Lot if guys I work with are saying they burn nasty wood in their outdoor boilers and have done so for years. Obviously clean good hardwood will burn better. But my dilemma is I have 17 acres of downed wood ,storm damage and rotten stuff just sitting back there to provide years of heat. I have debated the entry level central boiler unit. A lot of trees downed or leaning have been there for 1-5 years and the ton of junk wood has been there since who knows. But if I can burn this stuff in an outdoor boiler non epa then I may consider the large cost for one of these! Thanks again