Outdoor wood burning furnace

[Addicting]

because you don't have to be concerned with creosote build-up

Yes you do! Not in the chimney but in the door, seal, and blower. All of which will get caked and cause hot spots. Those hot spots warp and leak air causing a runaway fire. That is one of the reasons why wood consumption is greatly increased. Green wood actually helps prevent that as the coals have to dry it out and it can only burn so fast.

 

[Hem]

Might also consider the best way to spend money in case you need to sell the house down the line.

 

[David5155]

I’m getting ready to buy one as well been doing a lot of research. you’ll find out there’s two different kinds the old-fashioned kind that just burn and heat the water and then the new EPA certified ones with a reburner on them. the new EPA ones burn a lot less wood but it would have to be seasoned and kept dry most people are saying under a roof during burning season not just stacked. that doesn’t seem good for me considering I’m looking at one because I own a small excavation business and we do a lot of clearing work and are hauling in dump truck loads of logs right now. Also I have been priced 14k !! For the new epa ones were I can get a new traditional one for under 10k

 

[Blue Rope]

Yes you do! Not in the chimney but in the door, seal, and blower. All of which will get caked and cause hot spots. Those hot spots warp and leak air causing a runaway fire. That is one of the reasons why wood consumption is greatly increased. Green wood actually helps prevent that as the coals have to dry it out and it can only burn so fast.

It takes more green wood to produce X number of BTU's than seasoned wood since you're basically using some of the heat energy to "season" the rest of the wood so that it can burn. It will burn slower (although not that much slower with an airtight system) but it will output less heat while doing it. The principles and reasons for seasoning wood don't change because the fire is outdoors. The only difference is that creosote build-up is far less of a concern. I owned a tree service and sold firewood for 20 years and saw a whole lot of different wood heat set-ups. Good quality outdoor boilers shrug off chimney fires like nothing happened. I would imagine that lower budget ones, built with thinner materials, would be more subject to warpage.

 

[Kaitum]

My dad had an outdoor furnace for the better part of 35 years. Older, 2 story home - maybe 2,200 SQ ft. Several of them actually. He recently switched to propane just due to age and the physical toll of cutting that much wood. In a typical NW PA winter he'd burn 10-12 cord of wood I think (Nov - March). He had access to plenty of hardwood so supply wasn't an issue. I remember him saying he wouldn't split the wood any smaller than needed to get it into the firebox door. It lasted longer when kept in bigger chunks.

 

[Mrc]

If you want to do it long term you will want to limit the amount of times handling it. I started out stacking it in long rows. Re-stacking it under cover in the fall and then loading it in the house. One year I had three stacks fall over that I had to stack again. Now I chunk it it up where the tree falls.Chunks in the bucket of my tractor.Drive up to the splitter and split right into a basket.Move with the forks on my tractor. Hand the wood thru the window to my wife. Heat 2000 sq.foot house and 48 by 40 garage.Never use any other heat.

 

[seeth07]

I remember him saying he wouldn't split the wood any smaller than needed to get it into the firebox door. It lasted longer when kept in bigger chunks.

That is the the biggest key I've found in 10 years of running our wood burner. The bigger the better. Harder to handle and get into the fire door but a piece that just barely fits where you only need 1-2 pieces in the box will last all night compared to putting in 8 smaller chunks. If the log is under 10 inches in diameter, I don't even split them anymore.

 

[Mrc]

I always have 2 years supply of wood spilt. Because I’m not stacking single row it gives more time to dry. I also have some hickory and it is slow to dry. Modern wood burners want dry wood. Dry wood is like gasoline and wood with moisture is slow burning and never reaches the temperatures that dry wood does. I still stare at the fire every night!

 

[BigHornRam]

Friend has one. It's an inefficient low tech model that smokes and loads up with creosote. Doesn't burn hot enough, so you get the creosote build up. The efficient high tech models turn the wood to syngas and then burn the gas. They are very expensive. The only way I would consider one is if I had a large shop and house and wanted to heat both from the same source. Also would want an available local wood source. Most jurisdictions have emission standards now and won't allow the cheap burners to be used anyway. Your neighbors will thank you for not putting in an inefficient one.

 

[Mrc]

I looked at the Garn before I built with the idea of heating my garage and house with it. At the time they had a fifteen hundred gallon and a two thousand gallon model. Found someone that had one and went to look at it. Has lots of pumps and valves. Electricity out. No heat. You’re supposed test the water and treat it regularly to prevent rusting. They want you to send the water to a lab and sell you the chemicals. The owner said he wouldn’t do it again.Burned more wood then they advertised.No matter how well you insulate you lose heat in the ground when you run lines between buildings. Oh yea,I think it was $25,000 back in 2014.

 

[Nemont]

My uncle lives in Seeley and heats his 6,000 square foot “cabin” with a wood fired boiler and radiant floor heat.
He goes through a lot of wood but it works for him.

He

 

[Nick87]

Bumping this thread been thinking about possibly a wood burning furnace in conjunction with my propane furnace? Any experiences?

 

[Blue Rope]

Bumping this thread been thinking about possibly a wood burning furnace in conjunction with my propane furnace? Any experiences?

Advantage of an outdoor furnace is that the mess isn't in the house and you can burn bigger wood. Disadvantage is that it uses more wood and requires electricity to work. IMO, basic functions of a house, like heat, should not require electricity to function. Obviously most people don't share that opinion, so you can take that however you will.

 

[Steiny77]

Everyone I know that has an outdoor wood boiler becomes a slave to their wood stove, and pretty soon it's not much fun.
It's nice to have the mess outdoors, and you don't have the house fire hazard, but I don't want to go outdoors to load the stove.

Strictly personal opinion, but I much prefer a well insulated house that doesn't need much heat and a good indoor wood stove for supplemental heat on cold days. Nothing like the radiant heat of sitting around near a hot wood stove .... you don't get that with the outside units. Since it's a new house, set things up so you can keep a good amount of dry wood in the attached garage or a pass thru wood box and you won't have to go outdoors to feed the stove.

 

[seeth07]

Everyone I know that has an outdoor wood boiler becomes a slave to their wood stove, and pretty soon it's not much fun.
It's nice to have the mess outdoors, and you don't have the house fire hazard, but I don't want to go outdoors to load the stove.

Strictly personal opinion, but I much prefer a well insulated house that doesn't need much heat and a good indoor wood stove for supplemental heat on cold days. Nothing like the radiant heat of sitting around near a hot wood stove .... you don't get that with the outside units. Since it's a new house, set things up so you can keep a good amount of dry wood in the attached garage or a pass thru wood box and you won't have to go outdoors to feed the stove.

Couldn't agree more. @Nick87 I would give some serious thought to setting things up this way

 

[Straight Arrow]

Strictly personal opinion, but I much prefer a well insulated house that doesn't need much heat and a good indoor wood stove for supplemental heat on cold days. Nothing like the radiant heat of sitting around near a hot wood stove

I agree and my wife adamantly agrees. Our home is moderately sized and open spaced in design, so the wood heat from the Vermont Hearthstone woodstove with soapstone panels heats our home well during the winter, without extensive use of the electric baseboard heaters. The soapstone retains and distributes the heat very well.
However, as I typically express, "Since retirement this old boy seems to be either splitting firewood or mowing the lawn!"

 

[Mrc]

The best thing to do is go to woodheat.org. Lots of information.

 

[Chama Grande]

Guys with outdoor furnaces every winter

 

[Dan O]

25-30 cords of wood per year would be the "Nope" for me. We built our house in 2017, so it has all the updated building codes, like 30 some inches of insulation in the attic, 6" walls etc.
House is 2800 sq ft, we heat with a BlazeKing, King Ultra, fill the firebox once a day and it will keep the house 75 degrees plus. All this while going through less than 4 cords of tamarack/doug fir a winter. Our furnace is propane, so it keeps the house warm when we are gone, but the BlazeKing will burn for about 30 hours with a full firebox. A couple wheelbarrows of wood on the patio for a week, refill on my day off. Wish we had a source for hardwood.

We have the Blaze King "King", Also. We go through 3 to 4 cords a winter. The burn time on this stove is amazing. We cut Pine, Spruce and Larch whichever is close to the road. When were gone the propane boiler hot water baseboards keeps the house warm.

 

[David5155]

It is definitely some work in the winter but it’s definitely money saver I would say in the long run if you have access to the wood. I heat my house 1700 ft.² to car garage and a 30 x 48 barn as well as hot water. My power bill in the winter is never more than $100 since the only power we use is for lights, I have propane for back up for the chilly nights in the spring and fall. I’ve never used more than 10% of my 500 gallon tank. I use her on my boiler from early November to early April. If my pipes were not in my crawlspace and cost too much radiant heat in there, I would run it all year just for the hot water savings but I also own a small excavating company that dose a lot of land clearing so I have an endless supply of wood.