16 inch vs. 18 inch

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drewmo

Feeling the Heat
Nov 20, 2006
360
Topsham, ME
I was going to title this thread "Does length matter?," but I wanted a chance for some serious responses before the thread got derailed.

With that said, my PE Summit insert recommends 18" splits. What, if any difference, would I see if I went with 16" lengths? BTU output would be lower per load with the shorter lengths, but I'm thinking the burn time would roughly be the same. On those really cold days, this could be an issue, but for 60-70 percent of the time, I'd think the 16" logs would keep the house comfortably warm while conserving on the wood moving through the stove. This stove puts out the heat and I'm often faced with it being *too* warm when I don't want it. But I like to stuff the stove to get the good burn times.
 
No problem at all with burning 16" splits. Your stove will be quite happy with them.
 
Yeah and you will actually get a better burn of the gases cooking out of the front of the splits with a N/S load with the 16" splits. With the longer splits more goes straight up and over the baffle. With the shorter splits more is behind the coals and you will notice the gases burning on the ends of the splits better.
 
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Also less issue with excess coals. If the max length is 18 inches you'll end up angling pieces if you have lots of coals in the back of the stove. I find the longer pieces almost touch the glass when I load up.
 
Also less issue with excess coals. If the max length is 18 inches you'll end up angling pieces if you have lots of coals in the back of the stove. I find the longer pieces almost touch the glass when I load up.

Recommended is 18", and 20" is about the max for this stove. She really is a great stove and when the burn is on, she cooks. I'll probably save on wood by burning shorter splits.
 
I'm going with 16" for my Mansfield for all reasons mentioned above.
 
It sure stinks when you can't quite fit that next piece in where you want it due to it being too long. I overcompensated and cut mine all a couple of inches too short. I will aim to get a little closer to the max next time. I hate leaving space in the firebox. Each additional split could mean additional hours of burntime.
 
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My stove loads E/W, and is also a top-loader... so some different issues. However I'll say I like having a range of lengths in the stack. I cut maybe 80% of my stuff at 20", which is close to the max length I can angle thru the doors and set into an empty firebox E/W. Then I like to have some slightly shorter (18" or even 16") to load in last, when the firebox is too filled to get any more of the 20" pieces angled thru the doors. Goal = stuffing the stove to the point where the front and top doors just barely close, and keep that stove top at 500F as long as humanly possible. My burn time is fixed by my work schedule, and my stoves will never keep up with the losses of my house, but I can crank more BTU's/hour if I can stuff more in the box and run the stove a little hotter.

I suspect that loading N/S, there may be more opportunities where one length just works. In E/W loading, I think a range of lengths will always help get the most out of your firebox space.
 
I was going to title this thread "Does length matter?," but I wanted a chance for some serious responses before the thread got derailed.

With that said, my PE Summit insert recommends 18" splits. What, if any difference, would I see if I went with 16" lengths? BTU output would be lower per load with the shorter lengths, but I'm thinking the burn time would roughly be the same. On those really cold days, this could be an issue, but for 60-70 percent of the time, I'd think the 16" logs would keep the house comfortably warm while conserving on the wood moving through the stove. This stove puts out the heat and I'm often faced with it being *too* warm when I don't want it. But I like to stuff the stove to get the good burn times.
I don't see much difference in heat output burning shorter lengths. I usually go with something a little smaller than the max-length. Fitting in a split at max-length there is too much finagling squeezing split in the stove while the fire is going. Do you process your own wood or do you buy pre-split?
 
I find I can load much more precisely with splits that are a tad short than with splits that are a tad long. If you split for 16" some 17" splits are bound to sneak in and it will be no big deal. It's those 20" splits that are a pain to deal with.
 
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My current stove takes 22" splits, but my wood is all cut 16 - 18" (all exactly 16" if I cut it). I find it easier to handle, easier to stack, 3 rows is exactly 4 feet wide (so I can calculate how many cord I have). It is also easier to split by hand than 22".

You can't STUFF your stove to the gills, but you really shouldn't be doing that anyway. Besides, if you fill it with 16" splits and it leaves a 2" gap at the end, are you really gonna notice a significant difference in burn times?


If you split for 16" some 17" splits are bound to sneak in

+1 to that
 
It's those 20" splits that are a pain to deal with.
Depends on the stove. I can fit 22" splits E/W, so 20 +/- 1 inch is a nice fit. If you use 16" where you could've used 20", then your burn time or BTU/h output decreases by 20%.

BTU's input x efficiency = BTU's output... pretty simple equation.
 
I think you won't notice any difference - not saying there won't be a difference, just saying you won't notice - in burn times or heat output, but you will find reloading easier with less-than-max-length splits. And before anyone jumps in to correct me, 18" is the max you can load N/S.
 
The wood I cut for our new home is at 20". I had the side loading progress hybrid in mind while cutting. It now looks like we are going to order the ideal steel soon. Wish I cut shorter for n/s loading.
 
Mine is cut 16 - 18, so when the ideal steel gets ordered (wife still hasn't picked the design she likes best) I can order NS or EW.

Yippee
 
I think you won't notice any difference - not saying there won't be a difference, just saying you won't notice - in burn times or heat output, but you will find reloading easier with less-than-max-length splits. And before anyone jumps in to correct me, 18" is the max you can load N/S.
Big redd I notice quite a difference when I use 18-20 inch splits versus 12-16 inch splits for an overnight burn. I have a better coal bed for restarts and I think I get better heat output with larger splits. I have a 1.7 cu ft stove - jotul castine and my goal has been to fill as much of the firebox as I could so went with max length splits around 6 inch diameter, quite the jigsaw puzzle to fill but I usually get four splits in and it goes for around eight hours to reload.
Just my thoughts and experience.
 
But I think that varies from stove to stove.......I also think you are talking about trying to get a long burn from a small box. With a 3.2 cu ft firebox, you should be able to get an 8 hour burn from 16" splits. Not so much from a 1.7 cu ft firebox.

Now you got me wondering though (because it makes NO difference in my current stove). I have some long stuff a friend helped me cut seasoning for next winter. I may try some of that stuff (21 - 22") and then on a similar night burn 16" splits and see if there is a difference in flue and stove top temps.
 
But I think that varies from stove to stove.......I also think you are talking about trying to get a long burn from a small box. With a 3.2 cu ft firebox, you should be able to get an 8 hour burn from 16" splits. Not so much from a 1.7 cu ft firebox.

Now you got me wondering though (because it makes NO difference in my current stove). I have some long stuff a friend helped me cut seasoning for next winter. I may try some of that stuff (21 - 22") and then on a similar night burn 16" splits and see if there is a difference in flue and stove top temps.
Smoke dragon I would get lost in a 3.2 cu ft box!! I used to burn an old heritage stove which was around 3 cu ft and could put all kinds of lengths into it. It has now moved to my shop and it is fun to load it up with any size split I want. My new stove can only take ew 18-20 inch splits and it is great. I would think that your longer splits would give you better stove and flue temps but the best test is how long you get the heat you want in the space you are heating. Biggest change I have noticed is that dry wood , less than 20% moisture regardless of split length burns longest.

 
Big redd I notice quite a difference when I use 18-20 inch splits versus 12-16 inch splits for an overnight burn. I have a better coal bed for restarts and I think I get better heat output with larger splits. I have a 1.7 cu ft stove - jotul castine and my goal has been to fill as much of the firebox as I could so went with max length splits around 6 inch diameter, quite the jigsaw puzzle to fill but I usually get four splits in and it goes for around eight hours to reload.
Just my thoughts and experience.
The OP was asking about this WRT an 18" square 2 cu ft firebox. The Castine and other stoves are completely different cases.
 
The OP was asking about this WRT an 18" square 2 cu ft firebox. The Castine and other stoves are completely different cases.
I thought he was asking about a summit? Isnt that 3cf?
My stove box is 18" x 18" so I cut everything 16, I do notice a difference when I burn 12-14" in burn time, I prefer to have all my wood 2" less than the box size.
 
Big redd I notice quite a difference when I use 18-20 inch splits versus 12-16 inch splits for an overnight burn. I have a better coal bed for restarts and I think I get better heat output with larger splits. I have a 1.7 cu ft stove - jotul castine and my goal has been to fill as much of the firebox as I could so went with max length splits around 6 inch diameter, quite the jigsaw puzzle to fill but I usually get four splits in and it goes for around eight hours to reload.
Just my thoughts and experience.


I was referring specifically to his stove. The PE Summit has a 3.0 cu ft firebox and is exactly 20" E/W and 18" N/S - brick to brick. If he's loading 16" splits N/S he won't notice any difference except that reloads are easier when the splits are not at maximum length.
 
Maximum length in my stove is 22 inches. Well you can fit about 1-2 splits in that are 21.5 inches. 22 inches really doesn't work. 18 inch pieces are ideal, but If i want to stack it to the toploading plate I need 15-16 inch pieces for the top.

16-18 inch logs all the way. In my stove I need a little of both for a full load.

2.3cuft firebox.
 
I was referring specifically to his stove. The PE Summit has a 3.0 cu ft firebox and is exactly 20" E/W and 18" N/S - brick to brick. If he's loading 16" splits N/S he won't notice any difference except that reloads are easier when the splits are not at maximum length.
Thanks for the correction Redd. I confused this thread with another and was thinking the Super27. The point being is that this is a roughly square firebox that allows both N/S and E/W burning. It's hard to do that in a shallow firebox like the Castines. Not impossible, but a challenge unless you have lots of short splits. I have a lot of 18" splits and they just fit N/S. But of course they are not all exactly 18". The 18.5" ones have to ride up on the front boost manifold cover. I don't cut my own wood that much anymore, so now I insist on 16" and hope that all the rounds are under 18".
 
Big redd I notice quite a difference when I use 18-20 inch splits versus 12-16 inch splits for an overnight burn.
Ditto. A very significant difference, exactly proportional to the length of the splits used.

I have a fixed width x depth x height in my 3.0 cu.ft. firebox. If I use 20" splits, I can fill 2.7 cu.ft. of that box. If I use 16" splits, I can only fill 2.1 cu.ft. of that box, with a lot of unused space left left and right that I can't really fill with anything other than little chunks or splitter trash. This is simple math, guys. More wood in the box = more BTU's in the box.

In reality, I use 20" stuff for the bottom 60% or 70% of the firebox, and then must throw a few shorter (16" - 18") pieces on top, as I get to a point where I don't have the room left to angle 20" pieces thru the door. The above math is just for demonstration purposes.
 
You can't STUFF your stove to the gills, but you really shouldn't be doing that anyway.

Yes, you can stuff your stove to the gills. All the way to to the top whether it's cat or non-cat. That's why they make the stove as big as they do. Just like beer glasses.

If I get 30 hours out of 10 splits then I feel pretty good that adding an additional split (the equivalent of 2 extra inches times 10) would give me a significant amount of additional burn time. Thermostatic cat stove, may be different than a non-cat in the burn time addition.
 
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