Cold vs Warm Wood

[jadm]

I know this is a stupid question but here goes anyway.

Usually I enough wood indoors when I start or reload. It is room temp.

Occasionally I need an extra hard piece of wood - when I want a longer burn but hadn't planned for it - so I will go out to my oak pile (Have to 'import' it so it is used sparingly.) and grab a piece. Obviously it is a cold piece of wood. (It is dry (covered) and seasoned (4 Years))

Will the cold temp. of that piece of wood make any difference in how it burns?

 

[Fsappo]

Wood needs to reach a certain temp to burn, so I would assume some energy is used to get that wood hot enough. Probably the same way energy is used to dry wet/green wood before it burns. I'm sure someone here will offer a more scientific reply, but thats my two pennies.

 

[FireWalker]

Nope. A full load of cold wood is what my stove gets every time. I would imagine that with a cat stove this would delay recovery time but not a lot once the fire is going again.

 

[LLigetfa]

The only time you might notice a difference is if you were trying to start a fire from scratch. The cold wood picks up some damp and can be a bit harder to get going. It's the same as when you take something out of the freezer and see moisture condense on it.

On a good bed of coals, I doubt you could tell the difference. I don't think it's a good comparison to the energy lost to unseasoned wood.

 

[Backwoods Savage]

If I bring in a piece of wood from outside that is perhaps 20 degrees vs one that has been indoors at perhaps 75 degrees, that is 55 degrees difference in temperature. Inside a 1000 degree stove I doubt that would make a whole lot of difference. However, if the wood is damp, then that indoor wood would be dry and you could notice a bit of a difference, but still so small it might be difficult to measure.

 

[jadm]

Thanks for your replies. Now I can rest assured that my insert is more flexible than I am. ;-P

 

[Martin Strand III]

"The pyrolysis of wood is dependent on external factors, such as the way of heating, warming-up rate of the material, etc. Therefore, wood products do not have an explicit ignition temperature, but ignition takes place on a certain temperature range where the probability of ignition becomes large enough. The temperature for the piloted ignition of wood is typically about 350 °C, whereas the spontaneous ignition requires a temperature of approximately 600 °C."

If you like that, there is much more that can be found here:

http://virtual.vtt.fi/virtual/innofirewood/stateoftheart/database/burning/burning.html

Aye,
Marty

 

[Jags]

If I bring in a piece of wood from outside that is perhaps 20 degrees vs one that has been indoors at perhaps 75 degrees, that is 55 degrees difference in temperature. Inside a 1000 degree stove I doubt that would make a whole lot of difference. However, if the wood is damp, then that indoor wood would be dry and you could notice a bit of a difference, but still so small it might be difficult to measure.

And if I might even expand on Dennis' point. Your loading 35 pounds of wood with a possible temp difference of 55 degrees into a 400 pound stove at 1000 degrees. Thats like driving a nail with a wreaking ball - it don't stand a chance. :cheese:

 

[firefighterjake]

Yes . . . you need to pre-warm the wood before putting it into the firebox. Options to pre-warm the wood include tucking it under a nice quilt, putting a few hot water bottles around it or placing it in the oven at a low temp for 10-15 minutes.

Sorry . . . couldn't help myself . . . as others have said, there really isn't much of a difference between cold wood and warm wood . . . not like seasoned and unseasoned.

 

[cre73]

I had to laugh when I read this post. I keep a little wood in the house next to the stove for the next load. I always tell my wife I'm preheating it before I load it in the stove. I will say that it does seem that this wood takes off faster than cold wood when I bring it straight from the wood shed.

 

[Backwoods Savage]

If you can't dazzle them with brilliance, baffle them with......

 

[LLigetfa]

If you can't dazzle them with brilliance, baffle them with......

bull

 

[LLigetfa]

Yes . . . you need to pre-warm the wood before putting it into the firebox...
or placing it in the oven...

My mother used to put splits in the oven but that was because my father never subscribed to the notion of well seasoned wood.

 

[firefighterjake]

Yes . . . you need to pre-warm the wood before putting it into the firebox...
or placing it in the oven...

My mother used to put splits in the oven but that was because my father never subscribed to the notion of well seasoned wood.

Yum . . . nothing quite like nice, warm ash for dinner with a heaping side of maple with fresh butter drizzled over the top . . . and for desert oak a la mode.

 

[Hiram Maxim]

Well I guess I'm the only one who notice a HUGE difference?

I honestly don't ever even consider putting wood in the stove unless its been inside for at least 24hrs. :cheese:



Dennis, its not even fair to compare your wood to anyones on the planet...LOL

Its so seasoned I bet it has its own spice rack. ;-P

Cheers,Hiram

 

[wood spliter]

I make sure my wood for the re-start is in the house the night before. I think that's good enough for the small stuff. Once its going I bring in load when I need it.

 

[Deadcalm]

With our Esse woodburning range (what you Americans call a cook stove, I think), I always leave 3 or 4 splits in the bottom oven overnight. They catch readily when put in the firebox next morning...

 

[Battenkiller]

Of course it makes a difference, and it has nothing to do with a tiny bit of moisture that condenses onto the surface of the wood on the way from the wood pile to the stove.

Water uses up a lot of heat just going from the ice phase to the liquid phase. Not nearly as much as going from the liquid to the vapor phase, but enough to undo some of those precious percentage points of MC you achieved with that extra year of seasoning. Then there's the heat lost raising the frozen wood up to room temp from maybe -20º. That's about a 200 BTU total loss for every pound of water in the wood. For a 5-pound split at the much revered 20% MC, that's 200 BTU per split, gone for good... right inside your firebox.

 

[PapaDave]

Well, some of us are loaded with enough hot air that all we'd need do is breath on the splits as they come in the house. :cheese:
I doubt that would help Perplexed though.

 

[Slow1]

Of course it makes a difference, and it has nothing to do with a tiny bit of moisture that condenses onto the surface of the wood on the way from the wood pile to the stove.

Water uses up a lot of heat just going from the ice phase to the liquid phase. Not nearly as much as going from the liquid to the vapor phase, but enough to undo some of those precious percentage points of MC you achieved with that extra year of seasoning. Then there's the heat lost raising the frozen wood up to room temp from maybe -20º. That's about a 200 BTU total loss for every pound of water in the wood. For a 5-pound split at the much revered 20% MC, that's 200 BTU per split, gone for good... right inside your firebox.

Of course that same 200BTU per split is going to come from the room anyway as it warms up to room temperature, thus cooling the stove room and requiring more heat from the stove right? So it is just a question of when you "pay the price" - slowly over time as it warms up in the room, or quickly when it gets tossed in the stove. Sounds like a zero sum game to me.

However, with this said I bring my wood in and let it sit in the rack for a day or two - always try to keep ahead of things. This is not just because I hate "Having" to go outside to get wood just in time, but also because I don't have a properly covered wood stack on the deck near the door so there will be snow, ice, or rain on the stack at least some days of the year. I simply refuse to put wet wood into the stove (even if it is 'just surface moisture'). So, as a course of habit and insurance I figure 24-48 hours sitting in the rack near the stove is a good policy.

A full rack of cold wood does cool the area down for a short while, but we seldom notice unless you are standing right next to it with bare feet 5 minutes after bringing in particularly cold wood.

 

[Battenkiller]

Of course that same 200BTU per split is going to come from the room anyway as it warms up to room temperature, thus cooling the stove room and requiring more heat from the stove right? So it is just a question of when you "pay the price" - slowly over time as it warms up in the room, or quickly when it gets tossed in the stove. Sounds like a zero sum game to me.

As far as net BTUs delivered to the living space, you're absolutely right. But what is most significant is what goes on inside the box, in that it lowers burn temps - by as much as about a 5% increase in MC in the wood does. With all the talk here of the absolute necessity of getting the wood down to at least a 20% moisture content in order to get a good, safe burn, I think this issue of frozen wood is very important to address. It's particularly important to those new burners stuck with marginal wood in the first place. If they are leaving their damp frozen wood outside until they're ready to burn it, they are being penalizing twice for the same sin.

And yes, bringing in frozen wood lowers the room temps somewhat. I know that because I routinely bring in up to a cord of frozen, green wood into my basement about every other week. In my case, the loss of heat in welcome as it keeps the temps in the stove room out of the 90º range and adds needed moisture to the air. Wood is cheap and my stove is a good match in output for my living space. The most important thing to me is getting a clean burn, not in squabbling about a little loss in net heating efficiency.

FWIW, much of the latent heat of vaporization is eventually condensed back into the sheetrock walls and cement floor and floor joists and the whole rest of the house in general. Therefore, I regain just about all of the heat that is lost during evaporation, so there is a net gain at times, at least up to the equilibrium MC of the surrounds. At all times, however, it is not lost inside the firebox where it can do the most harm to clean burns.

 

[LLigetfa]

Well, some of us are loaded with enough hot air that ...

they probably don't need a wood stove.

I would not discount the amount of moisture that condenses on frozen wood particularly when trying to start a fire with already marginal wood. As for those that are leaving their damp frozen wood outside until they’re ready to burn it, being penalizing twice for the same sin, it's like having fines doubled for speeding in a construction or school zone.

 

[roddy]

when you cook a big ole turkey,do you chuck the frozen bird in the oven,or do you thaw it out for a few days then cook it,same principle for wood.....

 

[LLigetfa]

it,same principle for wood.....

Really? Do you serve up baked firewood with a side of gravy? Turkey you cook, wood you burn until there's nothing left to burn.

 

[roddy]

it,same principle for wood.....

Really? Do you serve up baked firewood with a side of gravy? Turkey you cook, wood you burn until there's nothing left to burn.

just saying,wood burns better the closer it gets to its optimal burning temp,giving it a head start cant hurt,same as turkey.never had baked firewood,must be a regional thing