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Put this way, more heat into dwelling than up the stack with a newer stove per volume of fuel, for the most part. Can't create what isn't there in the first place but you can use what there is more efficiently.
 
I'm most definitely getting more heat with less wood. I think there are more factors at play than your simple math. IMHO. Like I said, my new stove cranks out heat far more than my previous stove. Another added benefit that doesn't go unnoticed is that my wife wears significantly less clothing in the house now than before and she's a very modest woman! :blob2:
You know the rule, pics or it didn't happen:)
 
Ahh...spideys favorite subject...I think he has 2 user names and is actually the OP. :laugh:
I have both types of stoves, bottom line, they both work. The old school burners are less finicky about their diet and method of operation. The EPA style burner, with dry wood, IS more efficient and runs cleaner in my experience. Heck, I have made mods to my (smoke dragon) Yukon, which burns on grates, to be more like a EPA firebox (and made changes in my SOP as a result) and by doing so have cut wood consumption WAY down. I'd say 1/3 to 1/2-ish. Right now with our weather running 20s at night, 30s in the day I have been feeding it (1) small Maple split and (1) larger Oak split three times per day and have maintained a steady 70-71 in the house. FYI heating about 2000 sq ft, average insulation. Anyways, before the mods we would have froze feeding the Yukon this skimpy diet in this kind of weather.
I know your experience with the EPA style box has been negative spidey, but there are plenty of people out there that stay nice and toasty with 'em though too. My personal opinion on why it didn't work out for you is that your heat load was too large for that particular unit and they seem to have to be kind of "matched" heat output to heat load to work really well. I think that if you would have had a large EPA style wood furnace (say Caddy, or Max Caddy for instance)(those still have a smaller firebox than your DAKA BTW) you would have had completely different results. But hey, you're warm, I'm warm, were all warm with wood heat. (kinda poetic, no? :laugh:) So what ever warms your cockels man! :rock:
 
We cut down wood consumption quite a bit. I will say the old furnace put out more heat at a given time, but petered out quickly. This resulted in an 80 degree home then 6-8 hours later a 68 degree home (where the thermostat was set). The chimney remains much cleaner and the heat is spread into the home over a longer time. I remember the march before we retired the old furnace. We burned over a cord of wood for that month alone. I'll never forget it because it was a large load from the amish. That amount now in the same weather would last at least twice as long. Now, our home is much tighter, but even before we improved things, the first year we reduced usage at least 2 cord.
 
The tests these stoves have to meet essentially measure the mass of particulates that go up the stack compared to the mass of wood that was in the firebox. That can roughly convert into the efficiency energy release of the wood that was in the firebox, as most of those particulates are molecules with carbon bonds, and the energy is stored in the carbon bonds of the wood. So if carbon molecules go up the stack then energy went up the stack.

But that is total energy recovery, and it tells you nothing about rate of energy output because you don't know how long it took. However, since the energy is recovered by burning the particulates then generally you get a boost in output rate. Most of what I have read is that you can get a 50% increase in energy output rate (BTU/time) when the secondaries are running. But that is only for a portion of the fuel load. After the volatiles are cooked out and combusted the secondary combustion stops and the energy output rate decreases.

It's important to note that the EPA tests don't tell you the energy output rate, that's a manufacturer's spec and may be total BS, and is probably the maximum output if it means anything. If there were a 3rd party test to determine that then one could put some faith in it, but for now it's just marketing. I think it makes more sense to measure the volume of the firebox to determine relative energy output rate (BTU/hour, etc).
 
I remember a while back I tried to say the same basic thing Chris-PA... they darn near ran me out'a here on a rail.
You'd have thought I was some sort of Nazi :rolleyes:

The EPA efficiency rating is simply the combustion efficiency... it ain't based on heating output verses heat lost to the stack. In other words, the way the testing is done, it would be possible to achieve an 85% EPA efficiency rating while allowing 85% of the heat to flow out the stack. And then, those tests are done with oven-dried dimensional lumber (2x4 and 4x4 fir nailed together with spacers between them... called cribs). Meaning even the combustion efficiency number is worthless in the "real world"... a 75% "combustion" efficient stove could easily burn cleaner than a 85% "combustion" efficient stove once ya' start stuffin' cord wood in it. And none of it tells you what to expect as far as heating output... although it is reasonable to assume a higher "combustion" efficiency would give more heat (for the entire burn cycle, not per hour) if the stoves are of like design.

Since so many are speakin' from "observation" in this thread, I'll toss this out...
Goin' on the observation of heat waves, and holdin' my hand over the chimney when on the roof, my elitist stove dumps a lot more heat out the stack than my smoke dragon does... a whole lot more‼
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I remember a while back I tried to say the same basic thing Chris-PA... they darn near ran me out'a here on a rail.
You'd have thought I was some sort of Nazi :rolleyes:

The EPA efficiency rating is simply the combustion efficiency... it ain't based on heating output verses heat lost to the stack. In other words, the way the testing is done, it would be possible to achieve an 85% EPA efficiency rating while allowing 85% of the heat to flow out the stack. And then, those tests are done with oven-dried dimensional lumber (2x4 and 4x4 fir nailed together with spacers between them... called cribs). Meaning even the combustion efficiency number is worthless in the "real world"... a 75% "combustion" efficient stove could easily burn cleaner than a 85% "combustion" efficient stove once ya' start stuffin' cord wood in it. And none of it tells you what to expect as far as heating output... although it is reasonable to assume a higher "combustion" efficiency would give more heat (for the entire burn cycle, not per hour) if the stoves are of like design.

Since so many are speakin' from "observation" in this thread, I'll toss this out...
Goin' on the observation of heat waves, and holdin' my hand over the chimney when on the roof, my elitist stove dumps a lot more heat out the stack than my smoke dragon does... a whole lot more‼
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I recall your speculation that the secondary combustion stoves dump more heat out the stack, but you've never provided any evidence of that nor any theory as to why that would be.

When my welded, sealed stove is
cranking with a major secondary combustion burn, the total air inlet is vey tiny - maybe the size of a dime or nickle (I'll have to try to measure it). The heat output into the room is almost frightening. The stack is not very hot, and there isn't much sign of anything exciting looking at the chimney top.

As to the crib wood - it is important to be consistent, and that is not easy with a fuel like wood. So if they had to trade off a bit of realism for consistency I can understand that. If you were submitting a product you'd like a level playing field. I think the fuel load still guves a decent relative comparison.
 
Look, the idea is to extend the burn time without caking up the chimney with creosote, without losing BTUs and sending heat up the chimney, and thus improving thermal efficiency. Any other objective doesn't mean very much. Simple as that.

However, it ain't so simple to execute. Stove designers have been trying to do it for decades. And, we also lose energy cleaning chimneys clogged by energy efficient stoves. Somehow, that never gets added into the efficiency equation.

Great topic and fun to debate. :popcorn:
 
As to the crib wood - it is important to be consistent, and that is not easy with a fuel like wood. So if they had to trade off a bit of realism for consistency I can understand that. If you were submitting a product you'd like a level playing field.
Interestingly, the new proposed regulations change the test fuel to cord wood... not sure how (or if) they're gonna' keep the playing field level, they don't specify. (shrug)
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Interestingly, the new proposed regulations change the test fuel to cord wood... not sure how (or if) they're gonna' keep the playing field level, they don't specify. (shrug)
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Yes, I had seen that and initially thought it was a good idea, but then was not so sure. I thought I read somewhere that's been dropped for now? It's probably too expensive to change the test and may not even work well.

I'd prefer they leave the standard and test alone, but adapt it to include furnaces and OWBs.
 
I don't buy the seccondary air inlet being nickle sized.
The smallest epa stove I looked at had a inlet size of 1 inch by 1.75 inch. The "primary" inlet at the top of the door was less than one half of that area.
It was impossible to start a fire in that stove without leaving the door open.
Air flows thru the secondary all the time, removing heated room air without contributing anything to combustion for a great part of the burning cycle.
A good part of the time when many people think they are seeing secondary burn, what they are seeing is a hole being blown thru the flames by wasted air on the way up the stove pipe.
The heat derived from secondary burn could have been gotten by getting enough air at the base of the fire to burn the gasses given off the wood in the first place.
 
The last few days have been quite warm and I have been using the stove to make charcoal for for grilling next summer. Charcoal is made by heating wood while depriving it of enough air for complete combustion. Epa stoves excel at turning firewood into grilling charcoal!
 
@Whitespider

I have never heard of a elitist stove, what is it? Do you have a thread on it?

Further
Goin' on the observation of heat waves, and holdin' my hand over the chimney when on the roof, my elitist stove dumps a lot more heat out the stack than my smoke dragon does... a whole lot more‼
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if you have more heat out the chimney something is not correctly set up. I might have something mixed up but I do presume we are talking about something like a wood gasifier. Usually you have to fine tune your system so that you have enough heat even comming out your chimney to get out the carbon dioxide, etc. Or your system already has a lambda sensor and is virtually self regulating. Then you can dump in whatever type of wood you like it will always be close to perfect.

7
 
So… more heat from half the wood??
Let’s figure there’s 7000 BTUs in a pound of wood…

Let’s say, in 12 hours, I burn 100 pounds of it in my (supposedly) 55% efficient smoke dragon…
7000 × 100 × .55 ÷ 12 = 32083 BTU’s per hour (average).

Now let’s say, in 12 hours, you burn half that much wood in your (supposedly) 85% efficient elitist stove…
7000 × 50 × .85 ÷ 12 = 24791 BTU’s per hour (average).

Heck, even if we say the smoke dragon is only 50% efficient and the elitist stove is 90% efficient… it still comes up short…
7000 × 100 × .50 ÷ 12 = 29167 BTU’s per hour (average) for the smoke dragon.
7000 × 50 × .90 ÷ 12 = 26250 BTU’s per hour (average) for the elitist stove.

More likely the “real world” efficiency numbers are closer to 60% and 80%...
7000 × 100 × .60 ÷ 12 = 35000 BTU’s per hour (average) for the smoke dragon.
7000 × 50 × .80 ÷ 12 = 23333 BTU’s per hour (average) for the elitist stove.

More heat from half the wood??
Must be magic.
I don't believe in magic, so I don't believe claims of more heat from half the wood... actually I call BS‼

Now if the claim was the same amount of heat from 20% or 25% less wood I might buy that... maybe.
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The average smoke dragon is lucky if it's 50% efficient, more like 40% and most EPA cat/non cat stoves are in the low 70's or high 60's.
 
I know for a fact that not all wood burning stoves are equal. If tested correctly, I can see where one stove design could be more efficient then other designs. At what stage during the entire burn does it produce the best heat?
I have only been exposed to a very few types of wood heaters, but all of them seemed to put off heat in deferent ways and some better then others.
Proper testing may prove the theory but I can see it being true.
 
I don't care much about particulate emissions or EPA ratings . I do care about long burns and ability to keep my house comfortable on a small load of wood . I switched from a smoke dragon furnace to a EPA furnace and realistically cut my wood usage down by 25-30% . It is definitely a huge difference in wood use and we don't have the wild heat swings or 85 degree house at 2 in the morning .the cleaner burns are a nice side benefit . No math needed it's flat out better
 
I don't buy the seccondary air inlet being nickle sized.
The smallest epa stove I looked at had a inlet size of 1 inch by 1.75 inch. The "primary" inlet at the top of the door was less than one half of that area.
It was impossible to start a fire in that stove without leaving the door open.
Air flows thru the secondary all the time, removing heated room air without contributing anything to combustion for a great part of the burning cycle.
A good part of the time when many people think they are seeing secondary burn, what they are seeing is a hole being blown thru the flames by wasted air on the way up the stove pipe.
The heat derived from secondary burn could have been gotten by getting enough air at the base of the fire to burn the gasses given off the wood in the first place.
The Magnolia has a single air inlet that runs from the bottom of the stove up the back of the firebox - the tube is much larger than a nickle. There is a damper on the inlet of the tube and I was estimating the opening size when burning. There is no separate secondary inlet in that stove. The smaller stove we have upstairs does have a fixed secondary inlet, but it is small. They are not all built the same.

This proposition that secondary burn stove lose more heat up the flue is just a wild-assed-guess with no mechanism to back it up. The secondary burn was not expected to last for the entire burn cycle of a load. Nevertheless, I have not seen any stoves pass the particulate emissions tests without secondary burn or a catalyst, and reduced particulate emissions means you extracted more energy from the wood. So the improved extraction of energy from the wood is shown by testing while greater losses of heat up the flue is a guess that has nothing behind it.
 
I have never heard of a elitist stove, what is it? Do you have a thread on it?
http://www.arboristsite.com/communi...l-with-epa-phase-2.267043/page-3#post-5051173

The average smoke dragon is lucky if it's 50% efficient, more like 40% and most EPA cat/non cat stoves are in the low 70's or high 60's.
You're talkin' "energy" efficient rather than "combustion" efficient?? Well... I don't know what the numbers are. I'm thinking your numbers are a bit low for the smoke dragon, and even more likely a bit high for the "real world" elitist stove... but let's use them. Even using your numbers it don't change my point...
7000 × 100 × .40 ÷ 12 = 23333 BTU’s per hour (average) for the smoke dragon.
7000 × 50 × .70 ÷ 12 = 204166 BTU’s per hour (average) for the elitist stove.

You still ain't getting more heat from half the wood... unless, of course, magic is involved.
Like I said, I might buy the same heat from 20%-25% less wood... maybe.
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