Kuuma vaporfire vs gasification boiler

[stee6043]

Don't get me wrong, I agree with your thoughts that the unit's claims seem a little fishy, but am not clear on the quick math. Are you saying that the house only has a heat load of 30 kbtu. I would expect the unit (with a 100 # load of white oak) to be capable of providing much more than a 30 kbtu output. If the house/user only had a demand that size, it certainly wouldn't require a full load of premium fuel to accommodate.

I was just basing that on the Kuma website. The claims are not abundantly clear but there is a page that says "30k-40k btu/hr output" and immediately below it seems to suggest it can go "up to 10 hours - heats up to 3500 square feet" in that scenario. If the output is 30k over a period of 10 hours and you had a mostly full load of theoretically perfect white oak you'd be rocking sub 50% efficiency. Of course, you're going to need to forget you saw immediately above this that the unit will burn happily on 28% moisture content wood as well.

Again, this is not exclusive to Kuma. I think most burner/boiler MFG's are marketing whizbangs that are doing everything they can to baffle the wood burner buying public with lots of numbers. 99% combustion efficiency is the most awesome example of marketing awesomeness. I think even my EKO claims something north of 95% "efficiency" even though all of us EKO owners know we're running in the 80's with storage and properly tuned air setups. My point is only that buyers should do their own math before investing their hard earned greenbacks in any heating technology.

 

[flyingcow]

STIHLY DAN---Did your KUMA replace an oil furnace by chance? just curious if you have any good numbers on what the unit uses in wood vs oil/propane, etc.

MC of wood you burn?

 

[lampmfg]

I was just basing that on the Kuma website. The claims are not abundantly clear but there is a page that says "30k-40k btu/hr output" and immediately below it seems to suggest it can go "up to 10 hours - heats up to 3500 square feet" in that scenario. If the output is 30k over a period of 10 hours and you had a mostly full load of theoretically perfect white oak you'd be rocking sub 50% efficiency. Of course, you're going to need to forget you saw immediately above this that the unit will burn happily on 28% moisture content wood as well.

Again, this is not exclusive to Kuma. I think most burner/boiler MFG's are marketing whizbangs that are doing everything they can to baffle the wood burner buying public with lots of numbers. 99% combustion efficiency is the most awesome example of marketing awesomeness. I think even my EKO claims something north of 95% "efficiency" even though all of us EKO owners know we're running in the 80's with storage and properly tuned air setups. My point is only that buyers should do their own math before investing their hard earned greenbacks in any heating technology.

The difference with us is our numbers match-up to actual copies of test results (Intertek-Very Reputable if you research) posted directly on our website.

Please understand that we are a small manufacturer and only produce 200 or so per year so it's pretty hard to have a huge install base. This has grown from 25 or so 8 years ago. On the other hand you will have a hard time finding anyone that owns one who doesn't love it's quality and ease of use especially if they have burned wood using a different furnace prior.

 

[JRHAWK9]

STIHLY DAN---Did your KUMA replace an oil furnace by chance? just curious if you have any good numbers on what the unit uses in wood vs oil/propane, etc.

MC of wood you burn?

-THIS- post may answer some of what you asked until he answers you direct.

 

[stee6043]

The difference with us is our numbers match-up to actual copies of test results (Intertek-Very Reputable if you research) posted directly on our website.

Please understand that we are a small manufacturer and only produce 200 or so per year so it's pretty hard to have a huge install base. This has grown from 25 or so 8 years ago. On the other hand you will have a hard time finding anyone that owns one who doesn't love it's quality and ease of use especially if they have burned wood using a different furnace prior.

I think it's awesome that you guys are building these units right here in the USA. I really do. I also hope you are wildly successful with your burners.

I work with Intertek very regularly (nothing related to wood burning). I'm aware of what their reports say, and equally as important, what they don't say.

Central Boiler has reports easily accessible online indicating their e-classic 3200 runs at a cool .06 gr/hr particulate emissions (.02 gr/hr per 10k btu, adjusted to match your output). This would suggest that the Central Boiler 3200 is, btu for btu, a whopping FIFTEEN (15) TIMES more environmentally friendly than a Kuma 100 running at 0.91 gr/hr. Does this seem reasonable? No way.

I'm not disputing any numbers on any signed piece of paper anywhere. I'm merely suggesting people need to do the math. Pounds of wood in, btu's out, period of time. Buyers beware always and forever. My burn barrel, properly tuned, can achieve 99% combustion efficiency for whatever that's worth. It's not, however, EPA/Intertek tested...yet.

 

[brenndatomu]

My point isn't to bash the Kuma. But if you're looking to invest in a system that, by design, sends 50%+ of the available energy out your flue then there are much lower cost ways to do it. Yukon Eagles are cheaper and well reviewed.

The Yukon Husky is $600 or so more than the VF100, the Yukon Polar line is even more. Sure the Jack line is cheaper than the Kuuma, but those are meant to be add-on furnaces, been there with a Big jack, ain't goin back! Now, for my current furnace, the Yukon Husky, it is a quality built furnace and they have pretty good customer service, BUT, my Yukon isn't qualified to sit in the nosebleed bleachers at the ballpark that the Kuumas are the star players in...as far as efficiency and clean burn are concerned anyways. There are half a dozen or so people between here and Arboristsite that have the Kuumas, they all rave about them, a couple guys have even bought (or are gonna buy) a second one for their garage!
To the OP, if the initial install cost isn't really a huge factor, go with the gasification boiler and storage, the cadillac of wood heating. Only downside to me is the install cost, JMO.

 

[lampmfg]

I think it's awesome that you guys are building these units right here in the USA. I really do. I also hope you are wildly successful with your burners.

I work with Intertek very regularly (nothing related to wood burning). I'm aware of what their reports say, and equally as important, what they don't say.

Central Boiler has reports easily accessible online indicating their e-classic 3200 runs at a cool .06 gr/hr particulate emissions (.02 gr/hr per 10k btu, adjusted to match your output). This would suggest that the Central Boiler 3200 is, btu for btu, a whopping FIFTEEN (15) TIMES more environmentally friendly than a Kuma 100 running at 0.91 gr/hr. Does this seem reasonable? No way.

I'm not disputing any numbers on any signed piece of paper anywhere. I'm merely suggesting people need to do the math. Pounds of wood in, btu's out, period of time. Buyers beware always and forever. My burn barrel, properly tuned, can achieve 99% combustion efficiency for whatever that's worth. It's not, however, EPA/Intertek tested...yet.

Thanks we appreciate that!! I haven't seen an actual copy of anyone else's exact test. Do you have a link? I really don't know a lot about boilers except that my best buddy growing up hated it when his dad made him run outside and load it during the winter

 

[STIHLY DAN]

STIHLY DAN---Did your KUMA replace an oil furnace by chance? just curious if you have any good numbers on what the unit uses in wood vs oil/propane, etc.

MC of wood you burn?

Flyingcow, I had an oil boiler 85% eff. 100-125,000 btu can't remember exactly. This also supplied my hot H2O, I kept my house at 62* at all times. I used 750 gal of oil during the heating season and another 250 for H2O during non heating season. 1,000 gallons a year. $3,700 was the cost of my last year 2011. Oil was at it's highest then and thought it would only go up. Probably would have if I didn't get off oil.
With the Kuuma in 2013 a burned 5 cords of mostly red maple keeping the house 70-72* Basement which is not insulated 60-65*, This year 2014 about 6 cord of red oak and bumping the basement up to 65-70* I have a heatpump hot water heater down there blowing 50* air for 8 to 12 hrs a day as well.
I have a lot of wood so moisture content is always mid teens. I am sure they can't get the eff stated at 28% MC. Never did like that statement in the manual, wish they would modify that. With the computer adjusting the air intake keeping a steady fire box temp I'm sure it can burn it, obviously not as efficiently.
I run it on low above 10* med 0-10* high -1 and below. Fan runs on low most of the time, it will automatically switch to high a few times a night when it's 5* or less outside.

 

[stee6043]

Thanks we appreciate that!! I haven't seen an actual copy of anyone else's exact test. Do you have a link? I really don't know a lot about boilers except that my best buddy growing up hated it when his dad made him run outside and load it during the winter

This is linked from the CB website, FAQ section.

(broken link removed to http://www.outdoorfurnacefacts.com/wood-corn-heating-facts/emissions-standards/index.html)

 

[flyingcow]

So basically you're saying you replaced 1000 gals of oil with 6 cord of wood?

BTW, what little i know, I like the draft control the Kuuma has. It's the back bone of the design IMO. Seems like a nice unit.

 

[STIHLY DAN]

750 gal. hot H2O gets 250. But ya. Although this winter was very cold.

 

[JRHAWK9]

So basically you're saying you replaced 1000 gals of oil with 6 cord of wood?

BTW, what little i know, I like the draft control the Kuuma has. It's the back bone of the design IMO. Seems like a nice unit.

Not so sure you can conclude that by comparing the two different years. They have differing amount of heating degree days and he kept the house at drastically different temperatures (62° vs 72°).......all favoring the need for MORE heat during this winter. In order to compare things one must limit the amount of variables to just the one you want to compare. Way too many variables to make an accurate comparison.

 

[glacialhills]

The gaskets are fine. The furnace is only two years old. I do however need to put a manometer on it and check my draft speed. I have a barometric damper but I tuned it by feel, right or wrong.

When we were in the middle of the polar vortex I was chucking wood into the furnace every few hours to keep my house up to temp. Yes my house has good insulation. I can go 10 - 12 hours if I load the furnace up to the gills but then my house will be 75F on the front end of the burn cycle and then 68F at the back end of the burn cycle. 75F is too hot and 68F is too cold. I like my house to be a even 71F. And honestly I do not think it is possibe to get even heat distribution from a wood fired furnace.

I guess my point is, a wood furnace_IMHO_is not as set and it and forget as a boiler with lots of storage or something that burns pellets.

That is why I love my vapor fire and chose it over the caddy. It DOES burn evenly over the entire load and my house temp stays a steady temp from first loading to having only a few coals left. It is as set and forget as it comes. Even in the worst of the vortex with temps in the minus 20's and 30's and 40mph winds it was only burning a full load every 4-6 hours and keeping the house at 68.. And those facts that are given on efficiency are true for the vaporfire. I kept thinking my math was wrong when figuring how much wood I need to replace the LP gas we had used our first year in our new house. It kept coming up about 40% short but it was because I was not figuring the efficiency correctly. The vapor fire flu temp. is so low I would guess less than 200. you can quickly(very quickly) touch the black stove pipe directly out the back when it is running full blast.Bet you can not do that with your caddy. This truly IS a Gassifier,.just like a tarm or other outdoor boiler gassifier. Only difference is this is in your nice warm house and not exposed to the elements or freezing temps and worries about leaks like a boiler.Everyone around me ran out of wood a month or more ago. I just brought in my last wheelbarrow full yesterday. And I only had 5 cords for this winter. I will have eight for next. But you do need cut and split and season your wood for the vaporfire to work this well. I have yet to see any creosote in my chimney and only clean it once a summer. and then get about 6 cups of brown fuzzy soot.

I may be biased but the furnace vs boiler (with storage) really isn't a debate at all. If you're in it for efficiency and ease of use there is only one direction you should go. If initial investment is the primary concern then yes, all things should be considered. And shoot, for those heating with uber expensive heating oil you could pick just about any wood appliance and come out ahead.

I'm curious about these Kuma Vaporfire units. We only appear to have two or three users on this site familiar with them. I know there are loads of boiler manufacturers out there selling snake oil but there's just something about a picture of an unsplit 6" round going into a boiler right next to a claim of no smoke, no pollution and no creosote that concerns me. Not to mention a claim of 10 hour burn times with a 4 cubic foot firebox, 82% average efficiency while heating a 3500 square foot home? Oiy vey.

Quick math - toss 100lbs of white oak into a 4 cubic foot firebox. Burn it for 10 hours. If the wood is gone after 10 hours and you're average heat load is ballpark 30,000 btu/hr you've achieved somewhere around 48% efficiency. This math is true for any burner, not specific to the Kuma.

My point isn't to bash the Kuma. But if you're looking to invest in a system that, by design, sends 50%+ of the available energy out your flue then there are much lower cost ways to do it. Yukon Eagles are cheaper and well reviewed. Caddy's too I think. There are units down at Menards that are ultra low cost. Shoot, for the time spent collecting that extra 50% of wood you could probably justify a modulating pellet burner that wouldn't waste so much fuel.

My two cents only of course.

Yep I can get a 10 hour burn easily with a full load of hickory or oak. I have used many different stoves and furnaces in my life and this vaporfire has them all beat hands down. It controls the burn perfectly thoughout the entire burn. If you run your chimney right in the peak of your house the draft will just about suck your watch off your arm. and you can watch the computer control open and close the draft to keep the temp constant. Overfire is a thing of the past. And if you open the furnace door it almost looks like the fire is out because it is just burning the wood gas and no flame is present. I know many people that would not dare leave home with their stove or furnace going, Heck I will fill mine to the gunnels, turn the setting to low and go to grandmas for the whole day knowing the stove is safely keeping the house warm and cant and,wont overfire, and will have plenty of coals to fire up when we get home. What more can you ask?

 

[woodsmaster]

this is in your nice warm house and not exposed to the elements or freezing temps and worries about leaks like a boiler.E

A boiler can be in a house. A boiler with storage is way more convenient on your firing schedule, Can even leave for a couple days and still have only wood heat. You do have to worry about leaks with a wood furnace. They can leak carbon monoxide into your heat duct if they get a crack or hole in the fire pot. I'm not at all against any wood furnace. In fact I think its a great way to go for the guy that doesn't want to spend the money on a luxury system.

 

[sloeffle]

That is why I love my vapor fire and chose it over the caddy. It DOES burn evenly over the entire load and my house temp stays a steady temp from first loading to having only a few coals left. It is as set and forget as it comes. Even in the worst of the vortex with temps in the minus 20's and 30's and 40mph winds it was only burning a full load every 4-6 hours and keeping the house at 68.. And those facts that are given on efficiency are true for the vaporfire. I kept thinking my math was wrong when figuring how much wood I need to replace the LP gas we had used our first year in our new house. It kept coming up about 40% short but it was because I was not figuring the efficiency correctly. The vapor fire flu temp. is so low I would guess less than 200. you can quickly(very quickly) touch the black stove pipe directly out the back when it is running full blast.Bet you can not do that with your caddy.

I see flu temps around 200F. I can touch the single wall also very quickly and not get burned.

I know the PSG Max Caddy has some computer controls built into. Sadly the "regular" Caddy is stuck in the 60's with a fan limit switch and full open or fully closed damper. I was surprised when I bought it that it did not have any type of computer controlled damper. I use the Caddy mostly when temps are below 30F so I usually only burn around 2 cord of so a year.

From your comments and other peoples comments it sound like the Kuma is the way to go if you want to spend the extra $$$ over the Caddy for a furnace.

 

[glacialhills]

A boiler can be in a house. A boiler with storage is way more convenient on your firing schedule, Can even leave for a couple days and still have only wood heat. You do have to worry about leaks with a wood furnace. They can leak carbon monoxide into your heat duct if they get a crack or hole in the fire pot. I'm not at all against any wood furnace. In fact I think its a great way to go for the guy that doesn't want to spend the money on a luxury system.

I have seen a couple of those boilers and storage tanks installed by friends and I agree they are really cool, will hold the heat produced in storage for a long time and are very high tech, high efficiency systems,That's what a new gassifying boiler is/does. Where the vapor fire on the other hand, without the optional water coil to add storage, is a furnace with no way to store any btus for later.Unlike with a boiler system though, I already had all the duct work needed installed for my lp gas furnace, and I installed my Vapor fire 100 in an afternoon mostly by myself and a chimney guy.

Only if you are building a new house and build the house around it,have a walkout basement with large egress, or build a shed around it and install it outside like you did woodsmaster, can you just "add" one of the gassification boiler systems to your house without major remodeling,special lifting, digging and moving ability. and are able to hire a specialized crew to help install all of the components required for it.

Further more, Unless you are highly skilled, which I can say,I am not.You are not putting in one of the boiler systems/with storage all by your lonesome.

. And yes like any appliance that burns a fuel, you must check for carbon monoxide with the Vaporfire,But that is the case for burning candles, kerosene heaters and lp gas furnaces as well as your boiler,When I said you did not have to worry about leaks I was referring to the water jacket and or all the send and return piping fluid leaks, that unfortunately I have seen all to often with "luxury" wood boiler/gassification systems the last few years. I considered the vapor fire to be pretty expensive, but not even close to the price of a boiler fully installed. And with far fewer things to go wrong.I also dont want to have to practically get a degree in boiler technology (And I actually was an HT in the Navy) and also spend 10,000+ to get a luxury....boiler system?

And after all is said and done, you save ...what? one maybe two cords of wood a season and the ability to leave home for a few days in the winter over a furnace with no storage?I can leave home for a few days also. I still have a lp gas furnace for those rare occurrences.

For me, it just was not worth it..but to each their own and like I said, some of the new boiler systems are really cool!

Just for Bragging rights, I will save my luxury purchases to a new fishing boat, nice vacation, or new car. I will stack my vapor fire 100 up against any other indoor wood furnace and if you can find one, outdoor or indoor boiler/gassifier system with storage, of anywhere near the same price.

 

[woodsmaster]

I didn't have any duct work in my house, or a place for the wood furnace to sit. I had another building that I also needed to heat. That and the ability to heat my domestic hot water and hot tub on top of coming into some money is what made me decide to go with a boiler. Each persons situation will be different and both options are much better than oil or propane IMO.

I also wanted something that would last 20 years as most of these pressurized boilers will with some maintenance. If I'm going to be using it for 20 years I want it to be convenient.

 

[STIHLY DAN]

The op's situation is definitely a boiler. All houses have different applications and needs.

 

[jrod770]

When this thread started, my biggest hurdle was cost. However, the more I read and the more I think about the difference between the two, the more I am willing to overlook cost. In my installation, I think the garage installation of a boiler may be the better route. Like I said, I'm not getting any younger and I think supplying wood to the garage will be much simpler than continuing with the basement route I am currently using. Being a plumbing contractor, I will do installaton myself

The op's situation is definitely a boiler. All houses have different applications and needs.

The wood furnace has served me well since we built the house 5 years ago. It has also taught me alot about heating with wood. I went the cheap route the first time with the Clayton. It works, it's messy, it's a pain in the back to get wood to the basement, and it burns alot of wood. However, it's still better than paying for propane. I think it's replacement will end up being a boiler in the garage. Not the cheapest route, but it will end up being less work for me in getting wood to it. I'm not too worried about cost, I'm a plumbing contractor and will do all installation myself. I already have 500 gallons of storage and the 6" stainless steel vent ready and waiting to go. I guess it's time to start on the garage addition. Thanks for all of your help and confirming my thoughts.

 

[maple1]

Pretty hard to beat hydronics for comfortable heat.

 

[JRHAWK9]

Flyingcow, I had an oil boiler 85% eff. 100-125,000 btu can't remember exactly. This also supplied my hot H2O, I kept my house at 62* at all times. I used 750 gal of oil during the heating season and another 250 for H2O during non heating season. 1,000 gallons a year. $3,700 was the cost of my last year 2011. Oil was at it's highest then and thought it would only go up. Probably would have if I didn't get off oil.

Assuming:
- #2 fuel oil has a BTU rating of 138,500 BTU's/gal and a oil boiler efficiency of 85%
- 6,000 BTU's per lb wood
- 3,230lbs/cord Red Maple
- 85% wood furnace efficiency

If you would have burned wood that winter using the above assumptions, you would have consumed approximately a little over 5 cords of Red Maple keeping your house at 62° that winter. Does my math check?

OK, I'll show my work....lol

138,500 (0.85) = 117,725 BTU's going for heat, the rest is lost
117,725 (750) = 88,293,750 total BTU's to keep house at 62°
88,293,750/6,000 = 14,716lbs wood used at 100% efficiency
14,716/0.85 = 17,312.5 lbs wood corrected for wood furnace efficiency
17,312.5/3,230 = 5.36 cords of Red Maple

Trying to get a grasp on these calcs for my own use.

 

[STIHLY DAN]

Assuming:
- #2 fuel oil has a BTU rating of 138,500 BTU's/gal and a oil boiler efficiency of 85%
- 6,000 BTU's per lb wood
- 3,230lbs/cord Red Maple
- 85% wood furnace efficiency

If you would have burned wood that winter using the above assumptions, you would have consumed approximately a little over 5 cords of Red Maple keeping your house at 62° that winter. Does my math check?

OK, I'll show my work....lol

138,500 (0.85) = 117,725 BTU's going for heat, the rest is lost
117,725 (750) = 88,293,750 total BTU's to keep house at 62°
88,293,750/6,000 = 14,716lbs wood used at 100% efficiency
14,716/0.85 = 17,312.5 lbs wood corrected for wood furnace efficiency
17,312.5/3,230 = 5.36 cords of Red Maple

Trying to get a grasp on these calcs for my own use.

That would be about right. That year it was an average of a 1/2 degree colder for dec-feb than this year. But this year was colder earlier and later. Actually may be less for this year the house was 70-72 and the basement was heated as well.

 

[glacialhills]

I didn't have any duct work in my house, or a place for the wood furnace to sit. I had another building that I also needed to heat. That and the ability to heat my domestic hot water and hot tub on top of coming into some money is what made me decide to go with a boiler. Each persons situation will be different and both options are much better than oil or propane IMO.

I also wanted something that would last 20 years as most of these pressurized boilers will with some maintenance. If I'm going to be using it for 20 years I want it to be convenient.

If I had multiple buildings to heat,no room in my basement and no duct work already installed and also had a hot tub to heat like you have woodsmaster, that would make a boiler system much more attractive.

Also Jrod770 you being a plumber and willing and able to install yourself, and willing to overlook cost? heck I would go with the latest greatest boiler system too. Good luck