Advise from a soon to be former wood burner-
I used 1000+ gallons a fuel oil in my house the last time I burned oil. When oil went over $1.00 per gallon, the handwriting was on the wall that I had no control over my wallet. I installed a used indoor wood boiler, an HS tarm model 502 with oil backup. I have done some energy improvements since. I cut 20 face cords but burned about 15 face cords a year except last year I burned all 20 due to extended cold weather. I am switching to coal for convienence and due to the of firewood in my area has driven up the price to where trucking in coal is competitive. Same cost, less work, why not?, Wood boiler is due for replacement (built in 1983).
The guy that supplied my logs stated that his best customers are the ones with outdoor wood furnaces.
A guy down the road heats a single wide trailer with an outdoor wood furnace and burns about twice the wood I do. I drive by him every day and shake my head.
I know another guy that heats his house and business with one and he goes through an absolutly huge pile of firewood.
The biggest advantage of them is that they are economical to install compared to a conventional system but you don't get what you don't pay for. Outdoor burners built to compete in a very competitive market place. The are a non-pressurize vessel that requires chemical treatment and monitoring of water level. Hooking them into a standard house pressurized system requires a plate heat exchanger. They do not last as long as indoor models of wood or coal boilers.
If you have an economical source of wood, then wood may be a good option. I would think twice about an OWB, even a EPA compliant one.
Also factor in the cost of a chainsaw, woodsplitter, and the time it takes to mess with it.
Look at this site if you want to burn wood.http://www.hearth.com/econtent/index.ph ... ategory/1/