i have had one for 2 years now and always ask myself why i didn't get one years ago. no need to split wood anymore. just cut it to whatever size you can handle. wet wood,green wood it dont matter,,if there are coals in the furnace it will burn. i heat a 3000 square foot home plus a 2 car garage,,plus my hot water for the home and my outdoor furnace could probably take care of another home like mine too. i did alot of searching and question asking and finally bought the one i thought was the best. i went to dealers that sold other brands of outdoor boilers and when i would ask how it compares to the central boiler they were tounge-tied.
check it out here:
http://www.centralboiler.com/home.html
i have the CL5648.
it is a $$ salty $$ investment but i feel it is well worth it. the main thing is that there is no need to worry about chimney fires in your home and all the dirt,bugs in the wood etc that go along with indoor wood burners.
in order for you to see a savings with going to an outdoor boiler you must have a supply of FREE wood. if you have to buy wood then you might as well pay for gas or electric or whatever you use.
i wouldn't recommend it if you live in a neighborhood with other homes close to you because when the draft door opens to maintain the water temp the stove will let some smoke roll from time to time.
the furnace has it's own 385 gallon water tank. the water is circulated by a small pump into your home and through a water to air exchanger( if you use forced hot air) and then to your water heater,hot tub,or whatever else you want heated and then back to the furnace to be reheated. the furnace water never comes in contact with your potable/drinking water. i haven't had to add water to the furnace tank since i've had mine. it is a open/non-pressurized system. the website above will help you understand how it works. they will send you a video and paperwork for a refundable fee.
any questions ?? feel free to ask.