Large Stove Comparison

[tarzan]

It would be wonderful if the manufactures would post the bell curve plot of the stoves operation, wouldn't it?

BK does a pretty good job. Average BTU's over a given amount of time on a defined setting with a known species of wood is about as much transparency as one could realistically expect.

The other method of using the last reading before the stove melted is flawed IMO. Ok, that's an axaggeration, maybe? But the way I've heard many stove mfg achieve there max output numbers, well, they wouldn't do it in MY living room!

 

[Marshy]

Eh, then you'd be trusting them to use standardized burn conditions to get the data points for the plot. I wouldn't take such numbers to the bank, but you could probably draw some useful generalizations from them, especially if they were rigorous as to what they standardized. (For example, does the flue "go outside", or does it go a fixed distance into an actively pressure-and-temperature controlled environment? Since turbulence is important to stove operation, how is the pressure in the exhaust space maintained smoothly as the stove's draw varies? Etc.)

Anyone who thinks anything's simple probably hasn't thought about it much!

I agree with you. The point of having a standardized test would take care of those variables. They some already run standard tests for HHV and LHV, why can't they determine the heat transfer rate while consisting those tests?

 

[lsucet]

Interesting that they don't state in the manual what the peak output of the King is. I wonder why that is. Why stick a vauge reference to its peak output in an obscure location buried on their site? Wouldn't you want to tell the world you have 900hp and 29 mpg?

King calculations for BTUs and burn times *You can fit 91lbs of wood into the King 40 size firebox (4.32 cu.ft.). Based on an EPA recognized equivalent of one pound of non-resinous wood equal to 8,500 BTU’s and one pound of resinous wood equal to 9,700 BTU’s per pound, giving a weighted average of 9,100 BTU’s per pound. (9,100 BTU’s per lb. x 91lbs = 827,518 BTU’s - 15% moisture content = 703,390 BTU’s) **LHV 703,390 x 88% efficiency = 618,913 BTU’s ÷ 12 hours = 51,582 BTU’s. HHV 703,390 x 82% efficiency = 576,780 BTU’s ÷ 12 hours = 48,056 BTU’s. ***LHV 703,390 x 88% efficiency = 618,913 BTU’s ÷ 40 hours = 15,475 BTU’s. HHV 703,390 x 82% efficiency = 576,780 BTU’s ÷ 40 hours = 14,419 BTU’s. ˚Length of burn time, sq. ft. heated, Heat Output and BTU’s depend on type of wood, moisture content, house insulation and climate conditions.


Maybe you can get this like reference and and weight how many # going in and the amount of hrs that take you to burn it and you can see at the rate you burn how many btu and peak.

 

[Highbeam]

Given that any stove's BTU output is bell curve-ish over a burn cycle, saying 'this stove puts out X BTUs' is a little bit silly in the first place.

BK, in their king/princess brochure, posted the famous data log of a low burn since honestly that is where the majority of people burn them and that is what is special about the BK. You can look it up your own dang self! If they could rerun that test at max stat setting then the buyers could see the available range of output. Not quite a bell curve of btu output but close.

I think a big reason that BK doesn't post the peak output number because if you were replacing a furnace with this stove you wouldn't want to use the peak number. You would want to know the sustained number so that you can be sure to meet or exceed the furnace output that is being replaced.

The minority of customers run a stove at max. It's really rare and not what a stove manufacturer wants to see. It is fun for us to know what these stoves are capable of if pushed though.

 

[Marshy]

King calculations for BTUs and burn times *You can fit 91lbs of wood into the King 40 size firebox (4.32 cu.ft.). Based on an EPA recognized equivalent of one pound of non-resinous wood equal to 8,500 BTU’s and one pound of resinous wood equal to 9,700 BTU’s per pound, giving a weighted average of 9,100 BTU’s per pound. (9,100 BTU’s per lb. x 91lbs = 827,518 BTU’s - 15% moisture content = 703,390 BTU’s) **LHV 703,390 x 88% efficiency = 618,913 BTU’s ÷ 12 hours = 51,582 BTU’s. HHV 703,390 x 82% efficiency = 576,780 BTU’s ÷ 12 hours = 48,056 BTU’s. ***LHV 703,390 x 88% efficiency = 618,913 BTU’s ÷ 40 hours = 15,475 BTU’s. HHV 703,390 x 82% efficiency = 576,780 BTU’s ÷ 40 hours = 14,419 BTU’s. ˚Length of burn time, sq. ft. heated, Heat Output and BTU’s depend on type of wood, moisture content, house insulation and climate conditions.


Maybe you can get this like reference and and weight how many # going in and the amount of hrs that take you to burn it and you can see at the rate you burn how many btu and peak.

I already have used those numbers to calculate the average btu/hr but theres a large assumption that affects the calculation. That is, even though I can burn a max load of wood in 8 or 9 hours there are some small amount of coals in the bottom of the firebox that will take days to burn out completely. I don't know, maybe BK claims the cycle is complete when the cat becomes inactive or maybe they burn the coals to complete ash..? Either way, at the end of 8 hours there is no usable heat compared to my demand but the amount of coals remaining might be 2, 5, 9% (?) of the fuel loaded and still providing some heat. Even if you adjust the cycle time to 8 hrs for both LHV and HHV that still is not representative of the peak output.

 

[Highbeam]

King calculations for BTUs and burn times *You can fit 91lbs of wood into the King 40 size firebox (4.32 cu.ft.). Based on an EPA recognized equivalent of one pound of non-resinous wood equal to 8,500 BTU’s and one pound of resinous wood equal to 9,700 BTU’s per pound, giving a weighted average of 9,100 BTU’s per pound. (9,100 BTU’s per lb. x 91lbs = 827,518 BTU’s - 15% moisture content = 703,390 BTU’s) **LHV 703,390 x 88% efficiency = 618,913 BTU’s ÷ 12 hours = 51,582 BTU’s. HHV 703,390 x 82% efficiency = 576,780 BTU’s ÷ 12 hours = 48,056 BTU’s. ***LHV 703,390 x 88% efficiency = 618,913 BTU’s ÷ 40 hours = 15,475 BTU’s. HHV 703,390 x 82% efficiency = 576,780 BTU’s ÷ 40 hours = 14,419 BTU’s. ˚Length of burn time, sq. ft. heated, Heat Output and BTU’s depend on type of wood, moisture content, house insulation and climate conditions.


Maybe you can get this like reference and and weight how many # going in and the amount of hrs that take you to burn it and you can see at the rate you burn how many btu and peak.

Never use LHV. It is NOT just the efficiency at a low burn. It is the efficiency assuming false things and erroneously high to appease the politicians.

 

[Squisher]

So if my stove is say 75hhv maybe only 74 (I can't find any hhv numbers on the summit, just on other pe stoves, so I'm taking a bit of a shot in the dark here)efficiency and the king is 82 and a princess is 81, I see the ashford and chinook listed at just 75. IMO those numbers are not substantial given that the setup, fuel, and operation are going to play into effect a lot.

The only significant difference I see is the burn time and the ability to spread that heat out over a looooong time. Which as I've said before is great if that works for you. But why does no one say that back? Lol. So I have a stove that's certainly well within the efficiency range of what the BK's do but I have no replaceable parts, unless you count gaskets which every stove has that will need replacing, but no extra replaceable parts like a cat and it's gasket, or extra moving parts like a bypass and it's gasket. I can see and accept the argument that the cat is paid for by the efficiency difference over time. Still I don't ever have to source one and actually replace anything. There are many, many PE's going on decades of use with all factory parts.

But I would question then since the cat is a part that 'wears out' how is efficiency affected over its life span, particularly near the end?

Everyone's situation is different. Not only do I have one stove, but two that I run in my home to keep warm when it drops right down. And having a third stove that I run quite regularly(old Lakewood in my shop) I can really see a use for cat technology and long burn times of the king in my shop. So again every situation is different. I wouldn't see any point to running one in my home(not that it couldn't heat my home I'm sure) but I'm quite pleased with my heating ability and control of heat and all that that I have right now from my baffle stoves.

It is fun to discuss. I've learned a lot about cat technology and BK's in general from y'all here. Thanks.

 

[Highbeam]

But I would question then since the cat is a part that 'wears out' how is efficiency affected over its life span, particularly near the end?

You have no idea, maybe PE has no idea, what the actual HHV efficiency of the summit is. My NC30 burns with very low emissions (cleaner than my BK) and has only a 70% HHV efficiency. Sure I can be less efficient or even more efficient than the test procedure allows, like by adding a huge blower to strip more heat from the exhaust!, but we have to use a baseline specification to compare. The new BK 30 series stoves take a hit on efficiency compared to the princess but managed to cut emissions significantly. I suspect that these two are related.

So we concluded that you save one cord of wood per two years. Which in most every market pays for a new cat every other year. The cat efficiency/effectiveness of aftermarket cats is warranted to be as-new for more than three years. Full warranty for three years and then prorated after that. The cat warranty from BK is for TEN years. So the cost of cats is covered while always keeping a super active cat less than two years old, really I don't expect folks to change out their cats for 5 years or more. Also, lets not forget the time involved with handling and processing that extra cord of wood per year. That amount of time is much more than the 5 minutes to replace the cat.

I'm with you about a big cat stove in the shop. The biggest reason for me is long burn times and thermostatic control. My non-cat can heat the shop but I have to be there to babysit it, adjust the air control a few times during the load, reload the wood every three hours or less, etc. I want to go back to the house and trust that the stove will keep humming away safely for 12-40 hours. Too bad I have a 6" flue in the shop. I'm stuck with a princess or a wood furnace and no wood furnaces are clean enough to pass muster in WA.

 

[Squisher]

No I couldn't find any hhv info on the summit or even the super. The neo1.6 was 75% and 2.5 was 74%hhv. But PE doesn't seem to have a lot of hhv info that I could find? So certainly it is a guess at best.

I would say we didn't really establish the wood savings that you claim over two years as I think you extrapolated that using a 10% efficiency difference. Which I feel is generous. But regardless, that you can save the cost of the cat with wood over the serviceable life of the cat through efficiency I will give you. And obviously we're assuming that in theory we would be comparing two similar setups being run with proficiency. And those things will be one of the biggest unknowns IMO that make it almost impossible to truly compare.

I clean stoves and chimneys so I'm well aware of how people sometimes perceive how they burn and what is actually happening inside their stove and chimney. That I'm applying to the general public. Most here, just through actually being here and educating themselves are probably at the higher end of efficient wood stove users. Y'all would make good customers more than likely.

 

[bholler]

Y'all would make good customers more than likely.

I think allot of the guys here would be a pita to work for. LOL

 

[Squisher]

Lol, you could be right. But I bet on an average Hearth.com members are running some clean flues. Could possibly be the odd ocdc person around though.

 

[bholler]

But I bet on an average Hearth.com members are running some clean flues.

yes on average I would bet the flues of regulars here are much cleaner than most others.

 

[Highbeam]

Y'all would make good customers more than likely.

Many of us know how to sweep our own pipes and install our own stoves so we might not be customers at all!

 

[Squisher]

True. Which is the best way. Take ownership of your own safety. I always encourage people to look after it themselves if they have the ability and interest. Can't blame the sweep, if you are the sweep.

 

[Ashful]

My local stove shop burns the 5100, it's huge, he said you can load 90lbs of wood. I asked him about burn times but he said he hasn't put a full load in, it was throwing some serious heat in the shop.

Classic limited control range of a non-cat stove? You can load it full, but you can't slow it down sufficiently for the space it's heating, so what's the point? This is the beauty of the King... load her full, and then slowly sip on those BTU's for 40 hours.

 

[Highbeam]

Classic limited control range of a non-cat stove? You can load it full, but you can't slow it down sufficiently for the space it's heating, so what's the point? This is the beauty of the King... load her full, and then slowly sip on those BTU's for 40 hours.

The 5100 is actually a cat stove. "Triple burn design" so probably has secondary air so really more of a hybrid. Manual draft control and as you might expect lacking a wide range of output.

https://www.regency-fire.com/Products/Wood/Wood-Stoves/F5100

8" flue, 80k max btu, 4.42 CF. Looks like it was meant to be a king competitor but without the stat or a low burn rate, it's in a market of its own.

 

[bholler]

Classic limited control range of a non-cat stove? You can load it full, but you can't slow it down sufficiently for the space it's heating, so what's the point? This is the beauty of the King... load her full, and then slowly sip on those BTU's for 40 hours.

It is a cat stove and can be run pretty low. Oh I missed highbeams post sorry

8" flue, 80k max btu, 4.42 CF. Looks like it was meant to be a king competitor but without the stat or a low burn rate, it's in a market of its own.

It does have a low burn rate just not the tstat. The difference is that in this area at least it is cheaper than a king by a fair amount. And it looks a lot better. But honestly for me between the two I would pick the king because it would be in my basement. If it was going to be upstairs I might go for the 5100

 

[heavy hammer]

That is how the sequoia is it doesn't have that tstat like the blaze King. The burn times on the sequoia are 12 hours. It can be dialed down pretty good but your not going to get those burn times, the best I have gotten is 16 hours. But I do believe the sequoia is up there in efficiency and heat output. It can throw some real heat if needed, the guys at kuma claim they have people in Idaho heating large houses 3000plus sq feet with just this stove. I can heat 3500 plus sq feet with it if temps stay around 30. Anyways after reading all the posts from where I left off it seems there are a lot of great stoves out there, and many different heating setups and requirements. I want to know how the blaze King does heating when it gets real cold single digits and below, and what kind of burn times you see in those temps. Not to start any kind of argument, but to see how my stoves compare especially the sequoia.

 

[Highbeam]

That is how the sequoia is it doesn't have that tstat like the blaze King. The burn times on the sequoia are 12 hours. It can be dialed down pretty good but your not going to get those burn times, the best I have gotten is 16 hours. But I do believe the sequoia is up there in efficiency and heat output. It can throw some real heat if needed, the guys at kuma claim they have people in Idaho heating large houses 3000plus sq feet with just this stove. I can heat 3500 plus sq feet with it if temps stay around 30. Anyways after reading all the posts from where I left off it seems there are a lot of great stoves out there, and many different heating setups and requirements. I want to know how the blaze King does heating when it gets real cold single digits and below, and what kind of burn times you see in those temps. Not to start any kind of argument, but to see how my stoves compare especially the sequoia.

My princess heats fine in single digits. Reloads at 12 hours on coals. No big deal. 1700 sf rambler from 1963.

 

[Highbeam]

No I couldn't find any hhv info on the summit or even the super. The neo1.6 was 75% and 2.5 was 74%hhv. But PE doesn't seem to have a lot of hhv info that I could find? So certainly it is a guess at best.

I would say we didn't really establish the wood savings that you claim over two years as I think you extrapolated that using a 10% efficiency difference. Which I feel is generous. But regardless, that you can save the cost of the cat with wood over the serviceable life of the cat through efficiency I will give you. And obviously we're assuming that in theory we would be comparing two similar setups being run with proficiency. And those things will be one of the biggest unknowns IMO that make it almost impossible to truly compare.

I clean stoves and chimneys so I'm well aware of how people sometimes perceive how they burn and what is actually happening inside their stove and chimney. That I'm applying to the general public. Most here, just through actually being here and educating themselves are probably at the higher end of efficient wood stove users. Y'all would make good customers more than likely.

I found the actual current list and your summit also has a reduced EPA range of only up to 37,500 btu. Seems that there is the "EPA" btu output that the EPA uses and then some other peak for bragging rights that is discovered by some other method.

https://www.epa.gov/sites/production/files/2013-08/documents/certifiedwood.pdf

PE has not tested the summit for efficiency.

 

[Squisher]

Yes I see that. The more I've tried looking into btu info the more confusing or misleading some of the manufacturers claims look. I will say hats off to BK for posting/testing their info in a manner that seems to be quantifiable.

 

[Highbeam]

Yes I see that. The more I've tried looking into btu info the more confusing or misleading some of the manufacturers claims look. I will say hats off to BK for posting/testing their info in a manner that seems to be quantifiable.

I was surprised how inefficient and dirty the pellet stoves are. You would think with controlled combustion and forced air that they would be awesomely efficient and clean.

 

[Squisher]

Yah it's been interesting to me to start looking at some of these numbers a bit and wading into this efficiency thing. It's disappointing to me that The summit has no hhv numbers to be found. To me that's not a great sign I would think?

 

[Ashful]

Good catch on the cat / non-cat slip, guys. But it does not change the point. His stove shop reports they cannot load the stove full without overheating the joint. A monster stove is not practical for most installations, if it can't be dialed back to a reasonable level. 12 hours is a mighty fast "slow burn" for a 4.0 cubic foot box. It seems to limit the practicality of these stoves to spaces with very high heat demand, whereas the King can work quite nicely in the average home.

 

[Squisher]

But as long as you haven't forgotten how to light your stove, which I know some of you cat guys may have, you can just let the stove go out, and then relight it. I mean in the shoulder season I don't cook myself out because I can't turn my stove down low enough. I just heat as I always do with my temps being very cyclical, like I'm ok with, and heat my house up and then let the fire go out.