What's better value in this situation?

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What's better value?

  • Split / seasoned hardwood mix for $315 / cord

    Votes: 1 100.0%
  • A pallet of compressed sawdust blocks - 1920 lbs for $320

    Votes: 0 0.0%

  • Total voters
    1

Caydel

Member
Oct 3, 2011
35
Ontario, Canada
Hi all,

I've been burning wood for the last 10 years. For most of that time, I've been buying well seasoned, pre-split from a local supplier with a good product for $90 per face cord delivered (1/3rd cord).

This past year, I've moved and the 'best' price around here for a similar product is $105 per face cord. I am planning to order ~10 face cords.

Now, the same supplier also carries the Canawick compressed sawdust blocks, and they are offering a 1920-lb pallet for $320 delivered - roughly comparable in price to a full cord of hardwood.

Certainly the compressed blocks are easier to manage / stack / store and I would pay a small premium for it... but how does the heat output compare? Obviously, a 1920lb pallet is lighter than a full cord of maple, oak, and ash... but the moisture content in the compressed product it lower, which means I'm not paying the water and losing the heat value to boil that water off.

I guess the basic question is - how do you compare the value of these two products?

For all those who suggest I cut, split and season my own wood - I'd love to, but at this point in my life I just don't have the time without making compromises elsewhere. That will probably change in another 5 years once my sons get to the age they can help with the work!

Thanks in advance for any suggestions!
 
Hi all,

I've been burning wood for the last 10 years. For most of that time, I've been buying well seasoned, pre-split from a local supplier with a good product for $90 per face cord delivered (1/3rd cord).

This past year, I've moved and the 'best' price around here for a similar product is $105 per face cord. I am planning to order ~10 face cords.

Now, the same supplier also carries the Canawick compressed sawdust blocks, and they are offering a 1920-lb pallet for $320 delivered - roughly comparable in price to a full cord of hardwood.

Certainly the compressed blocks are easier to manage / stack / store and I would pay a small premium for it... but how does the heat output compare? Obviously, a 1920lb pallet is lighter than a full cord of maple, oak, and ash... but the moisture content in the compressed product it lower, which means I'm not paying the water and losing the heat value to boil that water off.

I guess the basic question is - how do you compare the value of these two products?

For all those who suggest I cut, split and season my own wood - I'd love to, but at this point in my life I just don't have the time without making compromises elsewhere. That will probably change in another 5 years once my sons get to the age they can help with the work!

Thanks in advance for any suggestions!

Impossible to say without knowing what species you're paying $105 per 1/3 cord or what the moisture content is of that 1920 lb. pallet of sawdust blocks. Probably somewhere in the same neighborhood, just go with whatever you prefer. The two products deliver heat differently over time so they can't be compared directly on a BTU/BTU basis anyway. The sawdust blocks take up less storage but are more sensitive to dampness so they need a dryer storage than cordwood.

If it's for this winter I wouldn't buy 3 1/3 cords or the cordwood without splitting three of the larger pieces open and measuring the MC with a meter you know is accurate.
 
Impossible to say without knowing what species you're paying $105 per 1/3 cord or what the moisture content is of that 1920 lb. pallet of sawdust blocks. Probably somewhere in the same neighborhood, just go with whatever you prefer. The two products deliver heat differently over time so they can't be compared directly on a BTU/BTU basis anyway. The sawdust blocks take up less storage but are more sensitive to dampness so they need a dryer storage than cordwood.

If it's for this winter I wouldn't buy 3 1/3 cords or the cordwood without splitting three of the larger pieces open and measuring the MC with a meter you know is accurate.

Well, there's no way to know what I'm getting for the wood other than 'mixed hardwood'.

The sawdust blocks would be in dry storage (in a barn), so assume the best case scenario for moisture content / dryness.

And unfortunately, it's for this winter. I have a moisture meter, but yes, I understand your point that there is no guarantee about how seasoned the wood actually is.
 
I think it would make some sense to compare the amount of fuel in each purchase. As a rough guess - a cord of mixed hardwoods will come in somewhere around 3500/3700# (just an average guess considering the weight spread of different species and this would be the dry version).

So - 1920# of dry fuel vs ~3500# of dry fuel for roughly the same money. Toss in the ease of use (or lack of) between the two and make the call that best fits you.
 
I think it would make some sense to compare the amount of fuel in each purchase. As a rough guess - a cord of mixed hardwoods will come in somewhere around 3500/3700# (just an average guess considering the weight spread of different species and this would be the dry version).

So - 1920# of dry fuel vs ~3500# of dry fuel for roughly the same money. Toss in the ease of use (or lack of) between the two and make the call that best fits you.

Thanks, I've taken some time to run some better numbers. I'm going to do some metric conversion for a second to make some calculations easier.

3500lbs of Cordwood = 1590kg
1920lb of pressed blocks = 872kg

Now, let's look at the amount of net heat content in each material, defined as the energy content of the wood minus the amount of energy required to turn any moisture content into water vapour. Using the formula and numbers from http://www.fao.org/3/a-i4441e.pdf, wood at 20% moisture (decent seasoned firewood) provides 3.98 kWh per kg of energy while wood at 7% moisture (like the pressed blocks) produces about 4.74 kWh per kg of energy. Wood at 30% moisture provides 3.40 kWh per kg. So, pound for pound, the compressed bricks at 7% moisture content provide ~20% more heat than firewood at 20% moisture content, and 40% more heat value than wetter wood at 30% moisture.

Taking raw heat value only into consideration, it looks like the pallet of compressed bricks provides minimum of 66-77% of the heat value of the cord of mixed hardwoods, depending on the moisture level of the firewood:

Wood relative values.png


The other consideration is wood stove efficiency, and how that is impacted by moisture. For instance, the cooler fire from moister wood will reduce the amount of secondary burn you get as the combustion gasses have more non-flammable water vapour as well as cooler combustion temperatures due to the energy required to vapourize the moisture. I don't have numbers to put to this and they are likely specific to different stove designs, but I wouldn't be shocked if this impacts heat output by an additional 10-20% (depending on initial moisture content of the firewood you are comparing too).

So, the bottom line when all this is done is that I would believe that the pallet of compressed blocks probably provides somewhere around 80-90% of the actual stove output heat value of a cord of mixed hardwoods.

P.S. Here's an expanded version of the heat value formula from the FAO PDF linked above - I ran it for every moisture content from 0-50%:

Raw heat value by moisture content.png
 
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This thread makes my head hurt. ;)

Honestly . . . if the wood was truly seasoned I would be more inclined to go with that.

If the wood was marginal or not seasoned I would be more inclined to go with the blocks.
 
@Caydel , welcome.

In general, in North America the folks saving money burning wood are buying green wood and seasoning it themselves.

What you got this year is really a toss up.

Have you got room for two years of wood? If you do, pick whatever from the OP, and get tour 18/19 wood delivered green now too. Get that stacked over the winter so tou dont miss a single day of seasoning time summer 18, and get your 19/20 wood delivered green asap, maybe april 18 or so.

If you can get pine or similar (spruce?) delivered in the next few months it will be ready to burn in one summer of seasoning if top covered.

I tend to order my green wood for next winter as soon as i have good snow cover. That way the trees land on snow instead of dirt and my carpet in the stove room stays cleaner.
 
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What kind of boiler/stove are you using? My gasification boiler burns small diameter (6" and less) round wood and splits very well, well seasoned and stored outside under cover, assumed MC 20%+/-. If I burn scrap lumber 2 x 4's in 18" length, or 4 x 4's same length, stored inside, assumed MC 5-10%, they tend to pack tightly in the firebox not only do not burn as well, but also burn much hotter than the round wood and splits. Best burning for the scrap lumber is to mix it with the round wood and splits.
 
@Caydel , welcome.

In general, in North America the folks saving money burning wood are buying green wood and seasoning it themselves.

What you got this year is really a toss up.

Have you got room for two years of wood? If you do, pick whatever from the OP, and get tour 18/19 wood delivered green now too. Get that stacked over the winter so tou dont miss a single day of seasoning time summer 18, and get your 19/20 wood delivered green asap, maybe april 18 or so.

If you can get pine or similar (spruce?) delivered in the next few months it will be ready to burn in one summer of seasoning if top covered.

I tend to order my green wood for next winter as soon as i have good snow cover. That way the trees land on snow instead of dirt and my carpet in the stove room stays cleaner.

I grew up in a woodburning family and we cut all our own wood, and I did that myself for a few years before we had kids. However, like anything else it depends on time availability and priorities.

All three suppliers I am talking to this year are only selling Ash as the Emerald Ash Borer swept through this region the last year or two, so there is a lot of standing dead to clean up. The Ash should be in good shape to burn this year, especially as it has a year of seasoning.

I have a lot of room here, so this winter I am thinking of ordering a double load of logs from a local logging company and bucking them over the winter. If I split the best for use next season, and leave the rest to season another year, that will get me a year ahead. This season is also about seeing how much wood I am actually going to burn here - we haven't wintered in this home yet. When I moved in in February, it only had plugin electric heaters.

What kind of boiler/stove are you using? My gasification boiler burns small diameter (6" and less) round wood and splits very well, well seasoned and stored outside under cover, assumed MC 20%+/-. If I burn scrap lumber 2 x 4's in 18" length, or 4 x 4's same length, stored inside, assumed MC 5-10%, they tend to pack tightly in the firebox not only do not burn as well, but also burn much hotter than the round wood and splits. Best burning for the scrap lumber is to mix it with the round wood and splits.

I have a Napoleon HMF200 wood furnace (https://napoleonheatingandcooling.com/products/hmf200-hybrid-combination-furnace/). Well, I actually have the 'Continental' version, which is an alternate brand by the same manufacturer. The only difference is the heat shields are blue instead of red, and some of the items that are standard on the Napoleon (ie., a UV light) are merely options on the Continental version.

Thanks for sharing your experience. I've read a lot of mixed reviews about how people feel about the compressed blocks and how they burn, so last winter I bought a few packs from our local hardware store, and they burnt great - hot, clean, secondaries starting early, fast, and lasting forever!
 
Ok, so I ended up buying 10 face cords of split ash from another supplier, to be delivered this week for $96 per face cord. Apparently C/S/S spring 2016, so should be good and dry. And I figure with it being ash, even if it's not as seasoned as advertised, it should be relatively burnable.
 
Ok, so I ended up buying 10 face cords of split ash from another supplier, to be delivered this week for $96 per face cord. Apparently C/S/S spring 2016, so should be good and dry. And I figure with it being ash, even if it's not as seasoned as advertised, it should be relatively burnable.

If it was c/s/s AND top covered spring 2016 it should be ready to burn. He didn't say he top covered it? I would want to check it with a moisture meter just because you would be the one paying the price if not as described. I'm not sure what "relatively burnable" means. Relative to unburnable wood? Most wood will burn, even green wood. If that ash is 28% water, then your $960 worth might only provide the heat of $640 worth of dry Ash.
 
I would by some bricks as I read a lot of fellow burners recommend when less than desirable wood is being burned. Mix the two together and figure out a reasonable ratio to make the bricks go farther.

I always look at a stove load as an overall moisture content. The bricks should get the temp up quick and help "cook" some of the moisture out of the cord wood. As long as you know you are burning somewhat wet wood and keep an eye on your chimney and keep it clean you should be ok. Its gotta be cheaper than relying on full electric heat.