially seasoned wood and the results will be a dirty chimney.
 
Yes, a new stove can be run poorly and smolder or forced to burned partially seasoned wood and the results will be a dirty chimney.
yeah and some people just wont listen
 
It isn't that simple to me. This winter was mild. My wood was not seasoned perfectly. Starting a big huge fire and letting it go out, gives you a hot room and then a cool room.
Frankly, I'd rather clean the chimney every season and knock out some buildup, then go hot and cold, and have to start more fires from scratch. I like to keep it going and maintain a good coal bed..then throw 3-5 splits on and let that cook down for a few hrs.
 
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For sure there are other methods. What works best depends on the house insulation, area heated and stove. The cast iron jacket on the T6 slows down warming and release of the heat, then after the fire has died down it continues to slowly release heat for hours. When it's 45F outside, and 68F inside, I can start up a 7-8 split fire, let the stove top get up to about 550F, then gradually die down. Interior temp never gets above 72F and will stay that way until about 6-8pm depending on how hight the daytime outside temps got. If I want more evening heat I do another short fire with just 4 splits. Often there are enough coals for a quick restart at that time.
 
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