mixing green and seasoned wood

[blackie65]

I am approaching, I hope, the end of the heating season and have pretty much exhausted my supply of seasoned wood. I do have a decent start on next years wood with a decent stack of wood that was cut this winter. My question is: If I have a good fire already going in my wood furnace, is it ok to mix in a few logs of the green wood with the seasoned wood. I know I don't want to burn exclusively green wood but I still have a few nights that I need a fire. If you guys have input please let me know what an acceptable ratio of seasoned to green wood would be. Thanks for your infinite wisdom :thumbsup:

 

[Car Doc]

Yeah you and me both I am doing it again this year I wasn't prepared as I want to be.

I don't like it but its still better than turning up the gas heat, they say its more creosote heck I don't know but if it burns I do it.

The pipe needs cleaned or replaced anyway come next winter if you use the black thin wall stove pipe like I do, 2 years is it for me fwtw.

 

[20 20]

just keep check of the chimney, green wood no matter what it is will give a lot of creosote.

 

[blackie65]

Yeah you and me both I am doing it again this year I wasn't prepared as I want to be.

I don't like it but its still better than turning up the gas heat, they say its more creosote heck I don't know but if it burns I do it.

The pipe needs cleaned or replaced anyway come next winter if you use the black thin wall stove pipe like I do, 2 years is it for me fwtw.

that was kinda my thought. I'm close enough to the end of the season that I don't feel the creasote buildup will be that much

 

[DAY]

Green or not, the 'creosote' percentage is the same. It condenses in the pipe due to temperature- all that water in the green wood makes it tend to burn cooler. Burn your stove hot, and it leaves the chimney as smoke.
That said, hardwoods are better, both from a BTU, and a creosote POV, than soft woods.
In a pinch, if you haven't cut a good supply by Fall, felling a tree with the leaves still on can provide an acceptable source of wood for the winter. (The leaves will transpire a lot of the moisture from the wood, before they curl up their toes.)

Wood warms you twice; once when cutting, again when burned.

 

[grnspot110]

As stated, keep a check on the chimney. Some woods (Honey Locust, for example) burn better green than dry! The amount of heat going up the flue makes more difference than the dryness of the wood. ~~ grnspot

 

[Western]

Try this link, It may help set a few facts for you.
Best burning wood firewood

worth the read, dispels a few myths too, such as burning pines.

 

[LD1]

Yes you can do it, but as others have mentioned, keep an eye on the chimney.

And I will offer two peices of advice on this subject.

Assuming you have some wood in the house ready for the next time you fix the fire (my parents start the season with about 5 cords already tossed in the basement). Try to get as MUCH of the "green" wood indoors and near the fire. Also, split it as small as you can and still keep good coals. This will help it dry out.

Second peice of advise, if you must burn green wood, try to burn ash. It has a lot less moisture even when green compared to most other woods. And it tends to burn decient when green as well.

 

[DAY]

Madrone? Eucalyptus? Good for fires, yes, but here on the East Coast the delivery cost is a killer!:laughing:

-Other than that, lots of good info in the link on burning wood.:thumbsup:

 

[20 20]

Green or not, the 'creosote' percentage is the same. It condenses in the pipe due to temperature- all that water in the green wood makes it tend to burn cooler. Burn your stove hot, and it leaves the chimney as smoke.
That said, hardwoods are better, both from a BTU, and a creosote POV, than soft woods.
In a pinch, if you haven't cut a good supply by Fall, felling a tree with the leaves still on can provide an acceptable source of wood for the winter. (The leaves will transpire a lot of the moisture from the wood, before they curl up their toes.)

Wood warms you twice; once when cutting, again when burned.

I agree with what you wrote except about dry soft wood. I burn pine and have been for years it makes no difference on the amount of creosote, from what I have witnessed creosote becomes a problem with wet/green wood whether it be hard or soft. With that being written, you are correct most hard wood will give more BTU's. The ole "don't burn soft wood" is nothing more then a wives tail. The key to having a good burning fire is, make sure the wood is seasoned/dry, that goes for either soft or hard.

 

[DAY]

You're right; the link above has good info on hard/soft. The "problem", if there is one, with soft woods is they have less BTU's per pound. That's fancy talk for they burn faster. As noted in the link, you get more bang for your buck burning hardwoods. But I bet most of the folks here don't buy firewood!

We burn cottonwood ( a trash tree) during the daytime, and seasoned walnut and/or locust overnight. Getting up to feed a baby is one thing- feeding a fire is another!:laughing:

The secret to a creosote free chimney is (A) insulated pipe, and (B) hot fires. The masonry stoves popular in Europe, where wood is scarce, burn small, very hot fires to heat the masonry mass, instead of cranking up a blast furnace the way we do here.

 

[beenthere]

have less BTU's per pound

I think Day meant less BTU's per volume. As wood has the same BTU's per pound, and given pine has some extra resins may even have slightly more than hardwoods.

Just takes more cords (volume) or number of trips (volume again) to the stove with lower density woods than the higher density woods.

And cottonwood is less dense than some of the pines. So dry wood is the key. Just waste potential wood energy when having to convert the water to steam.

Some woods, like ash and hickory, burn better when green than other woods. So there is another variable to add to the OP original question/dilema.

 

[arrow]

I think Day meant less BTU's per volume. As wood has the same BTU's per pound, and given pine has some extra resins may even have slightly more than hardwoods.

Just takes more cords (volume) or number of trips (volume again) to the stove with lower density woods than the higher density woods.

And cottonwood is less dense than some of the pines. So dry wood is the key. Just waste potential wood energy when having to convert the water to steam.

Some woods, like ash and hickory, burn better when green than other woods. So there is another variable to add to the OP original question/dilema.

Correct Creosote has little to do with wood type and more to do with chimney temps. People who damp down their fires to get a slow and longer burn are subject to creosote build up because this method also produces cooler stack temps. This is where an insulated or internal chimney helps. If you burn hot fires and mix in some green wood, you will simply convert excess moisture in green wood to water vapor first instead of ambient heat as BT states. If you keep up your stack temp with hotter rather than damped down fires, you'll get little additional creosote build up. Your green wood will simply not attain the heating efficiency of drier wood is all.

 

[kco]

Many in my rural area in the interior of BC heat entirely with firewood. I have an electric furnance and wood furnace connected to the same hot air duct system and never use the electric furnace.

Most furnaces and stoves had metal pipes feeding into masonary chimneys. But that is changing because companies will not insure such a setup. The acceptable solution is to run a stainless steel liner inside the masonary chimney and connect to that.

I imagine it is effective in reducing creosote build up.

It took me four years to learn how to run the system so we weren't forcing ourselves out with the heat or wasting wood. The key for us seems to be to let the house cool a bit at night and start each morning with a hot fire to warm up it up again. Then we maintain heat as required through the day by regulating the size of the fire by how much wood we put in at one time.

I err on the safe side and have the chimney professionally cleaned and checked once per year. We have never had a creosote problem and the chimney sweep said we could safely go 2 years between cleanings. I'll continue to have him come each year simply to check everything. This year we replaced 4 cracked fire bricks that line the bottom sides of the furnance.

It also helps that I split my wood fairly small, stored under a roof, and keep one year ahead on the supply.

So the dry wood certainly helps. But I believe a hot fire once per day helps in keeping that harmful shiny creosote out of the system.

 

[tcartwri]

I used to own a wood electric furnace in my first home. Like you, I ran out of dry timber before the season was half over.. anyways, started mixing green with dry, and then eventually mostly green. The result was a river of creosote flowing out of the chimney clean out, two chimney fires, and an etched basement floor from the acids in the creosote. My experience was that a forced air furnace pulls too much heat out of the flew gasses, and that it was almost impossible to monitor the furnace closely enough to prevent the creation of creosote.

I will never forget the evening I came from work, started the fire in the box, walked away for ten minutes, and came back to an out of control chimney fire. The pipe exiting the furnace was white.. almost see through.

The furnace was sold that summer. Wood was far too expensive anyways.

 

[arrow]

I used to own a wood electric furnace in my first home. Like you, I ran out of dry timber before the season was half over.. anyways, started mixing green with dry, and then eventually mostly green. The result was a river of creosote flowing out of the chimney clean out, two chimney fires, and an etched basement floor from the acids in the creosote. My experience was that a forced air furnace pulls too much heat out of the flew gasses, and that it was almost impossible to monitor the furnace closely enough to prevent the creation of creosote.

I will never forget the evening I came from work, started the fire in the box, walked away for ten minutes, and came back to an out of control chimney fire. The pipe exiting the furnace was white.. almost see through.

The furnace was sold that summer. Wood was far too expensive anyways.

You raise a critical point. Creosote condenses in a cooler chimney. Burning green wood or I should say all green wood creates a situation that causes chimneys to not acquire sufficient temps to thwart creosote build up. Too much heat is wasted in attaining steam instead of heat, This water vapor actually cools the chimney and creates a creosote condensate lining the chimney. This is what fuels and sustains a chimney fire better than any other type of creosote. Its as if you poured liquid wax down the chimney and it can get you in trouble right quick. Some people do not even realize they have had a chimney fire when just the flakes catch and are quickly extinguished. Have the condensate catch fire, and now its as if there is a locomotive in the house. Unseasoned wood rounds should never out number the seasoned rounds and for safety sake, should not amount to more than 1/4 of the wood in the furnace. Thanks much for bringing this up.

 

[kco]

I used to own a wood electric furnace in my first home. Like you, I ran out of dry timber before the season was half over.. anyways, started mixing green with dry, and then eventually mostly green. The result was a river of creosote flowing out of the chimney clean out, two chimney fires, and an etched basement floor from the acids in the creosote. My experience was that a forced air furnace pulls too much heat out of the flew gasses, and that it was almost impossible to monitor the furnace closely enough to prevent the creation of creosote.

I will never forget the evening I came from work, started the fire in the box, walked away for ten minutes, and came back to an out of control chimney fire. The pipe exiting the furnace was white.. almost see through.

The furnace was sold that summer. Wood was far too expensive anyways.

The key to heating with wood is proper installation, operation and maintenance.
My installation seems different from the one you had. I've attached a photo. The electric furnace is the white box on the right side and its blower only circulates air in the plenum that surrounds the wood furnace. Except for the chimney and thermostat-controlled air inlet below the furnace door the firebox is sealed. The blower does not move any air from around the chimney.

A thermostat opens the furnace air intake if the room temperature calls for it. If the fire gets too hot the other thermostat closes the air intake until it cools. The blower only operates if the furnace is fairly warm. Otherwise heat circulates by convection. We set the electric furnace at 64 F and it will take over if there is no wood fire.

The cleanout in the bottom left of the photo is no longer operative. The stainless steel liner (which was installed to meet insurance requirements) runs directly to the furnace chimney outlet. Although it looks bad, the blackened area about the furnace door is not dangerous. It is from over 25 years of small amounts of smoke that sometimes escapes as you start or reload the fire.

Because it is also setup for air conditioning the system is a bit more complex than for just wood. The "winter" setting directs air from the furnace blower along the bottom duct to the bottom of the wood furnace. The "summer" setting directs it up through the air conditioner exchanger to the left of the electric furnace and top of the plenum above the furnace.

I think a key to operating safely is to use only dry wood (my dries for at least 18 months in a covered area). Also, we make a point of burning at least one hot fire each morning and never have the dangerous shiny-black creosote. I have the furnace and chimney cleaned by a certified installer once per year. I could do it myself but find in worth the $120 for the peace of mind.

Wood is free where I live except for the work (which I enjoy) and fuel for cutting. There is more than enough naturally recycling wood on my acreage but unlimited amounts in the surrounding area. Wood gathering is allowed on crown land (which is the vast majority) simply by downloading and signing a form with the rules and having it with you while cutting. The rules are reasonable--no cutting live trees or "wildlife apartment" trees and within maximum lengths and diameters meant to prevent lumber and log harvesting. I've attached a copy of the permit.

Another advantage of the wood furnace is that it continually puts out heat rather than the hot-cool cycles of a typical gas, oil or electric hot air furnace.

Although the wood is free and heat is more comfortable it would not make sense to do this if I didn't enjoy the work. But I would end up burning much of the wood in open piles anyhow just to maintain access to the property.

The main advantage is it provides another excuse to play with the tractor.

 

[arrow]

The key to heating with wood is proper installation, operation and maintenance.
My installation seems different from the one you had. I've attached a photo. The electric furnace is the white box on the right side and its blower only circulates air in the plenum that surrounds the wood furnace. Except for the chimney and thermostat-controlled air inlet below the furnace door the firebox is sealed. The blower does not move any air from around the chimney.

A thermostat opens the furnace air intake if the room temperature calls for it. If the fire gets too hot the other thermostat closes the air intake until it cools. The blower only operates if the furnace is fairly warm. Otherwise heat circulates by convection. We set the electric furnace at 64 F and it will take over if there is no wood fire.

The cleanout in the bottom left of the photo is no longer operative. The stainless steel liner (which was installed to meet insurance requirements) runs directly to the furnace chimney outlet. Although it looks bad, the blackened area about the furnace door is not dangerous. It is from over 25 years of small amounts of smoke that sometimes escapes as you start or reload the fire.

Because it is also setup for air conditioning the system is a bit more complex than for just wood. The "winter" setting directs air from the furnace blower along the bottom duct to the bottom of the wood furnace. The "summer" setting directs it up through the air conditioner exchanger to the left of the electric furnace and top of the plenum above the furnace.

I think a key to operating safely is to use only dry wood (my dries for at least 18 months in a covered area). Also, we make a point of burning at least one hot fire each morning and never have the dangerous shiny-black creosote. I have the furnace and chimney cleaned by a certified installer once per year. I could do it myself but find in worth the $120 for the peace of mind.

Wood is free where I live except for the work (which I enjoy) and fuel for cutting. There is more than enough naturally recycling wood on my acreage but unlimited amounts in the surrounding area. Wood gathering is allowed on crown land (which is the vast majority) simply by downloading and signing a form with the rules and having it with you while cutting. The rules are reasonable--no cutting live trees or "wildlife apartment" trees and within maximum lengths and diameters meant to prevent lumber and log harvesting. I've attached a copy of the permit.

Another advantage of the wood furnace is that it continually puts out heat rather than the hot-cool cycles of a typical gas, oil or electric hot air furnace.

Although the wood is free and heat is more comfortable it would not make sense to do this if I didn't enjoy the work. But I would end up burning much of the wood in open piles anyhow just to maintain access to the property.

The main advantage is it provides another excuse to play with the tractor.

In my mind, the best way to heat with wood.

 

[beenthere]

I'll stick with my indoor wood "boiler" that is plumbed into my gas boiler. It just keeps the water warm (up to 180 deg) and if there is a call for heat in any of the 3 zones, the circulator pumps kick in. Has been heating a couple thousand sq. ft. every winter for over 30 years now. Can put too little wood in, but can't put too much in and get an over-run of heat.
There is a 9 gal waterjacket around the burning chamber, with sealed cast door and aquastat-controlled damper.

 

[kco]

I'll stick with my indoor wood "boiler" that is plumbed into my gas boiler. It just keeps the water warm (up to 180 deg) and if there is a call for heat in any of the 3 zones, the circulator pumps kick in. Has been heating a couple thousand sq. ft. every winter for over 30 years now. Can put too little wood in, but can't put too much in and get an over-run of heat.
There is a 9 gal waterjacket around the burning chamber, with sealed cast door and aquastat-controlled damper.

That's a real nice setup. I think hot water heating is best, producing an even heat without the "ups and downs" of the hot air system. We had a gas fired hot water system in our previous house.