Outdoor Wood Furnace

[penokee]

Appreciate comments pro and con on Outdoor Wood Furnaces. Have burned wood for many years as a supplement to natural gas. Enjoy being in the woods and the physical exercise part of cutting. splitting, pileing, etc. My wife has asthma and the inside wood furnace has got to go.

Looking at a Central Boiler stove made in Greenbush, Minnesota. Will use a heat Exchanger in the Plenum of my forced air furnace. Don't plan to heat domestic water, just for home heat.

Would locate it about 100' from the house and put on chimney extensions to help with dissipating the smoke. Will only use in winter months so it burns hot.
penokee /forums/images/graemlins/smile.gif

 

[Av8r3400]

Don't be afraid to put the heat exchanger on the water heater too. I'm told it will save you a bunch on the gas bill.

I'm not an expert, its just what I've been told.

I'd like to do the same on the house the wife and I are planning. I would fit well into the radiant heat plan we are examining. /forums/images/graemlins/smile.gif

 

[skent]

I crunched the numbers years ago when I was thinking about an outdoor boiler. $6,000 to 7,000 for a steel boiler with a 3 year warrenty. $8,000 or more for a stainless steel model, 6 or more cords per year (even processing it my self off my own woodlot costs $20 a cord in gas/oil/transportition). Figured it would save me $450 a year in heating costs. Payback was in the 15 to 18 year time frame. It's a great idea, but not very efficient. Lots of wasted BTU's. The TARM wood boiler looked good, but needs a large heat storage tank.

I thought long and hard and decided to stay with the system I have.

 

[dlabrie]

I ordered a Central Boiler unit to heat my 2000sq/ft house and my domestic Hot water. It is at the local dealers awaiting the spring so I can dig the trench for the insulated lines and put in the footing for the unit.

I have been looking at them for a couple of years now and decided to go with the Central Boiler. I have seen a couple of set up and they work great! If you already have an electric, gas or whatever, domestic Water heater, It is no job to connect the CB to heat the unit. You can set it up so you can isolate it in the summer if you don't want to burn then.

I have an oil FHW system in the house. I will connect the CB to it and run 3 heating zones off it as well as a zone for my DHW. We currently have an indoor wood boiler hooked up to the oil furnace but it is 32 years old and not very efficient. It is going to be so nice to have all of the mess associated with burning wood out side.

I looked at the TARM furnaces, They look like a great unit. But, once you add up the costs involved, they are very expensive, and the wood mess is still in the house.

 

[dlabrie]

There was some discussion at this site
Mother Earth News

 

[Varmintmist]

www.centralboiler.com
www.hydrofire.com

I have the hydrofire, the hf36 with the dual fuel option. It heats a full basment and garage that I put radient heat in, the upstairs through forced hot air and the domestic hot water. right around 3600 sq feet total.

It is a lousy oil burner but a great wood burner. The oil only gets run when we go away so it is just for backup and to give me a excuse to keep that much fuel oil for the tractor /forums/images/graemlins/grin.gif

 

[thcri]

I would seriously think about doing the water heater also. My reason for it is even though your wood boiler will cool down when heat is not needed it is a slow process. You have to have a dump zone to dump the heat off to. Our company has installed a few of these and we found adding the hot water heater even isn't enough for a dump zone. We typically will add a fan coil for in a garage and it only is used to get rid of the excess heat while the other zones are satisfied. Also, you are spending a lot of money and your payback is a long time. However, if you like the woods and enjoy the work, go for it.


murph

 

[dmp437]

Neighbor down the road has had an outdoor boiler for about 4 years and before that an indoor wood furnace for 15+ years. His opinion after four years is he should have never bought it and instead gotten another indoor furnace.
For my money, in your situation, I would buy a new 95% efficient natural gas furnace, double the attic insulation and still come out ahead over the outside boiler. The firewood you generate from "Enjoy being in the woods and the physical exercise part of cutting. splitting, pileing, etc. " I would sell to the public either tax free (cash) or Schedule C so you could write off associated expenses.

 

[penokee]

Appreciate all the comments, helping me to make a decision on what I'm going to do. May end up without wood heat in the house altogether. Burn wood in my camp, sauna, garage and shop, so have places to cut wood for - sure like that constant wood heat in the basement tho, but have to defer because of the wife's health problems.
penokee /forums/images/graemlins/smile.gif

 

[Varmintmist]

First, you wont be splitting that much. You might lop the 15-20 in ones in half just to make them eaiser to handle. Other than that, splitting is not real nessassary.

Second, if you are looking for that "wood warmth" , it isnt there. This is a wood fired non pressurized boiler. The heat is the same as a oil or gas fired boiler. The heat exchanger runs hot water into a radiator that air is forced through to the ducts. It is a lower intensity heat than a gas or oil furnace, it also doesnt get as dry.

Third, the temp in the furnace only varies 10 degrees. It is not fire on demand. The water in the stove and pipes holds the heat. Domestic hot water is run off a heat exchanger. The water tank DOES NOT hold heat for your other applications. I guess it could, but this is not a pressurized system. My floor is radient heat so that retains my heat.