Efficiency & Emissions on EPA Stoves (Englander 30 and Heatilator Eco-Choice 22)

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

kjayhawk

Member
Dec 6, 2008
46
North of St. Louis
As I stated in another thread, we are looking at upgrading our Napoleon 1400 to a larger stove. We've been considering the Englander 30 and the Heatilator Eco-Choice 22. The two stoves seem comparable (in price and heating ability), although many here have advised us to go with the Englander. We are in line to receive the Progress Hybrid in a few weeks, but some unanticipated expenses will likely mean a cancellation of our order ... and the purchase of a less-expensive stove.

So here's my question: what is the relationship between efficiency and emissions in an EPA wood stove?

For example, the Eco-Choice 22 boasts an efficiency of 82%, while the emissions are 2.7 grams/hr. The Englander has the minimal stated effeciency of an EPA stove (63%), but it's emissions are lower at 1.6 grams/hr.

Does fewer grams/hr translate into greater efficiency? Will the Englander throw more heat into the living space than the Eco-Choice 22 because it is emitting fewer grams/hr?

We are looking to get the best bang for our buck ... so if a greater efficiency stove results in less wood consumption, that's likely the stove we will purchase.
 
Both are great stoves. IF there is a difference in this regard, I will guarantee that you will never tell during the course of general operation.

My suggestion is to go check out both of these stoves in person, get the feel for them, the looks in person, operate all the parts, and make your decision based upon which stove you feel most comfortable with after examination.

pen
 
I see your confusion. I don't have all the numbers, but I do have this.

If you look at the EPA's sheet, you will find the efficiency of the WS22 and the 30NCH are both listed by the EPA at 63%. this is a standard number assigned to all stoves that have a secondary burn system.

The higher efficiency rating that you see listed on the Heatilator site must be from some in-house testing. I don't know if the 30 has its own set of numbers from ESW or not.
 
I have no data, but my impression from owning a stove is that efficiency varies greatly depending on how the stove is used. I am sure my stove's efficiency varies a lot from fire to fire (I'd like to dial it in at the high end of the range). I think fuel has much more to do with efficiency than the details of stove design. Operator skill/attention/giving a crap about efficiency are also more important than the differences between the two stoves, I think.
 
I know of no correlation between emissions rate and overall efficiency.
 
SmokingAndPoking said:
I know of no correlation between emissions rate and overall efficiency.
I can't argue against this, but I would think there is a correlation, but that's it.

I think it's most important to mention that the emissions measured are particulate emissions. efficient woodstoves do turn more of the wood mass into energy, but it's more than just that, there are all those extra gasses that they burn, too! looking at a particulate emission number won't give you any idea of how well they do that!
 
kjayhawk said:
As I stated in another thread, we are looking at upgrading our Napoleon 1400 to a larger stove. We've been considering the Englander 30 and the Heatilator Eco-Choice 22. The two stoves seem comparable (in price and heating ability), although many here have advised us to go with the Englander. We are in line to receive the Progress Hybrid in a few weeks, but some unanticipated expenses will likely mean a cancellation of our order ... and the purchase of a less-expensive stove.

So here's my question: what is the relationship between efficiency and emissions in an EPA wood stove?

For example, the Eco-Choice 22 boasts an efficiency of 82%, while the emissions are 2.7 grams/hr. The Englander has the minimal stated effeciency of an EPA stove (63%), but it's emissions are lower at 1.6 grams/hr.

Does fewer grams/hr translate into greater efficiency? Will the Englander throw more heat into the living space than the Eco-Choice 22 because it is emitting fewer grams/hr?

We are looking to get the best bang for our buck ... so if a greater efficiency stove results in less wood consumption, that's likely the stove we will purchase.


I ignore efficiency ratings. Those claims seem to be as meaningless to the burn time as the BTU ratings are.

The Heatilator is a smaller stove than the 30NC. The Heatilator is a 2.7 cu ft stove and the 30NC is a 3.5 cu ft stove. Your Nap 1400 is a 2.25 cu ft stove. The difference between the Heatilator and the Napoleon is only .45 cu ft. If you are looking for a noticeable difference in heat output and burn times I would go with the larger stove.
 
  • Like
Reactions: wkpoor
BrowningBAR said:
kjayhawk said:
As I stated in another thread, we are looking at upgrading our Napoleon 1400 to a larger stove. We've been considering the Englander 30 and the Heatilator Eco-Choice 22. The two stoves seem comparable (in price and heating ability), although many here have advised us to go with the Englander. We are in line to receive the Progress Hybrid in a few weeks, but some unanticipated expenses will likely mean a cancellation of our order ... and the purchase of a less-expensive stove.

So here's my question: what is the relationship between efficiency and emissions in an EPA wood stove?

For example, the Eco-Choice 22 boasts an efficiency of 82%, while the emissions are 2.7 grams/hr. The Englander has the minimal stated effeciency of an EPA stove (63%), but it's emissions are lower at 1.6 grams/hr.

Does fewer grams/hr translate into greater efficiency? Will the Englander throw more heat into the living space than the Eco-Choice 22 because it is emitting fewer grams/hr?

We are looking to get the best bang for our buck ... so if a greater efficiency stove results in less wood consumption, that's likely the stove we will purchase.

I ignore efficiency ratings. Those claims seem to be as meaningless to the burn time as the BTU ratings are.

The Heatilator is a smaller stove than the 30NC. The Heatilator is a 2.7 cu ft stove and the 30NC is a 3.5 cu ft stove. Your Nap 1400 is a 2.25 cu ft stove. The difference between the Heatilator and the Napoleon is only .45 cu ft. If you are looking for a noticeable difference in heat output and burn times I would go with the larger stove.
I tried to hint that in the other thread, leave it to BBar to just say it! I was almost there...
 
Danno77 said:
I tried to hint that in the other thread, leave it to BBar to just say it! I was almost there...

When comparing, always listen to a man who's running multiple stoves. Between BBar and BBart I think they've run half the stoves in existence today. ;-)
 
True dat.
 
A woodstove's heating efficiency rating doesn't correlate directly to its emissions rating. In fact, those numbers are arrived at in two different tests:

Emissions testing is performed in EPA-approved test labs using the EPA's prescribed protocol. When testing for emissions, a nailed-together "charge" of dimensional Pine is burned, and the particulate matter in the exhaust is measured throughout the duration of several fires at various draft control settings. In this way, an average grams/hour particulate emissions rating is derived. Heating efficiency is not measured during EPA emissions testing.

Heating Efficiency testing is performed using full loads of seasoned cordwood, and is designed to measure how much of the heat value contained in the wood is extracted and delivered into the living space. When testing for heating efficiency, the following criteria are examined:
Extraction Efficiency: the load is weighed going in, and the particulate emissions and ashes are weighed after the fire to determine how effectively a given firebox design breaks down the fuel to extract the available heat.
Heat Transfer Efficiency: this testing is performed in calorimeter rooms equipped with temperature sensors. Similar temperature sensors are installed in the exhaust flue. The degree changes in the room and flue are monitored for the duration of the test fires to determine how much of the heat extracted by the fire is delivered into the room, as compared to the heat lost up the flue.

Although a low emissions weight can improve a given stove's Extraction Efficiency score, the total amount of particulate emissions produced by today's EPA approved woodstoves is so small that the affect of particulate emissions on the overall heating efficiency score is negligable. Thus, even a model with an unusually low Emissions rating doesn't necessarily score a high Heating Efficiency rating.

Consider the two models you mention: the 1.1 gram/hr difference would lighten the total weight of emissions from the cleaner-burning stove by about 9 grams at the end of an 8-hour test burn. Most likely, those 9 grams would be found in the ash remaining in the firebox, eliminating any advantage in Extraction Efficiency. Even if the 9 grams weren't found in the ashes, a difference of 9 grams of particulates from a 40 lb. load of wood would only amount to a .05% advantage in Extraction Efficiency, which would have virtually no affect on the overall Heating Efficiency score.

You can read more about woodstove efficiency testing, from the viewpoint of the test labs, at http://www.omni-test.com/publications/Efficiency_article.pdf
 
thechimneysweep said:
A woodstove's heating efficiency rating doesn't correlate directly to its emissions rating. In fact, those numbers are arrived at in two different tests:

Emissions testing is performed in EPA-approved test labs using the EPA's prescribed protocol. When testing for emissions, a nailed-together "charge" of dimensional Pine is burned, and the particulate matter in the exhaust is measured throughout the duration of several fires at various draft control settings. In this way, an average grams/hour particulate emissions rating is derived. Heating efficiency is not measured during EPA emissions testing.

Heating Efficiency testing is performed using full loads of seasoned cordwood, and is designed to measure how much of the heat value contained in the wood is extracted and delivered into the living space. When testing for heating efficiency, the following criteria are examined:
Extraction Efficiency: the load is weighed going in, and the particulate emissions and ashes are weighed after the fire to determine how effectively a given firebox design breaks down the fuel to extract the available heat.
Heat Transfer Efficiency: this testing is performed in calorimeter rooms equipped with temperature sensors. Similar temperature sensors are installed in the exhaust flue. The degree changes in the room and flue are monitored for the duration of the test fires to determine how much of the heat extracted by the fire is delivered into the room, as compared to the heat lost up the flue.

Although a low emissions weight can improve a given stove's Extraction Efficiency score, the total amount of particulate emissions produced by today's EPA approved woodstoves is so small that the affect of particulate emissions on the overall heating efficiency score is negligable. Thus, even a model with an unusually low Emissions rating doesn't necessarily score a high Heating Efficiency rating.

Consider the two models you mention: the 1.1 gram/hr difference would lighten the total weight of emissions from the cleaner-burning stove by about 9 grams at the end of an 8-hour test burn. Most likely, those 9 grams would be found in the ash remaining in the firebox, eliminating any advantage in Extraction Efficiency. Even if the 9 grams weren't found in the ashes, a difference of 9 grams of particulates from a 40 lb. load of wood would only amount to a .05% advantage in Extraction Efficiency, which would have virtually no affect on the overall Heating Efficiency score.

You can read more about woodstove efficiency testing, from the viewpoint of the test labs, at http://www.omni-test.com/publications/Efficiency_article.pdf

WOW! Thanks for the valuable info! That's why I love hearth.com ... the guys (and gals) who hang out here are geniuses!
 
My stove (VC Vigilant) was tested many years ago by Shelton Research Inc, but only in conventional airtight mode, not in its secondary combustion mode (bypass damper closed). It's combustion efficiency factor when operated as a conventional airtight (i.e "smoke dragon") was .80 using "green" oak (38% MCdb) and .78 using seasoned oak (24% MCdb). It's heat transfer efficiency factor was .71 using green oak and .81 using seasoned oak.

Multiplying the factors together to get overall efficiency would give .80 x .71 = .568 x 100 = 56.8% overall efficiency using green oak and .78 x .81 = .632 x 100 = 63.2% overall efficiency using seasoned oak. Interesting that its overall efficiency using good seasoned oak is the same as the efficiency rating arbitrarily assigned to all non-cat EPA certified stoves.

So, what's so inefficient about a conventional airtight when operated correctly? Higher PM emissions, yes, but not substantially reduced overall heating efficiency as is usually claimed.
 
Battenkiller said:
So, what's so inefficient about a conventional airtight when operated correctly? Higher PM emissions, yes, but not substantially reduced overall heating efficiency as is usually claimed.

I can only tell you what I have directly experienced, and I'll use the three current stoves I am using as an example.

The Vigilant is the largest of the three stoves in terms of firebox size and heating output. The Encore is second, and the Heritage is third (The heritage might produce as much heat as the Encore, but I am unsure since the room layouts and air movement differ quite a bit between the two).

Vigilant: I can fit 6-8 large splits. On a hot burn (600 degrees stove top) it will last 5-6 hours before temps get down to about 300 degrees.

Heritage: I can fit three large splits in the stove with enough room for a small split wedged in there. On a hot burn (600 degrees stove top) it will last 5-6 hours before temps get down to about 300 degrees. Nearly identical as to the burn time as the Vigilant.

The Encore: I can fit 4 large splits and maybe an additional small split (depending upon how things sit). On a hot burn (600 degrees stove top) I am getting 8 hours before the stove top falls to 300.

Let me know what you think and what questions this raises and I will try to answer them the best I can.
 
BBar, what's to question? You're a thoughtful and careful guy. I'm sure your real world observations are right on for your situation.

I was mostly addressing the comments made by Tom Oyen regarding stove efficiencies and PM emissions during the test procedure. But there is no doubt in my mind that the better modern stoves have both greater combustion and overall heating efficiency. I'm sure your Heritage is more than 63% efficient, so that accounts for some of the difference.

One thought I have, though, is that you are putting a lot of wood in the Vig. It's been shown many times in controlled situations that the older stoves (and most modern stoves) are more efficient when not loaded up all the way. If nothing else, gas mixing in the primary fire zone suffers when this is done. The older stoves really need this as they lack an efficient way to burn the gases once they escape the area of adequate ignition temperature.

I rarely put more than 3-4 big splits in my stove, except when going to bed at night. I am home all day, so I can feed the stove whenever the temps drop too low. I can get a 3-4 hour burn from those 3-4 splits, starting at about 700-750º griddle temp and getting down to about 200-250º after maybe four hours. That's a lot of heat altogether. For long burn times, however, I have to fill it right up. I know this is not the most efficient way to run the stove, but I want to be able to get up and have some hot coals leftover in the morning, so I live with a little less efficiency at night.

There's a lot more going up that flue than PMs, though. I'm both secondary and catalytic combustion processes handle the "invisible" gases like CO and the numerous VOCs that are created during the burn. Loss of these compounds up the flue won't show up during the EPA test procedure, nor will they form creosote in the pipe, but they are wasted fuel gases nonetheless.

Still, if they can use cordwood in the lab to get 63% overall efficiency, it would be hard for any stove to double that (as your wood consumption in both stoves would imply).

Maybe we just aren't running the damn Vigilant right? Who knows? All I know is that somebody has gotten EPA kind of efficiency out of it, and published the results as well.
 
So, what’s so inefficient about a conventional airtight when operated correctly? Higher PM emissions, yes, but not substantially reduced overall heating efficiency as is usually claimed.

Batten, I'm not following your usually razor-sharp logic here. You're admitting that the EPA's 63% efficiency figure is arbitrary, then using for a point of comparison to your VC Vigilant anyway. Since the Vigilant's 63.2% rating was the result of laboratory testing, let's compare it to laboratory test results for the models we carry:

Highest efficiency: 88%
Mean efficiency: 80.8%
Lowest efficiency: 75%

Your Vigilant: 63.2%

Seems to me this shows that today's EPA approved models are substantially more efficient (12% - 25%) than your conventional airtight.
 
one should also note , if you look at the efficiency ratings at epa.gov the list is full of non-cats at 63% and cats at 72% reason is that most (including us at ESW) accept "default" or the minimum allowable as its extremely expensive to maintain a "true" rating which requires recertification at a much shorter interval compared to the default recert. its a minimum of 10K to put one on the test stand , so if you had to do so every thousand stoves or whatever the interval is it would cost way more to keep that rating, so we accept the 63% which it was easily above im sure but the cost is somthing that obviously would be transferred to the consumer and we simply do not want to have people pay more for a stove just for a number that doesnt really mean anything to the guy tossing splits in his stove.

now we have our lab and could feasibly do this test ourselves(actually we do) but we cannot "publish" these numbers as "gospel" as they are not done by the underwriting lab. trust me , its better than 63%
 
thechimneysweep said:
So, what’s so inefficient about a conventional airtight when operated correctly? Higher PM emissions, yes, but not substantially reduced overall heating efficiency as is usually claimed.

Batten, I'm not following your usually razor-sharp logic here. You're admitting that the EPA's 63% efficiency figure is arbitrary, then using for a point of comparison to your VC Vigilant anyway. Since the Vigilant's 63.2% rating was the result of laboratory testing, let's compare it to laboratory test results for the models we carry:

Highest efficiency: 88%
Mean efficiency: 80.8%
Lowest efficiency: 75%

Your Vigilant: 63.2%

Seems to me this shows that today's EPA approved models are substantially more efficient (12% - 25%) than your conventional airtight.

Like I already said above, the modern stoves are more efficient, there's no doubt. The stoves you carry sport pretty high efficiency numbers (overall heating efficiency, I'm assuming), but not every EPA stove works as well as yours do. They don't have to be efficient at all to meet EPA standards, just produce less PMs/hr than they used to. It's when I hear that folks are using half the wood they used in their old stoves that I begin to have doubts. And although a 12% increase in heating efficiency may be significant, I wouldn't call it substantial enough for me to stop using my Vigilant to theoretically save some wood.

My wife's Corolla got 35 MPG and her new Jetta only gets 28 hwy. She loves the Jetta compared to the Corolla, so a 7 MPH reduction in fuel economy is worth it for us. Likewise, I pay for most of my firewood and it costs me about $750/yr. Even if I could get by on only $500/yr with a newer stove (which I doubt) and get the same heat output, it would take me about 12 years to break even. $250/yr extra for heat is nothing to me. There has to be more compelling reasons for guys like me to make the switch. Long controlled burn times at low heat output would make about half of the heating season a bit more bearable for me. I like the idea of cat stoves for that reason. But just to squeeze 12% more out of my wood is not enough reason.

A very interesting thing to me, though, is that when we have a thread here about how much wood is used in a season, most 24/7 burners with a similar size home as mine use about the same amount of wood in a season as I do, so even more.

Anyway, sorry if my logic isn't as razor-sharp as usual, I'm dealing with a very sad granddaughter who just had to have her dog put down, a dog I loved like hell as well. :-S
 
stoveguy2esw said:
one should also note , if you look at the efficiency ratings at epa.gov the list is full of non-cats at 63% and cats at 72% reason is that most (including us at ESW) accept "default" or the minimum allowable as its extremely expensive to maintain a "true" rating which requires recertification at a much shorter interval compared to the default recert. its a minimum of 10K to put one on the test stand , so if you had to do so every thousand stoves or whatever the interval is it would cost way more to keep that rating, so we accept the 63% which it was easily above im sure but the cost is somthing that obviously would be transferred to the consumer and we simply do not want to have people pay more for a stove just for a number that doesnt really mean anything to the guy tossing splits in his stove.

now we have our lab and could feasibly do this test ourselves(actually we do) but we cannot "publish" these numbers as "gospel" as they are not done by the underwriting lab. trust me , its better than 63%

Would there be any way possible to give us a clue at what that number might be ... ballpark figure? Just a hint, maybe??!! Would we be getting warm at 80% perhaps?
 
Battenkiller said:
BBar, what's to question? You're a thoughtful and careful guy. I'm sure your real world observations are right on for your situation.

I was mostly addressing the comments made by Tom Oyen regarding stove efficiencies and PM emissions during the test procedure. But there is no doubt in my mind that the better modern stoves have both greater combustion and overall heating efficiency. I'm sure your Heritage is more than 63% efficient, so that accounts for some of the difference.

One thought I have, though, is that you are putting a lot of wood in the Vig. It's been shown many times in controlled situations that the older stoves (and most modern stoves) are more efficient when not loaded up all the way. If nothing else, gas mixing in the primary fire zone suffers when this is done. The older stoves really need this as they lack an efficient way to burn the gases once they escape the area of adequate ignition temperature.

I rarely put more than 3-4 big splits in my stove, except when going to bed at night. I am home all day, so I can feed the stove whenever the temps drop too low. I can get a 3-4 hour burn from those 3-4 splits, starting at about 700-750º griddle temp and getting down to about 200-250º after maybe four hours. That's a lot of heat altogether. For long burn times, however, I have to fill it right up. I know this is not the most efficient way to run the stove, but I want to be able to get up and have some hot coals leftover in the morning, so I live with a little less efficiency at night.

There's a lot more going up that flue than PMs, though. I'm both secondary and catalytic combustion processes handle the "invisible" gases like CO and the numerous VOCs that are created during the burn. Loss of these compounds up the flue won't show up during the EPA test procedure, nor will they form creosote in the pipe, but they are wasted fuel gases nonetheless.

Still, if they can use cordwood in the lab to get 63% overall efficiency, it would be hard for any stove to double that (as your wood consumption in both stoves would imply).

Maybe we just aren't running the damn Vigilant right? Who knows? All I know is that somebody has gotten EPA kind of efficiency out of it, and published the results as well.

Thank you for the kind words, but I think you miss-understood my reasoning for making that post. I was giving you the ability to see how much wood can fit into each firebox and how long the burn times were which speaks to the stoves efficiency. I figured once I posted the example given you might have a few questions to support or alter the theory that the Vigilant is, seemingly, as efficient as an EPA stove.
 
kjayhawk said:
stoveguy2esw said:
one should also note , if you look at the efficiency ratings at epa.gov the list is full of non-cats at 63% and cats at 72% reason is that most (including us at ESW) accept "default" or the minimum allowable as its extremely expensive to maintain a "true" rating which requires recertification at a much shorter interval compared to the default recert. its a minimum of 10K to put one on the test stand , so if you had to do so every thousand stoves or whatever the interval is it would cost way more to keep that rating, so we accept the 63% which it was easily above im sure but the cost is somthing that obviously would be transferred to the consumer and we simply do not want to have people pay more for a stove just for a number that doesnt really mean anything to the guy tossing splits in his stove.

now we have our lab and could feasibly do this test ourselves(actually we do) but we cannot "publish" these numbers as "gospel" as they are not done by the underwriting lab. trust me , its better than 63%

Would there be any way possible to give us a clue at what that number might be ... ballpark figure? Just a hint, maybe??!! Would we be getting warm at 80% perhaps?


i'll see what i can find out, i personally do not have those numbers we may have them squirreled away somewhere if i can find them i'll let ya know
 
kjayhawk said:
stoveguy2esw said:
one should also note , if you look at the efficiency ratings at epa.gov the list is full of non-cats at 63% and cats at 72% reason is that most (including us at ESW) accept "default" or the minimum allowable as its extremely expensive to maintain a "true" rating which requires recertification at a much shorter interval compared to the default recert. its a minimum of 10K to put one on the test stand , so if you had to do so every thousand stoves or whatever the interval is it would cost way more to keep that rating, so we accept the 63% which it was easily above im sure but the cost is somthing that obviously would be transferred to the consumer and we simply do not want to have people pay more for a stove just for a number that doesnt really mean anything to the guy tossing splits in his stove.

now we have our lab and could feasibly do this test ourselves(actually we do) but we cannot "publish" these numbers as "gospel" as they are not done by the underwriting lab. trust me , its better than 63%

Would there be any way possible to give us a clue at what that number might be ... ballpark figure? Just a hint, maybe??!! Would we be getting warm at 80% perhaps?


I think you are putting too much value on the efficiency numbers.
 
BrowningBAR said:
I think you are putting too much value on the efficiency numbers.

Actually, I'm just curious. After the info posted here, I've realized that small differences in efficiency are not a big deal. We've decided to either bite the bullet and go with the Progress Hybrid as originally planned ... or save $1500 and go with the Englander 30.
 
now we have our lab and could feasibly do this test ourselves(actually we do) but we cannot "publish" these numbers as "gospel" as they are not done by the underwriting lab. trust me , its better than 63%

So can you give us a hint about the NC 30 efficiency range as tested at the factory? Say the EPA 63% plus:

a) 5%
b) 10%
c) 15%
d) 20%
e) 25%
f) 30%
 
So can you give us a hint about the NC 30 efficiency range as tested at the factory? Say the EPA 63% plus:

a) 5%
b) 10%
c) 15%
d) 20%
e) 25%
f) 30%

The EPA needs to get those numbers off of their website. The things were whipped up in 1987, probably by three guys in a bar. No relevance whatsoever to stoves designed in the 2000's that emit less than 2 GPH of emissions. These stoves today are getting everything out of the hog but the squeal. The interpolated numbers used for the tax credit program prove that.
 
Status
Not open for further replies.