Why You Should Only Burn Seasoned Firewood

wood-stove-glass-door

With winter approaching and cooler weather upon us, people are beginning to load their their wood stoves with firewood. Hopefully they have purchased (or procured themselves) wood from early this year or last year, so that it has had a chance to dry out (‘season’). Burning wet wood or only partially seasoned wood in your wood stove is not a very good idea, and here’s why…


 
Wet wood provides MUCH LESS heat, and causes MUCH MORE creosote to form in the chimney.

Here’s why:

Today’s airtight wood stoves extract heat from wood in two ways.

1. The primary source of heat from a wood stove is the combustion of the wood itself.

2. The secondary source of heat is from the combustion of the gasified resins and unburned wood particles from the primary fire.

Unless your wood stove is a very primitive model, you’ll find a baffle plate of some kind near the top of your stove, between the fire chamber and the flue outlet. This is where the secondary burn occurs, and where your stove creates up to half the heat it delivers to you. The amount of secondary combustion that occurs varies widely from model to model, mainly due to advances in heat extraction technology over the years…

A twelve-year-old baffled airtight can be presumed to operate at about 45% efficiency, while many of today’s EPA approved wood stoves exceed 70% efficiency. The big difference between the older wood stoves and today’s wood stoves can be found in the baffle area, where newer, more sophisticated techniques have been incorporated to re-burn the exhaust gases.

When you add an unseasoned or wet piece of wood to your fire, the water contained in the wood heats up and turns to steam, which mixes with the exhaust gases and extinguishes the secondary burn. Regardless of how sophisticated your baffle system is, this cuts your heat output by up to 50%, and results in cool, water-laden exhaust filled with unburned particles and exhaust gases. This wet, heavy, high-density smoke travels very slowly up the chimney, where it cools even further, condensing onto the walls of the flue and causing excessive creosote formation. So, when you burn unseasoned or wet wood, you dramatically DECREASE your heat output, while dramatically INCREASING the likelihood of chimney fires.

Another drawback to burning wet or unseasoned wood is creosote formation on the viewing window. No matter how good the airwash design that keeps the window clean, it won’t work when the firebox is full of wet smoke. A blackened viewing window is one of the most reliable indicators that the wood is improperly seasoned.

 
The bottom line: Think ahead, and allow enough time for your wood to season before use in your wood stove.

 
Some data sourced from chimneysweeponline.com (no affiliation with us)

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28 Comments

  1. We burn two woodstoves each year to heat our home. One in the living room and one in the basement. Both stoves are soapstone with a catalyst. We have used them to heat our home since 2008 and have had no other heating bills. With the centrally located double flue chimney initially constructed in 1923, we felt that it would be safest to install two double walled stainless flue liners before attempting to heat the house with the wood stoves. The liners are 30’and 25′ in length. It is very important to burn only dry, seasoned wood as we have learned that burning damp or green wood will quickly block the liners with creosote, cutting down the draft and efficiency of the wood stoves. When burning dry, seasoned wood from late October to April, cleaning the flue liners each year reveals a slight accumulation of ash and light creosote buildup which flakes right off with the cleaning brush. We really enjoy the view and warmth of the wood stoves in the winter months. Using dry, seasoned wood allows us to maintain wood stove efficiency and safety throughout the burning season.

  2. Several years ago we had a fireplace put in our home. Within a matter of weeks we had a chimney fire. I did not know anything about a chimney fire but I knew what it was immediately. Sounded like a helicopter landing on the roof. When the following spring came some of the logs that were left over started to sprout leaves as it turned out the wood I was burning was from a large willow tree. One should pay close attention to the type of wood you burn. Lesson learned!

  3. I also have 2 wood burning stoves in my current home along with furnaces and in-floor hot water heat. The poor furnaces and in-floor never get used. Basically I HATE to buy propane. :-)

    For firewood I use about anything that will burn and is dry, scrap lumber off of construction sites, trees that have blown over, Firewood/trees that we cut at sites, and hundreds of Pallets/Crates. I do keep enough wood (trees) around to allow it to sit at least 1 year, most of the time a few years.

    I have no wish to have a flue fire, bad news for sure. FYI a lot of people refuse to burn Elm or Cottonwood, they say it “stinks to burn…. My reply, “get your nose out of the stove and you wont smell it, it’s not a loaf of bread cooking in there” :-)

    Fortunately I only need to clean my flues once a year and do an inspection on the flashings.
    NRP

  4. I use a pellet stove. It produces a lot of heat. Is also very efficient. Very little heat goes to exhaust. Does have the drawback of requiring electricity to operate.

    I could have put in a wood burner but didn’t want to deal with about forty feet of double or triple wall woodstove pipe for exhaust. Was over $30/foot when I looked.

    Has anybody tried using Presto Logs in a woodstove? They can be had for about $200/ton locally. Well 390 5lb logs anyway. Maybe even burn the pallet that they come on.

    Anyway, the most efficient wood stove out there is a lot less efficient than the least efficient pellet stove.

    1. @ Mr. Presto
      I actually cut up Presto Logs for starting when I get lazy—er.
      Cut em up on the old Band-Saw in 1″ long, than 1/2 the pieces and light with a match. Not sure I need a full pallet though hehehehe

      I will agree pellet stoves are very efficient, unfortunately you still have to purchase the fuel. My problem is I’m a cheep old SOB HAHAHA, plus the fact I’m fat and need the exercise :-) :-)
      NRP

        1. @ Mr. Presto
          No No, I just use a small piece to start the rest of the firewood, I’m an old fart that burns Trees by the hundreds. You know, an Environmentalist worst nightmare. :-)
          NRP

          1. Kindling. A lot cheaper than buying firestarter. Presto Logs are very easy to break into shorter pieces. Strike against a rock or a curb. Not trying to take away playtime with the bandsaw.

          2. @ NRP Oh my, I think I was cut from the same mold, burn 5 to 6 cords of seasoned hardwood a year in the wood stoves but love my new garage stove. It burns anthracite and/or bituminous coal. The anthracite burns as hot and clean as ever but wow, the bituminous puts a nice cloud out the chimney for the “environmentalist” until it “cokes” and then it burns hot and clean.

      1. Odd thing about prices this year. Bagged pellets cost less than Presto Logs.

        With oil prices being lower right now there are discussions going on about whether pellet prices will go down. The argument being that it is cheaper, and more convenient, to use oil.

  5. Clean your chimney each year, before heating season
    Burning fir increases the creosote build up.

    Chimney fires are a bad thing, the older the chimney, the worse they are.

    1. Wrong on the fir causing creosote. Up here in Prince Edward Island, we have mostly spruce (both White and Black). I’ve been burning it for sixteen years, no issues. Only clean my flue every three years and only get about two cups of creosote. As the article mentions, wood dryness is the factor, not the type. You can get creosote with wet Oak

  6. If you only have damp wood, does it help to bring it inside and dry it out before burning it?

  7. I had mine cleaned after 7 years for the first time and it really needed it. I thought the cleaning logs would work but they don’t. I was lucky I didn’t have a chimney fire. I usually burn about a cord to a cord and a half during the winter and some in the fire pit in the spring, summer and fall. Had to have a new cap put on and found out how cheap the original was made when it started leaking. Its ready now.

  8. We are VERY new to wood burning. Our stove was put in a month ago (Lopi Cape Cod). I hate going into our first winter not knowing how much wood we will burn. I’m guessing we will run out. We have no clue what we are doing. Thank god for YouTube videos. :)

  9. We have a wood stove here in Hawaii. At our elevation it does get chilly at night in the fall and winter. Not any where as low as some of you live with that’s for sure! But still, when it goes from 75 down to 50 it feels cold. It snows here too at the summit and it’s funny that people go play in the snow in the morning then go to the beach in the afternoon.
    I have quite a bit of good seasoned wood. People give it to you just to haul it away. We have a fire ring in the yard too. It’s funny how comforting sitting around a fire on a cool night can be…

    1. @ steelheart
      Sitting around a nice “camp fire” is the most hypnotizing there is, period. Then when the “stories” get started, I have had many of absolutely wonderful nights just enjoying family and company in the mist of a GREAT camp-fire, and ya know it’s funny you never even notice the snow falling at times like that, it just adds to the gratification of the moment. Your comment sure did bring back good memories.
      NRP

  10. I have a high efficiency wood stove and don’t use wet wood, but there are sometimes desperate purchases that include wet wood like when I ran out 2 years ago do to an extended cold winter. Dry wood was non-existent to buy since people ran out long before I did and bought it all up. Those who sold me the wet wood are on my Sh*t list, but I had to do extra work to make it burn hot.

    I split the wood quarters into smaller pieces and stood them next to the stove to cook out the moisture with what dry wood I could find in the forest to heat the stove. I never left the stacks unattended next to the stove. I also had boxes of this split-down “cooked” wood stored inside, so when one batch was dry, it was stored to burn and dry the next batch of wet wood. I still do this practice because some wood is wetter than others, especially the big chunks.

    If you happen to get wet wood and want to season it faster, splitting it up into thinner pieces and stacking it for air-flow can cut drying time in half.

  11. I have been burning wood for heat all of my adult life, and through all the years I have never had a creosote problem, ever. When I lived up north I burned 20 cord a year, but now down here in the south, I burn about 5 cord. Yes the wood must be hardwood, and yes it must be seasoned as wet wood does not burn hot enough, even seasoned wood that is wet does not burn hot enough. Notice I am using the word HOT a lot. To keep the chimney clean, the fire must be hot because that is when the creosote builds up. As the exhaust goes up the chimney, it cools, thus allowing the creosote and smoke particles to attach to the chimney. Burn it hot, but do not allow so much air to enter to cause the pipes to turn cherry red, as that is when the fire starts. Proper control of the input air is essential for proper burning. I had a fireplace in my home I live in now and I tore that out, rebuilt the opening and installed a wood stove with outside air to feed the stove. This is important as well as you need to create a “positive” in the house. With using inside air to feed the stove, this creates a “negative” in the house and all the air going up the chimney, thus seeps in where ever it can, bringing the cold air with it, through doors, windows, cracks etc. The object is to heat the house and not all the cold air the stove is sucking in because is is using inside air and not outside air. Now back to the chimney. When I rebuilt the fireplace, turning it into a wood stove, I also installed a new dual wall insulated chimney from the stove all the way up through the roof. I have just a foot and a half of normal black wall stove pipe for the damper, and all the rest is shiny stainless steel insulated chimney. This is a very safe chimney as it stays a constant temp inside the chimney all the way to the top, reducing any cooling of the wood stove smoke, reducing creosote build up. It is so effective that I can actually put my hand on the chimney right above the wood stove for a few seconds without burning my hand. My temp meter shows 103 degrees even when that stove is rolling for all its worth. Very, very safe chimney to use as it helps to prevent fires due to improper operation of the stove. Even if the stove gets too much air, such as running it with the doors open, the chimney exterior does not get hot enough to set anything on fire.
    Just my two cents worth, (not that two cents is worth anything these days), of what I have learned with over 30 years of heating by wood. It is the best heat in the world!!!

  12. We use an outside wood burner. It heats water that runs through special hoses in the floors. It’s great though it can take a few days for the entire house mass to heat up, especially if the cold snap comes on suddenly. Our hot water for personal use is also heated.

    We have a firewood business, selling nearly 100 cords some years. Only seasoned hardwood. My favorite is honey-locust. Burns hot and sweet smelling wood smoke. I love that smell, but we will burn any hardwood but sweet gum. Too gooey and nasty when heated.

    In addition to the outside burner, we have a fireplace with insert in the living room. We have found that besides being nice and cozy, it really takes the chill out of the air during those damp, nasty cold days. (We live in the Midwest.)

    In our last house, we had a wood burner in the basement that blew hot air through the duct system.and a free-standing wood burner in the living room with a blower. That house was never warm. That’s why we went with a central system when we built the new one. We can run the electric pump (which moves the hot water) with a small generator if needed.

    1. With that much wood around you should look into converting the generator to run on wood. The technology has been around since WW2.

      1. Interesting you would say that. My husband is investigating some technology that uses wood to produce electricity on a scale large enough to run the house. Anyway, we shall see…..

        1. It’s called gasification. Used a lot in Europe during WW2. Has almost certainly improved since then.

    2. Something you might investigate is installing a small generator in the fluid line. You won’t be able to power a house. You might be able to charge a battery or a USB device. Micro or Nano hydro.

  13. We live on the Canadian prairies & it is often in the -30’s in the winter. We heat with wood but have a back-up high efficient propane furnace for when we go to visit the kids for a few days. We burn between 3 & 4 cords of white poplar each year. Our wood stove is in the basement & we use a fan to help with circulation. If we didn’t have power we would still be OK as even if it got to -40 we could live down there to be cozy & the upstairs would still be livable even if a little need a sweater chilly. Our house has well insulated 2″ X 6″ walls & a lot of insulation in the attic. Another thing we have is a good shelter belt that slows down those nasty NE winds we get in the winter.

  14. I too have woodburners on both ends of my house .2600 sq. ft. We burn mostly ash and white oak. But Maple trees are also plentiful.In agreement with all that seasoning of wood is critical to successful wood burning. I had a chimney fire early on and took great measures to over design the replacement chimney. Double wall stainless in a run that keeps the flue not less than 8 inches away from any combustable, and appropriate cap.

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