Kuuma vaporfire vs gasification boiler

Both would be good choices where each excels. If current hydronic system, the scale might tip towards the boiler. If current forced air system, tips towards the furnace, although water/air hx is cross-over. The furnace has to be burning wood to produce heat; boiler with sufficient storage allows for intermittent burns and heat from storage only between burns.

That said, we heat our 1500 sq ft house with a wood stove in the living room, and at times, lots of times this past winter, we were feeding the stove every two hours to maintain house temperature. And we don't have hydronic. I have hydronic in my shop, and the Tarm boiler + 1000 gal storage is perfect, one burn every other day on the coldest days in winter, less often otherwise.

As my wife and I think about the future long term, the stove being almost 25 years old, we are right in the middle of boiler vs furnace for the house. For a wood furnace, I've seen the Kuuma Vapor Fire at the factory, read user experience, and it is a very good wood furnace. Still leaves us right in the middle.

I am thinking about and planning for a wood boiler. We have heated with stoves for approx. 35 years. As I've progressed in planning, I am thinking that attempting to control the inside temp. by varying the firing rate of a stove is truly not the best idea. I'm sure the Kuuma is a whole world better, but burning full out in a boiler, and delivering the heat as needed, probably almost always will give a better result, and this type of burn, should almost always be cleaner and more efficient. Having given thought to wood burning for years, and having now been sold on the idea of heat storage, I am anticipating the day when I will burn several loads of wood at my convenience, and not have to be concerned with the care and feeding of a stove or furnace the rest of the time.

I am looking to put wood heat in my truck garage. Debating on a gasser(or garn) with storage or the Kumma, forced air. All I need is heat, no DHW. The cost and ease of install of the Kumma has me scratching my head. Looks like a nice unit.

kooslf said:

I am thinking about and planning for a wood boiler. We have heated with stoves for approx. 35 years. As I've progressed in planning, I am thinking that attempting to control the inside temp. by varying the firing rate of a stove is truly not the best idea. I'm sure the Kuuma is a whole world better, but burning full out in a boiler, and delivering the heat as needed, probably almost always will give a better result, and this type of burn, should almost always be cleaner and more efficient. Having given thought to wood burning for years, and having now been sold on the idea of heat storage, I am anticipating the day when I will burn several loads of wood at my convenience, and not have to be concerned with the care and feeding of a stove or furnace the rest of the time.

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Very good post.

There is one major aspect to making such a decision that seems to get overlooked or brushed over or not fully considered quite often in the decision making - and that is, living with it for the rest of its life. That takes in when & how often you have to feed it, and also ease of maintenance. That means cleaning of the unit, and also the chimney. All too easily overlooked when simply comparing price tags up front on a new unit. I shudder now when I think back to many aspects of that which I had to live with for the 17 years I operated my old unit.

My boiler is next door in my garage. Fire once a day in the winter. I don't usually make extra trips to start fire. Just do it when I come home. As your thinking the less handling of wood out weighs heat loss.

keep in mind most ins co won't allow a wood burner in the same envelope as vehicles/mowers/gas cans etc. If i't got an overhead door they get nervous. We reclassified my garage as a wood storage facility. But the boiler is in it's own insulated room, but i can access it from inside the garage.

Also, note the pic in my avatar, i am very spoiled, move all my wood on pallets. Once stacked on the pallet i don't handle the wood. until i put it in the boiler

jrod, I'm moving towards flyingcow's approach. The "touch" of each split adds up to an amazing amount of time. Right now I'm at about 7-8 "touches" from log on ground to split into boiler. Cut log section in woods to trailer, trailer to stack, stack to splitter, split to pile, pile to dry storage, dry storage to boiler room floor, sometime re-split smaller, floor to boiler. No advice on Kuuma vs boiler. My point is don't neglect the effort of getting splits to the boiler or furnace. Welcome.

I don't think you can burn wood safer than with a Kuuma Vapor-Fire. Safety is the main reason my dad designed it the way he did. With less than 1 gr/hr of emissions I don't think we're blowing smoke (pun intended ).

flyingcow said:

keep in mind most ins co won't allow a wood burner in the same envelope as vehicles/mowers/gas cans etc. If i't got an overhead door they get nervous. We reclassified my garage as a wood storage facility. But the boiler is in it's own insulated room, but i can access it from inside the garage.

Also, note the pic in my avatar, i am very spoiled, move all my wood on pallets. Once stacked on the pallet i don't handle the wood. until i put it in the boiler

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Me too.

Depending on how big the stuff is I'm working with, I either cut & split where it falls, throw on trailer right off splitter, pile on pallet right off trailer, then feed boiler right off pallet. Or - pile long lengths on trailer, buck right on trailer using it for a sawbuck, split right there & pile right on pallet if I have some help. Or I might split a bunch, then pile a bunch on pallets. Either way, it goes from right beside my splitter, to right beside my boiler, with one touch. With help from a FEL & pallet jack.

With no walk out basement the boiler would be the way to go. If I could not bring wheelbarrow loads into the basement, I would be burning with a stove upstairs.

jrod770 said:

I guess this whole way of thinking is swaying me towards boiler. I'm trying to cut down on the processing time/amount I handle every piece of wood. Right now, I'm right there with you Tenman. I'd like to be able to cut split and stack directly into the garage where the boiler will be housed. This should reduce a couple of steps.

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You will never have dry wood for a gasifier if you cut, split and stack it right into the garage.

gg

Tennman said:

jrod, I'm moving towards flyingcow's approach. The "touch" of each split adds up to an amazing amount of time. Right now I'm at about 7-8 "touches" from log on ground to split into boiler. Cut log section in woods to trailer, trailer to stack, stack to splitter, split to pile, pile to dry storage, dry storage to boiler room floor, sometime re-split smaller, floor to boiler. No advice on Kuuma vs boiler. My point is don't neglect the effort of getting splits to the boiler or furnace. Welcome.

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AMEN

I have a wood burning furnace ( caddy ) and they are somewhat of a PITA. You need to constantly feed it like a stove. I am jealous of the guys with storage. Come home, make a fire and forget about it vs feeding the furnace every few hours and coming home to a cold house. Or you load the furnace up when you go to bed and you have to listen to it run in order to keep the plenum temps down and then wake up to a cold house because it burned through all of the wood. A boiler beats a furnace any day of the week IMHO.

Working full time, spending and hour a day in the car, kids, and farm chores. If I had to do it all over again I would get some type of pellet burning boiler or stove and call it a day. Knowing my luck though, the price of pellets would double the next year.

Scott

sloeffle said:

AMEN

I have a wood burning furnace ( caddy ) and they are somewhat of a PITA. You need to constantly feed it like a stove. I am jealous of the guys with storage. Come home, make a fire and forget about it vs feeding the furnace every few hours and coming home to a cold house. Or you load the furnace up when you go to bed and you have to listen to it run in order to keep the plenum temps down and then wake up to a cold house because it burned through all of the wood. A boiler beats a furnace any day of the week IMHO.

Working full time, spending and hour a day in the car, kids, and farm chores. If I had to do it all over again I would get some type of pellet burning boiler or stove and call it a day. Knowing my luck though, the price of pellets would double the next year.

Scott

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Something must be wrong with your caddy. That is a good unit and should burn for a long time. My Kuuma furnace is nothing like a stove. I can load it and forget about it for 10 to 12 hrs and NEVER have a cold house. 5 minutes a day effort. How are your gaskets?

The huge advantage to the wood furnace is the price of the furnace and installation parts, and labor / work to install it. Other than that I cant think of any other advantage at the moment.

STIHLY DAN said:

Something must be wrong with your caddy. That is a good unit and should burn for a long time. My Kuuma furnace is nothing like a stove. I can load it and forget about it for 10 to 12 hrs and NEVER have a cold house. 5 minutes a day effort. How are your gaskets?

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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.

As I said in an earlier post, I have become sold on heat storage. Also I am glad to see the discussion about reducing the handling of the wood. I have burned wood forever, and am always looking to simplify handling. I used to have the assistance of wife and two kids, but now accomplish much the same result without help.

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.

stee6043 said:

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.

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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.